Hello,
syzbot found the following crash on:
HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169fa049100000
kernel config: https://syzkaller.appspot.com/x/.config?x=be4578b3f1083656
dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
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: [email protected]
==================================================================
BUG: KASAN: use-after-free in dev_uevent+0x30a/0x580 drivers/base/core.c:1486
Read of size 8 at addr ffff888098662098 by task systemd-udevd/29958
CPU: 0 PID: 29958 Comm: systemd-udevd Not tainted 5.7.0-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+0x1e9/0x30e lib/dump_stack.c:118
print_address_description+0x66/0x5a0 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
dev_uevent+0x30a/0x580 drivers/base/core.c:1486
uevent_show+0x1b2/0x2f0 drivers/base/core.c:1557
dev_attr_show+0x50/0xc0 drivers/base/core.c:1261
sysfs_kf_seq_show+0x30e/0x4e0 fs/sysfs/file.c:60
seq_read+0x41a/0xce0 fs/seq_file.c:208
__vfs_read+0x9c/0x6d0 fs/read_write.c:426
vfs_read+0x1c4/0x400 fs/read_write.c:462
ksys_read+0x11b/0x220 fs/read_write.c:588
do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7f28fc677910
Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 de 9b 01 00 48 89 04 24
RSP: 002b:00007ffe3053dd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00005562a17eb920 RCX: 00007f28fc677910
RDX: 0000000000001000 RSI: 00005562a17fe8c0 RDI: 0000000000000007
RBP: 00007f28fc932440 R08: 00007f28fc9361e8 R09: 0000000000001010
R10: 00005562a17eb920 R11: 0000000000000246 R12: 0000000000001000
R13: 0000000000000d68 R14: 00005562a17fe8c0 R15: 00007f28fc931900
Allocated by task 29904:
save_stack mm/kasan/common.c:48 [inline]
set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551
kmalloc include/linux/slab.h:555 [inline]
kzalloc include/linux/slab.h:669 [inline]
dev_new drivers/usb/gadget/legacy/raw_gadget.c:182 [inline]
raw_open+0x87/0x500 drivers/usb/gadget/legacy/raw_gadget.c:372
misc_open+0x346/0x3c0 drivers/char/misc.c:141
chrdev_open+0x498/0x580 fs/char_dev.c:414
do_dentry_open+0x808/0x1020 fs/open.c:828
do_open fs/namei.c:3229 [inline]
path_openat+0x2790/0x38b0 fs/namei.c:3346
do_filp_open+0x191/0x3a0 fs/namei.c:3373
do_sys_openat2+0x463/0x770 fs/open.c:1179
do_sys_open fs/open.c:1195 [inline]
ksys_open include/linux/syscalls.h:1388 [inline]
__do_sys_open fs/open.c:1201 [inline]
__se_sys_open fs/open.c:1199 [inline]
__x64_sys_open+0x1af/0x1e0 fs/open.c:1199
do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
Freed by task 29956:
save_stack mm/kasan/common.c:48 [inline]
set_track mm/kasan/common.c:56 [inline]
kasan_set_free_info mm/kasan/common.c:316 [inline]
__kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
__cache_free mm/slab.c:3426 [inline]
kfree+0x10a/0x220 mm/slab.c:3757
raw_release+0x130/0x1e0 drivers/usb/gadget/legacy/raw_gadget.c:411
__fput+0x2ed/0x750 fs/file_table.c:281
task_work_run+0x147/0x1d0 kernel/task_work.c:123
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x5ef/0x1f80 kernel/exit.c:806
do_group_exit+0x15e/0x2c0 kernel/exit.c:904
get_signal+0x13cf/0x1d60 kernel/signal.c:2739
do_signal+0x33/0x610 arch/x86/kernel/signal.c:810
exit_to_usermode_loop arch/x86/entry/common.c:161 [inline]
prepare_exit_to_usermode+0x32a/0x600 arch/x86/entry/common.c:196
entry_SYSCALL_64_after_hwframe+0x49/0xb3
The buggy address belongs to the object at ffff888098662000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 152 bytes inside of
4096-byte region [ffff888098662000, ffff888098663000)
The buggy address belongs to the page:
page:ffffea0002619880 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea0002619880 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00021d0908 ffffea0002a5a808 ffff8880aa402000
raw: 0000000000000000 ffff888098662000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888098661f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888098662000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888098662080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888098662100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888098662180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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 [email protected].
