This is a note to let you know that I've just added the patch titled
bpf: Fix propagation of signed bounds from 64-bit min/max into 32-bit.
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-fix-propagation-of-signed-bounds-from-64-bit-min.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fccba2d478a1e5f84407131f5d96114d83de3682
Author: Alexei Starovoitov <ast@xxxxxxxxxx>
Date: Mon Nov 1 15:21:52 2021 -0700
bpf: Fix propagation of signed bounds from 64-bit min/max into 32-bit.
[ Upstream commit 388e2c0b978339dee9b0a81a2e546f8979e021e2 ]
Similar to unsigned bounds propagation fix signed bounds.
The 'Fixes' tag is a hint. There is no security bug here.
The verifier was too conservative.
Fixes: 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
Link: https://lore.kernel.org/bpf/20211101222153.78759-2-alexei.starovoitov@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index b9fb079559a6d..4dd9cedfc453d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1397,7 +1397,7 @@ static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
static bool __reg64_bound_s32(s64 a)
{
- return a > S32_MIN && a < S32_MAX;
+ return a >= S32_MIN && a <= S32_MAX;
}
static bool __reg64_bound_u32(u64 a)
