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| author | Daniel Rosenberg <drosen@google.com> | 2023-05-06 03:31:33 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-05-07 01:42:57 +0200 |
| commit | 2012c867c8005d72c949e274133df429ece78808 (patch) | |
| tree | fd441764144679effb80bb2047ecafef71b35985 | |
| parent | selftests/bpf: Check overflow in optional buffer (diff) | |
| download | linux-2012c867c8005d72c949e274133df429ece78808.tar.xz linux-2012c867c8005d72c949e274133df429ece78808.zip | |
bpf: verifier: Accept dynptr mem as mem in helpers
This allows using memory retrieved from dynptrs with helper functions
that accept ARG_PTR_TO_MEM. For instance, results from bpf_dynptr_data
can be passed along to bpf_strncmp.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20230506013134.2492210-5-drosen@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | kernel/bpf/verifier.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7e6bbae9db81..754129d41225 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7495,12 +7495,16 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, * ARG_PTR_TO_MEM + MAYBE_NULL is compatible with PTR_TO_MEM and PTR_TO_MEM + MAYBE_NULL, * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM but NOT with PTR_TO_MEM + MAYBE_NULL * + * ARG_PTR_TO_MEM is compatible with PTR_TO_MEM that is tagged with a dynptr type. + * * Therefore we fold these flags depending on the arg_type before comparison. */ if (arg_type & MEM_RDONLY) type &= ~MEM_RDONLY; if (arg_type & PTR_MAYBE_NULL) type &= ~PTR_MAYBE_NULL; + if (base_type(arg_type) == ARG_PTR_TO_MEM) + type &= ~DYNPTR_TYPE_FLAG_MASK; if (meta->func_id == BPF_FUNC_kptr_xchg && type & MEM_ALLOC) type &= ~MEM_ALLOC; |