[syzbot] KASAN: use-after-free Read in driver_register

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a2673d570bd6 usb: gadget: uvc: track frames in format entr..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=1100a2f8f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d7b232ec3adf5c8d
dashboard link: https://syzkaller.appspot.com/bug?extid=dc7c3ca638e773db07f6
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dc7c3c...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in driver_find drivers/base/driver.c:223 [inline]
BUG: KASAN: use-after-free in driver_register+0x34d/0x3a0 drivers/base/driver.c:164
Read of size 8 at addr ffff88810f8cd0c8 by task syz-executor.0/8326

CPU: 0 PID: 8326 Comm: syz-executor.0 Not tainted 5.18.0-rc5-syzkaller-00112-ga2673d570bd6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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+0xeb/0x495 mm/kasan/report.c:313
print_report mm/kasan/report.c:429 [inline]
kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
driver_find drivers/base/driver.c:223 [inline]
driver_register+0x34d/0x3a0 drivers/base/driver.c:164
usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1546
raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:513 [inline]
raw_ioctl+0x1883/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1220
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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: 0033:0x7f7b05256ea7
Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 34 54 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7b049cb098 EFLAGS: 00000246
ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7b049cc110 RCX: 00007f7b05256ea7
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 0000000000000003 R08: 000000000000ffff R09: 000000000000000b
R10: 00007f7b049cb140 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000020000000 R15: 0000000000000000
</TASK>

Allocated by task 8324:
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+0x81/0xa0 mm/kasan/common.c:524
kmalloc include/linux/slab.h:581 [inline]
kzalloc include/linux/slab.h:714 [inline]
bus_add_driver+0xd4/0x630 drivers/base/bus.c:602
driver_register+0x220/0x3a0 drivers/base/driver.c:171
usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1546
raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:513 [inline]
raw_ioctl+0x1883/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1220
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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 8326:
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+0x10f/0x190 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook mm/slub.c:1754 [inline]
slab_free mm/slub.c:3510 [inline]
kfree+0xc1/0x4f0 mm/slub.c:4552
kobject_cleanup lib/kobject.c:673 [inline]
kobject_release lib/kobject.c:704 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c8/0x540 lib/kobject.c:721
driver_find drivers/base/driver.c:221 [inline]
driver_register+0x1e3/0x3a0 drivers/base/driver.c:164
usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1546
raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:513 [inline]
raw_ioctl+0x1883/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1220
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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 ffff88810f8cd000
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 200 bytes inside of
256-byte region [ffff88810f8cd000, ffff88810f8cd100)

The buggy address belongs to the physical page:
page:ffffea00043e3300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10f8cc
head:ffffea00043e3300 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x200000000010200(slab|head|node=0|zone=2)
raw: 0200000000010200 ffffea000433cb00 dead000000000005 ffff888100041b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 206, tgid 206 (kworker/u4:3), ts 5899855484, free_ts 0
prep_new_page mm/page_alloc.c:2441 [inline]
get_page_from_freelist+0x1373/0x27b0 mm/page_alloc.c:4182
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272
alloc_slab_page mm/slub.c:1799 [inline]
allocate_slab+0x26c/0x3c0 mm/slub.c:1944
new_slab mm/slub.c:2004 [inline]
___slab_alloc+0x95a/0x1010 mm/slub.c:3005
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092
slab_alloc_node mm/slub.c:3183 [inline]
slab_alloc mm/slub.c:3225 [inline]
kmem_cache_alloc_trace+0x2fd/0x3b0 mm/slub.c:3256
kmalloc include/linux/slab.h:581 [inline]
kzalloc include/linux/slab.h:714 [inline]
set_kthread_struct+0xc5/0x250 kernel/kthread.c:117
copy_process+0x332c/0x6db0 kernel/fork.c:2161
kernel_clone+0xe7/0xab0 kernel/fork.c:2639
kernel_thread+0xb5/0xf0 kernel/fork.c:2691
call_usermodehelper_exec_work kernel/umh.c:174 [inline]
call_usermodehelper_exec_work+0xcc/0x180 kernel/umh.c:160
process_one_work+0x996/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2ef/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
page_owner free stack trace missing

Memory state around the buggy address:
ffff88810f8ccf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810f8cd000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810f8cd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88810f8cd100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810f8cd180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: d3fde8ff50ab Add linux-next specific files for 20220527
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=154faf23f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=ccb8d66fc9489ef

dashboard link: https://syzkaller.appspot.com/bug?extid=dc7c3ca638e773db07f6
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=17315ad6f00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12087513f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dc7c3c...@syzkaller.appspotmail.com

