crypto: asymmetric_keys - remove redundant pointer secs

The pointer secs is being assigned a value however secs is never
read afterwards. The pointer secs is redundant and can be removed.

Cleans up clang scan build warning:
warning: Although the value stored to 'secs' is used in the enclosing
expression, the value is never actually read from 'secs'
[deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

KEYS: fix kernel-doc warnings in verify_pefile

Fix kernel-doc warnings in verify_pefile:

crypto/asymmetric_keys/verify_pefile.c:423: warning: Excess function
parameter 'trust_keys' description in 'verify_pefile_signature'

crypto/asymmetric_keys/verify_pefile.c:423: warning: Function parameter
or member 'trusted_keys' not described in 'verify_pefile_signature'

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

asymmetric_keys: log on fatal failures in PE/pkcs7

These particular errors can be encountered while trying to kexec when
secureboot lockdown is in place. Without this change, even with a
signed debug build, one still needs to reboot the machine to add the
appropriate dyndbg parameters (since lockdown blocks debugfs).

Accordingly, upgrade all pr_debug() before fatal error into pr_warn().

Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jarkko Sakkinen <jarkko@kernel.org>
cc: Eric Biederman <ebiederm@xmission.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: keyrings@vger.kernel.org
cc: linux-crypto@vger.kernel.org
cc: kexec@lists.infradead.org
Link: https://lore.kernel.org/r/20230220171254.592347-3-rharwood@redhat.com/ # v2

verify_pefile: relax wrapper length check

The PE Format Specification (section "The Attribute Certificate Table
(Image Only)") states that `dwLength` is to be rounded up to 8-byte
alignment when used for traversal. Therefore, the field is not required
to be an 8-byte multiple in the first place.

Accordingly, pesign has not performed this alignment since version
0.110. This causes kexec failure on pesign'd binaries with "PEFILE:
Signature wrapper len wrong". Update the comment and relax the check.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jarkko Sakkinen <jarkko@kernel.org>
cc: Eric Biederman <ebiederm@xmission.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: keyrings@vger.kernel.org
cc: linux-crypto@vger.kernel.org
cc: kexec@lists.infradead.org
Link: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#the-attribute-certificate-table-image-only
Link: https://github.com/rhboot/pesign
Link: https://lore.kernel.org/r/20230220171254.592347-2-rharwood@redhat.com/ # v2

mm, treewide: rename kzfree() to kfree_sensitive()

As said by Linus:

A symmetric naming is only helpful if it implies symmetries in use.
Otherwise it's actively misleading.

In "kzalloc()", the z is meaningful and an important part of what the
caller wants.

In "kzfree()", the z is actively detrimental, because maybe in the
future we really _might_ want to use that "memfill(0xdeadbeef)" or
something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

git grep -w --name-only kzfree |\
xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE

This is a preparatory patch for kexec_file_load() lockdown. A locked down
kernel needs to prevent unsigned kernel images from being loaded with
kexec_file_load(). Currently, the only way to force the signature
verification is compiling with KEXEC_VERIFY_SIG. This prevents loading
usigned images even when the kernel is not locked down at runtime.

This patch splits KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE.
Analogous to the MODULE_SIG and MODULE_SIG_FORCE for modules, KEXEC_SIG
turns on the signature verification but allows unsigned images to be
loaded. KEXEC_SIG_FORCE disallows images without a valid signature.

Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
cc: kexec@lists.infradead.org
Signed-off-by: James Morris <jmorris@namei.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public licence as published by
the free software foundation either version 2 of the licence or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

crypto: shash - remove shash_desc::flags

The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.

With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP. These would all need to be fixed if any shash algorithm
actually started sleeping. For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API. However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.

Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk. It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.

Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto : asymmetric_keys : verify_pefile:zero memory content before freeing

Signed-off-by: Loganaden Velvindron <logan@hackers.mu>
Signed-off-by: Yasir Auleear <yasirmx@hackers.mu>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

PKCS#7: Make trust determination dependent on contents of trust keyring

Make the determination of the trustworthiness of a key dependent on whether
a key that can verify it is present in the supplied ring of trusted keys
rather than whether or not the verifying key has KEY_FLAG_TRUSTED set.

verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust
chain cannot be verified.

Signed-off-by: David Howells <dhowells@redhat.com>

KEYS: Generalise system_verify_data() to provide access to internal content

Generalise system_verify_data() to provide access to internal content
through a callback. This allows all the PKCS#7 stuff to be hidden inside
this function and removed from the PE file parser and the PKCS#7 test key.

If external content is not required, NULL should be passed as data to the
function. If the callback is not required, that can be set to NULL.

The function is now called verify_pkcs7_signature() to contrast with
verify_pefile_signature() and the definitions of both have been moved into
linux/verification.h along with the key_being_used_for enum.

Signed-off-by: David Howells <dhowells@redhat.com>

X.509: Make algo identifiers text instead of enum

Make the identifier public key and digest algorithm fields text instead of
enum.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>

PKCS#7: Appropriately restrict authenticated attributes and content type

A PKCS#7 or CMS message can have per-signature authenticated attributes
that are digested as a lump and signed by the authorising key for that
signature. If such attributes exist, the content digest isn't itself
signed, but rather it is included in a special authattr which then
contributes to the signature.

Further, we already require the master message content type to be
pkcs7_signedData - but there's also a separate content type for the data
itself within the SignedData object and this must be repeated inside the
authattrs for each signer [RFC2315 9.2, RFC5652 11.1].

