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| author | Daniel Borkmann <daniel@iogearbox.net> | 2018-06-02 05:21:59 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-06-01 20:41:35 -0700 |
| commit | 36f9814a494a874d5a0f44843544b4b2539022db (patch) | |
| tree | f70e8f924bf1ff9de0ac3892f5b0044f30495624 /include | |
| parent | 8005b09d99fac78e6f5fb9da30b5ae94840af03b (diff) | |
| download | linux-36f9814a494a874d5a0f44843544b4b2539022db.tar.bz2 | |
bpf: fix uapi hole for 32 bit compat applications
In 64 bit, we have a 4 byte hole between ifindex and netns_dev in the
case of struct bpf_map_info but also struct bpf_prog_info. In net-next
commit b85fab0e67b ("bpf: Add gpl_compatible flag to struct bpf_prog_info")
added a bitfield into it to expose some flags related to programs. Thus,
add an unnamed __u32 bitfield for both so that alignment keeps the same
in both 32 and 64 bit cases, and can be naturally extended from there
as in b85fab0e67b.
Before:
# file test.o
test.o: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not stripped
# pahole test.o
struct bpf_map_info {
__u32 type; /* 0 4 */
__u32 id; /* 4 4 */
__u32 key_size; /* 8 4 */
__u32 value_size; /* 12 4 */
__u32 max_entries; /* 16 4 */
__u32 map_flags; /* 20 4 */
char name[16]; /* 24 16 */
__u32 ifindex; /* 40 4 */
__u64 netns_dev; /* 44 8 */
__u64 netns_ino; /* 52 8 */
/* size: 64, cachelines: 1, members: 10 */
/* padding: 4 */
};
After (same as on 64 bit):
# file test.o
test.o: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not stripped
# pahole test.o
struct bpf_map_info {
__u32 type; /* 0 4 */
__u32 id; /* 4 4 */
__u32 key_size; /* 8 4 */
__u32 value_size; /* 12 4 */
__u32 max_entries; /* 16 4 */
__u32 map_flags; /* 20 4 */
char name[16]; /* 24 16 */
__u32 ifindex; /* 40 4 */
/* XXX 4 bytes hole, try to pack */
__u64 netns_dev; /* 48 8 */
__u64 netns_ino; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
/* size: 64, cachelines: 1, members: 10 */
/* sum members: 60, holes: 1, sum holes: 4 */
};
Reported-by: Dmitry V. Levin <ldv@altlinux.org>
Reported-by: Eugene Syromiatnikov <esyr@redhat.com>
Fixes: 52775b33bb507 ("bpf: offload: report device information about offloaded maps")
Fixes: 675fc275a3a2d ("bpf: offload: report device information for offloaded programs")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/uapi/linux/bpf.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c5ec89732a8d..8c317737ba3f 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1017,6 +1017,7 @@ struct bpf_prog_info { __aligned_u64 map_ids; char name[BPF_OBJ_NAME_LEN]; __u32 ifindex; + __u32 :32; __u64 netns_dev; __u64 netns_ino; } __attribute__((aligned(8))); @@ -1030,6 +1031,7 @@ struct bpf_map_info { __u32 map_flags; char name[BPF_OBJ_NAME_LEN]; __u32 ifindex; + __u32 :32; __u64 netns_dev; __u64 netns_ino; } __attribute__((aligned(8))); |