In the Linux kernel, the following vulnerability has been resolved:
ocfs2: handle a symlink read error correctly
Patch series "Convert ocfs2 to use folios".
Mark did a conversion of ocfs2 to use folios and sent it to me as a
giant patch for review ;-)
So I've redone it as individual patches, and credited Mark for the patches
where his code is substantially the same. It's not a bad way to do it;
his patch had some bugs and my patches had some bugs. Hopefully all our
bugs were different from each other. And hopefully Mark likes all the
changes I made to his code!
This patch (of 23):
If we can't read the buffer, be sure to unlock the page before returning.
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: bsg: Set bsg_queue to NULL after removal
Currently, this does not cause any issues, but I believe it is necessary to
set bsg_queue to NULL after removing it to prevent potential use-after-free
(UAF) access.
In the Linux kernel, the following vulnerability has been resolved:
net: rose: fix timer races against user threads
Rose timers only acquire the socket spinlock, without
checking if the socket is owned by one user thread.
Add a check and rearm the timers if needed.
BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174
Read of size 2 at addr ffff88802f09b82a by task swapper/0/0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174
call_timer_fn+0x187/0x650 kernel/time/timer.c:1793
expire_timers kernel/time/timer.c:1844 [inline]
__run_timers kernel/time/timer.c:2418 [inline]
__run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430
run_timer_base kernel/time/timer.c:2439 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
__do_softirq kernel/softirq.c:595 [inline]
invoke_softirq kernel/softirq.c:435 [inline]
__irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
</IRQ>
In the Linux kernel, the following vulnerability has been resolved:
net/rose: prevent integer overflows in rose_setsockopt()
In case of possible unpredictably large arguments passed to
rose_setsockopt() and multiplied by extra values on top of that,
integer overflows may occur.
Do the safest minimum and fix these issues by checking the
contents of 'opt' and returning -EINVAL if they are too large. Also,
switch to unsigned int and remove useless check for negative 'opt'
in ROSE_IDLE case.
In the Linux kernel, the following vulnerability has been resolved:
md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime
After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:
Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
<TASK>
md_seq_show+0x2d2/0x5b0
seq_read_iter+0x2b9/0x470
seq_read+0x12f/0x180
proc_reg_read+0x57/0xb0
vfs_read+0xf6/0x380
ksys_read+0x6c/0xf0
do_syscall_64+0x82/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.
Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.
In the Linux kernel, the following vulnerability has been resolved:
net_sched: sch_sfq: don't allow 1 packet limit
The current implementation does not work correctly with a limit of
1. iproute2 actually checks for this and this patch adds the check in
kernel as well.
This fixes the following syzkaller reported crash:
UBSAN: array-index-out-of-bounds in net/sched/sch_sfq.c:210:6
index 65535 is out of range for type 'struct sfq_head[128]'
CPU: 0 PID: 2569 Comm: syz-executor101 Not tainted 5.10.0-smp-DEV #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x125/0x19f lib/dump_stack.c:120
ubsan_epilogue lib/ubsan.c:148 [inline]
__ubsan_handle_out_of_bounds+0xed/0x120 lib/ubsan.c:347
sfq_link net/sched/sch_sfq.c:210 [inline]
sfq_dec+0x528/0x600 net/sched/sch_sfq.c:238
sfq_dequeue+0x39b/0x9d0 net/sched/sch_sfq.c:500
sfq_reset+0x13/0x50 net/sched/sch_sfq.c:525
qdisc_reset+0xfe/0x510 net/sched/sch_generic.c:1026
tbf_reset+0x3d/0x100 net/sched/sch_tbf.c:319
qdisc_reset+0xfe/0x510 net/sched/sch_generic.c:1026
dev_reset_queue+0x8c/0x140 net/sched/sch_generic.c:1296
netdev_for_each_tx_queue include/linux/netdevice.h:2350 [inline]
dev_deactivate_many+0x6dc/0xc20 net/sched/sch_generic.c:1362
__dev_close_many+0x214/0x350 net/core/dev.c:1468
dev_close_many+0x207/0x510 net/core/dev.c:1506
unregister_netdevice_many+0x40f/0x16b0 net/core/dev.c:10738
unregister_netdevice_queue+0x2be/0x310 net/core/dev.c:10695
unregister_netdevice include/linux/netdevice.h:2893 [inline]
__tun_detach+0x6b6/0x1600 drivers/net/tun.c:689
tun_detach drivers/net/tun.c:705 [inline]
tun_chr_close+0x104/0x1b0 drivers/net/tun.c:3640
__fput+0x203/0x840 fs/file_table.c:280
task_work_run+0x129/0x1b0 kernel/task_work.c:185
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x5ce/0x2200 kernel/exit.c:931
do_group_exit+0x144/0x310 kernel/exit.c:1046
__do_sys_exit_group kernel/exit.c:1057 [inline]
__se_sys_exit_group kernel/exit.c:1055 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1055
do_syscall_64+0x6c/0xd0
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe5e7b52479
Code: Unable to access opcode bytes at RIP 0x7fe5e7b5244f.