==================================================================

BUG: KASAN: use-after-free in driver_find drivers/base/driver.c:293 [inline]
BUG: KASAN: use-after-free in driver_register+0x352/0x3a0 drivers/base/driver.c:233
Read of size 8 at addr ffff88807813bec8 by task syz-executor372/10628

CPU: 1 PID: 10628 Comm: syz-executor372 Not tainted 5.18.0-next-20220527-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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+0xeb/0x495 mm/kasan/report.c:313
print_report mm/kasan/report.c:429 [inline]
kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491

driver_find drivers/base/driver.c:293 [inline]
driver_register+0x352/0x3a0 drivers/base/driver.c:233
usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1558
raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:515 [inline]
raw_ioctl+0x188d/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1222

vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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+0x46/0xb0
RIP: 0033:0x7fddef18d7d7
Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 14 59 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fddef12b258 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fddef12c2d0 RCX: 00007fddef18d7d7
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000007
RBP: 0000000000000000 R08: 000000000000ffff R09: 000000000000000b
R10: 00007fddef12b300 R11: 0000000000000246 R12: 00007fddef211360
R13: 00007fddef12b2a0 R14: 00007fddef12d400 R15: 0000000000000007
</TASK>

Allocated by task 10078:

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+0xa9/0xd0 mm/kasan/common.c:524
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
bus_add_driver+0xd4/0x640 drivers/base/bus.c:602
driver_register+0x220/0x3a0 drivers/base/driver.c:240
usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1558
raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:515 [inline]
raw_ioctl+0x188d/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1222

vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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+0x46/0xb0

Freed by task 10628:

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+0x166/0x1a0 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1727 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753
slab_free mm/slub.c:3507 [inline]
kfree+0xd6/0x4d0 mm/slub.c:4555

kobject_cleanup lib/kobject.c:673 [inline]
kobject_release lib/kobject.c:704 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c8/0x540 lib/kobject.c:721

driver_find drivers/base/driver.c:291 [inline]
driver_register+0x1e3/0x3a0 drivers/base/driver.c:233
usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1558
raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:515 [inline]
raw_ioctl+0x188d/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1222

vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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+0x46/0xb0

Last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
kvfree_call_rcu+0x74/0x990 kernel/rcu/tree.c:3647
drop_sysctl_table+0x3c0/0x4e0 fs/proc/proc_sysctl.c:1716
unregister_sysctl_table fs/proc/proc_sysctl.c:1754 [inline]
unregister_sysctl_table+0xc0/0x190 fs/proc/proc_sysctl.c:1729
__addrconf_sysctl_unregister net/ipv6/addrconf.c:7108 [inline]
addrconf_sysctl_unregister+0xee/0x1c0 net/ipv6/addrconf.c:7136
addrconf_notify+0x7f6/0x1ba0 net/ipv6/addrconf.c:3679
notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1943
call_netdevice_notifiers_extack net/core/dev.c:1981 [inline]
call_netdevice_notifiers net/core/dev.c:1995 [inline]
dev_change_name+0x571/0x820 net/core/dev.c:1224
do_setlink+0x19a9/0x3bb0 net/core/rtnetlink.c:2760
__rtnl_newlink+0xd6a/0x17e0 net/core/rtnetlink.c:3546
rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3593
rtnetlink_rcv_msg+0x43a/0xc90 net/core/rtnetlink.c:6089
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:734
__sys_sendto+0x21a/0x320 net/socket.c:2119
__do_sys_sendto net/socket.c:2131 [inline]
__se_sys_sendto net/socket.c:2127 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2127

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+0x46/0xb0

The buggy address belongs to the object at ffff88807813be00

which belongs to the cache kmalloc-256 of size 256
The buggy address is located 200 bytes inside of

256-byte region [ffff88807813be00, ffff88807813bf00)

The buggy address belongs to the physical page:

