* [syzbot] KASAN: use-after-free Write in null_skcipher_crypt
@ 2021-08-17 17:24 syzbot
2021-08-17 19:04 ` Pavel Skripkin
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2021-08-17 17:24 UTC (permalink / raw)
To: calvin.johnson, davem, grant.likely, herbert, ioana.ciornei,
johan.hedberg, kuba, linux-bluetooth, linux-crypto, linux-kernel,
luiz.dentz, marcel, netdev, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: a9a507013a6f Merge tag 'ieee802154-for-davem-2021-08-12' o..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=16647ca1300000
kernel config: https://syzkaller.appspot.com/x/.config?x=343fd21f6f4da2d6
dashboard link: https://syzkaller.appspot.com/bug?extid=d2c5e6980bfc84513464
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14989fe9300000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b1a779300000
The issue was bisected to:
commit 8d2cb3ad31181f050af4d46d6854cf332d1207a9
Author: Calvin Johnson <calvin.johnson@oss.nxp.com>
Date: Fri Jun 11 10:53:55 2021 +0000
of: mdio: Refactor of_mdiobus_register_phy()
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106b97d6300000
final oops: https://syzkaller.appspot.com/x/report.txt?x=126b97d6300000
console output: https://syzkaller.appspot.com/x/log.txt?x=146b97d6300000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d2c5e6980bfc84513464@syzkaller.appspotmail.com
Fixes: 8d2cb3ad3118 ("of: mdio: Refactor of_mdiobus_register_phy()")
==================================================================
BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline]
BUG: KASAN: use-after-free in null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
Write of size 4096 at addr ffff88801c040000 by task syz-executor554/8455
CPU: 0 PID: 8455 Comm: syz-executor554 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
__kasan_report mm/kasan/report.c:419 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
memcpy+0x39/0x60 mm/kasan/shadow.c:66
memcpy include/linux/fortify-string.h:191 [inline]
null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
crypto_skcipher_encrypt+0xaa/0xf0 crypto/skcipher.c:630
crypto_authenc_encrypt+0x3b4/0x510 crypto/authenc.c:222
crypto_aead_encrypt+0xaa/0xf0 crypto/aead.c:94
esp6_output_tail+0x777/0x1a90 net/ipv6/esp6.c:659
esp6_output+0x4af/0x8a0 net/ipv6/esp6.c:735
xfrm_output_one net/xfrm/xfrm_output.c:552 [inline]
xfrm_output_resume+0x2997/0x5ae0 net/xfrm/xfrm_output.c:587
xfrm_output2 net/xfrm/xfrm_output.c:614 [inline]
xfrm_output+0x2e7/0xff0 net/xfrm/xfrm_output.c:744
__xfrm6_output+0x4c3/0x1260 net/ipv6/xfrm6_output.c:87
NF_HOOK_COND include/linux/netfilter.h:296 [inline]
xfrm6_output+0x117/0x550 net/ipv6/xfrm6_output.c:92
dst_output include/net/dst.h:448 [inline]
ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:161
ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1935
ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1955
rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
rawv6_sendmsg+0x2a87/0x3990 net/ipv6/raw.c:956
inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821
sock_sendmsg_nosec net/socket.c:703 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:723
____sys_sendmsg+0x6e8/0x810 net/socket.c:2392
___sys_sendmsg+0xf3/0x170 net/socket.c:2446
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2475
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43f4b9
Code: 1d 01 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc1e9cfff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f4b9
RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000004
RBP: 0000000000000005 R08: 6c616b7a79732f2e R09: 6c616b7a79732f2e
R10: 00000000000000e8 R11: 0000000000000246 R12: 00000000004034b0
R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488
Allocated by task 1:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slub.c:2956 [inline]
slab_alloc mm/slub.c:2964 [inline]
kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2969
getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
getname_flags fs/namei.c:2747 [inline]
user_path_at_empty+0xa1/0x100 fs/namei.c:2747
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x142/0x390 fs/stat.c:203
vfs_fstatat fs/stat.c:225 [inline]
vfs_lstat include/linux/fs.h:3386 [inline]
__do_sys_newlstat+0x91/0x110 fs/stat.c:380
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 1:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1625 [inline]
slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1650
