| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
tracing/synthetic: Fix races on freeing last_cmd
Currently, the "last_cmd" variable can be accessed by multiple processes
asynchronously when multiple users manipulate synthetic_events node
at the same time, it could lead to use-after-free or double-free.
This patch add "lastcmd_mutex" to prevent "last_cmd" from being accessed
asynchronously.
================================================================
It's easy to reproduce in the KASAN environment by running the two
scripts below in different shells.
script 1:
while :
do
echo -n -e '\x88' > /sys/kernel/tracing/synthetic_events
done
script 2:
while :
do
echo -n -e '\xb0' > /sys/kernel/tracing/synthetic_events
done
================================================================
double-free scenario:
process A process B
------------------- ---------------
1.kstrdup last_cmd
2.free last_cmd
3.free last_cmd(double-free)
================================================================
use-after-free scenario:
process A process B
------------------- ---------------
1.kstrdup last_cmd
2.free last_cmd
3.tracing_log_err(use-after-free)
================================================================
Appendix 1. KASAN report double-free:
BUG: KASAN: double-free in kfree+0xdc/0x1d4
Free of addr ***** by task sh/4879
Call trace:
...
kfree+0xdc/0x1d4
create_or_delete_synth_event+0x60/0x1e8
trace_parse_run_command+0x2bc/0x4b8
synth_events_write+0x20/0x30
vfs_write+0x200/0x830
...
Allocated by task 4879:
...
kstrdup+0x5c/0x98
create_or_delete_synth_event+0x6c/0x1e8
trace_parse_run_command+0x2bc/0x4b8
synth_events_write+0x20/0x30
vfs_write+0x200/0x830
...
Freed by task 5464:
...
kfree+0xdc/0x1d4
create_or_delete_synth_event+0x60/0x1e8
trace_parse_run_command+0x2bc/0x4b8
synth_events_write+0x20/0x30
vfs_write+0x200/0x830
...
================================================================
Appendix 2. KASAN report use-after-free:
BUG: KASAN: use-after-free in strlen+0x5c/0x7c
Read of size 1 at addr ***** by task sh/5483
sh: CPU: 7 PID: 5483 Comm: sh
...
__asan_report_load1_noabort+0x34/0x44
strlen+0x5c/0x7c
tracing_log_err+0x60/0x444
create_or_delete_synth_event+0xc4/0x204
trace_parse_run_command+0x2bc/0x4b8
synth_events_write+0x20/0x30
vfs_write+0x200/0x830
...
Allocated by task 5483:
...
kstrdup+0x5c/0x98
create_or_delete_synth_event+0x80/0x204
trace_parse_run_command+0x2bc/0x4b8
synth_events_write+0x20/0x30
vfs_write+0x200/0x830
...
Freed by task 5480:
...
kfree+0xdc/0x1d4
create_or_delete_synth_event+0x74/0x204
trace_parse_run_command+0x2bc/0x4b8
synth_events_write+0x20/0x30
vfs_write+0x200/0x830
... |
| In the Linux kernel, the following vulnerability has been resolved:
skbuff: Fix a race between coalescing and releasing SKBs
Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment
recycling") allowed coalescing to proceed with non page pool page and page
pool page when @from is cloned, i.e.
to->pp_recycle --> false
from->pp_recycle --> true
skb_cloned(from) --> true
However, it actually requires skb_cloned(@from) to hold true until
coalescing finishes in this situation. If the other cloned SKB is
released while the merging is in process, from_shinfo->nr_frags will be
set to 0 toward the end of the function, causing the increment of frag
page _refcount to be unexpectedly skipped resulting in inconsistent
reference counts. Later when SKB(@to) is released, it frees the page
directly even though the page pool page is still in use, leading to
use-after-free or double-free errors. So it should be prohibited.
The double-free error message below prompted us to investigate:
BUG: Bad page state in process swapper/1 pfn:0e0d1
page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000
index:0x2 pfn:0xe0d1
flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000
raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000
page dumped because: nonzero _refcount
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G E 6.2.0+
Call Trace:
<IRQ>
dump_stack_lvl+0x32/0x50
bad_page+0x69/0xf0
free_pcp_prepare+0x260/0x2f0
free_unref_page+0x20/0x1c0
skb_release_data+0x10b/0x1a0
napi_consume_skb+0x56/0x150
net_rx_action+0xf0/0x350
? __napi_schedule+0x79/0x90
__do_softirq+0xc8/0x2b1
__irq_exit_rcu+0xb9/0xf0
common_interrupt+0x82/0xa0
</IRQ>
<TASK>
asm_common_interrupt+0x22/0x40
RIP: 0010:default_idle+0xb/0x20 |
| In the Linux kernel, the following vulnerability has been resolved:
mm: fix zswap writeback race condition
The zswap writeback mechanism can cause a race condition resulting in
memory corruption, where a swapped out page gets swapped in with data that
was written to a different page.
The race unfolds like this:
1. a page with data A and swap offset X is stored in zswap
2. page A is removed off the LRU by zpool driver for writeback in
zswap-shrink work, data for A is mapped by zpool driver
3. user space program faults and invalidates page entry A, offset X is
considered free
4. kswapd stores page B at offset X in zswap (zswap could also be
full, if so, page B would then be IOed to X, then skip step 5.)
5. entry A is replaced by B in tree->rbroot, this doesn't affect the
local reference held by zswap-shrink work
6. zswap-shrink work writes back A at X, and frees zswap entry A
7. swapin of slot X brings A in memory instead of B
The fix:
Once the swap page cache has been allocated (case ZSWAP_SWAPCACHE_NEW),
zswap-shrink work just checks that the local zswap_entry reference is
still the same as the one in the tree. If it's not the same it means that
it's either been invalidated or replaced, in both cases the writeback is
aborted because the local entry contains stale data.