page:ffffea0001e04e80 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807813ba00 pfn:0x7813a
head:ffffea0001e04e80 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010c41b40
raw: ffff88807813ba00 000000008010000f 00000001ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3682, tgid 3682 (syz-executor372), ts 1120620374205, free_ts 1120617564582
prep_new_page mm/page_alloc.c:2464 [inline]
get_page_from_freelist+0xa64/0x3d10 mm/page_alloc.c:4283
__alloc_pages+0x1c7/0x510 mm/page_alloc.c:5507
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272
alloc_slab_page mm/slub.c:1797 [inline]
allocate_slab+0x26c/0x3c0 mm/slub.c:1942
new_slab mm/slub.c:2002 [inline]
___slab_alloc+0x985/0xd90 mm/slub.c:3002
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3089
slab_alloc_node mm/slub.c:3180 [inline]
slab_alloc mm/slub.c:3222 [inline]
__kmalloc+0x318/0x350 mm/slub.c:4413
kmalloc include/linux/slab.h:605 [inline]
kzalloc include/linux/slab.h:733 [inline]
fib_create_info+0xdbe/0x4ac0 net/ipv4/fib_semantics.c:1448
fib_table_insert+0x19a/0x1bd0 net/ipv4/fib_trie.c:1233
fib_magic+0x455/0x540 net/ipv4/fib_frontend.c:1098
fib_add_ifaddr+0x16b/0x540 net/ipv4/fib_frontend.c:1120
fib_inetaddr_event+0x162/0x2a0 net/ipv4/fib_frontend.c:1434
notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
blocking_notifier_call_chain kernel/notifier.c:382 [inline]
blocking_notifier_call_chain+0x67/0x90 kernel/notifier.c:370
__inet_insert_ifa+0x919/0xbd0 net/ipv4/devinet.c:554
inet_rtm_newaddr+0x54d/0x980 net/ipv4/devinet.c:960
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1379 [inline]
free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1429
free_unref_page_prepare mm/page_alloc.c:3315 [inline]
free_unref_page+0x19/0x7b0 mm/page_alloc.c:3430
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
kasan_slab_alloc include/linux/kasan.h:224 [inline]
slab_post_alloc_hook mm/slab.h:750 [inline]
slab_alloc_node mm/slub.c:3214 [inline]
kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3264
__alloc_skb+0x215/0x340 net/core/skbuff.c:414
alloc_skb include/linux/skbuff.h:1426 [inline]
nlmsg_new include/net/netlink.h:953 [inline]
netlink_ack+0x1f0/0xa80 net/netlink/af_netlink.c:2436
netlink_rcv_skb+0x33d/0x420 net/netlink/af_netlink.c:2507
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:734
__sys_sendto+0x21a/0x320 net/socket.c:2119
__do_sys_sendto net/socket.c:2131 [inline]
__se_sys_sendto net/socket.c:2127 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2127

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+0x46/0xb0

Memory state around the buggy address:

ffff88807813bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807813be00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807813be80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807813bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807813bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

[Hillf Danton]

On Sat, 28 May 2022 19:07:19 -0700

To fix the uaf, avoid derefering kobj after putting it.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git d3fde8ff50ab

--- y/drivers/base/driver.c
+++ x/drivers/base/driver.c
@@ -287,10 +287,13 @@ struct device_driver *driver_find(const
struct driver_private *priv;

if (k) {
+ struct device_driver *drv;
+
+ priv = to_driver(k);
+ drv = priv->driver;
/* Drop reference added by kset_find_obj() */
kobject_put(k);
- priv = to_driver(k);
- return priv->driver;
+ return drv;
}
return NULL;
}
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+dc7c3c...@syzkaller.appspotmail.com

Tested on:

commit: d3fde8ff Add linux-next specific files for 20220527
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

kernel config: https://syzkaller.appspot.com/x/.config?x=ccb8d66fc9489ef
dashboard link: https://syzkaller.appspot.com/bug?extid=dc7c3ca638e773db07f6
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=14fdf0ebf00000

Note: testing is done by a robot and is best-effort only.

[Alan Stern]

This sounds a lot like the "WARNING in driver_unregister" bug. Let's see
if the same fix works.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 97fa5887cf28

Index: usb-devel/drivers/usb/gadget/legacy/raw_gadget.c
===================================================================
--- usb-devel.orig/drivers/usb/gadget/legacy/raw_gadget.c
+++ usb-devel/drivers/usb/gadget/legacy/raw_gadget.c
@@ -11,6 +11,7 @@
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
+#include <linux/idr.h>
#include <linux/kref.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
@@ -36,6 +37,9 @@ MODULE_LICENSE("GPL");

/*----------------------------------------------------------------------*/

+static DEFINE_IDA(driver_id_numbers);
+#define DRIVER_DRIVER_NAME_LENGTH_MAX 32
+
#define RAW_EVENT_QUEUE_SIZE 16

struct raw_event_queue {
@@ -145,6 +149,7 @@ enum dev_state {
STATE_DEV_INVALID = 0,
STATE_DEV_OPENED,
STATE_DEV_INITIALIZED,
+ STATE_DEV_REGISTERING,
STATE_DEV_RUNNING,
STATE_DEV_CLOSED,
STATE_DEV_FAILED
@@ -160,6 +165,9 @@ struct raw_dev {
/* Reference to misc device: */
struct device *dev;

+ /* Make driver names unique */
+ int driver_id_number;
+
/* Protected by lock: */
enum dev_state state;
bool gadget_registered;
@@ -188,6 +196,7 @@ static struct raw_dev *dev_new(void)
spin_lock_init(&dev->lock);
init_completion(&dev->ep0_done);
raw_event_queue_init(&dev->queue);
+ dev->driver_id_number = -1;
return dev;
}