We should really validate the authattrs if they exist or forbid them
entirely as appropriate. To this end:

(1) Alter the PKCS#7 parser to reject any message that has more than one
signature where at least one signature has authattrs and at least one
that does not.

(2) Validate authattrs if they are present and strongly restrict them.
Only the following authattrs are permitted and all others are
rejected:

(a) contentType. This is checked to be an OID that matches the
content type in the SignedData object.

(b) messageDigest. This must match the crypto digest of the data.

(c) signingTime. If present, we check that this is a valid, parseable
UTCTime or GeneralTime and that the date it encodes fits within
the validity window of the matching X.509 cert.

(d) S/MIME capabilities. We don't check the contents.

(e) Authenticode SP Opus Info. We don't check the contents.

(f) Authenticode Statement Type. We don't check the contents.

The message is rejected if (a) or (b) are missing. If the message is
an Authenticode type, the message is rejected if (e) is missing; if
not Authenticode, the message is rejected if (d) - (f) are present.

The S/MIME capabilities authattr (d) unfortunately has to be allowed
to support kernels already signed by the pesign program. This only
affects kexec. sign-file suppresses them (CMS_NOSMIMECAP).

The message is also rejected if an authattr is given more than once or
if it contains more than one element in its set of values.

(3) Add a parameter to pkcs7_verify() to select one of the following
restrictions and pass in the appropriate option from the callers:

(*) VERIFYING_MODULE_SIGNATURE

This requires that the SignedData content type be pkcs7-data and
forbids authattrs. sign-file sets CMS_NOATTR. We could be more
flexible and permit authattrs optionally, but only permit minimal
content.

(*) VERIFYING_FIRMWARE_SIGNATURE

This requires that the SignedData content type be pkcs7-data and
requires authattrs. In future, this will require an attribute
holding the target firmware name in addition to the minimal set.

(*) VERIFYING_UNSPECIFIED_SIGNATURE

This requires that the SignedData content type be pkcs7-data but
allows either no authattrs or only permits the minimal set.

(*) VERIFYING_KEXEC_PE_SIGNATURE

This only supports the Authenticode SPC_INDIRECT_DATA content type
and requires at least an SpcSpOpusInfo authattr in addition to the
minimal set. It also permits an SPC_STATEMENT_TYPE authattr (and
an S/MIME capabilities authattr because the pesign program doesn't
remove these).

(*) VERIFYING_KEY_SIGNATURE
(*) VERIFYING_KEY_SELF_SIGNATURE

These are invalid in this context but are included for later use
when limiting the use of X.509 certs.

(4) The pkcs7_test key type is given a module parameter to select between
the above options for testing purposes. For example:

echo 1 >/sys/module/pkcs7_test_key/parameters/usage
keyctl padd pkcs7_test foo @s </tmp/stuff.pkcs7

will attempt to check the signature on stuff.pkcs7 as if it contains a
firmware blob (1 being VERIFYING_FIRMWARE_SIGNATURE).

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: David Woodhouse <David.Woodhouse@intel.com>

PEFILE: Relax the check on the length of the PKCS#7 cert

Relax the check on the length of the PKCS#7 cert as it appears that the PE
file wrapper size gets rounded up to the nearest 8.

The debugging output looks like this:

PEFILE: ==> verify_pefile_signature()
PEFILE: ==> pefile_parse_binary()
PEFILE: checksum @ 110
PEFILE: header size = 200
PEFILE: cert = 968 @547be0 [68 09 00 00 00 02 02 00 30 82 09 56 ]
PEFILE: sig wrapper = { 968, 200, 2 }
PEFILE: Signature data not PKCS#7

The wrapper is the first 8 bytes of the hex dump inside []. This indicates a
length of 0x968 bytes, including the wrapper header - so 0x960 bytes of
payload.

The ASN.1 wrapper begins [ ... 30 82 09 56 ]. That indicates an object of size
0x956 - a four byte discrepency, presumably just padding for alignment
purposes.

So we just check that the ASN.1 container is no bigger than the payload and
reduce the recorded size appropriately.

Whilst we're at it, allow shorter PKCS#7 objects that manage to squeeze within
127 or 255 bytes. It's just about conceivable if no X.509 certs are included
in the PKCS#7 message.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Peter Jones <pjones@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

pefile: Validate PKCS#7 trust chain

Validate the PKCS#7 trust chain against the contents of the system keyring.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

pefile: Digest the PE binary and compare to the PKCS#7 data

Digest the signed parts of the PE binary, canonicalising the section table
before we need it, and then compare the the resulting digest to the one in the
PKCS#7 signed content.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

pefile: Parse the "Microsoft individual code signing" data blob

The PKCS#7 certificate should contain a "Microsoft individual code signing"
data blob as its signed content. This blob contains a digest of the signed
content of the PE binary and the OID of the digest algorithm used (typically
SHA256).

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

pefile: Parse the presumed PKCS#7 content of the certificate blob

Parse the content of the certificate blob, presuming it to be PKCS#7 format.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

pefile: Strip the wrapper off of the cert data block

The certificate data block in a PE binary has a wrapper around the PKCS#7
signature we actually want to get at. Strip this off and check that we've got
something that appears to be a PKCS#7 signature.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

pefile: Parse a PE binary to find a key and a signature contained therein

Parse a PE binary to find a key and a signature contained therein. Later
patches will check the signature and add the key if the signature checks out.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>