#
a5a858f6 |
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14-Mar-2024 |
Casey Schaufler <casey@schaufler-ca.com> |
lsm: use 32-bit compatible data types in LSM syscalls Change the size parameters in lsm_list_modules(), lsm_set_self_attr() and lsm_get_self_attr() from size_t to u32. This avoids the need to have different interfaces for 32 and 64 bit systems. Cc: stable@vger.kernel.org Fixes: a04a1198088a ("LSM: syscalls for current process attributes") Fixes: ad4aff9ec25f ("LSM: Create lsm_list_modules system call") Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reported-and-reviewed-by: Dmitry V. Levin <ldv@strace.io> [PM: subject and metadata tweaks, syscall.h fixes] Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
b8d99703 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce key_post_create_or_update hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the key_post_create_or_update hook. Depending on policy, IMA measures the key content after creation or update, so that remote verifiers are aware of the operation. Other LSMs could similarly take some action after successful key creation or update. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
2d705d80 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce inode_post_remove_acl hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_remove_acl hook. At inode_remove_acl hook, EVM verifies the file's existing HMAC value. At inode_post_remove_acl, EVM re-calculates the file's HMAC with the passed POSIX ACL removed and other file metadata. Other LSMs could similarly take some action after successful POSIX ACL removal. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
8b9d0b82 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce inode_post_set_acl hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_set_acl hook. At inode_set_acl hook, EVM verifies the file's existing HMAC value. At inode_post_set_acl, EVM re-calculates the file's HMAC based on the modified POSIX ACL and other file metadata. Other LSMs could similarly take some action after successful POSIX ACL change. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
a7811e34 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce inode_post_create_tmpfile hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_create_tmpfile hook. As temp files can be made persistent, treat new temp files like other new files, so that the file hash is calculated and stored in the security xattr. LSMs could also take some action after temp files have been created. The new hook cannot return an error and cannot cause the operation to be canceled. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
08abce60 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce path_post_mknod hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the path_post_mknod hook. IMA-appraisal requires all existing files in policy to have a file hash/signature stored in security.ima. An exception is made for empty files created by mknod, by tagging them as new files. LSMs could also take some action after files are created. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
f09068b5 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce file_release hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the file_release hook. IMA calculates at file close the new digest of the file content and writes it to security.ima, so that appraisal at next file access succeeds. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
8f46ff57 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce file_post_open hook In preparation to move IMA and EVM to the LSM infrastructure, introduce the file_post_open hook. Also, export security_file_post_open() for NFS. Based on policy, IMA calculates the digest of the file content and extends the TPM with the digest, verifies the file's integrity based on the digest, and/or includes the file digest in the audit log. LSMs could similarly take action depending on the file content and the access mask requested with open(). The new hook returns a value and can cause the open to be aborted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
dae52cbf |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce inode_post_removexattr hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_removexattr hook. At inode_removexattr hook, EVM verifies the file's existing HMAC value. At inode_post_removexattr, EVM re-calculates the file's HMAC with the passed xattr removed and other file metadata. Other LSMs could similarly take some action after successful xattr removal. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
77fa6f31 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Introduce inode_post_setattr hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_setattr hook. At inode_setattr hook, EVM verifies the file's existing HMAC value. At inode_post_setattr, EVM re-calculates the file's HMAC based on the modified file attributes and other file metadata. Other LSMs could similarly take some action after successful file attribute change. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
314a8dc7 |
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15-Feb-2024 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Align inode_setattr hook definition with EVM Add the idmap parameter to the definition, so that evm_inode_setattr() can be registered as this hook implementation. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
f568a3d4 |
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23-Jan-2024 |
Andrii Nakryiko <andrii@kernel.org> |
bpf,lsm: Add BPF token LSM hooks Wire up bpf_token_create and bpf_token_free LSM hooks, which allow to allocate LSM security blob (we add `void *security` field to struct bpf_token for that), but also control who can instantiate BPF token. This follows existing pattern for BPF map and BPF prog. Also add security_bpf_token_allow_cmd() and security_bpf_token_capable() LSM hooks that allow LSM implementation to control and negate (if necessary) BPF token's delegation of a specific bpf_cmd and capability, respectively. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-12-andrii@kernel.org
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#
a2431c7e |
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23-Jan-2024 |
Andrii Nakryiko <andrii@kernel.org> |
bpf,lsm: Refactor bpf_map_alloc/bpf_map_free LSM hooks Similarly to bpf_prog_alloc LSM hook, rename and extend bpf_map_alloc hook into bpf_map_create, taking not just struct bpf_map, but also bpf_attr and bpf_token, to give a fuller context to LSMs. Unlike bpf_prog_alloc, there is no need to move the hook around, as it currently is firing right before allocating BPF map ID and FD, which seems to be a sweet spot. But like bpf_prog_alloc/bpf_prog_free combo, make sure that bpf_map_free LSM hook is called even if bpf_map_create hook returned error, as if few LSMs are combined together it could be that one LSM successfully allocated security blob for its needs, while subsequent LSM rejected BPF map creation. The former LSM would still need to free up LSM blob, so we need to ensure security_bpf_map_free() is called regardless of the outcome. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-11-andrii@kernel.org
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#
1b67772e |
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23-Jan-2024 |
Andrii Nakryiko <andrii@kernel.org> |
bpf,lsm: Refactor bpf_prog_alloc/bpf_prog_free LSM hooks Based on upstream discussion ([0]), rework existing bpf_prog_alloc_security LSM hook. Rename it to bpf_prog_load and instead of passing bpf_prog_aux, pass proper bpf_prog pointer for a full BPF program struct. Also, we pass bpf_attr union with all the user-provided arguments for BPF_PROG_LOAD command. This will give LSMs as much information as we can basically provide. The hook is also BPF token-aware now, and optional bpf_token struct is passed as a third argument. bpf_prog_load LSM hook is called after a bunch of sanity checks were performed, bpf_prog and bpf_prog_aux were allocated and filled out, but right before performing full-fledged BPF verification step. bpf_prog_free LSM hook is now accepting struct bpf_prog argument, for consistency. SELinux code is adjusted to all new names, types, and signatures. Note, given that bpf_prog_load (previously bpf_prog_alloc) hook can be used by some LSMs to allocate extra security blob, but also by other LSMs to reject BPF program loading, we need to make sure that bpf_prog_free LSM hook is called after bpf_prog_load/bpf_prog_alloc one *even* if the hook itself returned error. If we don't do that, we run the risk of leaking memory. This seems to be possible today when combining SELinux and BPF LSM, as one example, depending on their relative ordering. Also, for BPF LSM setup, add bpf_prog_load and bpf_prog_free to sleepable LSM hooks list, as they are both executed in sleepable context. Also drop bpf_prog_load hook from untrusted, as there is no issue with refcount or anything else anymore, that originally forced us to add it to untrusted list in c0c852dd1876 ("bpf: Do not mark certain LSM hook arguments as trusted"). We now trigger this hook much later and it should not be an issue anymore. [0] https://lore.kernel.org/bpf/9fe88aef7deabbe87d3fc38c4aea3c69.paul@paul-moore.com/ Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-10-andrii@kernel.org
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#
5a287d3d |
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26-Jan-2024 |
Ondrej Mosnacek <omosnace@redhat.com> |
lsm: fix default return value of the socket_getpeersec_*() hooks For these hooks the true "neutral" value is -EOPNOTSUPP, which is currently what is returned when no LSM provides this hook and what LSMs return when there is no security context set on the socket. Correct the value in <linux/lsm_hooks.h> and adjust the dispatch functions in security/security.c to avoid issues when the BPF LSM is enabled. Cc: stable@vger.kernel.org Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
d17aff80 |
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19-Dec-2023 |
Andrii Nakryiko <andrii@kernel.org> |
