BUG: bad usercopy in ld_usb_read

From: syzbot <syzbot+45b2f40f0778cfa7634e@syzkaller.appspotmail.com>
To: akpm@linux-foundation.org, andreyknvl@google.com, cai@lca.pw,
	gregkh@linuxfoundation.org, keescook@chromium.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	tglx@linutronix.de
Subject: BUG: bad usercopy in ld_usb_read
Date: Thu, 08 Aug 2019 05:38:06 -0700	[thread overview]
Message-ID: <0000000000005c056c058f9a5437@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=13aeaece600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
dashboard link: https://syzkaller.appspot.com/bug?extid=45b2f40f0778cfa7634e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+45b2f40f0778cfa7634e@syzkaller.appspotmail.com

ldusb 6-1:0.124: Read buffer overflow, -131383996186150 bytes dropped
usercopy: Kernel memory exposure attempt detected from SLUB  
object 'kmalloc-2k' (offset 8, size 65062)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:98!
invalid opcode: 0000 [#1] SMP KASAN
CPU: 0 PID: 15185 Comm: syz-executor.2 Not tainted 5.3.0-rc2+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:usercopy_abort+0xb9/0xbb mm/usercopy.c:98
Code: e8 c1 f7 d6 ff 49 89 d9 4d 89 e8 4c 89 e1 41 56 48 89 ee 48 c7 c7 e0  
f3 cd 85 ff 74 24 08 41 57 48 8b 54 24 20 e8 15 98 c1 ff <0f> 0b e8 95 f7  
d6 ff e8 80 9f fd ff 8b 54 24 04 49 89 d8 4c 89 e1
RSP: 0018:ffff8881ccb3fc38 EFLAGS: 00010286
RAX: 0000000000000067 RBX: ffffffff86a659d4 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed1039967f79
RBP: ffffffff85cdf2c0 R08: 0000000000000067 R09: fffffbfff11acdaa
R10: fffffbfff11acda9 R11: ffffffff88d66d4f R12: ffffffff86a696e8
R13: ffffffff85cdf180 R14: 000000000000fe26 R15: ffffffff85cdf140
FS:  00007ff6daf91700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1de6600000 CR3: 00000001ca554000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  __check_heap_object+0xdd/0x110 mm/slub.c:3914
  check_heap_object mm/usercopy.c:234 [inline]
  __check_object_size mm/usercopy.c:280 [inline]
  __check_object_size+0x32d/0x39b mm/usercopy.c:250
  check_object_size include/linux/thread_info.h:119 [inline]
  check_copy_size include/linux/thread_info.h:150 [inline]
  copy_to_user include/linux/uaccess.h:151 [inline]
  ld_usb_read+0x304/0x780 drivers/usb/misc/ldusb.c:495
  __vfs_read+0x76/0x100 fs/read_write.c:425
  vfs_read+0x1ea/0x430 fs/read_write.c:461
  ksys_read+0x1e8/0x250 fs/read_write.c:587
  do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff6daf90c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 000000000000fe26 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff6daf916d4
R13: 00000000004c6c73 R14: 00000000004dbee8 R15: 00000000ffffffff
Modules linked in:
---[ end trace 4fe8dba032d24ceb ]---
RIP: 0010:usercopy_abort+0xb9/0xbb mm/usercopy.c:98
Code: e8 c1 f7 d6 ff 49 89 d9 4d 89 e8 4c 89 e1 41 56 48 89 ee 48 c7 c7 e0  
f3 cd 85 ff 74 24 08 41 57 48 8b 54 24 20 e8 15 98 c1 ff <0f> 0b e8 95 f7  
d6 ff e8 80 9f fd ff 8b 54 24 04 49 89 d8 4c 89 e1
RSP: 0018:ffff8881ccb3fc38 EFLAGS: 00010286
RAX: 0000000000000067 RBX: ffffffff86a659d4 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed1039967f79
RBP: ffffffff85cdf2c0 R08: 0000000000000067 R09: fffffbfff11acdaa
R10: fffffbfff11acda9 R11: ffffffff88d66d4f R12: ffffffff86a696e8
R13: ffffffff85cdf180 R14: 000000000000fe26 R15: ffffffff85cdf140
FS:  00007ff6daf91700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1de6600000 CR3: 00000001ca554000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
This bug 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 bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.