| Message ID | 20180602032159.21199-1-daniel@iogearbox.net |
|---|---|
| State | Accepted, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf] bpf: fix uapi hole for 32 bit compat applications | expand |
On Sat, Jun 02, 2018 at 05:21:59AM +0200, Daniel Borkmann wrote: > 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. > > > 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> Applied, Thanks.
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c5ec897..8c31773 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))); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index c5ec897..8c31773 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/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)));
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> --- include/uapi/linux/bpf.h | 2 ++ tools/include/uapi/linux/bpf.h | 2 ++ 2 files changed, 4 insertions(+)