Revert BPF token-related functionality This patch includes the following revert (one conflicting BPF FS patch and three token patch sets, represented by merge commits): - revert 0f5d5454c723 "Merge branch 'bpf-fs-mount-options-parsing-follow-ups'"; - revert 750e785796bb "bpf: Support uid and gid when mounting bpffs"; - revert 733763285acf "Merge branch 'bpf-token-support-in-libbpf-s-bpf-object'"; - revert c35919dcce28 "Merge branch 'bpf-token-and-bpf-fs-based-delegation'". Link: https://lore.kernel.org/bpf/CAHk-=wg7JuFYwGy=GOMbRCtOL+jwSQsdUaBsRWkDVYbxipbM5A@mail.gmail.com Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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#
d734ca7b |
|
30-Nov-2023 |
Andrii Nakryiko <andrii@kernel.org> |
bpf,lsm: add BPF token LSM hooks Wire up bpf_token_create and bpf_token_free LSM hooks, which allow to allocate LSM security blob (we add `void *security` field to struct bpf_token for that), but also control who can instantiate BPF token. This follows existing pattern for BPF map and BPF prog. Also add security_bpf_token_allow_cmd() and security_bpf_token_capable() LSM hooks that allow LSM implementation to control and negate (if necessary) BPF token's delegation of a specific bpf_cmd and capability, respectively. Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231130185229.2688956-12-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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#
66d636d7 |
|
30-Nov-2023 |
Andrii Nakryiko <andrii@kernel.org> |
bpf,lsm: refactor bpf_map_alloc/bpf_map_free LSM hooks Similarly to bpf_prog_alloc LSM hook, rename and extend bpf_map_alloc hook into bpf_map_create, taking not just struct bpf_map, but also bpf_attr and bpf_token, to give a fuller context to LSMs. Unlike bpf_prog_alloc, there is no need to move the hook around, as it currently is firing right before allocating BPF map ID and FD, which seems to be a sweet spot. But like bpf_prog_alloc/bpf_prog_free combo, make sure that bpf_map_free LSM hook is called even if bpf_map_create hook returned error, as if few LSMs are combined together it could be that one LSM successfully allocated security blob for its needs, while subsequent LSM rejected BPF map creation. The former LSM would still need to free up LSM blob, so we need to ensure security_bpf_map_free() is called regardless of the outcome. Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231130185229.2688956-11-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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#
c3dd6e94 |
|
30-Nov-2023 |
Andrii Nakryiko <andrii@kernel.org> |
bpf,lsm: refactor bpf_prog_alloc/bpf_prog_free LSM hooks Based on upstream discussion ([0]), rework existing bpf_prog_alloc_security LSM hook. Rename it to bpf_prog_load and instead of passing bpf_prog_aux, pass proper bpf_prog pointer for a full BPF program struct. Also, we pass bpf_attr union with all the user-provided arguments for BPF_PROG_LOAD command. This will give LSMs as much information as we can basically provide. The hook is also BPF token-aware now, and optional bpf_token struct is passed as a third argument. bpf_prog_load LSM hook is called after a bunch of sanity checks were performed, bpf_prog and bpf_prog_aux were allocated and filled out, but right before performing full-fledged BPF verification step. bpf_prog_free LSM hook is now accepting struct bpf_prog argument, for consistency. SELinux code is adjusted to all new names, types, and signatures. Note, given that bpf_prog_load (previously bpf_prog_alloc) hook can be used by some LSMs to allocate extra security blob, but also by other LSMs to reject BPF program loading, we need to make sure that bpf_prog_free LSM hook is called after bpf_prog_load/bpf_prog_alloc one *even* if the hook itself returned error. If we don't do that, we run the risk of leaking memory. This seems to be possible today when combining SELinux and BPF LSM, as one example, depending on their relative ordering. Also, for BPF LSM setup, add bpf_prog_load and bpf_prog_free to sleepable LSM hooks list, as they are both executed in sleepable context. Also drop bpf_prog_load hook from untrusted, as there is no issue with refcount or anything else anymore, that originally forced us to add it to untrusted list in c0c852dd1876 ("bpf: Do not mark certain LSM hook arguments as trusted"). We now trigger this hook much later and it should not be an issue anymore. [0] https://lore.kernel.org/bpf/9fe88aef7deabbe87d3fc38c4aea3c69.paul@paul-moore.com/ Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231130185229.2688956-10-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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#
f1bb47a3 |
|
19-Dec-2023 |
Alfred Piccioni <alpic@google.com> |
lsm: new security_file_ioctl_compat() hook Some ioctl commands do not require ioctl permission, but are routed to other permissions such as FILE_GETATTR or FILE_SETATTR. This routing is done by comparing the ioctl cmd to a set of 64-bit flags (FS_IOC_*). However, if a 32-bit process is running on a 64-bit kernel, it emits 32-bit flags (FS_IOC32_*) for certain ioctl operations. These flags are being checked erroneously, which leads to these ioctl operations being routed to the ioctl permission, rather than the correct file permissions. This was also noted in a RED-PEN finding from a while back - "/* RED-PEN how should LSM module know it's handling 32bit? */". This patch introduces a new hook, security_file_ioctl_compat(), that is called from the compat ioctl syscall. All current LSMs have been changed to support this hook. Reviewing the three places where we are currently using security_file_ioctl(), it appears that only SELinux needs a dedicated compat change; TOMOYO and SMACK appear to be functional without any change. Cc: stable@vger.kernel.org Fixes: 0b24dcb7f2f7 ("Revert "selinux: simplify ioctl checking"") Signed-off-by: Alfred Piccioni <alpic@google.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> [PM: subject tweak, line length fixes, and alignment corrections] Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
a04a1198 |
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12-Sep-2023 |
Casey Schaufler <casey@schaufler-ca.com> |
LSM: syscalls for current process attributes Create a system call lsm_get_self_attr() to provide the security module maintained attributes of the current process. Create a system call lsm_set_self_attr() to set a security module maintained attribute of the current process. Historically these attributes have been exposed to user space via entries in procfs under /proc/self/attr. The attribute value is provided in a lsm_ctx structure. The structure identifies the size of the attribute, and the attribute value. The format of the attribute value is defined by the security module. A flags field is included for LSM specific information. It is currently unused and must be 0. The total size of the data, including the lsm_ctx structure and any padding, is maintained as well. struct lsm_ctx { __u64 id; __u64 flags; __u64 len; __u64 ctx_len; __u8 ctx[]; }; Two new LSM hooks are used to interface with the LSMs. security_getselfattr() collects the lsm_ctx values from the LSMs that support the hook, accounting for space requirements. security_setselfattr() identifies which LSM the attribute is intended for and passes it along. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
b36995b8 |
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31-Oct-2023 |
Ondrej Mosnacek <omosnace@redhat.com> |
lsm: fix default return value for inode_getsecctx -EOPNOTSUPP is the return value that implements a "no-op" hook, not 0. Without this fix having only the BPF LSM enabled (with no programs attached) can cause uninitialized variable reads in nfsd4_encode_fattr(), because the BPF hook returns 0 without touching the 'ctxlen' variable and the corresponding 'contextlen' variable in nfsd4_encode_fattr() remains uninitialized, yet being treated as valid based on the 0 return value. Cc: stable@vger.kernel.org Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Reported-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
866d6480 |
|
31-Oct-2023 |
Ondrej Mosnacek <omosnace@redhat.com> |
lsm: fix default return value for vm_enough_memory 1 is the return value that implements a "no-op" hook, not 0. Cc: stable@vger.kernel.org Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
20a2aa47 |
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23-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify 'sb' parameter in security_sb_kern_mount() The "sb_kern_mount" hook has implementation registered in SELinux. Looking at the function implementation we observe that the "sb" parameter is not changing. Mark the "sb" parameter of LSM hook security_sb_kern_mount() as "const" since it will not be changing in the LSM hook. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> [PM: minor merge fuzzing due to other constification patches] Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
a721f7b8 |
|
23-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify 'bprm' parameter in security_bprm_committed_creds() Three LSMs register the implementations for the 'bprm_committed_creds()' hook: AppArmor, SELinux and tomoyo. Looking at the function implementations we may observe that the 'bprm' parameter is not changing. Mark the 'bprm' parameter of LSM hook security_bprm_committed_creds() as 'const' since it will not be changing in the LSM hook. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> [PM: minor merge fuzzing due to other constification patches] Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
64fc9526 |
|
22-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify 'bprm' parameter in security_bprm_committing_creds() The 'bprm_committing_creds' hook has implementations registered in SELinux and Apparmor. Looking at the function implementations we observe that the 'bprm' parameter is not changing. Mark the 'bprm' parameter of LSM hook security_bprm_committing_creds() as 'const' since it will not be changing in the LSM hook. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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#