RSP: 002b:00007ffd3c800398 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe5e7b52479
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007fe5e7bcd2d0 R08: ffffffffffffffb8 R09: 0000000000000014
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe5e7bcd2d0
R13: 0000000000000000 R14: 00007fe5e7bcdd20 R15: 00007fe5e7b24270
The crash can be also be reproduced with the following (with a tc
recompiled to allow for sfq limits of 1):
tc qdisc add dev dummy0 handle 1: root tbf rate 1Kbit burst 100b lat 1s
../iproute2-6.9.0/tc/tc qdisc add dev dummy0 handle 2: parent 1:10 sfq limit 1
ifconfig dummy0 up
ping -I dummy0 -f -c2 -W0.1 8.8.8.8
sleep 1
Scenario that triggers the crash:
* the first packet is sent and queued in TBF and SFQ; qdisc qlen is 1
* TBF dequeues: it peeks from SFQ which moves the packet to the
gso_skb list and keeps qdisc qlen set to 1. TBF is out of tokens so
it schedules itself for later.
* the second packet is sent and TBF tries to queues it to SFQ. qdisc
qlen is now 2 and because the SFQ limit is 1 the packet is dropped
by SFQ. At this point qlen is 1, and all of the SFQ slots are empty,
however q->tail is not NULL.
At this point, assuming no more packets are queued, when sch_dequeue
runs again it will decrement the qlen for the current empty slot
causing an underflow and the subsequent out of bounds access.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: do proper folio cleanup when run_delalloc_nocow() failed
[BUG]
With CONFIG_DEBUG_VM set, test case generic/476 has some chance to crash
with the following VM_BUG_ON_FOLIO():
BTRFS error (device dm-3): cow_file_range failed, start 1146880 end 1253375 len 106496 ret -28
BTRFS error (device dm-3): run_delalloc_nocow failed, start 1146880 end 1253375 len 106496 ret -28
page: refcount:4 mapcount:0 mapping:00000000592787cc index:0x12 pfn:0x10664
aops:btrfs_aops [btrfs] ino:101 dentry name(?):"f1774"
flags: 0x2fffff80004028(uptodate|lru|private|node=0|zone=2|lastcpupid=0xfffff)
page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))
------------[ cut here ]------------
kernel BUG at mm/page-writeback.c:2992!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
CPU: 2 UID: 0 PID: 3943513 Comm: kworker/u24:15 Tainted: G OE 6.12.0-rc7-custom+ #87
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]
pc : folio_clear_dirty_for_io+0x128/0x258
lr : folio_clear_dirty_for_io+0x128/0x258
Call trace:
folio_clear_dirty_for_io+0x128/0x258
btrfs_folio_clamp_clear_dirty+0x80/0xd0 [btrfs]
__process_folios_contig+0x154/0x268 [btrfs]
extent_clear_unlock_delalloc+0x5c/0x80 [btrfs]
run_delalloc_nocow+0x5f8/0x760 [btrfs]
btrfs_run_delalloc_range+0xa8/0x220 [btrfs]
writepage_delalloc+0x230/0x4c8 [btrfs]
extent_writepage+0xb8/0x358 [btrfs]
extent_write_cache_pages+0x21c/0x4e8 [btrfs]
btrfs_writepages+0x94/0x150 [btrfs]
do_writepages+0x74/0x190
filemap_fdatawrite_wbc+0x88/0xc8
start_delalloc_inodes+0x178/0x3a8 [btrfs]
btrfs_start_delalloc_roots+0x174/0x280 [btrfs]
shrink_delalloc+0x114/0x280 [btrfs]
flush_space+0x250/0x2f8 [btrfs]
btrfs_async_reclaim_data_space+0x180/0x228 [btrfs]
process_one_work+0x164/0x408
worker_thread+0x25c/0x388
kthread+0x100/0x118
ret_from_fork+0x10/0x20
Code: 910a8021 a90363f7 a9046bf9 94012379 (d4210000)
---[ end trace 0000000000000000 ]---
[CAUSE]
The first two lines of extra debug messages show the problem is caused
by the error handling of run_delalloc_nocow().
E.g. we have the following dirtied range (4K blocksize 4K page size):
0 16K 32K
|//////////////////////////////////////|
| Pre-allocated |
And the range [0, 16K) has a preallocated extent.
- Enter run_delalloc_nocow() for range [0, 16K)
Which found range [0, 16K) is preallocated, can do the proper NOCOW
write.
- Enter fallback_to_fow() for range [16K, 32K)
Since the range [16K, 32K) is not backed by preallocated extent, we
have to go COW.
- cow_file_range() failed for range [16K, 32K)
So cow_file_range() will do the clean up by clearing folio dirty,
unlock the folios.
Now the folios in range [16K, 32K) is unlocked.
- Enter extent_clear_unlock_delalloc() from run_delalloc_nocow()
Which is called with PAGE_START_WRITEBACK to start page writeback.
But folios can only be marked writeback when it's properly locked,
thus this triggered the VM_BUG_ON_FOLIO().
Furthermore there is another hidden but common bug that
run_delalloc_nocow() is not clearing the folio dirty flags in its error
handling path.
This is the common bug shared between run_delalloc_nocow() and
cow_file_range().
[FIX]
- Clear folio dirty for range [@start, @cur_offset)
Introduce a helper, cleanup_dirty_folios(), which
will find and lock the folio in the range, clear the dirty flag and
start/end the writeback, with the extra handling for the
@locked_folio.
- Introduce a helper to clear folio dirty, start and end writeback
- Introduce a helper to record the last failed COW range end
This is to trace which range we should skip, to avoid double
unlocking.
- Skip the failed COW range for the e
---truncated---