syzbot will keep track of this bug report. See:
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syzbot has found a reproducer for the following issue on:
HEAD commit: 4f12b742eb2b Merge tag 'nfs-for-5.17-3' of git://git.linux..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110a6df2700000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6a069ed94a1ed1d
dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12377296700000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
==================================================================
BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320
Read of size 8 at addr ffff88802b934098 by task udevd/3689
CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
dev_uevent+0x712/0x780 drivers/base/core.c:2320
uevent_show+0x1b8/0x380 drivers/base/core.c:2391
dev_attr_show+0x4b/0x90 drivers/base/core.c:2094
sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
kernfs_fop_read_iter+0x514/0x6f0 fs/kernfs/file.c:241
call_read_iter include/linux/fs.h:2068 [inline]
new_sync_read+0x429/0x6e0 fs/read_write.c:400
vfs_read+0x35c/0x600 fs/read_write.c:481
ksys_read+0x12d/0x250 fs/read_write.c:619
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: 0033:0x7f964cc558fe
Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
RSP: 002b:00007ffc0133d258 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000056497b21a140 RCX: 00007f964cc558fe
RDX: 0000000000001000 RSI: 000056497b218650 RDI: 0000000000000008
RBP: 00007f964cd22380 R08: 0000000000000008 R09: 00007f964cd25a60
R10: 0000000000000008 R11: 0000000000000246 R12: 000056497b21a140
R13: 0000000000000d68 R14: 00007f964cd21780 R15: 0000000000000d68
</TASK>
Allocated by task 4316:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524
kasan_kmalloc include/linux/kasan.h:270 [inline]
kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3567
kmalloc include/linux/slab.h:581 [inline]
kzalloc include/linux/slab.h:715 [inline]
dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
raw_open+0x8d/0x4c0 drivers/usb/gadget/legacy/raw_gadget.c:373
misc_open+0x372/0x4a0 drivers/char/misc.c:141
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x4b9/0x1250 fs/open.c:824
do_open fs/namei.c:3476 [inline]
path_openat+0x1c9e/0x2940 fs/namei.c:3609
do_filp_open+0x1aa/0x400 fs/namei.c:3636
do_sys_openat2+0x16d/0x4d0 fs/open.c:1214
do_sys_open fs/open.c:1230 [inline]
__do_sys_openat fs/open.c:1246 [inline]
__se_sys_openat fs/open.c:1241 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
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 4315:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:236 [inline]
__cache_free mm/slab.c:3437 [inline]
kfree+0xf8/0x2b0 mm/slab.c:3794
kref_put include/linux/kref.h:65 [inline]
raw_release+0x218/0x290 drivers/usb/gadget/legacy/raw_gadget.c:412
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88802b934000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 152 bytes inside of
4096-byte region [ffff88802b934000, ffff88802b935000)
The buggy address belongs to the page:
page:ffffea0000ae4d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b934
head:ffffea0000ae4d00 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00008be908 ffffea0000612d08 ffff888010c40900
raw: 0000000000000000 ffff88802b934000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 4316, ts 254636955499, free_ts 240714313612
prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
__alloc_pages_slowpath.constprop.0+0x2eb/0x20d0 mm/page_alloc.c:4934
__alloc_pages+0x412/0x500 mm/page_alloc.c:5402
__alloc_pages_node include/linux/gfp.h:572 [inline]
kmem_getpages mm/slab.c:1378 [inline]
cache_grow_begin+0x75/0x390 mm/slab.c:2584
cache_alloc_refill+0x27f/0x380 mm/slab.c:2957
____cache_alloc mm/slab.c:3040 [inline]
____cache_alloc mm/slab.c:3023 [inline]
__do_cache_alloc mm/slab.c:3267 [inline]
slab_alloc mm/slab.c:3308 [inline]
kmem_cache_alloc_trace+0x380/0x4a0 mm/slab.c:3565
kmalloc include/linux/slab.h:581 [inline]
kzalloc include/linux/slab.h:715 [inline]
dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
raw_open+0x8d/0x4c0 drivers/usb/gadget/legacy/raw_gadget.c:373
misc_open+0x372/0x4a0 drivers/char/misc.c:141
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x4b9/0x1250 fs/open.c:824
do_open fs/namei.c:3476 [inline]
path_openat+0x1c9e/0x2940 fs/namei.c:3609
do_filp_open+0x1aa/0x400 fs/namei.c:3636
do_sys_openat2+0x16d/0x4d0 fs/open.c:1214
do_sys_open fs/open.c:1230 [inline]
__do_sys_openat fs/open.c:1246 [inline]
__se_sys_openat fs/open.c:1241 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
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:1352 [inline]
free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
free_unref_page_prepare mm/page_alloc.c:3325 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3404
slab_destroy mm/slab.c:1630 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1650
cache_flusharray mm/slab.c:3410 [inline]
___cache_free+0x303/0x600 mm/slab.c:3472
qlink_free mm/kasan/quarantine.c:157 [inline]
qlist_free_all+0x50/0x1a0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:446
kasan_slab_alloc include/linux/kasan.h:260 [inline]
slab_post_alloc_hook mm/slab.h:732 [inline]
slab_alloc_node mm/slab.c:3253 [inline]
kmem_cache_alloc_node+0x2ea/0x590 mm/slab.c:3591
__alloc_skb+0x215/0x340 net/core/skbuff.c:414
alloc_skb include/linux/skbuff.h:1158 [inline]
alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:5956
sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2586
unix_dgram_sendmsg+0x414/0x1a10 net/unix/af_unix.c:1896
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:725
__sys_sendto+0x21c/0x320 net/socket.c:2040
__do_sys_sendto net/socket.c:2052 [inline]
__se_sys_sendto net/socket.c:2048 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
Memory state around the buggy address:
ffff88802b933f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b934000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802b934080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b934100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b934180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
HEAD commit: 4f12b742eb2b Merge tag 'nfs-for-5.17-3' of git://git.linux..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110a6df2700000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6a069ed94a1ed1d
dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12377296700000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
==================================================================
BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689
CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
dev_uevent+0x712/0x780 drivers/base/core.c:2320
uevent_show+0x1b8/0x380 drivers/base/core.c:2391
dev_attr_show+0x4b/0x90 drivers/base/core.c:2094
sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
kernfs_fop_read_iter+0x514/0x6f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2068 [inline]
new_sync_read+0x429/0x6e0 fs/read_write.c:400
vfs_read+0x35c/0x600 fs/read_write.c:481
ksys_read+0x12d/0x250 fs/read_write.c:619
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: 0033:0x7f964cc558fe
Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
RSP: 002b:00007ffc0133d258 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000056497b21a140 RCX: 00007f964cc558fe
RDX: 0000000000001000 RSI: 000056497b218650 RDI: 0000000000000008
RBP: 00007f964cd22380 R08: 0000000000000008 R09: 00007f964cd25a60
R10: 0000000000000008 R11: 0000000000000246 R12: 000056497b21a140
R13: 0000000000000d68 R14: 00007f964cd21780 R15: 0000000000000d68 </TASK>
Hi All
This should be because when the raw_dev is released, the 'driver' address has expired,
although the usb_gadget_remove_driver() empty 'dev.driver ' NULL, but UAF cannot be avoided.
static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env) {
.....
if (dev->driver)
2320 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
.....
}
Whether protection can be added when operating 'dev->driver'?