4a00c673 |
|
22-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify 'file' parameter in security_bprm_creds_from_file() The 'bprm_creds_from_file' hook has implementation registered in commoncap. Looking at the function implementation we observe that the 'file' parameter is not changing. Mark the 'file' parameter of LSM hook security_bprm_creds_from_file() as 'const' since it will not be changing in the LSM hook. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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25cc71d1 |
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23-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify 'sb' parameter in security_quotactl() SELinux registers the implementation for the "quotactl" hook. Looking at the function implementation we observe that the parameter "sb" is not changing. Mark the "sb" parameter of LSM hook security_quotactl() as "const" since it will not be changing in the LSM hook. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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8e4672d6 |
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12-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify the 'file' parameter in security_binder_transfer_file() SELinux registers the implementation for the "binder_transfer_file" hook. Looking at the function implementation we observe that the parameter "file" is not changing. Mark the "file" parameter of LSM hook security_binder_transfer_file() as "const" since it will not be changing in the LSM hook. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> [PM: subject line whitespace fix] Signed-off-by: Paul Moore <paul@paul-moore.com>
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6672efbb |
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07-Aug-2023 |
Khadija Kamran <kamrankhadijadj@gmail.com> |
lsm: constify the 'target' parameter in security_capget() Three LSMs register the implementations for the "capget" hook: AppArmor, SELinux, and the normal capability code. Looking at the function implementations we may observe that the first parameter "target" is not changing. Mark the first argument "target" of LSM hook security_capget() as "const" since it will not be changing in the LSM hook. cap_capget() LSM hook declaration exceeds the 80 characters per line limit. Split the function declaration to multiple lines to decrease the line length. Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com> Acked-by: John Johansen <john.johansen@canonical.com> [PM: align the cap_capget() declaration, spelling fixes] Signed-off-by: Paul Moore <paul@paul-moore.com>
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5b52ad34 |
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11-Jul-2023 |
Guillaume Nault <gnault@redhat.com> |
security: Constify sk in the sk_getsecid hook. The sk_getsecid hook shouldn't need to modify its socket argument. Make it const so that callers of security_sk_classify_flow() can use a const struct sock *. Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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6bcdfd2c |
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10-Jun-2023 |
Roberto Sassu <roberto.sassu@huawei.com> |
security: Allow all LSMs to provide xattrs for inode_init_security hook Currently, the LSM infrastructure supports only one LSM providing an xattr and EVM calculating the HMAC on that xattr, plus other inode metadata. Allow all LSMs to provide one or multiple xattrs, by extending the security blob reservation mechanism. Introduce the new lbs_xattr_count field of the lsm_blob_sizes structure, so that each LSM can specify how many xattrs it needs, and the LSM infrastructure knows how many xattr slots it should allocate. Modify the inode_init_security hook definition, by passing the full xattr array allocated in security_inode_init_security(), and the current number of xattr slots in that array filled by LSMs. The first parameter would allow EVM to access and calculate the HMAC on xattrs supplied by other LSMs, the second to not leave gaps in the xattr array, when an LSM requested but did not provide xattrs (e.g. if it is not initialized). Introduce lsm_get_xattr_slot(), which LSMs can call as many times as the number specified in the lbs_xattr_count field of the lsm_blob_sizes structure. During each call, lsm_get_xattr_slot() increments the number of filled xattrs, so that at the next invocation it returns the next xattr slot to fill. Cleanup security_inode_init_security(). Unify the !initxattrs and initxattrs case by simply not allocating the new_xattrs array in the former. Update the documentation to reflect the changes, and fix the description of the xattr name, as it is not allocated anymore. Adapt both SELinux and Smack to use the new definition of the inode_init_security hook, and to call lsm_get_xattr_slot() to obtain and fill the reserved slots in the xattr array. Move the xattr->name assignment after the xattr->value one, so that it is done only in case of successful memory allocation. Finally, change the default return value of the inode_init_security hook from zero to -EOPNOTSUPP, so that BPF LSM correctly follows the hook conventions. Reported-by: Nicolas Bouchinet <nicolas.bouchinet@clip-os.org> Link: https://lore.kernel.org/linux-integrity/Y1FTSIo+1x+4X0LS@archlinux/ Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> [PM: minor comment and variable tweaks, approved by RS] Signed-off-by: Paul Moore <paul@paul-moore.com>
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d80a8f1b |
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08-Aug-2023 |
David Howells <dhowells@redhat.com> |
vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing When NFS superblocks are created by automounting, their LSM parameters aren't set in the fs_context struct prior to sget_fc() being called, leading to failure to match existing superblocks. This bug leads to messages like the following appearing in dmesg when fscache is enabled: NFS: Cache volume key already in use (nfs,4.2,2,108,106a8c0,1,,,,100000,100000,2ee,3a98,1d4c,3a98,1) Fix this by adding a new LSM hook to load fc->security for submount creation. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/165962680944.3334508.6610023900349142034.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165962729225.3357250.14350728846471527137.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/165970659095.2812394.6868894171102318796.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/166133579016.3678898.6283195019480567275.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/217595.1662033775@warthog.procyon.org.uk/ # v5 Fixes: 9bc61ab18b1d ("vfs: Introduce fs_context, switch vfs_kern_mount() to it.") Fixes: 779df6a5480f ("NFS: Ensure security label is set for root inode") Tested-by: Jeff Layton <jlayton@kernel.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: "Christian Brauner (Microsoft)" <brauner@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230808-master-v9-1-e0ecde888221@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
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e3d9387f |
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20-Apr-2023 |
Paolo Abeni <pabeni@redhat.com> |
security, lsm: Introduce security_mptcp_add_subflow() MPTCP can create subflows in kernel context, and later indirectly expose them to user-space, via the owning MPTCP socket. As discussed in the reported link, the above causes unexpected failures for server, MPTCP-enabled applications. Let's introduce a new LSM hook to allow the security module to relabel the subflow according to the owning user-space process, via the MPTCP socket owning the subflow. Note that the new hook requires both the MPTCP socket and the new subflow. This could allow future extensions, e.g. explicitly validating the MPTCP <-> subflow linkage. Link: https://lore.kernel.org/mptcp/CAHC9VhTNh-YwiyTds=P1e3rixEDqbRTFj22bpya=+qJqfcaMfg@mail.gmail.com/ Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
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b3816cf8 |
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08-Mar-2023 |
Paul Moore <paul@paul-moore.com> |
lsm: fix a badly named parameter in security_get_getsecurity() There is no good reason for why the "_buffer" parameter needs an underscore, get rid of it. Signed-off-by: Paul Moore <paul@paul-moore.com>
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700b7940 |
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12-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port acl to mnt_idmap Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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39f60c1c |
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12-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port xattr to mnt_idmap Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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4609e1f1 |
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12-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port ->permission() to pass mnt_idmap Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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b10b9c34 |
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09-Oct-2022 |
Paul Moore <paul@paul-moore.com> |
lsm: make security_socket_getpeersec_stream() sockptr_t safe Commit 4ff09db1b79b ("bpf: net: Change sk_getsockopt() to take the sockptr_t argument") made it possible to call sk_getsockopt() with both user and kernel address space buffers through the use of the sockptr_t type. Unfortunately at the time of conversion the security_socket_getpeersec_stream() LSM hook was written to only accept userspace buffers, and in a desire to avoid having to change the LSM hook the commit author simply passed the sockptr_t's userspace buffer pointer. Since the only sk_getsockopt() callers at the time of conversion which used kernel sockptr_t buffers did not allow SO_PEERSEC, and hence the security_socket_getpeersec_stream() hook, this was acceptable but also very fragile as future changes presented the possibility of silently passing kernel space pointers to the LSM hook. There are several ways to protect against this, including careful code review of future commits, but since relying on code review to catch bugs is a recipe for disaster and the upstream eBPF maintainer is "strongly against defensive programming", this patch updates the LSM hook, and all of the implementations to support sockptr_t and safely handle both user and kernel space buffers. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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72b3897e |
