* [PATCH bpf v2 0/1] bpf: fix OOB read when printing XDP link fdinfo @ 2021-07-19 8:51 Lorenz Bauer 2021-07-19 8:51 ` [PATCH bpf v2 1/1] " Lorenz Bauer 2021-07-19 22:31 ` [PATCH bpf v2 0/1] " Andrii Nakryiko 0 siblings, 2 replies; 4+ messages in thread From: Lorenz Bauer @ 2021-07-19 8:51 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko Cc: kernel-team, Lorenz Bauer, netdev, bpf See the first patch message for details. Same fix as before, except that the macro invocation is guarded by CONFIG_NET now. Lorenz Bauer (1): bpf: fix OOB read when printing XDP link fdinfo include/linux/bpf_types.h | 1 + 1 file changed, 1 insertion(+) -- 2.30.2 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH bpf v2 1/1] bpf: fix OOB read when printing XDP link fdinfo 2021-07-19 8:51 [PATCH bpf v2 0/1] bpf: fix OOB read when printing XDP link fdinfo Lorenz Bauer @ 2021-07-19 8:51 ` Lorenz Bauer 2021-07-19 23:11 ` John Fastabend 2021-07-19 22:31 ` [PATCH bpf v2 0/1] " Andrii Nakryiko 1 sibling, 1 reply; 4+ messages in thread From: Lorenz Bauer @ 2021-07-19 8:51 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, David S. Miller, Jakub Kicinski, Jesper Dangaard Brouer, John Fastabend Cc: kernel-team, Lorenz Bauer, Andrii Nakryiko, netdev, bpf, linux-kernel We got the following UBSAN report on one of our testing machines: ================================================================================ UBSAN: array-index-out-of-bounds in kernel/bpf/syscall.c:2389:24 index 6 is out of range for type 'char *[6]' CPU: 43 PID: 930921 Comm: systemd-coredum Tainted: G O 5.10.48-cloudflare-kasan-2021.7.0 #1 Hardware name: <snip> Call Trace: dump_stack+0x7d/0xa3 ubsan_epilogue+0x5/0x40 __ubsan_handle_out_of_bounds.cold+0x43/0x48 ? seq_printf+0x17d/0x250 bpf_link_show_fdinfo+0x329/0x380 ? bpf_map_value_size+0xe0/0xe0 ? put_files_struct+0x20/0x2d0 ? __kasan_kmalloc.constprop.0+0xc2/0xd0 seq_show+0x3f7/0x540 seq_read_iter+0x3f8/0x1040 seq_read+0x329/0x500 ? seq_read_iter+0x1040/0x1040 ? __fsnotify_parent+0x80/0x820 ? __fsnotify_update_child_dentry_flags+0x380/0x380 vfs_read+0x123/0x460 ksys_read+0xed/0x1c0 ? __x64_sys_pwrite64+0x1f0/0x1f0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 <snip> ================================================================================ ================================================================================ UBSAN: object-size-mismatch in kernel/bpf/syscall.c:2384:2 From the report, we can infer that some array access in bpf_link_show_fdinfo at index 6 is out of bounds. The obvious candidate is bpf_link_type_strs[BPF_LINK_TYPE_XDP] with BPF_LINK_TYPE_XDP == 6. It turns out that BPF_LINK_TYPE_XDP is missing from bpf_types.h and therefore doesn't have an entry in bpf_link_type_strs: pos: 0 flags: 02000000 mnt_id: 13 link_type: (null) link_id: 4 prog_tag: bcf7977d3b93787c prog_id: 4 ifindex: 1 Fixes: aa8d3a716b59 ("bpf, xdp: Add bpf_link-based XDP attachment API") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> --- include/linux/bpf_types.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index a9db1eae6796..ae3ac3a2018c 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -134,4 +134,5 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup) BPF_LINK_TYPE(BPF_LINK_TYPE_ITER, iter) #ifdef CONFIG_NET BPF_LINK_TYPE(BPF_LINK_TYPE_NETNS, netns) +BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp) #endif -- 2.30.2 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* RE: [PATCH bpf v2 1/1] bpf: fix OOB read when printing XDP link fdinfo 2021-07-19 8:51 ` [PATCH bpf v2 1/1] " Lorenz Bauer @ 2021-07-19 23:11 ` John Fastabend 0 siblings, 0 replies; 4+ messages in thread From: John Fastabend @ 2021-07-19 23:11 UTC (permalink / raw) To: Lorenz Bauer, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, David S. Miller, Jakub Kicinski, Jesper Dangaard Brouer, John Fastabend Cc: kernel-team, Lorenz Bauer, Andrii Nakryiko, netdev, bpf, linux-kernel Lorenz Bauer wrote: > We got the following UBSAN report on one of our testing machines: > > ================================================================================ > UBSAN: array-index-out-of-bounds in kernel/bpf/syscall.c:2389:24 > index 6 is out of range for type 'char *[6]' > CPU: 43 PID: 930921 Comm: systemd-coredum Tainted: G O 5.10.48-cloudflare-kasan-2021.7.0 #1 > Hardware name: <snip> > Call Trace: > dump_stack+0x7d/0xa3 > ubsan_epilogue+0x5/0x40 > __ubsan_handle_out_of_bounds.cold+0x43/0x48 > ? seq_printf+0x17d/0x250 > bpf_link_show_fdinfo+0x329/0x380 > ? bpf_map_value_size+0xe0/0xe0 > ? put_files_struct+0x20/0x2d0 > ? __kasan_kmalloc.constprop.0+0xc2/0xd0 > seq_show+0x3f7/0x540 > seq_read_iter+0x3f8/0x1040 > seq_read+0x329/0x500 > ? seq_read_iter+0x1040/0x1040 > ? __fsnotify_parent+0x80/0x820 > ? __fsnotify_update_child_dentry_flags+0x380/0x380 > vfs_read+0x123/0x460 > ksys_read+0xed/0x1c0 > ? __x64_sys_pwrite64+0x1f0/0x1f0 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > <snip> > ================================================================================ > ================================================================================ > UBSAN: object-size-mismatch in kernel/bpf/syscall.c:2384:2 > > From the report, we can infer that some array access in bpf_link_show_fdinfo at index 6 > is out of bounds. The obvious candidate is bpf_link_type_strs[BPF_LINK_TYPE_XDP] with > BPF_LINK_TYPE_XDP == 6. It turns out that BPF_LINK_TYPE_XDP is missing from bpf_types.h > and therefore doesn't have an entry in bpf_link_type_strs: > > pos: 0 > flags: 02000000 > mnt_id: 13 > link_type: (null) > link_id: 4 > prog_tag: bcf7977d3b93787c > prog_id: 4 > ifindex: 1 > > Fixes: aa8d3a716b59 ("bpf, xdp: Add bpf_link-based XDP attachment API") > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> > --- > include/linux/bpf_types.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h > index a9db1eae6796..ae3ac3a2018c 100644 > --- a/include/linux/bpf_types.h > +++ b/include/linux/bpf_types.h > @@ -134,4 +134,5 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup) > BPF_LINK_TYPE(BPF_LINK_TYPE_ITER, iter) > #ifdef CONFIG_NET > BPF_LINK_TYPE(BPF_LINK_TYPE_NETNS, netns) > +BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp) > #endif > -- > 2.30.2 > Still lgtm. Acked-by; John Fastabend <john.fastabend@gmail.com> ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf v2 0/1] bpf: fix OOB read when printing XDP link fdinfo 2021-07-19 8:51 [PATCH bpf v2 0/1] bpf: fix OOB read when printing XDP link fdinfo Lorenz Bauer 2021-07-19 8:51 ` [PATCH bpf v2 1/1] " Lorenz Bauer @ 2021-07-19 22:31 ` Andrii Nakryiko 1 sibling, 0 replies; 4+ messages in thread From: Andrii Nakryiko @ 2021-07-19 22:31 UTC (permalink / raw) To: Lorenz Bauer Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, kernel-team, Networking, bpf On Mon, Jul 19, 2021 at 1:51 AM Lorenz Bauer <lmb@cloudflare.com> wrote: > > See the first patch message for details. Same fix as before, except that the > macro invocation is guarded by CONFIG_NET now. > > Lorenz Bauer (1): > bpf: fix OOB read when printing XDP link fdinfo > Applied to bpf tree, thanks. There is no need to send a cover letter for a single patch, though, and it didn't contribute much to the description in this case, so I dropped it. > include/linux/bpf_types.h | 1 + > 1 file changed, 1 insertion(+) > > -- > 2.30.2 > ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-07-19 23:51 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-07-19 8:51 [PATCH bpf v2 0/1] bpf: fix OOB read when printing XDP link fdinfo Lorenz Bauer 2021-07-19 8:51 ` [PATCH bpf v2 1/1] " Lorenz Bauer 2021-07-19 23:11 ` John Fastabend 2021-07-19 22:31 ` [PATCH bpf v2 0/1] " Andrii Nakryiko
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