| Message ID | 20210821035045.373991-1-jiang.wang@bytedance.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] af_unix: fix NULL pointer bug in unix_shutdown | expand |
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 443c49081636..6965bc578a80 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2847,7 +2847,8 @@ static int unix_shutdown(struct socket *sock, int mode) int peer_mode = 0; const struct proto *prot = READ_ONCE(other->sk_prot); - prot->unhash(other); + if (sk->sk_type == SOCK_STREAM) + prot->unhash(other); if (mode&RCV_SHUTDOWN) peer_mode |= SEND_SHUTDOWN; if (mode&SEND_SHUTDOWN)
Commit 94531cfcbe79 ("af_unix: Add unix_stream_proto for sockmap") introduced a bug for af_unix SEQPACKET type. In unix_shutdown, the unhash function will call prot->unhash(), which is NULL for SEQPACKET. And kernel will panic. On ARM32, it will show following messages: (it likely affects x86 too). Fix the bug by checking the sk->type first. Kernel log: <--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = 2fba1ffb *pgd=00000000 Internal error: Oops: 80000005 [#1] PREEMPT SMP THUMB2 Modules linked in: CPU: 1 PID: 1999 Comm: falkon Tainted: G W 5.14.0-rc5-01175-g94531cfcbe79-dirty #9240 Hardware name: NVIDIA Tegra SoC (Flattened Device Tree) PC is at 0x0 LR is at unix_shutdown+0x81/0x1a8 pc : [<00000000>] lr : [<c08f3311>] psr: 600f0013 sp : e45aff70 ip : e463a3c0 fp : beb54f04 r10: 00000125 r9 : e45ae000 r8 : c4a56664 r7 : 00000001 r6 : c4a56464 r5 : 00000001 r4 : c4a56400 r3 : 00000000 r2 : c5a6b180 r1 : 00000000 r0 : c4a56400 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 50c5387d Table: 05aa804a DAC: 00000051 Register r0 information: slab PING start c4a56400 pointer offset 0 Register r1 information: NULL pointer Register r2 information: slab task_struct start c5a6b180 pointer offset 0 Register r3 information: NULL pointer Register r4 information: slab PING start c4a56400 pointer offset 0 Register r5 information: non-paged memory Register r6 information: slab PING start c4a56400 pointer offset 100 Register r7 information: non-paged memory Register r8 information: slab PING start c4a56400 pointer offset 612 Register r9 information: non-slab/vmalloc memory Register r10 information: non-paged memory Register r11 information: non-paged memory Register r12 information: slab filp start e463a3c0 pointer offset 0 Process falkon (pid: 1999, stack limit = 0x9ec48895) Stack: (0xe45aff70 to 0xe45b0000) ff60: e45ae000 c5f26a00 00000000 00000125 ff80: c0100264 c07f7fa3 beb54f04 fffffff7 00000001 e6f3fc0e b5e5e9ec beb54ec4 ffa0: b5da0ccc c010024b b5e5e9ec beb54ec4 0000000f 00000000 00000000 beb54ebc ffc0: b5e5e9ec beb54ec4 b5da0ccc 00000125 beb54f58 00785238 beb5529c beb54f04 ffe0: b5da1e24 beb54eac b301385c b62b6ee8 600f0030 0000000f 00000000 00000000 [<c08f3311>] (unix_shutdown) from [<c07f7fa3>] (__sys_shutdown+0x2f/0x50) [<c07f7fa3>] (__sys_shutdown) from [<c010024b>] (__sys_trace_return+0x1/0x16) Exception stack(0xe45affa8 to 0xe45afff0) Signed-off-by: Jiang Wang <jiang.wang@bytedance.com> Reported-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> --- net/unix/af_unix.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)