Thanks,
Zqiang
Allocated by task 4316:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524 kasan_kmalloc include/linux/kasan.h:270 [inline]
kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3567 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:715 [inline] dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
raw_open+0x8d/0x4c0 drivers/usb/gadget/legacy/raw_gadget.c:373
misc_open+0x372/0x4a0 drivers/char/misc.c:141
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x4b9/0x1250 fs/open.c:824 do_open fs/namei.c:3476 [inline]
path_openat+0x1c9e/0x2940 fs/namei.c:3609
do_filp_open+0x1aa/0x400 fs/namei.c:3636
do_sys_openat2+0x16d/0x4d0 fs/open.c:1214 do_sys_open fs/open.c:1230 [inline] __do_sys_openat fs/open.c:1246 [inline] __se_sys_openat fs/open.c:1241 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
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 4315:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] __cache_free mm/slab.c:3437 [inline]
kfree+0xf8/0x2b0 mm/slab.c:3794
kref_put include/linux/kref.h:65 [inline]
raw_release+0x218/0x290 drivers/usb/gadget/legacy/raw_gadget.c:412
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88802b934000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 152 bytes inside of 4096-byte region [ffff88802b934000, ffff88802b935000) The buggy address belongs to the page:
page:ffffea0000ae4d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b934
head:ffffea0000ae4d00 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00008be908 ffffea0000612d08 ffff888010c40900
raw: 0000000000000000 ffff88802b934000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 4316, ts 254636955499, free_ts 240714313612 prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
__alloc_pages_slowpath.constprop.0+0x2eb/0x20d0 mm/page_alloc.c:4934
__alloc_pages+0x412/0x500 mm/page_alloc.c:5402 __alloc_pages_node include/linux/gfp.h:572 [inline] kmem_getpages mm/slab.c:1378 [inline]
cache_grow_begin+0x75/0x390 mm/slab.c:2584
cache_alloc_refill+0x27f/0x380 mm/slab.c:2957 ____cache_alloc mm/slab.c:3040 [inline] ____cache_alloc mm/slab.c:3023 [inline] __do_cache_alloc mm/slab.c:3267 [inline] slab_alloc mm/slab.c:3308 [inline]
kmem_cache_alloc_trace+0x380/0x4a0 mm/slab.c:3565 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:715 [inline] dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
raw_open+0x8d/0x4c0 drivers/usb/gadget/legacy/raw_gadget.c:373
misc_open+0x372/0x4a0 drivers/char/misc.c:141
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x4b9/0x1250 fs/open.c:824 do_open fs/namei.c:3476 [inline]
path_openat+0x1c9e/0x2940 fs/namei.c:3609
do_filp_open+0x1aa/0x400 fs/namei.c:3636
do_sys_openat2+0x16d/0x4d0 fs/open.c:1214 do_sys_open fs/open.c:1230 [inline] __do_sys_openat fs/open.c:1246 [inline] __se_sys_openat fs/open.c:1241 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
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:1352 [inline]
free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3404 slab_destroy mm/slab.c:1630 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1650
cache_flusharray mm/slab.c:3410 [inline]
___cache_free+0x303/0x600 mm/slab.c:3472 qlink_free mm/kasan/quarantine.c:157 [inline]
qlist_free_all+0x50/0x1a0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:446 kasan_slab_alloc include/linux/kasan.h:260 [inline] slab_post_alloc_hook mm/slab.h:732 [inline] slab_alloc_node mm/slab.c:3253 [inline]
kmem_cache_alloc_node+0x2ea/0x590 mm/slab.c:3591
__alloc_skb+0x215/0x340 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1158 [inline]
alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:5956
sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2586
unix_dgram_sendmsg+0x414/0x1a10 net/unix/af_unix.c:1896 sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:725
__sys_sendto+0x21c/0x320 net/socket.c:2040 __do_sys_sendto net/socket.c:2052 [inline] __se_sys_sendto net/socket.c:2048 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
Memory state around the buggy address:
ffff88802b933f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b934000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802b934080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b934100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b934180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
syzbot has found a reproducer for the following issue on:
HEAD commit: 4f12b742eb2b Merge tag 'nfs-for-5.17-3' of git://git.linux..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110a6df2700000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6a069ed94a1ed1d
dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12377296700000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
==================================================================
BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689
CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
dev_uevent+0x712/0x780 drivers/base/core.c:2320
uevent_show+0x1b8/0x380 drivers/base/core.c:2391
dev_attr_show+0x4b/0x90 drivers/base/core.c:2094
sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
kernfs_fop_read_iter+0x514/0x6f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2068 [inline]
new_sync_read+0x429/0x6e0 fs/read_write.c:400
vfs_read+0x35c/0x600 fs/read_write.c:481
ksys_read+0x12d/0x250 fs/read_write.c:619
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: 0033:0x7f964cc558fe
Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
RSP: 002b:00007ffc0133d258 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000056497b21a140 RCX: 00007f964cc558fe
RDX: 0000000000001000 RSI: 000056497b218650 RDI: 0000000000000008
RBP: 00007f964cd22380 R08: 0000000000000008 R09: 00007f964cd25a60
R10: 0000000000000008 R11: 0000000000000246 R12: 000056497b21a140
R13: 0000000000000d68 R14: 00007f964cd21780 R15: 0000000000000d68 </TASK>
Cc: Alan Stern
Felipe Balbi
Hello syzbot, Please try it:
From 574d45ff924e2d2f9b9f5cc3e846f8004498a811 Mon Sep 17 00:00:00 2001
From: Zqiang <[email protected]>
Date: Wed, 23 Feb 2022 18:18:22 +0800
Subject: [PATCH] driver core: Fix use-after-free in dev_uevent()
In dev_uevent(), if the "dev->driver" is valid, the "dev->driver->name"
be accessed, there may be a window period between these two operations.