slab_free mm/slub.c:3210 [inline]
kmem_cache_free+0x8a/0x5b0 mm/slub.c:3226
putname+0xe1/0x120 fs/namei.c:259
filename_lookup+0x3df/0x5b0 fs/namei.c:2477
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x142/0x390 fs/stat.c:203
vfs_fstatat fs/stat.c:225 [inline]
vfs_lstat include/linux/fs.h:3386 [inline]
__do_sys_newlstat+0x91/0x110 fs/stat.c:380
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88801c040000
which belongs to the cache names_cache of size 4096
The buggy address is located 0 bytes inside of
4096-byte region [ffff88801c040000, ffff88801c041000)
The buggy address belongs to the page:
page:ffffea0000701000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c040
head:ffffea0000701000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff8880109c43c0
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4994, ts 28153491853, free_ts 28141276199
prep_new_page mm/page_alloc.c:2436 [inline]
get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244
alloc_slab_page mm/slub.c:1688 [inline]
allocate_slab+0x32e/0x4b0 mm/slub.c:1828
new_slab mm/slub.c:1891 [inline]
new_slab_objects mm/slub.c:2637 [inline]
___slab_alloc+0x4ba/0x820 mm/slub.c:2800
__slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2840
slab_alloc_node mm/slub.c:2922 [inline]
slab_alloc mm/slub.c:2964 [inline]
kmem_cache_alloc+0x3e1/0x4a0 mm/slub.c:2969
getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
getname_flags fs/namei.c:2747 [inline]
user_path_at_empty+0xa1/0x100 fs/namei.c:2747
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x142/0x390 fs/stat.c:203
vfs_fstatat fs/stat.c:225 [inline]
vfs_stat include/linux/fs.h:3382 [inline]
__do_sys_newstat+0x91/0x110 fs/stat.c:367
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1346 [inline]
free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
free_unref_page_prepare mm/page_alloc.c:3332 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3411
unfreeze_partials+0x17c/0x1d0 mm/slub.c:2418
put_cpu_partial+0x13d/0x230 mm/slub.c:2454
qlink_free mm/kasan/quarantine.c:146 [inline]
qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
__kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slub.c:2956 [inline]
slab_alloc mm/slub.c:2964 [inline]
kmem_cache_alloc_trace+0x26d/0x3c0 mm/slub.c:2981
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
call_usermodehelper_setup+0x97/0x340 kernel/umh.c:365
kobject_uevent_env+0xf73/0x1650 lib/kobject_uevent.c:614
kobject_synth_uevent+0x701/0x850 lib/kobject_uevent.c:208
uevent_store+0x42/0x90 drivers/base/bus.c:581
drv_attr_store+0x6d/0xa0 drivers/base/bus.c:77
sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:139
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2114 [inline]
new_sync_write+0x426/0x650 fs/read_write.c:518
Memory state around the buggy address:
ffff88801c03ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801c03ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88801c040000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801c040080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88801c040100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 1d 01 00 85 c0 sbb $0xc0850001,%eax
5: b8 00 00 00 00 mov $0x0,%eax
a: 48 0f 44 c3 cmove %rbx,%rax
e: 5b pop %rbx
f: c3 retq
10: 90 nop
11: 48 89 f8 mov %rdi,%rax
14: 48 89 f7 mov %rsi,%rdi
17: 48 89 d6 mov %rdx,%rsi
1a: 48 89 ca mov %rcx,%rdx
1d: 4d 89 c2 mov %r8,%r10
20: 4d 89 c8 mov %r9,%r8
23: 4c 8b 4c 24 08 mov 0x8(%rsp),%r9
28: 0f 05 syscall
2a: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction
30: 73 01 jae 0x33
32: c3 retq
33: 48 c7 c1 c0 ff ff ff mov $0xffffffffffffffc0,%rcx
3a: f7 d8 neg %eax
3c: 64 89 01 mov %eax,%fs:(%rcx)
3f: 48 rex.W
---
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.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] KASAN: use-after-free Write in null_skcipher_crypt
2021-08-17 17:24 [syzbot] KASAN: use-after-free Write in null_skcipher_crypt syzbot
@ 2021-08-17 19:04 ` Pavel Skripkin
2021-08-17 19:08 ` Grant Likely
2021-08-24 10:48 ` Pavel Skripkin
0 siblings, 2 replies; 4+ messages in thread
From: Pavel Skripkin @ 2021-08-17 19:04 UTC (permalink / raw)
To: syzbot, calvin.johnson, davem, grant.likely, herbert,
ioana.ciornei, johan.hedberg, kuba, linux-bluetooth,
linux-crypto, linux-kernel, luiz.dentz, marcel, netdev,
syzkaller-bugs, dkadashev
On 8/17/21 8:24 PM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: a9a507013a6f Merge tag 'ieee802154-for-davem-2021-08-12' o..