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22-Sep-2022 |
Christian Brauner <brauner@kernel.org> |
security: add get, remove and set acl hook The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. So far posix acls were passed as a void blob to the security and integrity modules. Some of them like evm then proceed to interpret the void pointer and convert it into the kernel internal struct posix acl representation to perform their integrity checking magic. This is obviously pretty problematic as that requires knowledge that only the vfs is guaranteed to have and has lead to various bugs. Add a proper security hook for setting posix acls and pass down the posix acls in their appropriate vfs format instead of hacking it through a void pointer stored in the uapi format. In the next patches we implement the hooks for the few security modules that do actually have restrictions on posix acls. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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3350607d |
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18-Oct-2022 |
Günther Noack <gnoack3000@gmail.com> |
security: Create file_truncate hook from path_truncate hook Like path_truncate, the file_truncate hook also restricts file truncation, but is called in the cases where truncation is attempted on an already-opened file. This is required in a subsequent commit to handle ftruncate() operations differently to truncate() operations. Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Günther Noack <gnoack3000@gmail.com> Link: https://lore.kernel.org/r/20221018182216.301684-2-gnoack3000@gmail.com Signed-off-by: Mickaël Salaün <mic@digikod.net>
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c8e477c6 |
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30-Jan-2022 |
Al Viro <viro@zeniv.linux.org.uk> |
->getprocattr(): attribute name is const char *, TYVM... cast of ->d_name.name to char * is completely wrong - nothing is allowed to modify its contents. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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7cd4c5c2 |
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15-Aug-2022 |
Frederick Lawler <fred@cloudflare.com> |
security, lsm: Introduce security_create_user_ns() User namespaces are an effective tool to allow programs to run with permission without requiring the need for a program to run as root. User namespaces may also be used as a sandboxing technique. However, attackers sometimes leverage user namespaces as an initial attack vector to perform some exploit. [1,2,3] While it is not the unprivileged user namespace functionality, which causes the kernel to be exploitable, users/administrators might want to more granularly limit or at least monitor how various processes use this functionality, while vulnerable kernel subsystems are being patched. Preventing user namespace already creation comes in a few of forms in order of granularity: 1. /proc/sys/user/max_user_namespaces sysctl 2. Distro specific patch(es) 3. CONFIG_USER_NS To block a task based on its attributes, the LSM hook cred_prepare is a decent candidate for use because it provides more granular control, and it is called before create_user_ns(): cred = prepare_creds() security_prepare_creds() call_int_hook(cred_prepare, ... if (cred) create_user_ns(cred) Since security_prepare_creds() is meant for LSMs to copy and prepare credentials, access control is an unintended use of the hook. [4] Further, security_prepare_creds() will always return a ENOMEM if the hook returns any non-zero error code. This hook also does not handle the clone3 case which requires us to access a user space pointer to know if we're in the CLONE_NEW_USER call path which may be subject to a TOCTTOU attack. Lastly, cred_prepare is called in many call paths, and a targeted hook further limits the frequency of calls which is a beneficial outcome. Therefore introduce a new function security_create_user_ns() with an accompanying userns_create LSM hook. With the new userns_create hook, users will have more control over the observability and access control over user namespace creation. Users should expect that normal operation of user namespaces will behave as usual, and only be impacted when controls are implemented by users or administrators. This hook takes the prepared creds for LSM authors to write policy against. On success, the new namespace is applied to credentials, otherwise an error is returned. Links: 1. https://nvd.nist.gov/vuln/detail/CVE-2022-0492 2. https://nvd.nist.gov/vuln/detail/CVE-2022-25636 3. https://nvd.nist.gov/vuln/detail/CVE-2022-34918 4. https://lore.kernel.org/all/1c4b1c0d-12f6-6e9e-a6a3-cdce7418110c@schaufler-ca.com/ Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Reviewed-by: KP Singh <kpsingh@kernel.org> Signed-off-by: Frederick Lawler <fred@cloudflare.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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2a584012 |
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15-Jul-2022 |
Luis Chamberlain <mcgrof@kernel.org> |
lsm,io_uring: add LSM hooks for the new uring_cmd file op io-uring cmd support was added through ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd"), this extended the struct file_operations to allow a new command which each subsystem can use to enable command passthrough. Add an LSM specific for the command passthrough which enables LSMs to inspect the command details. This was discussed long ago without no clear pointer for something conclusive, so this enables LSMs to at least reject this new file operation. [0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com Cc: stable@vger.kernel.org Fixes: ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Paul Moore <paul@paul-moore.com>
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fcfe0ac2 |
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08-Jun-2022 |
Micah Morton <mortonm@chromium.org> |
security: Add LSM hook to setgroups() syscall Give the LSM framework the ability to filter setgroups() syscalls. There are already analagous hooks for the set*uid() and set*gid() syscalls. The SafeSetID LSM will use this new hook to ensure setgroups() calls are allowed by the installed security policy. Tested by putting print statement in security_task_fix_setgroups() hook and confirming that it gets hit when userspace does a setgroups() syscall. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Micah Morton <mortonm@chromium.org>
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100f59d9 |
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06-May-2022 |
Mickaël Salaün <mic@digikod.net> |
LSM: Remove double path_rename hook calls for RENAME_EXCHANGE In order to be able to identify a file exchange with renameat2(2) and RENAME_EXCHANGE, which will be useful for Landlock [1], propagate the rename flags to LSMs. This may also improve performance because of the switch from two set of LSM hook calls to only one, and because LSMs using this hook may optimize the double check (e.g. only one lock, reduce the number of path walks). AppArmor, Landlock and Tomoyo are updated to leverage this change. This should not change the current behavior (same check order), except (different level of) speed boosts. [1] https://lore.kernel.org/r/20220221212522.320243-1-mic@digikod.net Cc: James Morris <jmorris@namei.org> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Serge E. Hallyn <serge@hallyn.com> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Mickaël Salaün <mic@digikod.net> Link: https://lore.kernel.org/r/20220506161102.525323-7-mic@digikod.net
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5e50f5d4 |
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12-Feb-2022 |
Ondrej Mosnacek <omosnace@redhat.com> |
security: add sctp_assoc_established hook security_sctp_assoc_established() is added to replace security_inet_conn_established() called in sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security subsystem and save the peer secid to asoc->peer_secid. Fixes: 72e89f50084c ("security: Add support for SCTP security hooks") Reported-by: Prashanth Prahlad <pprahlad@redhat.com> Based-on-patch-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Tested-by: Richard Haines <richard_c_haines@btinternet.com> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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7f5056b9 |
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26-Jan-2022 |
Vivek Goyal <vgoyal@redhat.com> |
