* [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 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
* 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
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2021-07-19 8:51 [PATCH bpf v2 0/1] bpf: fix OOB read when printing XDP link fdinfo Lorenz Bauer
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