From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: davem@davemloft.net
Cc: daniel@iogearbox.net, andrii@kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH v2 bpf-next 2/3] bpf: Fix propagation of signed bounds from 64-bit min/max into 32-bit.
Date: Mon, 1 Nov 2021 15:21:52 -0700 [thread overview]
Message-ID: <20211101222153.78759-2-alexei.starovoitov@gmail.com> (raw)
In-Reply-To: <20211101222153.78759-1-alexei.starovoitov@gmail.com>
From: Alexei Starovoitov <ast@kernel.org>
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>
---
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 29671ed49ee8..a4b48bd4e3ca 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1420,7 +1420,7 @@ 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)
--
2.30.2
next prev parent reply other threads:[~2021-11-01 22:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 22:21 [PATCH v2 bpf-next 1/3] bpf: Fix propagation of bounds from 64-bit min/max into 32-bit and var_off Alexei Starovoitov
2021-11-01 22:21 ` Alexei Starovoitov [this message]
2021-11-01 23:03 ` [PATCH v2 bpf-next 2/3] bpf: Fix propagation of signed bounds from 64-bit min/max into 32-bit Yonghong Song
2021-11-01 23:06 ` Alexei Starovoitov
2021-11-01 23:11 ` Yonghong Song
2021-11-01 22:21 ` [PATCH v2 bpf-next 3/3] selftests/bpf: Add a testcase for 64-bit bounds propagation issue Alexei Starovoitov
2021-11-02 1:10 ` [PATCH v2 bpf-next 1/3] bpf: Fix propagation of bounds from 64-bit min/max into 32-bit and var_off patchwork-bot+netdevbpf
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