security, lsm: dentry_init_security() Handle multi LSM registration A ceph user has reported that ceph is crashing with kernel NULL pointer dereference. Following is the backtrace. /proc/version: Linux version 5.16.2-arch1-1 (linux@archlinux) (gcc (GCC) 11.1.0, GNU ld (GNU Binutils) 2.36.1) #1 SMP PREEMPT Thu, 20 Jan 2022 16:18:29 +0000 distro / arch: Arch Linux / x86_64 SELinux is not enabled ceph cluster version: 16.2.7 (dd0603118f56ab514f133c8d2e3adfc983942503) relevant dmesg output: [ 30.947129] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 30.947206] #PF: supervisor read access in kernel mode [ 30.947258] #PF: error_code(0x0000) - not-present page [ 30.947310] PGD 0 P4D 0 [ 30.947342] Oops: 0000 [#1] PREEMPT SMP PTI [ 30.947388] CPU: 5 PID: 778 Comm: touch Not tainted 5.16.2-arch1-1 #1 86fbf2c313cc37a553d65deb81d98e9dcc2a3659 [ 30.947486] Hardware name: Gigabyte Technology Co., Ltd. B365M DS3H/B365M DS3H, BIOS F5 08/13/2019 [ 30.947569] RIP: 0010:strlen+0x0/0x20 [ 30.947616] Code: b6 07 38 d0 74 16 48 83 c7 01 84 c0 74 05 48 39 f7 75 ec 31 c0 31 d2 89 d6 89 d7 c3 48 89 f8 31 d2 89 d6 89 d7 c3 0 f 1f 40 00 <80> 3f 00 74 12 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 31 ff [ 30.947782] RSP: 0018:ffffa4ed80ffbbb8 EFLAGS: 00010246 [ 30.947836] RAX: 0000000000000000 RBX: ffffa4ed80ffbc60 RCX: 0000000000000000 [ 30.947904] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 30.947971] RBP: ffff94b0d15c0ae0 R08: 0000000000000000 R09: 0000000000000000 [ 30.948040] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 30.948106] R13: 0000000000000001 R14: ffffa4ed80ffbc60 R15: 0000000000000000 [ 30.948174] FS: 00007fc7520f0740(0000) GS:ffff94b7ced40000(0000) knlGS:0000000000000000 [ 30.948252] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 30.948308] CR2: 0000000000000000 CR3: 0000000104a40001 CR4: 00000000003706e0 [ 30.948376] Call Trace: [ 30.948404] <TASK> [ 30.948431] ceph_security_init_secctx+0x7b/0x240 [ceph 49f9c4b9bf5be8760f19f1747e26da33920bce4b] [ 30.948582] ceph_atomic_open+0x51e/0x8a0 [ceph 49f9c4b9bf5be8760f19f1747e26da33920bce4b] [ 30.948708] ? get_cached_acl+0x4d/0xa0 [ 30.948759] path_openat+0x60d/0x1030 [ 30.948809] do_filp_open+0xa5/0x150 [ 30.948859] do_sys_openat2+0xc4/0x190 [ 30.948904] __x64_sys_openat+0x53/0xa0 [ 30.948948] do_syscall_64+0x5c/0x90 [ 30.948989] ? exc_page_fault+0x72/0x180 [ 30.949034] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 30.949091] RIP: 0033:0x7fc7521e25bb [ 30.950849] Code: 25 00 00 41 00 3d 00 00 41 00 74 4b 64 8b 04 25 18 00 00 00 85 c0 75 67 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 0 0 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 91 00 00 00 48 8b 54 24 28 64 48 2b 14 25 Core of the problem is that ceph checks for return code from security_dentry_init_security() and if return code is 0, it assumes everything is fine and continues to call strlen(name), which crashes. Typically SELinux LSM returns 0 and sets name to "security.selinux" and it is not a problem. Or if selinux is not compiled in or disabled, it returns -EOPNOTSUP and ceph deals with it. But somehow in this configuration, 0 is being returned and "name" is not being initialized and that's creating the problem. Our suspicion is that BPF LSM is registering a hook for dentry_init_security() and returns hook default of 0. LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,...) I have not been able to reproduce it just by doing CONFIG_BPF_LSM=y. Stephen has tested the patch though and confirms it solves the problem for him. dentry_init_security() is written in such a way that it expects only one LSM to register the hook. Atleast that's the expectation with current code. If another LSM returns a hook and returns default, it will simply return 0 as of now and that will break ceph. Hence, suggestion is that change semantics of this hook a bit. If there are no LSMs or no LSM is taking ownership and initializing security context, then return -EOPNOTSUP. Also allow at max one LSM to initialize security context. This hook can't deal with multiple LSMs trying to init security context. This patch implements this new behavior. Reported-by: Stephen Muth <smuth4@gmail.com> Tested-by: Stephen Muth <smuth4@gmail.com> Suggested-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: <stable@vger.kernel.org> # 5.16.0 Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: James Morris <jmorris@namei.org>
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52f982f0 |
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06-Dec-2021 |
Ondrej Mosnacek <omosnace@redhat.com> |
security,selinux: remove security_add_mnt_opt() Its last user has been removed in commit f2aedb713c28 ("NFS: Add fs_context support."). Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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6326948f |
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29-Sep-2021 |
Paul Moore <paul@paul-moore.com> |
lsm: security_task_getsecid_subj() -> security_current_getsecid_subj() The security_task_getsecid_subj() LSM hook invites misuse by allowing callers to specify a task even though the hook is only safe when the current task is referenced. Fix this by removing the task_struct argument to the hook, requiring LSM implementations to use the current task. While we are changing the hook declaration we also rename the function to security_current_getsecid_subj() in an effort to reinforce that the hook captures the subjective credentials of the current task and not an arbitrary task on the system. Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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1aa3b220 |
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12-Nov-2021 |
Paul Moore <paul@paul-moore.com> |
net,lsm,selinux: revert the security_sctp_assoc_established() hook This patch reverts two prior patches, e7310c94024c ("security: implement sctp_assoc_established hook in selinux") and 7c2ef0240e6a ("security: add sctp_assoc_established hook"), which create the security_sctp_assoc_established() LSM hook and provide a SELinux implementation. Unfortunately these two patches were merged without proper review (the Reviewed-by and Tested-by tags from Richard Haines were for previous revisions of these patches that were significantly different) and there are outstanding objections from the SELinux maintainers regarding these patches. Work is currently ongoing to correct the problems identified in the reverted patches, as well as others that have come up during review, but it is unclear at this point in time when that work will be ready for inclusion in the mainline kernel. In the interest of not keeping objectionable code in the kernel for multiple weeks, and potentially a kernel release, we are reverting the two problematic patches. Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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32a370ab |
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11-Nov-2021 |
Paul Moore <paul@paul-moore.com> |
net,lsm,selinux: revert the security_sctp_assoc_established() hook This patch reverts two prior patches, e7310c94024c ("security: implement sctp_assoc_established hook in selinux") and 7c2ef0240e6a ("security: add sctp_assoc_established hook"), which create the security_sctp_assoc_established() LSM hook and provide a SELinux implementation. Unfortunately these two patches were merged without proper review (the Reviewed-by and Tested-by tags from Richard Haines were for previous revisions of these patches that were significantly different) and there are outstanding objections from the SELinux maintainers regarding these patches. Work is currently ongoing to correct the problems identified in the reverted patches, as well as others that have come up during review, but it is unclear at this point in time when that work will be ready for inclusion in the mainline kernel. In the interest of not keeping objectionable code in the kernel for multiple weeks, and potentially a kernel release, we are reverting the two problematic patches. Signed-off-by: Paul Moore <paul@paul-moore.com>
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7c2ef024 |
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02-Nov-2021 |
Xin Long <lucien.xin@gmail.com> |
security: add sctp_assoc_established hook security_sctp_assoc_established() is added to replace security_inet_conn_established() called in sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security subsystem and save the peer secid to asoc->peer_secid. v1->v2: - fix the return value of security_sctp_assoc_established() in security.h, found by kernel test robot and Ondrej. Fixes: 72e89f50084c ("security: Add support for SCTP security hooks") Reported-by: Prashanth Prahlad <pprahlad@redhat.com> Reviewed-by: Richard Haines <richard_c_haines@btinternet.com> Tested-by: Richard Haines <richard_c_haines@btinternet.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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c081d53f |
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02-Nov-2021 |
Xin Long <lucien.xin@gmail.com> |
security: pass asoc to sctp_assoc_request and sctp_sk_clone This patch is to move secid and peer_secid from endpoint to association, and pass asoc to sctp_assoc_request and sctp_sk_clone instead of ep. As ep is the local endpoint and asoc represents a connection, and in SCTP one sk/ep could have multiple asoc/connection, saving secid/peer_secid for new asoc will overwrite the old asoc's. Note that since asoc can be passed as NULL, security_sctp_assoc_request() is moved to the place right after the new_asoc is created in sctp_sf_do_5_1B_init() and sctp_sf_do_unexpected_init(). v1->v2: - fix the description of selinux_netlbl_skbuff_setsid(), as Jakub noticed. - fix the annotation in selinux_sctp_assoc_request(), as Richard Noticed. Fixes: 72e89f50084c ("security: Add support for SCTP security hooks") Reported-by: Prashanth Prahlad <pprahlad@redhat.com> Reviewed-by: Richard Haines <richard_c_haines@btinternet.com> Tested-by: Richard Haines <richard_c_haines@btinternet.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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15bf3239 |
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12-Oct-2021 |
Vivek Goyal <vgoyal@redhat.com> |
security: Return xattr name from security_dentry_init_security() Right now security_dentry_init_security() only supports single security label and is used by SELinux only. There are two users of this hook, namely ceph and nfs. NFS does not care about xattr name. Ceph hardcodes the xattr name to security.selinux (XATTR_NAME_SELINUX). I am making changes to fuse/virtiofs to send security label to virtiofsd and I need to send xattr name as well. I also hardcoded the name of xattr to security.selinux. Stephen Smalley suggested that it probably is a good idea to modify security_dentry_init_security() to also return name of xattr so that we can avoid this hardcoding in the callers. This patch adds a new parameter "const char **xattr_name" to security_dentry_init_security() and LSM puts the name of xattr too if caller asked for it (xattr_name != NULL). Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: James Morris <jamorris@linux.microsoft.com> [PM: fixed typos in the commit description] Signed-off-by: Paul Moore <paul@paul-moore.com>
