[syzbot] [io-uring] general protection fault in tomoyo_socket_bind_permission

[syzbot] [io-uring] general protection fault in tomoyo_socket_bind_permission

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3fe121b62282 Add linux-next specific files for 20240712
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=149a439e980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=98dd8c4bab5cdce
dashboard link: https://syzkaller.appspot.com/bug?extid=1e811482aa2c70afa9a0
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1746d385980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10c2be31980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c6fbf69718d/disk-3fe121b6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/39fc7e43dfc1/vmlinux-3fe121b6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0a78e70e4b4e/bzImage-3fe121b6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1e811482aa2c70afa9a0@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 UID: 0 PID: 5098 Comm: syz-executor321 Not tainted 6.10.0-rc7-next-20240712-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:tomoyo_socket_bind_permission+0xa5/0x340 security/tomoyo/network.c:727
Code: f3 f3 66 43 c7 44 2e 0e f3 f3 e8 e6 e6 2b fd ba 30 00 00 00 48 89 df 31 f6 e8 e7 6f 93 fd 49 8d 5c 24 18 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 fc 6c 93 fd 48 8b 03 48 89 44 24
RSP: 0018:ffffc9000348f860 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000348f8d0
RBP: ffffc9000348f950 R08: ffffc9000348f8cf R09: 0000000000000000
R10: ffffc9000348f8a0 R11: fffff52000691f1a R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff92000691f10 R15: ffff88801e82bca0
FS:  000055558d6cc480(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 0000000078dee000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 security_socket_bind+0x75/0xb0 security/security.c:4460
 __sys_bind_socket+0x28/0xb0 net/socket.c:1830
 io_bind+0x8f/0x190 io_uring/net.c:1746
 io_issue_sqe+0x3cf/0x1570 io_uring/io_uring.c:1710
 io_queue_sqe io_uring/io_uring.c:1924 [inline]
 io_submit_sqe io_uring/io_uring.c:2180 [inline]
 io_submit_sqes+0xaff/0x1bf0 io_uring/io_uring.c:2295
 __do_sys_io_uring_enter io_uring/io_uring.c:3205 [inline]
 __se_sys_io_uring_enter+0x2d4/0x2670 io_uring/io_uring.c:3142
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f744e4d88f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc942a3638 EFLAGS: 00000216 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f744e4d88f9
RDX: 0000000000000000 RSI: 0000000000002d3e RDI: 0000000000000003
RBP: 00000000000024fa R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 0000000000000001
R13: 431bde82d7b634db R14: 00007ffc942a3690 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:tomoyo_socket_bind_permission+0xa5/0x340 security/tomoyo/network.c:727
Code: f3 f3 66 43 c7 44 2e 0e f3 f3 e8 e6 e6 2b fd ba 30 00 00 00 48 89 df 31 f6 e8 e7 6f 93 fd 49 8d 5c 24 18 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 fc 6c 93 fd 48 8b 03 48 89 44 24
RSP: 0018:ffffc9000348f860 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000348f8d0
RBP: ffffc9000348f950 R08: ffffc9000348f8cf R09: 0000000000000000
R10: ffffc9000348f8a0 R11: fffff52000691f1a R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff92000691f10 R15: ffff88801e82bca0
FS:  000055558d6cc480(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 0000000078dee000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	f3 f3 66 43 c7 44 2e 	repz xrelease movw $0xf3f3,0xe(%r14,%r13,1)
   7:	0e f3 f3
   a:	e8 e6 e6 2b fd       	call   0xfd2be6f5
   f:	ba 30 00 00 00       	mov    $0x30,%edx
  14:	48 89 df             	mov    %rbx,%rdi
  17:	31 f6                	xor    %esi,%esi
  19:	e8 e7 6f 93 fd       	call   0xfd937005
  1e:	49 8d 5c 24 18       	lea    0x18(%r12),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 fc 6c 93 fd       	call   0xfd936d35
  39:	48 8b 03             	mov    (%rbx),%rax
  3c:	48                   	rex.W
  3d:	89                   	.byte 0x89
  3e:	44                   	rex.R
  3f:	24                   	.byte 0x24


---
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[PATCH] io_uring: Check socket is valid in io_bind()/io_listen()

[Tetsuo Handa]

We need to check that sock_from_file(req->file) != NULL.

Reported-by: syzbot <syzbot+1e811482aa2c70afa9a0@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=1e811482aa2c70afa9a0
Fixes: 7481fd93fa0a ("io_uring: Introduce IORING_OP_BIND")
Fixes: ff140cc8628a ("io_uring: Introduce IORING_OP_LISTEN")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 io_uring/net.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/io_uring/net.c b/io_uring/net.c
index 69af3df4dc48c..2cfe8bb6e17f2 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1741,9 +1741,13 @@ int io_bind(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_bind *bind = io_kiocb_to_cmd(req, struct io_bind);
 	struct io_async_msghdr *io = req->async_data;
+	struct socket *sock = sock_from_file(req->file);
 	int ret;
 
-	ret = __sys_bind_socket(sock_from_file(req->file),  &io->addr, bind->addr_len);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	ret = __sys_bind_socket(sock, &io->addr, bind->addr_len);
 	if (ret < 0)
 		req_set_fail(req);
 	io_req_set_res(req, ret, 0);
@@ -1764,9 +1768,13 @@ int io_listen_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 int io_listen(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_listen *listen = io_kiocb_to_cmd(req, struct io_listen);
+	struct socket *sock = sock_from_file(req->file);
 	int ret;
 
-	ret = __sys_listen_socket(sock_from_file(req->file), listen->backlog);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	ret = __sys_listen_socket(sock, listen->backlog);
 	if (ret < 0)
 		req_set_fail(req);
 	io_req_set_res(req, ret, 0);
-- 
2.43.5

Re: [PATCH] io_uring: Check socket is valid in io_bind()/io_listen()

[Jens Axboe]

On 7/13/24 4:05 AM, Tetsuo Handa wrote:
> We need to check that sock_from_file(req->file) != NULL.

Yep indeed, that was missed. Thanks, I'll apply this, just moving
the assignment to where the NULL check is for consistency's sake.

-- 
Jens Axboe

Re: [PATCH] io_uring: Check socket is valid in io_bind()/io_listen()

[Jens Axboe]

On Sat, 13 Jul 2024 19:05:02 +0900, Tetsuo Handa wrote:
> We need to check that sock_from_file(req->file) != NULL.
> 
> 

Applied, thanks!

[1/1] io_uring: Check socket is valid in io_bind()/io_listen()
      commit: ad00e629145b2b9f0d78aa46e204a9df7d628978

Best regards,
-- 
Jens Axboe