> git tree: net
> console output: https://syzkaller.appspot.com/x/log.txt?x=16647ca1300000
> kernel config: https://syzkaller.appspot.com/x/.config?x=343fd21f6f4da2d6
> dashboard link: https://syzkaller.appspot.com/bug?extid=d2c5e6980bfc84513464
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14989fe9300000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b1a779300000
>
> The issue was bisected to:
>
> commit 8d2cb3ad31181f050af4d46d6854cf332d1207a9
> Author: Calvin Johnson <calvin.johnson@oss.nxp.com>
> Date: Fri Jun 11 10:53:55 2021 +0000
>
> of: mdio: Refactor of_mdiobus_register_phy()
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106b97d6300000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=126b97d6300000
> console output: https://syzkaller.appspot.com/x/log.txt?x=146b97d6300000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d2c5e6980bfc84513464@syzkaller.appspotmail.com
> Fixes: 8d2cb3ad3118 ("of: mdio: Refactor of_mdiobus_register_phy()")
>
> ==================================================================
> BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline]
> BUG: KASAN: use-after-free in null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
> Write of size 4096 at addr ffff88801c040000 by task syz-executor554/8455
>
> CPU: 0 PID: 8455 Comm: syz-executor554 Not tainted 5.14.0-rc4-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
> print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
> __kasan_report mm/kasan/report.c:419 [inline]
> kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
> check_region_inline mm/kasan/generic.c:183 [inline]
> kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
> memcpy+0x39/0x60 mm/kasan/shadow.c:66
> memcpy include/linux/fortify-string.h:191 [inline]
> null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
> crypto_skcipher_encrypt+0xaa/0xf0 crypto/skcipher.c:630
> crypto_authenc_encrypt+0x3b4/0x510 crypto/authenc.c:222
> crypto_aead_encrypt+0xaa/0xf0 crypto/aead.c:94
> esp6_output_tail+0x777/0x1a90 net/ipv6/esp6.c:659
> esp6_output+0x4af/0x8a0 net/ipv6/esp6.c:735
> xfrm_output_one net/xfrm/xfrm_output.c:552 [inline]
> xfrm_output_resume+0x2997/0x5ae0 net/xfrm/xfrm_output.c:587
> xfrm_output2 net/xfrm/xfrm_output.c:614 [inline]
> xfrm_output+0x2e7/0xff0 net/xfrm/xfrm_output.c:744
> __xfrm6_output+0x4c3/0x1260 net/ipv6/xfrm6_output.c:87
> NF_HOOK_COND include/linux/netfilter.h:296 [inline]
> xfrm6_output+0x117/0x550 net/ipv6/xfrm6_output.c:92
> dst_output include/net/dst.h:448 [inline]
> ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:161
> ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1935
> ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1955
> rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
> rawv6_sendmsg+0x2a87/0x3990 net/ipv6/raw.c:956
> inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821
> sock_sendmsg_nosec net/socket.c:703 [inline]
> sock_sendmsg+0xcf/0x120 net/socket.c:723
> ____sys_sendmsg+0x6e8/0x810 net/socket.c:2392
> ___sys_sendmsg+0xf3/0x170 net/socket.c:2446
> __sys_sendmsg+0xe5/0x1b0 net/socket.c:2475
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x43f4b9
> Code: 1d 01 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffc1e9cfff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f4b9
> RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000004
> RBP: 0000000000000005 R08: 6c616b7a79732f2e R09: 6c616b7a79732f2e
> R10: 00000000000000e8 R11: 0000000000000246 R12: 00000000004034b0
> R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488
>
> Allocated by task 1:
> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
> kasan_set_track mm/kasan/common.c:46 [inline]
> set_alloc_info mm/kasan/common.c:434 [inline]
> __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:467
> kasan_slab_alloc include/linux/kasan.h:254 [inline]
> slab_post_alloc_hook mm/slab.h:519 [inline]
> slab_alloc_node mm/slub.c:2956 [inline]
> slab_alloc mm/slub.c:2964 [inline]
> kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2969
> getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
> getname_flags fs/namei.c:2747 [inline]
> user_path_at_empty+0xa1/0x100 fs/namei.c:2747
> user_path_at include/linux/namei.h:57 [inline]
> vfs_statx+0x142/0x390 fs/stat.c:203
> vfs_fstatat fs/stat.c:225 [inline]
> vfs_lstat include/linux/fs.h:3386 [inline]
> __do_sys_newlstat+0x91/0x110 fs/stat.c:380
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Freed by task 1:
> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
> kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
> kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
> ____kasan_slab_free mm/kasan/common.c:366 [inline]
> ____kasan_slab_free mm/kasan/common.c:328 [inline]
> __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
> kasan_slab_free include/linux/kasan.h:230 [inline]
> slab_free_hook mm/slub.c:1625 [inline]
> slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1650
> slab_free mm/slub.c:3210 [inline]
> kmem_cache_free+0x8a/0x5b0 mm/slub.c:3226
> putname+0xe1/0x120 fs/namei.c:259
(*)
> filename_lookup+0x3df/0x5b0 fs/namei.c:2477
> user_path_at include/linux/namei.h:57 [inline]
> vfs_statx+0x142/0x390 fs/stat.c:203
> vfs_fstatat fs/stat.c:225 [inline]
> vfs_lstat include/linux/fs.h:3386 [inline]
> __do_sys_newlstat+0x91/0x110 fs/stat.c:380
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
+CC Dmitry
I think, it was caused by 9d96ea38873f ("namei: change
filename_parentat() calling conventions").
Now what looks strange to me
Upstream version:
static struct filename *filename_parentat(...)
{
...
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
...
if (likely(!retval)) {
*last = nd.last;
*type = nd.last_type;
audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
} else {
putname(name); <-- putting name if retval if not-zero
name = ERR_PTR(retval);
}
}
Linux-next version:
static int __filename_parentat(...)
{
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
...
if (likely(!retval)) {
*last = nd.last;
*type = nd.last_type;
audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
}
restore_nameidata();
return retval;
}
static int filename_parentat(...)
{
int retval = __filename_parentat(...);
putname(name); <-- always putting the name
return retval;
}
And bug report says, that name was freed by this put (*)
I guess, we should do smth like:
if (retval)
putname(name);
I didn't dig into details, because Dmitry's patch series was really
huge, so it's just for thoughts ;)
With regards,
Pavel Skripkin
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] KASAN: use-after-free Write in null_skcipher_crypt
2021-08-17 19:04 ` Pavel Skripkin
@ 2021-08-17 19:08 ` Grant Likely
2021-08-24 10:48 ` Pavel Skripkin
1 sibling, 0 replies; 4+ messages in thread
From: Grant Likely @ 2021-08-17 19:08 UTC (permalink / raw)
To: Pavel Skripkin, syzbot, calvin.johnson, davem, herbert,
ioana.ciornei, johan.hedberg, kuba, linux-bluetooth,
linux-crypto, linux-kernel, luiz.dentz, marcel, netdev,
syzkaller-bugs, dkadashev
On 17/08/2021 20:04, Pavel Skripkin wrote:
> On 8/17/21 8:24 PM, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: a9a507013a6f Merge tag
>> 'ieee802154-for-davem-2021-08-12' o..
