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8032cad1 |
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13-Feb-2023 |
Joanne Koong <joannelkoong@gmail.com> |
selftests/bpf: Clean up user_ringbuf, cgrp_kfunc, kfunc_dynptr_param tests Clean up user_ringbuf, cgrp_kfunc, and kfunc_dynptr_param tests to use the generic verification tester for checking verifier rejections. The generic verification tester uses btf_decl_tag-based annotations for verifying that the tests fail with the expected log messages. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Acked-by: David Vernet <void@manifault.com> Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com> Link: https://lore.kernel.org/r/20230214051332.4007131-1-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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79168a66 |
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20-Jan-2023 |
Kumar Kartikeya Dwivedi <memxor@gmail.com> |
bpf: Fix missing var_off check for ARG_PTR_TO_DYNPTR Currently, the dynptr function is not checking the variable offset part of PTR_TO_STACK that it needs to check. The fixed offset is considered when computing the stack pointer index, but if the variable offset was not a constant (such that it could not be accumulated in reg->off), we will end up a discrepency where runtime pointer does not point to the actual stack slot we mark as STACK_DYNPTR. It is impossible to precisely track dynptr state when variable offset is not constant, hence, just like bpf_timer, kptr, bpf_spin_lock, etc. simply reject the case where reg->var_off is not constant. Then, consider both reg->off and reg->var_off.value when computing the stack pointer index. A new helper dynptr_get_spi is introduced to hide over these details since the dynptr needs to be located in multiple places outside the process_dynptr_func checks, hence once we know it's a PTR_TO_STACK, we need to enforce these checks in all places. Note that it is disallowed for unprivileged users to have a non-constant var_off, so this problem should only be possible to trigger from programs having CAP_PERFMON. However, its effects can vary. Without the fix, it is possible to replace the contents of the dynptr arbitrarily by making verifier mark different stack slots than actual location and then doing writes to the actual stack address of dynptr at runtime. Fixes: 97e03f521050 ("bpf: Add verifier support for dynptrs") Acked-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20230121002241.2113993-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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6b75bd3d |
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07-Dec-2022 |
Kumar Kartikeya Dwivedi <memxor@gmail.com> |
bpf: Refactor ARG_PTR_TO_DYNPTR checks into process_dynptr_func ARG_PTR_TO_DYNPTR is akin to ARG_PTR_TO_TIMER, ARG_PTR_TO_KPTR, where the underlying register type is subjected to more special checks to determine the type of object represented by the pointer and its state consistency. Move dynptr checks to their own 'process_dynptr_func' function so that is consistent and in-line with existing code. This also makes it easier to reuse this code for kfunc handling. Then, reuse this consolidated function in kfunc dynptr handling too. Note that for kfuncs, the arg_type constraint of DYNPTR_TYPE_LOCAL has been lifted. Acked-by: David Vernet <void@manifault.com> Acked-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221207204141.308952-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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00b85860 |
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17-Nov-2022 |
Kumar Kartikeya Dwivedi <memxor@gmail.com> |
bpf: Rewrite kfunc argument handling As we continue to add more features, argument types, kfunc flags, and different extensions to kfuncs, the code to verify the correctness of the kfunc prototype wrt the passed in registers has become ad-hoc and ugly to read. To make life easier, and make a very clear split between different stages of argument processing, move all the code into verifier.c and refactor into easier to read helpers and functions. This also makes sharing code within the verifier easier with kfunc argument processing. This will be more and more useful in later patches as we are now moving to implement very core BPF helpers as kfuncs, to keep them experimental before baking into UAPI. Remove all kfunc related bits now from btf_check_func_arg_match, as users have been converted away to refactored kfunc argument handling. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221118015614.2013203-12-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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b94fa9f9 |
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20-Sep-2022 |
Roberto Sassu <roberto.sassu@huawei.com> |
selftests/bpf: Add tests for dynamic pointers parameters in kfuncs Add tests to ensure that only supported dynamic pointer types are accepted, that the passed argument is actually a dynamic pointer, that the passed argument is a pointer to the stack, and that bpf_verify_pkcs7_signature() correctly handles dynamic pointers with data set to NULL. The tests are currently in the deny list for s390x (JIT does not support calling kernel function). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20220920075951.929132-14-roberto.sassu@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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