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    Subject[PATCH 5.14 548/849] bpf: Fix propagation of signed bounds from 64-bit min/max into 32-bit.
    Date
    From: Alexei Starovoitov <ast@kernel.org>

    [ 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@kernel.org>
    Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
    Acked-by: Yonghong Song <yhs@fb.com>
    Link: https://lore.kernel.org/bpf/20211101222153.78759-2-alexei.starovoitov@gmail.com
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    kernel/bpf/verifier.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    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)
    --
    2.33.0


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