>> git tree: net
>> console output: https://syzkaller.appspot.com/x/log.txt?x=16647ca1300000
>> kernel config:
>> https://syzkaller.appspot.com/x/.config?x=343fd21f6f4da2d6
>> dashboard link:
>> https://syzkaller.appspot.com/bug?extid=d2c5e6980bfc84513464
>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
>> Binutils for Debian) 2.35.1
>> syz repro:
>> https://syzkaller.appspot.com/x/repro.syz?x=14989fe9300000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b1a779300000
>>
>> The issue was bisected to:
>>
>> commit 8d2cb3ad31181f050af4d46d6854cf332d1207a9
>> Author: Calvin Johnson <calvin.johnson@oss.nxp.com>
>> Date: Fri Jun 11 10:53:55 2021 +0000
>>
>> of: mdio: Refactor of_mdiobus_register_phy()
>>
>> bisection log:
>> https://syzkaller.appspot.com/x/bisect.txt?x=106b97d6300000
>> final oops:
>> https://syzkaller.appspot.com/x/report.txt?x=126b97d6300000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=146b97d6300000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the
>> commit:
>> Reported-by: syzbot+d2c5e6980bfc84513464@syzkaller.appspotmail.com
>> Fixes: 8d2cb3ad3118 ("of: mdio: Refactor of_mdiobus_register_phy()")
>>
>> ==================================================================
>> BUG: KASAN: use-after-free in memcpy
>> include/linux/fortify-string.h:191 [inline]
>> BUG: KASAN: use-after-free in null_skcipher_crypt+0xa8/0x120
>> crypto/crypto_null.c:85
>> Write of size 4096 at addr ffff88801c040000 by task syz-executor554/8455
>>
>> CPU: 0 PID: 8455 Comm: syz-executor554 Not tainted
>> 5.14.0-rc4-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine,
>> BIOS Google 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:88 [inline]
>> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
>> print_address_description.constprop.0.cold+0x6c/0x309
>> mm/kasan/report.c:233
>> __kasan_report mm/kasan/report.c:419 [inline]
>> kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
>> check_region_inline mm/kasan/generic.c:183 [inline]
>> kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
>> memcpy+0x39/0x60 mm/kasan/shadow.c:66
>> memcpy include/linux/fortify-string.h:191 [inline]
>> null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
>> crypto_skcipher_encrypt+0xaa/0xf0 crypto/skcipher.c:630
>> crypto_authenc_encrypt+0x3b4/0x510 crypto/authenc.c:222
>> crypto_aead_encrypt+0xaa/0xf0 crypto/aead.c:94
>> esp6_output_tail+0x777/0x1a90 net/ipv6/esp6.c:659
>> esp6_output+0x4af/0x8a0 net/ipv6/esp6.c:735
>> xfrm_output_one net/xfrm/xfrm_output.c:552 [inline]
>> xfrm_output_resume+0x2997/0x5ae0 net/xfrm/xfrm_output.c:587
>> xfrm_output2 net/xfrm/xfrm_output.c:614 [inline]
>> xfrm_output+0x2e7/0xff0 net/xfrm/xfrm_output.c:744
>> __xfrm6_output+0x4c3/0x1260 net/ipv6/xfrm6_output.c:87
>> NF_HOOK_COND include/linux/netfilter.h:296 [inline]
>> xfrm6_output+0x117/0x550 net/ipv6/xfrm6_output.c:92
>> dst_output include/net/dst.h:448 [inline]
>> ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:161
>> ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1935
>> ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1955
>> rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
>> rawv6_sendmsg+0x2a87/0x3990 net/ipv6/raw.c:956
>> inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821
>> sock_sendmsg_nosec net/socket.c:703 [inline]
>> sock_sendmsg+0xcf/0x120 net/socket.c:723
>> ____sys_sendmsg+0x6e8/0x810 net/socket.c:2392
>> ___sys_sendmsg+0xf3/0x170 net/socket.c:2446
>> __sys_sendmsg+0xe5/0x1b0 net/socket.c:2475
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>> RIP: 0033:0x43f4b9