in this window period if the "dev->driver" is set to null
(in usb_gadget_unregister_driver function), when the "dev->driver->name"
is accessed again, invalid address will be accessed. fix it by checking
"dev->driver" again.
Signed-off-by: Zqiang <[email protected]>
---
drivers/base/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 3d6430eb0c6a..a45b927ee76e 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2317,7 +2317,7 @@ static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
if (dev->driver)
- add_uevent_var(env, "DRIVER=%s", dev->driver->name);
+ add_uevent_var(env, "DRIVER=%s", dev_driver_string(dev));
/* Add common DT information about the device */
of_device_uevent(dev, env);
--
2.25.1
Thanks,
Zqiang
Allocated by task 4316:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524 kasan_kmalloc include/linux/kasan.h:270 [inline]
kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3567 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:715 [inline] dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
raw_open+0x8d/0x4c0 drivers/usb/gadget/legacy/raw_gadget.c:373
misc_open+0x372/0x4a0 drivers/char/misc.c:141
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x4b9/0x1250 fs/open.c:824 do_open fs/namei.c:3476 [inline]
path_openat+0x1c9e/0x2940 fs/namei.c:3609
do_filp_open+0x1aa/0x400 fs/namei.c:3636
do_sys_openat2+0x16d/0x4d0 fs/open.c:1214 do_sys_open fs/open.c:1230 [inline] __do_sys_openat fs/open.c:1246 [inline] __se_sys_openat fs/open.c:1241 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
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 4315:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] __cache_free mm/slab.c:3437 [inline]
kfree+0xf8/0x2b0 mm/slab.c:3794
kref_put include/linux/kref.h:65 [inline]
raw_release+0x218/0x290 drivers/usb/gadget/legacy/raw_gadget.c:412
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88802b934000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 152 bytes inside of 4096-byte region [ffff88802b934000, ffff88802b935000) The buggy address belongs to the page:
page:ffffea0000ae4d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b934
head:ffffea0000ae4d00 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00008be908 ffffea0000612d08 ffff888010c40900
raw: 0000000000000000 ffff88802b934000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 4316, ts 254636955499, free_ts 240714313612 prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
__alloc_pages_slowpath.constprop.0+0x2eb/0x20d0 mm/page_alloc.c:4934
__alloc_pages+0x412/0x500 mm/page_alloc.c:5402 __alloc_pages_node include/linux/gfp.h:572 [inline] kmem_getpages mm/slab.c:1378 [inline]
cache_grow_begin+0x75/0x390 mm/slab.c:2584
cache_alloc_refill+0x27f/0x380 mm/slab.c:2957 ____cache_alloc mm/slab.c:3040 [inline] ____cache_alloc mm/slab.c:3023 [inline] __do_cache_alloc mm/slab.c:3267 [inline] slab_alloc mm/slab.c:3308 [inline]
kmem_cache_alloc_trace+0x380/0x4a0 mm/slab.c:3565 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:715 [inline] dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
raw_open+0x8d/0x4c0 drivers/usb/gadget/legacy/raw_gadget.c:373
misc_open+0x372/0x4a0 drivers/char/misc.c:141
chrdev_open+0x266/0x770 fs/char_dev.c:414
do_dentry_open+0x4b9/0x1250 fs/open.c:824 do_open fs/namei.c:3476 [inline]
