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bpf: fix out-of-bounds access warning in bpf_check

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The bpf_verifer_ops array is generated dynamically and may be
empty depending on configuration, which then causes an out
of bounds access:

kernel/bpf/verifier.c: In function 'bpf_check':
kernel/bpf/verifier.c:4320:29: error: array subscript is above array bounds [-Werror=array-bounds]

This adds a check to the start of the function as a workaround.
I would assume that the function is never called in that configuration,
so the warning is probably harmless.

Fixes: 00176a34d9 ("bpf: remove the verifier ops from program structure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnd Bergmann 2017-11-02 12:05:52 +01:00 committed by David S. Miller
parent 7cce782ef3
commit eba0c929d1
1 changed files with 4 additions and 0 deletions
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4
kernel/bpf/verifier.c
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@ -4474,6 +4474,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
struct bpf_verifer_log *log;
int ret = -EINVAL;
/* no program is valid */
if (ARRAY_SIZE(bpf_verifier_ops) == 0)
return -EINVAL;
/* 'struct bpf_verifier_env' can be global, but since it's not small,
* allocate/free it every time bpf_check() is called
*/