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* Re: KMSAN: kernel-infoleak in scsi_cmd_ioctl
@ 2020-09-30 15:53 Anant Thazhemadam
  0 siblings, 0 replies; 4+ messages in thread
From: Anant Thazhemadam @ 2020-09-30 15:53 UTC (permalink / raw)
  To: syzbot+85433a479a646a064ab3
  Cc: axboe, glider, linux-block, linux-kernel, syzkaller-bugs

#syz fix: ptrace: Prevent kernel-infoleak in ptrace_get_syscall_info()

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KMSAN: kernel-infoleak in scsi_cmd_ioctl
  2020-10-02 13:49 ` Peilin Ye
@ 2020-10-02 14:00   ` Greg Kroah-Hartman
  0 siblings, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2020-10-02 14:00 UTC (permalink / raw)
  To: Peilin Ye
  Cc: syzbot, axboe, glider, linux-block, linux-kernel, syzkaller-bugs,
	Anant Thazhemadam

On Fri, Oct 02, 2020 at 09:49:44AM -0400, Peilin Ye wrote:
> On Mon, Aug 31, 2020 at 03:28:22AM -0700, syzbot wrote:
> > BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
> > CPU: 1 PID: 12272 Comm: syz-executor.3 Not tainted 5.8.0-rc5-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> >  __dump_stack lib/dump_stack.c:77 [inline]
> >  dump_stack+0x21c/0x280 lib/dump_stack.c:118
> >  kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
> >  kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
> >  kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
> >  instrument_copy_to_user include/linux/instrumented.h:91 [inline]
> >  _copy_to_user+0x18e/0x260 lib/usercopy.c:33
> >  scsi_put_cdrom_generic_arg include/linux/uaccess.h:170 [inline]
> 
> + Cc: Greg Kroah-Hartman
> + Cc: Anant Thazhemadam
> 
> Hi all,
> 
> In looking at the report, I guess this patch should fix the issue, there's
> a 3-byte hole in `struct compat_cdrom_generic_command`:
> 
> [PATCH v3] block/scsi-ioctl: Prevent kernel-infoleak in scsi_put_cdrom_generic_arg()
> https://lore.kernel.org/lkml/20200909095057.1214104-1-yepeilin.cs@gmail.com/
> 
> But I cannot verify it, since syzbot doesn't have a reproducer for it.
> The patch adds a 3-byte padding field to `struct
> compat_cdrom_generic_command`. It hasn't been accepted yet.

Please resend it, it looks like it hasn't been taken yet :(

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KMSAN: kernel-infoleak in scsi_cmd_ioctl
  2020-08-31 10:28 syzbot
@ 2020-10-02 13:49 ` Peilin Ye
  2020-10-02 14:00   ` Greg Kroah-Hartman
  0 siblings, 1 reply; 4+ messages in thread
From: Peilin Ye @ 2020-10-02 13:49 UTC (permalink / raw)
  To: syzbot
  Cc: axboe, glider, linux-block, linux-kernel, syzkaller-bugs,
	Anant Thazhemadam, Greg Kroah-Hartman

On Mon, Aug 31, 2020 at 03:28:22AM -0700, syzbot wrote:
> BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
> CPU: 1 PID: 12272 Comm: syz-executor.3 Not tainted 5.8.0-rc5-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x21c/0x280 lib/dump_stack.c:118
>  kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
>  kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
>  kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
>  instrument_copy_to_user include/linux/instrumented.h:91 [inline]
>  _copy_to_user+0x18e/0x260 lib/usercopy.c:33
>  scsi_put_cdrom_generic_arg include/linux/uaccess.h:170 [inline]

+ Cc: Greg Kroah-Hartman
+ Cc: Anant Thazhemadam

Hi all,

In looking at the report, I guess this patch should fix the issue, there's
a 3-byte hole in `struct compat_cdrom_generic_command`:

[PATCH v3] block/scsi-ioctl: Prevent kernel-infoleak in scsi_put_cdrom_generic_arg()
https://lore.kernel.org/lkml/20200909095057.1214104-1-yepeilin.cs@gmail.com/

But I cannot verify it, since syzbot doesn't have a reproducer for it.
The patch adds a 3-byte padding field to `struct
compat_cdrom_generic_command`. It hasn't been accepted yet.

> Local variable ----cgc32.i42.i@scsi_cmd_ioctl created at:
>  scsi_put_cdrom_generic_arg block/scsi_ioctl.c:695 [inline]

#ifdef CONFIG_COMPAT
	if (in_compat_syscall()) {
		struct compat_cdrom_generic_command
		[...]