path_openat+0x1c9e/0x2940 fs/namei.c:3609
do_filp_open+0x1aa/0x400 fs/namei.c:3636
do_sys_openat2+0x16d/0x4d0 fs/open.c:1214 do_sys_open fs/open.c:1230 [inline] __do_sys_openat fs/open.c:1246 [inline] __se_sys_openat fs/open.c:1241 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
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:1352 [inline]
free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3404 slab_destroy mm/slab.c:1630 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1650
cache_flusharray mm/slab.c:3410 [inline]
___cache_free+0x303/0x600 mm/slab.c:3472 qlink_free mm/kasan/quarantine.c:157 [inline]
qlist_free_all+0x50/0x1a0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:446 kasan_slab_alloc include/linux/kasan.h:260 [inline] slab_post_alloc_hook mm/slab.h:732 [inline] slab_alloc_node mm/slab.c:3253 [inline]
kmem_cache_alloc_node+0x2ea/0x590 mm/slab.c:3591
__alloc_skb+0x215/0x340 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1158 [inline]
alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:5956
sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2586
unix_dgram_sendmsg+0x414/0x1a10 net/unix/af_unix.c:1896 sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:725
__sys_sendto+0x21c/0x320 net/socket.c:2040 __do_sys_sendto net/socket.c:2052 [inline] __se_sys_sendto net/socket.c:2048 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
Memory state around the buggy address:
ffff88802b933f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b934000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802b934080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b934100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b934180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
Hi Qiang1,
On 2/23/22 14:17, Zhang, Qiang1 wrote:
>
> Cc: Alan Stern
> Felipe Balbi
>
> Hello syzbot, Please try it:
>
> From 574d45ff924e2d2f9b9f5cc3e846f8004498a811 Mon Sep 17 00:00:00 2001
> From: Zqiang <[email protected]>
> Date: Wed, 23 Feb 2022 18:18:22 +0800
> Subject: [PATCH] driver core: Fix use-after-free in dev_uevent()
>
> In dev_uevent(), if the "dev->driver" is valid, the "dev->driver->name"
> be accessed, there may be a window period between these two operations.
> in this window period if the "dev->driver" is set to null
> (in usb_gadget_unregister_driver function), when the "dev->driver->name"
> is accessed again, invalid address will be accessed. fix it by checking
> "dev->driver" again.
>
> Signed-off-by: Zqiang <[email protected]>
> ---
> drivers/base/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 3d6430eb0c6a..a45b927ee76e 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2317,7 +2317,7 @@ static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
> add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
>
> if (dev->driver)
> - add_uevent_var(env, "DRIVER=%s", dev->driver->name);
> + add_uevent_var(env, "DRIVER=%s", dev_driver_string(dev));
>
> /* Add common DT information about the device */
> of_device_uevent(dev, env);
> --
> 2.25.1
>
you should use '#syz test' command to ask syzbot to test the patch.
Basic syntax is '#syz test: <git tree> <branch or sha>' and syzbot will
apply attached patch (if you have attached it)
More about syzbot interactions here [1].
