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| author | Daniel Borkmann <daniel@iogearbox.net> | 2017-12-22 16:23:09 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-25 14:26:32 +0100 |
| commit | c90268f7cbee0781331b96d1423d0f28a6183889 (patch) | |
| tree | 5dcdbe6680a632646d6777586b5c6e7038331439 /kernel | |
| parent | 2120fca0ecfb4552d27608d409ebd3403ce02ce4 (diff) | |
| download | linux-stable-c90268f7cbee0781331b96d1423d0f28a6183889.tar.gz linux-stable-c90268f7cbee0781331b96d1423d0f28a6183889.tar.bz2 linux-stable-c90268f7cbee0781331b96d1423d0f28a6183889.zip | |
bpf: force strict alignment checks for stack pointers
From: Jann Horn <jannh@google.com>
[ Upstream commit a5ec6ae161d72f01411169a938fa5f8baea16e8f ]
Force strict alignment checks for stack pointers because the tracking of
stack spills relies on it; unaligned stack accesses can lead to corruption
of spilled registers, which is exploitable.
Fixes: f1174f77b50c ("bpf/verifier: rework value tracking")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8aa98a0591d6..8c353554628e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1061,6 +1061,11 @@ static int check_ptr_alignment(struct bpf_verifier_env *env, break; case PTR_TO_STACK: pointer_desc = "stack "; + /* The stack spill tracking logic in check_stack_write() + * and check_stack_read() relies on stack accesses being + * aligned. + */ + strict = true; break; default: break; |