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52f88693 |
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12-Oct-2021 |
Todd Kjos <tkjos@google.com> |
binder: use cred instead of task for selinux checks Since binder was integrated with selinux, it has passed 'struct task_struct' associated with the binder_proc to represent the source and target of transactions. The conversion of task to SID was then done in the hook implementations. It turns out that there are race conditions which can result in an incorrect security context being used. Fix by using the 'struct cred' saved during binder_open and pass it to the selinux subsystem. Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables) Fixes: 79af73079d75 ("Add security hooks to binder and implement the hooks for SELinux.") Suggested-by: Jann Horn <jannh@google.com> Signed-off-by: Todd Kjos <tkjos@google.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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cdc1404a |
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01-Feb-2021 |
Paul Moore <paul@paul-moore.com> |
lsm,io_uring: add LSM hooks to io_uring A full expalantion of io_uring is beyond the scope of this commit description, but in summary it is an asynchronous I/O mechanism which allows for I/O requests and the resulting data to be queued in memory mapped "rings" which are shared between the kernel and userspace. Optionally, io_uring offers the ability for applications to spawn kernel threads to dequeue I/O requests from the ring and submit the requests in the kernel, helping to minimize the syscall overhead. Rings are accessed in userspace by memory mapping a file descriptor provided by the io_uring_setup(2), and can be shared between applications as one might do with any open file descriptor. Finally, process credentials can be registered with a given ring and any process with access to that ring can submit I/O requests using any of the registered credentials. While the io_uring functionality is widely recognized as offering a vastly improved, and high performing asynchronous I/O mechanism, its ability to allow processes to submit I/O requests with credentials other than its own presents a challenge to LSMs. When a process creates a new io_uring ring the ring's credentials are inhertied from the calling process; if this ring is shared with another process operating with different credentials there is the potential to bypass the LSMs security policy. Similarly, registering credentials with a given ring allows any process with access to that ring to submit I/O requests with those credentials. In an effort to allow LSMs to apply security policy to io_uring I/O operations, this patch adds two new LSM hooks. These hooks, in conjunction with the LSM anonymous inode support previously submitted, allow an LSM to apply access control policy to the sharing of io_uring rings as well as any io_uring credential changes requested by a process. The new LSM hooks are described below: * int security_uring_override_creds(cred) Controls if the current task, executing an io_uring operation, is allowed to override it's credentials with @cred. In cases where the current task is a user application, the current credentials will be those of the user application. In cases where the current task is a kernel thread servicing io_uring requests the current credentials will be those of the io_uring ring (inherited from the process that created the ring). * int security_uring_sqpoll(void) Controls if the current task is allowed to create an io_uring polling thread (IORING_SETUP_SQPOLL). Without a SQPOLL thread in the kernel processes must submit I/O requests via io_uring_enter(2) which allows us to compare any requested credential changes against the application making the request. With a SQPOLL thread, we can no longer compare requested credential changes against the application making the request, the comparison is made against the ring's credentials. Signed-off-by: Paul Moore <paul@paul-moore.com>
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8a922805 |
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08-Apr-2021 |
Zhongjun Tan <tanzhongjun@yulong.com> |
selinux: delete selinux_xfrm_policy_lookup() useless argument seliunx_xfrm_policy_lookup() is hooks of security_xfrm_policy_lookup(). The dir argument is uselss in security_xfrm_policy_lookup(). So remove the dir argument from selinux_xfrm_policy_lookup() and security_xfrm_policy_lookup(). Signed-off-by: Zhongjun Tan <tanzhongjun@yulong.com> [PM: reformat the subject line] Signed-off-by: Paul Moore <paul@paul-moore.com>
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83e804f0 |
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22-Apr-2021 |
Mickaël Salaün <mic@linux.microsoft.com> |
fs,security: Add sb_delete hook The sb_delete security hook is called when shutting down a superblock, which may be useful to release kernel objects tied to the superblock's lifetime (e.g. inodes). This new hook is needed by Landlock to release (ephemerally) tagged struct inodes. This comes from the unprivileged nature of Landlock described in the next commit. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Jann Horn <jannh@google.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210422154123.13086-7-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
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4ebd7651 |
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19-Feb-2021 |
Paul Moore <paul@paul-moore.com> |
lsm: separate security_task_getsecid() into subjective and objective variants Of the three LSMs that implement the security_task_getsecid() LSM hook, all three LSMs provide the task's objective security credentials. This turns out to be unfortunate as most of the hook's callers seem to expect the task's subjective credentials, although a small handful of callers do correctly expect the objective credentials. This patch is the first step towards fixing the problem: it splits the existing security_task_getsecid() hook into two variants, one for the subjective creds, one for the objective creds. void security_task_getsecid_subj(struct task_struct *p, u32 *secid); void security_task_getsecid_obj(struct task_struct *p, u32 *secid); While this patch does fix all of the callers to use the correct variant, in order to keep this patch focused on the callers and to ease review, the LSMs continue to use the same implementation for both hooks. The net effect is that this patch should not change the behavior of the kernel in any way, it will be up to the latter LSM specific patches in this series to change the hook implementations and return the correct credentials. Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA) Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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69c4a42d |
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26-Feb-2021 |
Olga Kornievskaia <kolga@netapp.com> |
lsm,selinux: add new hook to compare new mount to an existing mount Add a new hook that takes an existing super block and a new mount with new options and determines if new options confict with an existing mount or not. A filesystem can use this new hook to determine if it can share the an existing superblock with a new superblock for the new mount. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com> [PM: tweak the subject line, fix tab/space problems] Signed-off-by: Paul Moore <paul@paul-moore.com>
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71bc356f |
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21-Jan-2021 |
Christian Brauner <christian.brauner@ubuntu.com> |
commoncap: handle idmapped mounts When interacting with user namespace and non-user namespace aware filesystem capabilities the vfs will perform various security checks to determine whether or not the filesystem capabilities can be used by the caller, whether they need to be removed and so on. The main infrastructure for this resides in the capability codepaths but they are called through the LSM security infrastructure even though they are not technically an LSM or optional. This extends the existing security hooks security_inode_removexattr(), security_inode_killpriv(), security_inode_getsecurity() to pass down the mount's user namespace and makes them aware of idmapped mounts. In order to actually get filesystem capabilities from disk the capability infrastructure exposes the get_vfs_caps_from_disk() helper. For user namespace aware filesystem capabilities a root uid is stored alongside the capabilities. In order to determine whether the caller can make use of the filesystem capability or whether it needs to be ignored it is translated according to the superblock's user namespace. If it can be translated to uid 0 according to that id mapping the caller can use the filesystem capabilities stored on disk. If we are accessing the inode that holds the filesystem capabilities through an idmapped mount we map the root uid according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts: reading filesystem caps from disk enforces that the root uid associated with the filesystem capability must have a mapping in the superblock's user namespace and that the caller is either in the same user namespace or is a descendant of the superblock's user namespace. For filesystems that are mountable inside user namespace the caller can just mount the filesystem and won't usually need to idmap it. If they do want to idmap it they can create an idmapped mount and mark it with a user namespace they created and which is thus a descendant of s_user_ns. For filesystems that are not mountable inside user namespaces the descendant rule is trivially true because the s_user_ns will be the initial user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-11-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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215b674b |
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08-Jan-2021 |
Lokesh Gidra <lokeshgidra@google.com> |