[1]
https://github.com/google/syzkaller/blob/15439f1624735bde5ae3f3b66c1b964a98
With regards,
Pavel Skripkin
On Wed, Feb 23, 2022 at 11:17:07AM +0000, Zhang, Qiang1 wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 4f12b742eb2b Merge tag 'nfs-for-5.17-3' of git://git.linux..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=110a6df2700000
> kernel config: https://syzkaller.appspot.com/x/.config?x=f6a069ed94a1ed1d
> dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12377296700000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> ==================================================================
> BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689
>
> CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
> dev_uevent+0x712/0x780 drivers/base/core.c:2320
> uevent_show+0x1b8/0x380 drivers/base/core.c:2391
> dev_attr_show+0x4b/0x90 drivers/base/core.c:2094
> sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
> seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
> kernfs_fop_read_iter+0x514/0x6f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2068 [inline]
> new_sync_read+0x429/0x6e0 fs/read_write.c:400
> vfs_read+0x35c/0x600 fs/read_write.c:481
> ksys_read+0x12d/0x250 fs/read_write.c:619
> 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: 0033:0x7f964cc558fe
> Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
> RSP: 002b:00007ffc0133d258 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: ffffffffffffffda RBX: 000056497b21a140 RCX: 00007f964cc558fe
> RDX: 0000000000001000 RSI: 000056497b218650 RDI: 0000000000000008
> RBP: 00007f964cd22380 R08: 0000000000000008 R09: 00007f964cd25a60
> R10: 0000000000000008 R11: 0000000000000246 R12: 000056497b21a140
> R13: 0000000000000d68 R14: 00007f964cd21780 R15: 0000000000000d68 </TASK>
>
> Cc: Alan Stern
> Felipe Balbi
>
> Hello syzbot, Please try it:
>
> From 574d45ff924e2d2f9b9f5cc3e846f8004498a811 Mon Sep 17 00:00:00 2001
> From: Zqiang <[email protected]>
> Date: Wed, 23 Feb 2022 18:18:22 +0800
> Subject: [PATCH] driver core: Fix use-after-free in dev_uevent()
>
> In dev_uevent(), if the "dev->driver" is valid, the "dev->driver->name"
> be accessed, there may be a window period between these two operations.
There should not be any such window period. The bus locks should
prevent this, unless some driver is doing odd things with the pointers
that it should not be doing.
> in this window period if the "dev->driver" is set to null
> (in usb_gadget_unregister_driver function), when the "dev->driver->name"
> is accessed again, invalid address will be accessed. fix it by checking
> "dev->driver" again.
>
> Signed-off-by: Zqiang <[email protected]>
> ---
> drivers/base/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 3d6430eb0c6a..a45b927ee76e 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2317,7 +2317,7 @@ static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
> add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
>
> if (dev->driver)
> - add_uevent_var(env, "DRIVER=%s", dev->driver->name);
> + add_uevent_var(env, "DRIVER=%s", dev_driver_string(dev));
What's to prevent the "window" from happening in the middle of the
dev_driver_string() call?
thanks,
greg k-h
On Wed, Feb 23, 2022 at 12:29:03PM +0100, [email protected] wrote:
> On Wed, Feb 23, 2022 at 11:17:07AM +0000, Zhang, Qiang1 wrote:
> >
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit: 4f12b742eb2b Merge tag 'nfs-for-5.17-3' of git://git.linux..
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=110a6df2700000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=f6a069ed94a1ed1d
> > dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12377296700000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: [email protected]
> >
> > ==================================================================
> > BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689
> >
> > CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace:
> > <TASK>
> > __dump_stack lib/dump_stack.c:88 [inline]
> > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> > print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
> > dev_uevent+0x712/0x780 drivers/base/core.c:2320
> > uevent_show+0x1b8/0x380 drivers/base/core.c:2391
> > dev_attr_show+0x4b/0x90 drivers/base/core.c:2094
> > sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
> > seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
> > kernfs_fop_read_iter+0x514/0x6f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2068 [inline]
> > new_sync_read+0x429/0x6e0 fs/read_write.c:400
> > vfs_read+0x35c/0x600 fs/read_write.c:481
> > ksys_read+0x12d/0x250 fs/read_write.c:619
> > 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: 0033:0x7f964cc558fe
> > Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
> > RSP: 002b:00007ffc0133d258 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> > RAX: ffffffffffffffda RBX: 000056497b21a140 RCX: 00007f964cc558fe
> > RDX: 0000000000001000 RSI: 000056497b218650 RDI: 0000000000000008
> > RBP: 00007f964cd22380 R08: 0000000000000008 R09: 00007f964cd25a60
> > R10: 0000000000000008 R11: 0000000000000246 R12: 000056497b21a140
> > R13: 0000000000000d68 R14: 00007f964cd21780 R15: 0000000000000d68 </TASK>
> >
> > Cc: Alan Stern
> > Felipe Balbi
> >
> > Hello syzbot, Please try it:
> >
> > From 574d45ff924e2d2f9b9f5cc3e846f8004498a811 Mon Sep 17 00:00:00 2001
> > From: Zqiang <[email protected]>
> > Date: Wed, 23 Feb 2022 18:18:22 +0800
> > Subject: [PATCH] driver core: Fix use-after-free in dev_uevent()
> >
> > In dev_uevent(), if the "dev->driver" is valid, the "dev->driver->name"
> > be accessed, there may be a window period between these two operations.
