From: Dan Carpenter <dan.carpenter@oracle.com>
To: Andrii Nakryiko <andrii@kernel.org>, Yonghong Song <yhs@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] libbpf: fix sign expansion bug in btf_dump_get_enum_value()
Date: Tue, 19 Jul 2022 12:49:34 +0300 [thread overview]
Message-ID: <YtZ+LpgPADm7BeEd@kili> (raw)
The code here is supposed to take a signed int and store it in a
signed long long. Unfortunately, the way that the type promotion works
with this conditional statement is that it takes a signed int, type
promotes it to a __u32, and then stores that as a signed long long.
The result is never negative.
Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
tools/lib/bpf/btf_dump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 400e84fd0578..627edb5bb6de 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -2045,7 +2045,7 @@ static int btf_dump_get_enum_value(struct btf_dump *d,
*value = *(__s64 *)data;
return 0;
case 4:
- *value = is_signed ? *(__s32 *)data : *(__u32 *)data;
+ *value = is_signed ? (__s64)*(__s32 *)data : *(__u32 *)data;
return 0;
case 2:
*value = is_signed ? *(__s16 *)data : *(__u16 *)data;
--
2.35.1
next reply other threads:[~2022-07-19 9:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 9:49 Dan Carpenter [this message]
2022-07-19 17:26 ` [PATCH] libbpf: fix sign expansion bug in btf_dump_get_enum_value() Martin KaFai Lau
2022-07-19 18:34 ` Dan Carpenter
2022-07-19 23:39 ` Martin KaFai Lau
2022-07-21 12:30 ` patchwork-bot+netdevbpf
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