security: add inode_init_security_anon() LSM hook This change adds a new LSM hook, inode_init_security_anon(), that will be used while creating secure anonymous inodes. The hook allows/denies its creation and assigns a security context to the inode. The new hook accepts an optional context_inode parameter that callers can use to provide additional contextual information to security modules for granting/denying permission to create an anon-inode of the same type. This context_inode's security_context can also be used to initialize the newly created anon-inode's security_context. Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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41dd9596 |
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30-Nov-2020 |
Florian Westphal <fw@strlen.de> |
security: add const qualifier to struct sock in various places A followup change to tcp_request_sock_op would have to drop the 'const' qualifier from the 'route_req' function as the 'security_inet_conn_request' call is moved there - and that function expects a 'struct sock *'. However, it turns out its also possible to add a const qualifier to security_inet_conn_request instead. Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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3df98d79 |
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27-Sep-2020 |
Paul Moore <paul@paul-moore.com> |
lsm,selinux: pass flowi_common instead of flowi to the LSM hooks As pointed out by Herbert in a recent related patch, the LSM hooks do not have the necessary address family information to use the flowi struct safely. As none of the LSMs currently use any of the protocol specific flowi information, replace the flowi pointers with pointers to the address family independent flowi_common struct. Reported-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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200da27a |
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06-Oct-2020 |
Nathan Chancellor <nathan@kernel.org> |
LSM: Fix type of id parameter in kernel_post_load_data prototype Clang warns: security/security.c:1716:59: warning: implicit conversion from enumeration type 'enum kernel_load_data_id' to different enumeration type 'enum kernel_read_file_id' [-Wenum-conversion] ret = call_int_hook(kernel_post_load_data, 0, buf, size, id, ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~ security/security.c:715:22: note: expanded from macro 'call_int_hook' RC = P->hook.FUNC(__VA_ARGS__); \ ~ ^~~~~~~~~~~ 1 warning generated. There is a mismatch between the id parameter type in security_kernel_post_load_data and the function pointer prototype that is created by the LSM_HOOK macro in the security_list_options union. Fix the type in the LSM_HOOK macro as 'enum kernel_load_data_id' is what is expected. Fixes: b64fcae74b6d ("LSM: Introduce kernel_post_load_data() hook") Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Link: https://lore.kernel.org/r/20201006201115.716550-1-natechancellor@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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2039bda1 |
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02-Oct-2020 |
Kees Cook <keescook@chromium.org> |
LSM: Add "contents" flag to kernel_read_file hook As with the kernel_load_data LSM hook, add a "contents" flag to the kernel_read_file LSM hook that indicates whether the LSM can expect a matching call to the kernel_post_read_file LSM hook with the full contents of the file. With the coming addition of partial file read support for kernel_read_file*() API, the LSM will no longer be able to always see the entire contents of a file during the read calls. For cases where the LSM must read examine the complete file contents, it will need to do so on its own every time the kernel_read_file hook is called with contents=false (or reject such cases). Adjust all existing LSMs to retain existing behavior. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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b64fcae7 |
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02-Oct-2020 |
Kees Cook <keescook@chromium.org> |
LSM: Introduce kernel_post_load_data() hook There are a few places in the kernel where LSMs would like to have visibility into the contents of a kernel buffer that has been loaded or read. While security_kernel_post_read_file() (which includes the buffer) exists as a pairing for security_kernel_read_file(), no such hook exists to pair with security_kernel_load_data(). Earlier proposals for just using security_kernel_post_read_file() with a NULL file argument were rejected (i.e. "file" should always be valid for the security_..._file hooks, but it appears at least one case was left in the kernel during earlier refactoring. (This will be fixed in a subsequent patch.) Since not all cases of security_kernel_load_data() can have a single contiguous buffer made available to the LSM hook (e.g. kexec image segments are separately loaded), there needs to be a way for the LSM to reason about its expectations of the hook coverage. In order to handle this, add a "contents" argument to the "kernel_load_data" hook that indicates if the newly added "kernel_post_load_data" hook will be called with the full contents once loaded. That way, LSMs requiring full contents can choose to unilaterally reject "kernel_load_data" with contents=false (which is effectively the existing hook coverage), but when contents=true they can allow it and later evaluate the "kernel_post_load_data" hook once the buffer is loaded. With this change, LSMs can gain coverage over non-file-backed data loads (e.g. init_module(2) and firmware userspace helper), which will happen in subsequent patches. Additionally prepare IMA to start processing these cases. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: KP Singh <kpsingh@google.com> Link: https://lore.kernel.org/r/20201002173828.2099543-9-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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bb22d80b |
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17-Jul-2020 |
Randy Dunlap <rdunlap@infradead.org> |
LSM: drop duplicated words in header file comments Drop the doubled words "the" and "and" in comments. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Serge Hallyn <serge@hallyn.com> Cc: linux-security-module@vger.kernel.org Signed-off-by: James Morris <jmorris@namei.org>
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23e390cd |
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21-Jun-2020 |
KP Singh <kpsingh@google.com> |
security: Fix hook iteration and default value for inode_copy_up_xattr inode_copy_up_xattr returns 0 to indicate the acceptance of the xattr and 1 to reject it. If the LSM does not know about the xattr, it's expected to return -EOPNOTSUPP, which is the correct default value for this hook. BPF LSM, currently, uses 0 as the default value and thereby falsely allows all overlay fs xattributes to be copied up. The iteration logic is also updated from the "bail-on-fail" call_int_hook to continue on the non-decisive -EOPNOTSUPP and bail out on other values. Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: James Morris <jmorris@namei.org>
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4bc799dc |
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15-Jun-2020 |
Sami Tolvanen <samitolvanen@google.com> |
security: fix the key_permission LSM hook function type Commit 8c0637e950d6 ("keys: Make the KEY_NEED_* perms an enum rather than a mask") changed the type of the key_permission callback functions, but didn't change the type of the hook, which trips indirect call checking with Control-Flow Integrity (CFI). This change fixes the issue by changing the hook type to match the functions. Fixes: 8c0637e950d6 ("keys: Make the KEY_NEED_* perms an enum rather than a mask") Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <jmorris@namei.org>
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39030e13 |
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09-Jun-2020 |
Thomas Cedeno <thomascedeno@google.com> |
security: Add LSM hooks to set*gid syscalls The SafeSetID LSM uses the security_task_fix_setuid hook to filter set*uid() syscalls according to its configured security policy. In preparation for adding analagous support in the LSM for set*gid() syscalls, we add the requisite hook here. Tested by putting print statements in the security_task_fix_setgid hook and seeing them get hit during kernel boot. Signed-off-by: Thomas Cedeno <thomascedeno@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org>
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56305aa9 |
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29-May-2020 |
Eric W. Biederman <ebiederm@xmission.com> |
exec: Compute file based creds only once Move the computation of creds from prepare_binfmt into begin_new_exec so that the creds need only be computed once. This is just code reorganization no semantic changes of any kind are made. Moving the computation is safe. I have looked through the kernel and verified none of the binfmts look at bprm->cred directly, and that there are no helpers that look at bprm->cred indirectly. Which means that it is not a problem to compute the bprm->cred later in the execution flow as it is not used until it becomes current->cred. A new function bprm_creds_from_file is added to contain the work that needs to be done. bprm_creds_from_file first computes which file bprm->executable or most likely bprm->file that the bprm->creds will be computed from. The funciton bprm_fill_uid is updated to receive the file instead of accessing bprm->file. The now unnecessary work needed to reset the bprm->cred->euid, and bprm->cred->egid is removed from brpm_fill_uid. A small comment to document that bprm_fill_uid now only deals with the work to handle suid and sgid files. The default case is already heandled by prepare_exec_creds. The function security_bprm_repopulate_creds is renamed security_bprm_creds_from_file and now is explicitly passed the file from which to compute the creds. The documentation of the bprm_creds_from_file security hook is updated to explain when the hook is called and what it needs to do. The file is passed from cap_bprm_creds_from_file into get_file_caps so that the caps are computed for the appropriate file. The now unnecessary work in cap_bprm_creds_from_file to reset the ambient capabilites has been removed. A small comment to document that the work of cap_bprm_creds_from_file is to read capabilities from the files secureity attribute and derive capabilities from the fact the user had uid 0 has been added. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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112b7147 |
