syzbot


KASAN: out-of-bounds Read in bpf_test_finish

Status: fixed on 2018/08/07 13:43
Subsystems: bpf net
[Documentation on labels]
Reported-by: syzbot+54f39d6ab58f39720a55@syzkaller.appspotmail.com
Fix commit: 6e6fddc78323 bpf: fix panic due to oob in bpf_prog_test_run_skb
First crash: 2147d, last: 2141d
Discussions (3)
Title Replies (including bot) Last reply
[PATCH 4.14 00/45] 4.14.259-rc1 review 48 (48) 2021/12/21 23:12
[PATCH bpf] bpf: fix panic due to oob in bpf_prog_test_run_skb 2 (2) 2018/07/11 23:16
KASAN: out-of-bounds Read in bpf_test_finish 0 (1) 2018/07/09 12:44
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 KASAN: out-of-bounds Read in bpf_test_finish 2 2013d 1869d 0/1 auto-closed as invalid on 2019/05/19 12:33

Sample crash report:
EXT4-fs warning (device sda1): ext4_group_add:1636: No reserved GDT blocks, can't resize
EXT4-fs (sda1): re-mounted. Opts: 
==================================================================
BUG: KASAN: out-of-bounds in _copy_to_user+0xe9/0x110 lib/usercopy.c:27
Read of size 1012 at addr ffff880191bffff2 by task syz-executor3/11504

CPU: 1 PID: 11504 Comm: syz-executor3 Not tainted 4.18.0-rc3+ #4
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 _copy_to_user+0xe9/0x110 lib/usercopy.c:27
 copy_to_user include/linux/uaccess.h:155 [inline]
 bpf_test_finish.isra.7+0xee/0x1f0 net/bpf/test_run.c:59
 bpf_prog_test_run_skb+0x7d7/0xa30 net/bpf/test_run.c:144
 bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1688
 __do_sys_bpf kernel/bpf/syscall.c:2325 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:2269 [inline]
 __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2269
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455e29
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:00007fa8e9757c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fa8e97586d4 RCX: 0000000000455e29
RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004bbaee R14: 00000000004c8d20 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006468000 count:1 mapcount:1 mapping:ffff8801cfd7a4c9 index:0x20000 compound_mapcount: 1
flags: 0x2fffc0000048068(uptodate|lru|active|head|swapbacked)
raw: 02fffc0000048068 ffffea0007160ec8 ffffea000719af08 ffff8801cfd7a4c9
raw: 0000000000020000 0000000000000000 00000001ffffffff ffff8801cf6fccc0
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8801cf6fccc0

Memory state around the buggy address:
 ffff880191c00280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff880191c00300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff880191c00380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                          ^
 ffff880191c00400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff880191c00480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/07/09 21:04 bpf f292b87d3ac0 f25e5770 .config console log report ci-upstream-bpf-kasan-gce
2018/07/15 17:33 bpf-next 13f7432bdd8e 92a49505 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/11 12:10 bpf-next d90c936fb318 2e0e3130 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/11 11:02 bpf-next d90c936fb318 2e0e3130 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/11 02:39 bpf-next d90c936fb318 2e0e3130 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/10 07:57 bpf-next d90c936fb318 f25e5770 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/09 13:19 bpf-next d90c936fb318 f25e5770 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/09 11:23 bpf-next d90c936fb318 f25e5770 .config console log report ci-upstream-bpf-next-kasan-gce
2018/07/12 12:57 linux-next 3ee15ba60e6b 06c33b3a .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.