>> Code: 1d 01 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007ffc1e9cfff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>> RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f4b9
>> RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000004
>> RBP: 0000000000000005 R08: 6c616b7a79732f2e R09: 6c616b7a79732f2e
>> R10: 00000000000000e8 R11: 0000000000000246 R12: 00000000004034b0
>> R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488
>>
>> Allocated by task 1:
>> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
>> kasan_set_track mm/kasan/common.c:46 [inline]
>> set_alloc_info mm/kasan/common.c:434 [inline]
>> __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:467
>> kasan_slab_alloc include/linux/kasan.h:254 [inline]
>> slab_post_alloc_hook mm/slab.h:519 [inline]
>> slab_alloc_node mm/slub.c:2956 [inline]
>> slab_alloc mm/slub.c:2964 [inline]
>> kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2969
>> getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
>> getname_flags fs/namei.c:2747 [inline]
>> user_path_at_empty+0xa1/0x100 fs/namei.c:2747
>> user_path_at include/linux/namei.h:57 [inline]
>> vfs_statx+0x142/0x390 fs/stat.c:203
>> vfs_fstatat fs/stat.c:225 [inline]
>> vfs_lstat include/linux/fs.h:3386 [inline]
>> __do_sys_newlstat+0x91/0x110 fs/stat.c:380
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> Freed by task 1:
>> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
>> kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
>> kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
>> ____kasan_slab_free mm/kasan/common.c:366 [inline]
>> ____kasan_slab_free mm/kasan/common.c:328 [inline]
>> __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
>> kasan_slab_free include/linux/kasan.h:230 [inline]
>> slab_free_hook mm/slub.c:1625 [inline]
>> slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1650
>> slab_free mm/slub.c:3210 [inline]
>> kmem_cache_free+0x8a/0x5b0 mm/slub.c:3226
>> putname+0xe1/0x120 fs/namei.c:259
>
> (*)
>
>> filename_lookup+0x3df/0x5b0 fs/namei.c:2477
>> user_path_at include/linux/namei.h:57 [inline]
>> vfs_statx+0x142/0x390 fs/stat.c:203
>> vfs_fstatat fs/stat.c:225 [inline]
>> vfs_lstat include/linux/fs.h:3386 [inline]
>> __do_sys_newlstat+0x91/0x110 fs/stat.c:380
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>
> +CC Dmitry
>
>
>
> I think, it was caused by 9d96ea38873f ("namei: change
> filename_parentat() calling conventions").
>
> Now what looks strange to me
>
> Upstream version:
>
> static struct filename *filename_parentat(...)
> {
> ...
> retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
> ...
> if (likely(!retval)) {
> *last = nd.last;
> *type = nd.last_type;
> audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
> } else {
> putname(name); <-- putting name if retval if not-zero
> name = ERR_PTR(retval);
> }
>
> }
>
>
> Linux-next version:
>
> static int __filename_parentat(...)
> {
>
> retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
> ...
> if (likely(!retval)) {
> *last = nd.last;
> *type = nd.last_type;
> audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
> }
> restore_nameidata();
> return retval;
> }
>
> static int filename_parentat(...)
> {
> int retval = __filename_parentat(...);
>
> putname(name); <-- always putting the name
> return retval;
> }
>
> And bug report says, that name was freed by this put (*)
>
> I guess, we should do smth like:
>
> if (retval)
> putname(name);
>
> I didn't dig into details, because Dmitry's patch series was really
> huge, so it's just for thoughts ;)
Yup, that looks like the correct fix to me.
g.