>
> There should not be any such window period. The bus locks should
> prevent this, unless some driver is doing odd things with the pointers
> that it should not be doing.
Which bus locks are you referring to? I'm not aware of any locks that
synchronize dev_uevent() with anything (in particular, with driver
unbinding).
And as far as I know, usb_gadget_remove_driver() doesn't play any odd
tricks with pointers.
> > in this window period if the "dev->driver" is set to null
> > (in usb_gadget_unregister_driver function), when the "dev->driver->name"
> > is accessed again, invalid address will be accessed. fix it by checking
> > "dev->driver" again.
> >
> > Signed-off-by: Zqiang <[email protected]>
> > ---
> > drivers/base/core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 3d6430eb0c6a..a45b927ee76e 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -2317,7 +2317,7 @@ static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
> > add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
> >
> > if (dev->driver)
> > - add_uevent_var(env, "DRIVER=%s", dev->driver->name);
> > + add_uevent_var(env, "DRIVER=%s", dev_driver_string(dev));
>
> What's to prevent the "window" from happening in the middle of the
> dev_driver_string() call?
Nothing prevents it. But if you read the code for dev_driver_string(),
you will see that it doesn't matter if dev->driver gets set to NULL
while the routine is running.
(Of course, there is still the possibility that the driver structure
itself might get deallocated while dev_driver_string() is running.
This whole area could perhaps use a little careful thought. Driver
unbinding might be a good application for SRCU.)
Alan Stern
On Wed, Feb 23, 2022 at 06:51:10AM +0000, Zhang, Qiang1 wrote:
>
> HEAD commit: 4f12b742eb2b Merge tag 'nfs-for-5.17-3' of git://git.linux..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=110a6df2700000
> kernel config: https://syzkaller.appspot.com/x/.config?x=f6a069ed94a1ed1d
> dashboard link: https://syzkaller.appspot.com/bug?extid=348b571beb5eeb70a582
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12377296700000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> ==================================================================
> BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689
>
> CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
> dev_uevent+0x712/0x780 drivers/base/core.c:2320
> uevent_show+0x1b8/0x380 drivers/base/core.c:2391
> dev_attr_show+0x4b/0x90 drivers/base/core.c:2094
> sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
> seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
> kernfs_fop_read_iter+0x514/0x6f0 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2068 [inline]
> new_sync_read+0x429/0x6e0 fs/read_write.c:400
> vfs_read+0x35c/0x600 fs/read_write.c:481
> ksys_read+0x12d/0x250 fs/read_write.c:619
> 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: 0033:0x7f964cc558fe
> Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
> RSP: 002b:00007ffc0133d258 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: ffffffffffffffda RBX: 000056497b21a140 RCX: 00007f964cc558fe
> RDX: 0000000000001000 RSI: 000056497b218650 RDI: 0000000000000008
> RBP: 00007f964cd22380 R08: 0000000000000008 R09: 00007f964cd25a60
> R10: 0000000000000008 R11: 0000000000000246 R12: 000056497b21a140
> R13: 0000000000000d68 R14: 00007f964cd21780 R15: 0000000000000d68 </TASK>
>
>
> Hi All
>
> This should be because when the raw_dev is released, the 'driver' address has expired,
> although the usb_gadget_remove_driver() empty 'dev.driver ' NULL, but UAF cannot be avoided.
>
> static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env) {
> .....
> if (dev->driver)
> 2320 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
> .....
> }
>
> Whether protection can be added when operating 'dev->driver'?
When the driver structure is unbound, this should be set to NULL. Why
isn't that happening?
thanks,
greg k-h