syzbot


KASAN: slab-out-of-bounds Read in qrtr_endpoint_post

Status: fixed on 2020/07/20 08:03
Subsystems: arm-msm net
[Documentation on labels]
Reported-by: syzbot+b8fe393f999a291a9ea6@syzkaller.appspotmail.com
Fix commit: 8ff41cc21714 net: qrtr: Fix an out of bounds read qrtr_endpoint_post()
First crash: 1431d, last: 1430d
Discussions (5)
Title Replies (including bot) Last reply
[PATCH 5.7 000/166] 5.7.9-rc1 review 175 (175) 2020/07/16 07:46
[PATCH 4.19 00/58] 4.19.133-rc1 review 66 (66) 2020/07/16 07:45
[PATCH 5.4 000/109] 5.4.52-rc1 review 116 (116) 2020/07/15 16:43
[PATCH net] net: qrtr: Fix an out of bounds read qrtr_endpoint_post() 2 (2) 2020/07/01 01:36
KASAN: slab-out-of-bounds Read in qrtr_endpoint_post 1 (3) 2020/06/28 10:46
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in qrtr_endpoint_post (2) C done 41 1032d 1396d 20/26 fixed on 2021/11/10 00:50

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in qrtr_endpoint_post+0xeeb/0x1010 net/qrtr/qrtr.c:462
Read of size 2 at addr ffff88809e5d4a48 by task syz-executor050/6970

CPU: 0 PID: 6970 Comm: syz-executor050 Not tainted 5.8.0-rc2-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 qrtr_endpoint_post+0xeeb/0x1010 net/qrtr/qrtr.c:462
 qrtr_tun_write_iter+0xf5/0x180 net/qrtr/tun.c:92
 call_write_iter include/linux/fs.h:1907 [inline]
 do_iter_readv_writev+0x567/0x780 fs/read_write.c:694
 do_iter_write+0x188/0x5f0 fs/read_write.c:999
 vfs_writev+0x1aa/0x2e0 fs/read_write.c:1072
 do_pwritev fs/read_write.c:1169 [inline]
 __do_sys_pwritev fs/read_write.c:1216 [inline]
 __se_sys_pwritev fs/read_write.c:1211 [inline]
 __x64_sys_pwritev+0x231/0x310 fs/read_write.c:1211
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4401d9
Code: Bad RIP value.
RSP: 002b:00007fffc542c7a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401d9
RDX: 0000000000000001 RSI: 0000000020000440 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a60
R13: 0000000000401af0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6970:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x17a/0x340 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 qrtr_tun_write_iter+0x8a/0x180 net/qrtr/tun.c:83
 call_write_iter include/linux/fs.h:1907 [inline]
 do_iter_readv_writev+0x567/0x780 fs/read_write.c:694
 do_iter_write+0x188/0x5f0 fs/read_write.c:999
 vfs_writev+0x1aa/0x2e0 fs/read_write.c:1072
 do_pwritev fs/read_write.c:1169 [inline]
 __do_sys_pwritev fs/read_write.c:1216 [inline]
 __se_sys_pwritev fs/read_write.c:1211 [inline]
 __x64_sys_pwritev+0x231/0x310 fs/read_write.c:1211
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 4969:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 tomoyo_path_perm+0x234/0x3f0 security/tomoyo/file.c:842
 security_inode_getattr+0xcf/0x140 security/security.c:1278
 vfs_getattr fs/stat.c:121 [inline]
 vfs_statx+0x170/0x390 fs/stat.c:206
 vfs_lstat include/linux/fs.h:3301 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:374
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809e5d4a40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff88809e5d4a40, ffff88809e5d4a60)
The buggy address belongs to the page:
page:ffffea0002797500 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809e5d4fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000278cfc8 ffffea0002793548 ffff8880aa0001c0
raw: ffff88809e5d4fc1 ffff88809e5d4000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e5d4900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809e5d4980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88809e5d4a00: fb fb fb fb fc fc fc fc 04 fc fc fc fc fc fc fc
                                              ^
 ffff88809e5d4a80: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
 ffff88809e5d4b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/27 21:25 upstream 1590a2e1c681 ffec44b5 .config console log report syz C ci-upstream-kasan-gce
2020/06/27 21:19 upstream 1590a2e1c681 ffec44b5 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/06/27 21:14 upstream 1590a2e1c681 ffec44b5 .config console log report syz C ci-upstream-kasan-gce-root
2020/06/27 21:13 upstream 1590a2e1c681 ffec44b5 .config console log report syz C ci-upstream-kasan-gce-smack-root
2020/06/27 20:57 upstream 1590a2e1c681 ffec44b5 .config console log report syz C ci-upstream-kasan-gce-386
2020/06/28 01:20 linux-next 36e3135df4d4 ffec44b5 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/06/27 08:23 upstream 1590a2e1c681 ffec44b5 .config console log report ci-upstream-kasan-gce-root
2020/06/27 20:41 upstream 1590a2e1c681 ffec44b5 .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.