mirror/libbpf
1
0
Fork 0
mirror of https://github.com/netdata/libbpf.git synced 2026-03-21 16:59:07 +08:00
Code Issues Packages Projects Releases Wiki Activity

libbpf: Fix undefined behavior in {get,put}_unaligned_be32()

Browse Source 
These violate aliasing rules and may be miscompiled unless
-fno-strict-aliasing is used.  Replace them with the standard memcpy()
solution.  Note that compilers know how to optimize this properly.

Fixes: 4a1c9e544b8d ("libbpf: remove linux/unaligned.h dependency for libbpf_sha256()")
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20251006012037.159295-1-ebiggers@kernel.org
This commit is contained in:
Eric Biggers
2025-10-05 18:20:37 -07:00
committed by Andrii Nakryiko
parent 379ac32f2c
commit 2b940bcde1
1 changed files with 13 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
src/libbpf_utils.c
View File

@@ -148,16 +148,20 @@ const char *libbpf_errstr(int err)
}
}
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpacked"
#pragma GCC diagnostic ignored "-Wattributes"
struct __packed_u32 { __u32 __val; } __attribute__((packed));
#pragma GCC diagnostic pop
static inline __u32 get_unaligned_be32(const void *p)
{
__be32 val;
#define get_unaligned_be32(p) be32_to_cpu((((struct __packed_u32 *)(p))->__val))
#define put_unaligned_be32(v, p) do { \
((struct __packed_u32 *)(p))->__val = cpu_to_be32(v); \
} while (0)
memcpy(&val, p, sizeof(val));
return be32_to_cpu(val);
}
static inline void put_unaligned_be32(__u32 val, void *p)
{
__be32 be_val = cpu_to_be32(val);
memcpy(p, &be_val, sizeof(be_val));
}
#define SHA256_BLOCK_LENGTH 64
#define Ch(x, y, z) (((x) & (y)) ^ (~(x) & (z)))