diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2024-09-13 21:17:49 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-09-13 13:17:56 -0700 |
| commit | 18752d73c1898fd001569195ba4b0b8c43255f4a (patch) | |
| tree | f6895f9f0abcb467d9d19af936b1645cf5c5aba1 /kernel/bpf | |
| parent | 32556ce93bc45c730829083cb60f95a2728ea48b (diff) | |
bpf: Improve check_raw_mode_ok test for MEM_UNINIT-tagged types
When checking malformed helper function signatures, also take other argument
types into account aside from just ARG_PTR_TO_UNINIT_MEM.
This concerns (formerly) ARG_PTR_TO_{INT,LONG} given uninitialized memory can
be passed there, too.
The func proto sanity check goes back to commit 435faee1aae9 ("bpf, verifier:
add ARG_PTR_TO_RAW_STACK type"), and its purpose was to detect wrong func protos
which had more than just one MEM_UNINIT-tagged type as arguments.
The reason more than one is currently not supported is as we mark stack slots with
STACK_MISC in check_helper_call() in case of raw mode based on meta.access_size to
allow uninitialized stack memory to be passed to helpers when they just write into
the buffer.
Probing for base type as well as MEM_UNINIT tagging ensures that other types do not
get missed (as it used to be the case for ARG_PTR_TO_{INT,LONG}).
Fixes: 57c3bb725a3d ("bpf: Introduce ARG_PTR_TO_{INT,LONG} arg types")
Reported-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Link: https://lore.kernel.org/r/20240913191754.13290-4-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7d62fd576089..7df5c29293a4 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8291,6 +8291,12 @@ static bool arg_type_is_mem_size(enum bpf_arg_type type) type == ARG_CONST_SIZE_OR_ZERO; } +static bool arg_type_is_raw_mem(enum bpf_arg_type type) +{ + return base_type(type) == ARG_PTR_TO_MEM && + type & MEM_UNINIT; +} + static bool arg_type_is_release(enum bpf_arg_type type) { return type & OBJ_RELEASE; @@ -9340,15 +9346,15 @@ static bool check_raw_mode_ok(const struct bpf_func_proto *fn) { int count = 0; - if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg1_type)) count++; - if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg2_type)) count++; - if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg3_type)) count++; - if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg4_type)) count++; - if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) + if (arg_type_is_raw_mem(fn->arg5_type)) count++; /* We only support one arg being in raw mode at the moment, |