>
>
>
>
> With regards,
> Pavel Skripkin
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] KASAN: use-after-free Write in null_skcipher_crypt
2021-08-17 19:04 ` Pavel Skripkin
2021-08-17 19:08 ` Grant Likely
@ 2021-08-24 10:48 ` Pavel Skripkin
1 sibling, 0 replies; 4+ messages in thread
From: Pavel Skripkin @ 2021-08-24 10:48 UTC (permalink / raw)
To: syzbot, calvin.johnson, davem, grant.likely, herbert,
ioana.ciornei, johan.hedberg, kuba, linux-bluetooth,
linux-crypto, linux-kernel, luiz.dentz, marcel, netdev,
syzkaller-bugs, dkadashev, viro
On 8/17/21 10:04 PM, Pavel Skripkin wrote:
> On 8/17/21 8:24 PM, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: a9a507013a6f Merge tag 'ieee802154-for-davem-2021-08-12' o..
>> git tree: net
>> console output: https://syzkaller.appspot.com/x/log.txt?x=16647ca1300000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=343fd21f6f4da2d6
>> dashboard link: https://syzkaller.appspot.com/bug?extid=d2c5e6980bfc84513464
>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14989fe9300000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b1a779300000
>>
>> The issue was bisected to:
>>
>> commit 8d2cb3ad31181f050af4d46d6854cf332d1207a9
>> Author: Calvin Johnson <calvin.johnson@oss.nxp.com>
>> Date: Fri Jun 11 10:53:55 2021 +0000
>>
>> of: mdio: Refactor of_mdiobus_register_phy()
>>
>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106b97d6300000
>> final oops: https://syzkaller.appspot.com/x/report.txt?x=126b97d6300000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=146b97d6300000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+d2c5e6980bfc84513464@syzkaller.appspotmail.com
>> Fixes: 8d2cb3ad3118 ("of: mdio: Refactor of_mdiobus_register_phy()")
>>
>> ==================================================================
>> BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline]
>> BUG: KASAN: use-after-free in null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
>> Write of size 4096 at addr ffff88801c040000 by task syz-executor554/8455
>>
>> CPU: 0 PID: 8455 Comm: syz-executor554 Not tainted 5.14.0-rc4-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:88 [inline]
>> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
>> print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
>> __kasan_report mm/kasan/report.c:419 [inline]
>> kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
>> check_region_inline mm/kasan/generic.c:183 [inline]
>> kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
>> memcpy+0x39/0x60 mm/kasan/shadow.c:66
>> memcpy include/linux/fortify-string.h:191 [inline]
>> null_skcipher_crypt+0xa8/0x120 crypto/crypto_null.c:85
>> crypto_skcipher_encrypt+0xaa/0xf0 crypto/skcipher.c:630
>> crypto_authenc_encrypt+0x3b4/0x510 crypto/authenc.c:222
>> crypto_aead_encrypt+0xaa/0xf0 crypto/aead.c:94
>> esp6_output_tail+0x777/0x1a90 net/ipv6/esp6.c:659
>> esp6_output+0x4af/0x8a0 net/ipv6/esp6.c:735
>> xfrm_output_one net/xfrm/xfrm_output.c:552 [inline]
>> xfrm_output_resume+0x2997/0x5ae0 net/xfrm/xfrm_output.c:587
>> xfrm_output2 net/xfrm/xfrm_output.c:614 [inline]
>> xfrm_output+0x2e7/0xff0 net/xfrm/xfrm_output.c:744
>> __xfrm6_output+0x4c3/0x1260 net/ipv6/xfrm6_output.c:87
>> NF_HOOK_COND include/linux/netfilter.h:296 [inline]
>> xfrm6_output+0x117/0x550 net/ipv6/xfrm6_output.c:92
>> dst_output include/net/dst.h:448 [inline]
>> ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:161
>> ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1935
>> ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1955
>> rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
>> rawv6_sendmsg+0x2a87/0x3990 net/ipv6/raw.c:956
>> inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821
>> sock_sendmsg_nosec net/socket.c:703 [inline]
>> sock_sendmsg+0xcf/0x120 net/socket.c:723
>> ____sys_sendmsg+0x6e8/0x810 net/socket.c:2392
>> ___sys_sendmsg+0xf3/0x170 net/socket.c:2446
>> __sys_sendmsg+0xe5/0x1b0 net/socket.c:2475
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>> RIP: 0033:0x43f4b9
