On Sat, 23 Jun 2018 03:13:41 +0200, air icy wrote:
Hi, This bug was found in Linux Kernel v4.18-rc2 1521 if (id.subdevice < 0) 1522 id.subdevice = 0; 1523 else 1524 id.subdevice++; 1525 } 1526 }
$ cat report5
UBSAN: Undefined behaviour in sound/core/timer.c:1524:19 signed integer overflow: 2147483647 + 1 cannot be represented in type 'int' CPU: 0 PID: 7737 Comm: syz-executor0 Not tainted 4.18.0-rc1 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x122/0x1c8 lib/dump_stack.c:113 ubsan_epilogue+0x12/0x86 lib/ubsan.c:159 handle_overflow+0x1c2/0x21f lib/ubsan.c:190 __ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:198 snd_timer_user_next_device sound/core/timer.c:1524 [inline] __snd_timer_user_ioctl+0x204d/0x2520 sound/core/timer.c:1939 snd_timer_user_ioctl+0x67/0x95 sound/core/timer.c:1994 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1e8/0x1340 fs/ioctl.c:686 ksys_ioctl+0x9c/0xb0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x81/0xd0 fs/ioctl.c:706 do_syscall_64+0xb8/0x3a0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a09 Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f9d190edc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9d190ee6d4 RCX: 0000000000455a09 RDX: 0000000020000200 RSI: 00000000c0145401 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000359 R14: 00000000006fa0f8 R15: 0000000000000000 ================================================================================ SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7 sclass=netlink_route_socket pig=7762 comm=syz-executor0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7 sclass=netlink_route_socket pig=7766 comm=syz-executor0 sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sr 1:0:0:0: [sr0] tag#0 Sense Key : Illegal Request [current] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Invalid command operation code sr 1:0:0:0: [sr0] tag#0 CDB: Write(10) 2a 00 00 00 00 00 00 00 40 00 print_req_error: critical target error, dev sr0, sector 0 ... sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK sr 1:0:0:0: [sr0] tag#0 CDB: Write(16) 8a d0 47 23 7d 8d 1b 64 4d f6 e2 4e sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK sr 1:0:0:0: [sr0] tag#0 CDB: Write(16) 8a d0 47 23 7d 8d 1b 64 4d f6 e2 4e audit: type=1326 audit(1529712149.140:4): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=8226 comm="syz-executor1" exe="/syz-executor1" sig=31 arch=c000003e syscall=202 compat=0 ip=0x455a09 code=0x0
This bug can be repro, if you need it, please tell me.
bugzilla url: https://bugzilla.kernel.org/show_bug.cgi?id=200213
Thanks for the report. It looks like nothing too serious but still better to be addressed, of course. Does the patch below cover it?
Takashi
--- --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -1520,7 +1520,7 @@ static int snd_timer_user_next_device(struct snd_timer_id __user *_tid) } else { if (id.subdevice < 0) id.subdevice = 0; - else + else if (id.subdevice < INT_MAX) id.subdevice++; } }