@@ -198,6 +207,9 @@ static void dev_free(struct kref *kref)

kfree(dev->udc_name);
kfree(dev->driver.udc_name);
+ kfree(dev->driver.driver.name);
+ if (dev->driver_id_number >= 0)
+ ida_free(&driver_id_numbers, dev->driver_id_number);
if (dev->req) {
if (dev->ep0_urb_queued)
usb_ep_dequeue(dev->gadget->ep0, dev->req);
@@ -421,6 +433,7 @@ static int raw_ioctl_init(struct raw_dev
struct usb_raw_init arg;
char *udc_driver_name;
char *udc_device_name;
+ char *driver_driver_name;
unsigned long flags;

if (copy_from_user(&arg, (void __user *)value, sizeof(arg)))
@@ -439,36 +452,44 @@ static int raw_ioctl_init(struct raw_dev
return -EINVAL;
}

+ ret = ida_alloc(&driver_id_numbers, GFP_KERNEL);
+ if (ret < 0)
+ return ret;
+ dev->driver_id_number = ret;
+
+ driver_driver_name = kmalloc(DRIVER_DRIVER_NAME_LENGTH_MAX, GFP_KERNEL);
+ if (!driver_driver_name) {
+ ret = -ENOMEM;
+ goto out_free_driver_id_number;
+ }
+ snprintf(driver_driver_name, DRIVER_DRIVER_NAME_LENGTH_MAX,
+ DRIVER_NAME ".%d", dev->driver_id_number);
+
udc_driver_name = kmalloc(UDC_NAME_LENGTH_MAX, GFP_KERNEL);
- if (!udc_driver_name)
- return -ENOMEM;
+ if (!udc_driver_name) {
+ ret = -ENOMEM;
+ goto out_free_driver_driver_name;
+ }
ret = strscpy(udc_driver_name, &arg.driver_name[0],
UDC_NAME_LENGTH_MAX);
- if (ret < 0) {
- kfree(udc_driver_name);
- return ret;
- }
+ if (ret < 0)
+ goto out_free_udc_driver_name;
ret = 0;

udc_device_name = kmalloc(UDC_NAME_LENGTH_MAX, GFP_KERNEL);
if (!udc_device_name) {
- kfree(udc_driver_name);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out_free_udc_driver_name;
}
ret = strscpy(udc_device_name, &arg.device_name[0],
UDC_NAME_LENGTH_MAX);
- if (ret < 0) {
- kfree(udc_driver_name);
- kfree(udc_device_name);
- return ret;
- }
+ if (ret < 0)
+ goto out_free_udc_device_name;
ret = 0;

spin_lock_irqsave(&dev->lock, flags);
if (dev->state != STATE_DEV_OPENED) {
dev_dbg(dev->dev, "fail, device is not opened\n");
- kfree(udc_driver_name);
- kfree(udc_device_name);
ret = -EINVAL;
goto out_unlock;
}
@@ -483,14 +504,24 @@ static int raw_ioctl_init(struct raw_dev
dev->driver.suspend = gadget_suspend;
dev->driver.resume = gadget_resume;
dev->driver.reset = gadget_reset;
- dev->driver.driver.name = DRIVER_NAME;
+ dev->driver.driver.name = driver_driver_name;
dev->driver.udc_name = udc_device_name;
dev->driver.match_existing_only = 1;

dev->state = STATE_DEV_INITIALIZED;
+ spin_unlock_irqrestore(&dev->lock, flags);
+ return ret;

out_unlock:
spin_unlock_irqrestore(&dev->lock, flags);
+out_free_udc_device_name:
+ kfree(udc_device_name);
+out_free_udc_driver_name:
+ kfree(udc_driver_name);
+out_free_driver_driver_name:
+ kfree(driver_driver_name);
+out_free_driver_id_number:
+ ida_free(&driver_id_numbers, dev->driver_id_number);
return ret;
}

@@ -508,6 +539,7 @@ static int raw_ioctl_run(struct raw_dev
ret = -EINVAL;
goto out_unlock;
}
+ dev->state = STATE_DEV_REGISTERING;
spin_unlock_irqrestore(&dev->lock, flags);

ret = usb_gadget_register_driver(&dev->driver);

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+dc7c3c...@syzkaller.appspotmail.com

Tested on:

commit: 97fa5887 USB: new quirk for Dell Gen 2 devices
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
kernel config: https://syzkaller.appspot.com/x/.config?x=5a0efc262ca60947

dashboard link: https://syzkaller.appspot.com/bug?extid=dc7c3ca638e773db07f6
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=1224de7bf00000