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13-May-2020 |
Eric W. Biederman <ebiederm@xmission.com> |
exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds Rename bprm->cap_elevated to bprm->active_secureexec and initialize it in prepare_binprm instead of in cap_bprm_set_creds. Initializing bprm->active_secureexec in prepare_binprm allows multiple implementations of security_bprm_repopulate_creds to play nicely with each other. Rename security_bprm_set_creds to security_bprm_reopulate_creds to emphasize that this path recomputes part of bprm->cred. This recomputation avoids the time of check vs time of use problems that are inherent in unix #! interpreters. In short two renames and a move in the location of initializing bprm->active_secureexec. Link: https://lkml.kernel.org/r/87o8qkzrxp.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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b8bff599 |
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22-Mar-2020 |
Eric W. Biederman <ebiederm@xmission.com> |
exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds Today security_bprm_set_creds has several implementations: apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds, smack_bprm_set_creds, and tomoyo_bprm_set_creds. Except for cap_bprm_set_creds they all test bprm->called_set_creds and return immediately if it is true. The function cap_bprm_set_creds ignores bprm->calld_sed_creds entirely. Create a new LSM hook security_bprm_creds_for_exec that is called just before prepare_binprm in __do_execve_file, resulting in a LSM hook that is called exactly once for the entire of exec. Modify the bits of security_bprm_set_creds that only want to be called once per exec into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds behind. Remove bprm->called_set_creds all of it's former users have been moved to security_bprm_creds_for_exec. Add or upate comments a appropriate to bring them up to date and to reflect this change. Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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998f5040 |
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12-Feb-2020 |
David Howells <dhowells@redhat.com> |
security: Add hooks to rule on setting a watch Add security hooks that will allow an LSM to rule on whether or not a watch may be set. More than one hook is required as the watches watch different types of object. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jamorris@linux.microsoft.com> cc: Casey Schaufler <casey@schaufler-ca.com> cc: Stephen Smalley <sds@tycho.nsa.gov> cc: linux-security-module@vger.kernel.org
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344fa64e |
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12-Feb-2020 |
David Howells <dhowells@redhat.com> |
security: Add a hook for the point of notification insertion Add a security hook that allows an LSM to rule on whether a notification message is allowed to be inserted into a particular watch queue. The hook is given the following information: (1) The credentials of the triggerer (which may be init_cred for a system notification, eg. a hardware error). (2) The credentials of the whoever set the watch. (3) The notification message. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jamorris@linux.microsoft.com> cc: Casey Schaufler <casey@schaufler-ca.com> cc: Stephen Smalley <sds@tycho.nsa.gov> cc: linux-security-module@vger.kernel.org
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625236ba |
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12-May-2020 |
Anders Roxell <anders.roxell@linaro.org> |
security: Fix the default value of secid_to_secctx hook security_secid_to_secctx is called by the bpf_lsm hook and a successful return value (i.e 0) implies that the parameter will be consumed by the LSM framework. The current behaviour return success when the pointer isn't initialized when CONFIG_BPF_LSM is enabled, with the default return from kernel/bpf/bpf_lsm.c. This is the internal error: [ 1229.341488][ T2659] usercopy: Kernel memory exposure attempt detected from null address (offset 0, size 280)! [ 1229.374977][ T2659] ------------[ cut here ]------------ [ 1229.376813][ T2659] kernel BUG at mm/usercopy.c:99! [ 1229.378398][ T2659] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 1229.380348][ T2659] Modules linked in: [ 1229.381654][ T2659] CPU: 0 PID: 2659 Comm: systemd-journal Tainted: G B W 5.7.0-rc5-next-20200511-00019-g864e0c6319b8-dirty #13 [ 1229.385429][ T2659] Hardware name: linux,dummy-virt (DT) [ 1229.387143][ T2659] pstate: 80400005 (Nzcv daif +PAN -UAO BTYPE=--) [ 1229.389165][ T2659] pc : usercopy_abort+0xc8/0xcc [ 1229.390705][ T2659] lr : usercopy_abort+0xc8/0xcc [ 1229.392225][ T2659] sp : ffff000064247450 [ 1229.393533][ T2659] x29: ffff000064247460 x28: 0000000000000000 [ 1229.395449][ T2659] x27: 0000000000000118 x26: 0000000000000000 [ 1229.397384][ T2659] x25: ffffa000127049e0 x24: ffffa000127049e0 [ 1229.399306][ T2659] x23: ffffa000127048e0 x22: ffffa000127048a0 [ 1229.401241][ T2659] x21: ffffa00012704b80 x20: ffffa000127049e0 [ 1229.403163][ T2659] x19: ffffa00012704820 x18: 0000000000000000 [ 1229.405094][ T2659] x17: 0000000000000000 x16: 0000000000000000 [ 1229.407008][ T2659] x15: 0000000000000000 x14: 003d090000000000 [ 1229.408942][ T2659] x13: ffff80000d5b25b2 x12: 1fffe0000d5b25b1 [ 1229.410859][ T2659] x11: 1fffe0000d5b25b1 x10: ffff80000d5b25b1 [ 1229.412791][ T2659] x9 : ffffa0001034bee0 x8 : ffff00006ad92d8f [ 1229.414707][ T2659] x7 : 0000000000000000 x6 : ffffa00015eacb20 [ 1229.416642][ T2659] x5 : ffff0000693c8040 x4 : 0000000000000000 [ 1229.418558][ T2659] x3 : ffffa0001034befc x2 : d57a7483a01c6300 [ 1229.420610][ T2659] x1 : 0000000000000000 x0 : 0000000000000059 [ 1229.422526][ T2659] Call trace: [ 1229.423631][ T2659] usercopy_abort+0xc8/0xcc [ 1229.425091][ T2659] __check_object_size+0xdc/0x7d4 [ 1229.426729][ T2659] put_cmsg+0xa30/0xa90 [ 1229.428132][ T2659] unix_dgram_recvmsg+0x80c/0x930 [ 1229.429731][ T2659] sock_recvmsg+0x9c/0xc0 [ 1229.431123][ T2659] ____sys_recvmsg+0x1cc/0x5f8 [ 1229.432663][ T2659] ___sys_recvmsg+0x100/0x160 [ 1229.434151][ T2659] __sys_recvmsg+0x110/0x1a8 [ 1229.435623][ T2659] __arm64_sys_recvmsg+0x58/0x70 [ 1229.437218][ T2659] el0_svc_common.constprop.1+0x29c/0x340 [ 1229.438994][ T2659] do_el0_svc+0xe8/0x108 [ 1229.440587][ T2659] el0_svc+0x74/0x88 [ 1229.441917][ T2659] el0_sync_handler+0xe4/0x8b4 [ 1229.443464][ T2659] el0_sync+0x17c/0x180 [ 1229.444920][ T2659] Code: aa1703e2 aa1603e1 910a8260 97ecc860 (d4210000) [ 1229.447070][ T2659] ---[ end trace 400497d91baeaf51 ]--- [ 1229.448791][ T2659] Kernel panic - not syncing: Fatal exception [ 1229.450692][ T2659] Kernel Offset: disabled [ 1229.452061][ T2659] CPU features: 0x240002,20002004 [ 1229.453647][ T2659] Memory Limit: none [ 1229.455015][ T2659] ---[ end Kernel panic - not syncing: Fatal exception ]--- Rework the so the default return value is -EOPNOTSUPP. There are likely other callbacks such as security_inode_getsecctx() that may have the same problem, and that someone that understand the code better needs to audit them. Thank you Arnd for helping me figure out what went wrong. Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: James Morris <jamorris@linux.microsoft.com> Cc: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/bpf/20200512174607.9630-1-anders.roxell@linaro.org
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54261af4 |
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30-Apr-2020 |
KP Singh <kpsingh@google.com> |
security: Fix the default value of fs_context_parse_param hook security_fs_context_parse_param is called by vfs_parse_fs_param and a succussful return value (i.e 0) implies that a parameter will be consumed by the LSM framework. This stops all further parsing of the parmeter by VFS. Furthermore, if an LSM hook returns a success, the remaining LSM hooks are not invoked for the parameter. The current default behavior of returning success means that all the parameters are expected to be parsed by the LSM hook and none of them end up being populated by vfs in fs_context This was noticed when lsm=bpf is supplied on the command line before any other LSM. As the bpf lsm uses this default value to implement a default hook, this resulted in a failure to parse any fs_context parameters and a failure to mount the root filesystem. Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Reported-by: Mikko Ylinen <mikko.ylinen@linux.intel.com> Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: James Morris <jmorris@namei.org>
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98e828a0 |
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28-Mar-2020 |
KP Singh <kpsingh@google.com> |
security: Refactor declaration of LSM hooks The information about the different types of LSM hooks is scattered in two locations i.e. union security_list_options and struct security_hook_heads. Rather than duplicating this information even further for BPF_PROG_TYPE_LSM, define all the hooks with the LSM_HOOK macro in lsm_hook_defs.h which is then used to generate all the data structures required by the LSM framework. The LSM hooks are defined as: LSM_HOOK(<return_type>, <default_value>, <hook_name>, args...) with <default_value> acccessible in security.c as: LSM_RET_DEFAULT(<hook_name>) Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Florent Revest <revest@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/bpf/20200329004356.27286-3-kpsingh@chromium.org
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