$ # before
$ pahole -C "compat_cdrom_generic_command" !$
pahole -C "compat_cdrom_generic_command" block/scsi_ioctl.o
struct compat_cdrom_generic_command {
	unsigned char              cmd[12];              /*     0    12 */
	compat_caddr_t             buffer;               /*    12     4 */
	compat_uint_t              buflen;               /*    16     4 */
	compat_int_t               stat;                 /*    20     4 */
	compat_caddr_t             sense;                /*    24     4 */
	unsigned char              data_direction;       /*    28     1 */

	/* XXX 3 bytes hole, try to pack */

	compat_int_t               quiet;                /*    32     4 */
	compat_int_t               timeout;              /*    36     4 */
	compat_caddr_t             reserved[1];          /*    40     4 */

	/* size: 44, cachelines: 1, members: 9 */
	/* sum members: 41, holes: 1, sum holes: 3 */
	/* last cacheline: 44 bytes */
};
$ # after
$ pahole -C "compat_cdrom_generic_command" block/scsi_ioctl.o
struct compat_cdrom_generic_command {
	unsigned char              cmd[12];              /*     0    12 */
	compat_caddr_t             buffer;               /*    12     4 */
	compat_uint_t              buflen;               /*    16     4 */
	compat_int_t               stat;                 /*    20     4 */
	compat_caddr_t             sense;                /*    24     4 */
	unsigned char              data_direction;       /*    28     1 */
	unsigned char              pad[3];               /*    29     3 */
	compat_int_t               quiet;                /*    32     4 */
	compat_int_t               timeout;              /*    36     4 */
	compat_caddr_t             reserved[1];          /*    40     4 */

	/* size: 44, cachelines: 1, members: 10 */
	/* last cacheline: 44 bytes */
};
$ _

Thank you,
Peilin Ye


^ permalink raw reply	[flat|nested] 4+ messages in thread

* KMSAN: kernel-infoleak in scsi_cmd_ioctl
@ 2020-08-31 10:28 syzbot
  2020-10-02 13:49 ` Peilin Ye
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2020-08-31 10:28 UTC (permalink / raw)
  To: axboe, glider, linux-block, linux-kernel, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    3b3ea602 x86: add failure injection to get/put/clear_user
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14d89966900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3afe005fb99591f
dashboard link: https://syzkaller.appspot.com/bug?extid=85433a479a646a064ab3
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+85433a479a646a064ab3@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
CPU: 1 PID: 12272 Comm: syz-executor.3 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
 instrument_copy_to_user include/linux/instrumented.h:91 [inline]
 _copy_to_user+0x18e/0x260 lib/usercopy.c:33
 scsi_put_cdrom_generic_arg include/linux/uaccess.h:170 [inline]
 scsi_cdrom_send_packet block/scsi_ioctl.c:770 [inline]
 scsi_cmd_ioctl+0x2422/0x25a0 block/scsi_ioctl.c:827
 scsi_cmd_blk_ioctl+0x1f6/0x240 block/scsi_ioctl.c:876
 sd_ioctl_common+0x50a/0x5c0 drivers/scsi/sd.c:1531
 sd_compat_ioctl+0xc5/0x220 drivers/scsi/sd.c:1733
 compat_blkdev_ioctl+0x74b/0x1200 block/ioctl.c:691
 __do_compat_sys_ioctl fs/ioctl.c:847 [inline]
 __se_compat_sys_ioctl+0x55f/0x1100 fs/ioctl.c:798
 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:798
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2af/0x480 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fae549
Code: Bad RIP value.
RSP: 002b:00000000f55a80cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000005393
RDX: 0000000020002000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Local variable ----cgc32.i42.i@scsi_cmd_ioctl created at:
 scsi_put_cdrom_generic_arg block/scsi_ioctl.c:695 [inline]
 scsi_cdrom_send_packet block/scsi_ioctl.c:770 [inline]
 scsi_cmd_ioctl+0x2257/0x25a0 block/scsi_ioctl.c:827
 scsi_put_cdrom_generic_arg block/scsi_ioctl.c:695 [inline]
 scsi_cdrom_send_packet block/scsi_ioctl.c:770 [inline]
 scsi_cmd_ioctl+0x2257/0x25a0 block/scsi_ioctl.c:827

Bytes 29-31 of 44 are uninitialized
Memory access of size 44 starts at ffff8881c5bfbaa0
Data copied to user address 0000000020002000
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-10-02 14:01 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-09-30 15:53 KMSAN: kernel-infoleak in scsi_cmd_ioctl Anant Thazhemadam
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2020-08-31 10:28 syzbot
2020-10-02 13:49 ` Peilin Ye
2020-10-02 14:00   ` Greg Kroah-Hartman

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