>> Code: 1d 01 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007ffc1e9cfff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>> RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f4b9
>> RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000004
>> RBP: 0000000000000005 R08: 6c616b7a79732f2e R09: 6c616b7a79732f2e
>> R10: 00000000000000e8 R11: 0000000000000246 R12: 00000000004034b0
>> R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488
>>
>> Allocated by task 1:
>> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
>> kasan_set_track mm/kasan/common.c:46 [inline]
>> set_alloc_info mm/kasan/common.c:434 [inline]
>> __kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:467
>> kasan_slab_alloc include/linux/kasan.h:254 [inline]
>> slab_post_alloc_hook mm/slab.h:519 [inline]
>> slab_alloc_node mm/slub.c:2956 [inline]
>> slab_alloc mm/slub.c:2964 [inline]
>> kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2969
>> getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
>> getname_flags fs/namei.c:2747 [inline]
>> user_path_at_empty+0xa1/0x100 fs/namei.c:2747
>> user_path_at include/linux/namei.h:57 [inline]
>> vfs_statx+0x142/0x390 fs/stat.c:203
>> vfs_fstatat fs/stat.c:225 [inline]
>> vfs_lstat include/linux/fs.h:3386 [inline]
>> __do_sys_newlstat+0x91/0x110 fs/stat.c:380
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> Freed by task 1:
>> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
>> kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
>> kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
>> ____kasan_slab_free mm/kasan/common.c:366 [inline]
>> ____kasan_slab_free mm/kasan/common.c:328 [inline]
>> __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
>> kasan_slab_free include/linux/kasan.h:230 [inline]
>> slab_free_hook mm/slub.c:1625 [inline]
>> slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1650
>> slab_free mm/slub.c:3210 [inline]
>> kmem_cache_free+0x8a/0x5b0 mm/slub.c:3226
>> putname+0xe1/0x120 fs/namei.c:259
>
> (*)
>
>> filename_lookup+0x3df/0x5b0 fs/namei.c:2477
>> user_path_at include/linux/namei.h:57 [inline]
>> vfs_statx+0x142/0x390 fs/stat.c:203
>> vfs_fstatat fs/stat.c:225 [inline]
>> vfs_lstat include/linux/fs.h:3386 [inline]
>> __do_sys_newlstat+0x91/0x110 fs/stat.c:380
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>
> +CC Dmitry
>
>
>
> I think, it was caused by 9d96ea38873f ("namei: change
> filename_parentat() calling conventions").
>
> Now what looks strange to me
>
> Upstream version:
>
> static struct filename *filename_parentat(...)
> {
> ...
> retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
> ...
> if (likely(!retval)) {
> *last = nd.last;
> *type = nd.last_type;
> audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
> } else {
> putname(name); <-- putting name if retval if not-zero
> name = ERR_PTR(retval);
> }
>
> }
>
>
> Linux-next version:
>
> static int __filename_parentat(...)
> {
>
> retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
> ...
> if (likely(!retval)) {
> *last = nd.last;
> *type = nd.last_type;
> audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
> }
> restore_nameidata();
> return retval;
> }
>
> static int filename_parentat(...)
> {
> int retval = __filename_parentat(...);
>
> putname(name); <-- always putting the name
> return retval;
> }
>
> And bug report says, that name was freed by this put (*)
>
> I guess, we should do smth like:
>
> if (retval)
> putname(name);
>
> I didn't dig into details, because Dmitry's patch series was really
> huge, so it's just for thoughts ;)
>
>
>
+CC Alexander,
since people start getting this error while testing patches on top of
linux-next
With regards,
Pavel Skripkin
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-08-24 10:48 UTC | newest]
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2021-08-17 17:24 [syzbot] KASAN: use-after-free Write in null_skcipher_crypt syzbot
2021-08-17 19:04 ` Pavel Skripkin
2021-08-17 19:08 ` Grant Likely
2021-08-24 10:48 ` Pavel Skripkin
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