Reproducer:
I originally found this by running `stress` overnight to validate my work
on the zswap writeback mechanism, it manifested after hours on my test
machine. The key to make it happen is having zswap writebacks, so
whatever setup pumps /sys/kernel/debug/zswap/written_back_pages should do
the trick.
In order to reproduce this faster on a vm, I setup a system with ~100M of
available memory and a 500M swap file, then running `stress --vm 1
--vm-bytes 300000000 --vm-stride 4000` makes it happen in matter of tens
of minutes. One can speed things up even more by swinging
/sys/module/zswap/parameters/max_pool_percent up and down between, say, 20
and 1; this makes it reproduce in tens of seconds. It's crucial to set
`--vm-stride` to something other than 4096 otherwise `stress` won't
realize that memory has been corrupted because all pages would have the
same data. |
| In the Linux kernel, the following vulnerability has been resolved:
tty: serial: fsl_lpuart: fix race on RX DMA shutdown
From time to time DMA completion can come in the middle of DMA shutdown:
<process ctx>: <IRQ>:
lpuart32_shutdown()
lpuart_dma_shutdown()
del_timer_sync()
lpuart_dma_rx_complete()
lpuart_copy_rx_to_tty()
mod_timer()
lpuart_dma_rx_free()
When the timer fires a bit later, sport->dma_rx_desc is NULL:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
pc : lpuart_copy_rx_to_tty+0xcc/0x5bc
lr : lpuart_timer_func+0x1c/0x2c
Call trace:
lpuart_copy_rx_to_tty
lpuart_timer_func
call_timer_fn
__run_timers.part.0
run_timer_softirq
__do_softirq
__irq_exit_rcu
irq_exit
handle_domain_irq
gic_handle_irq
call_on_irq_stack
do_interrupt_handler
...
To fix this fold del_timer_sync() into lpuart_dma_rx_free() after
dmaengine_terminate_sync() to make sure timer will not be re-started in
lpuart_copy_rx_to_tty() <= lpuart_dma_rx_complete(). |
| In the Linux kernel, the following vulnerability has been resolved:
tee: amdtee: fix race condition in amdtee_open_session
There is a potential race condition in amdtee_open_session that may
lead to use-after-free. For instance, in amdtee_open_session() after
sess->sess_mask is set, and before setting:
sess->session_info[i] = session_info;
if amdtee_close_session() closes this same session, then 'sess' data
structure will be released, causing kernel panic when 'sess' is
accessed within amdtee_open_session().
The solution is to set the bit sess->sess_mask as the last step in
amdtee_open_session(). |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: Fix race condition in hci_cmd_sync_clear
There is a potential race condition in hci_cmd_sync_work and
hci_cmd_sync_clear, and could lead to use-after-free. For instance,
hci_cmd_sync_work is added to the 'req_workqueue' after cancel_work_sync
The entry of 'cmd_sync_work_list' may be freed in hci_cmd_sync_clear, and
causing kernel panic when it is used in 'hci_cmd_sync_work'.
Here's the call trace:
dump_stack_lvl+0x49/0x63
print_report.cold+0x5e/0x5d3
? hci_cmd_sync_work+0x282/0x320
kasan_report+0xaa/0x120
? hci_cmd_sync_work+0x282/0x320
__asan_report_load8_noabort+0x14/0x20
hci_cmd_sync_work+0x282/0x320
process_one_work+0x77b/0x11c0
? _raw_spin_lock_irq+0x8e/0xf0
worker_thread+0x544/0x1180
? poll_idle+0x1e0/0x1e0
kthread+0x285/0x320
? process_one_work+0x11c0/0x11c0
? kthread_complete_and_exit+0x30/0x30
ret_from_fork+0x22/0x30
</TASK>
Allocated by task 266:
kasan_save_stack+0x26/0x50
__kasan_kmalloc+0xae/0xe0
kmem_cache_alloc_trace+0x191/0x350
hci_cmd_sync_queue+0x97/0x2b0
hci_update_passive_scan+0x176/0x1d0
le_conn_complete_evt+0x1b5/0x1a00
hci_le_conn_complete_evt+0x234/0x340
hci_le_meta_evt+0x231/0x4e0
hci_event_packet+0x4c5/0xf00
hci_rx_work+0x37d/0x880
process_one_work+0x77b/0x11c0
worker_thread+0x544/0x1180
kthread+0x285/0x320
ret_from_fork+0x22/0x30
Freed by task 269:
kasan_save_stack+0x26/0x50
kasan_set_track+0x25/0x40
kasan_set_free_info+0x24/0x40
____kasan_slab_free+0x176/0x1c0
__kasan_slab_free+0x12/0x20
slab_free_freelist_hook+0x95/0x1a0
kfree+0xba/0x2f0
hci_cmd_sync_clear+0x14c/0x210
hci_unregister_dev+0xff/0x440
vhci_release+0x7b/0xf0
__fput+0x1f3/0x970
____fput+0xe/0x20
task_work_run+0xd4/0x160
do_exit+0x8b0/0x22a0
do_group_exit+0xba/0x2a0
get_signal+0x1e4a/0x25b0
arch_do_signal_or_restart+0x93/0x1f80
exit_to_user_mode_prepare+0xf5/0x1a0
syscall_exit_to_user_mode+0x26/0x50
ret_from_fork+0x15/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
mm/MADV_COLLAPSE: catch !none !huge !bad pmd lookups
In commit 34488399fa08 ("mm/madvise: add file and shmem support to
MADV_COLLAPSE") we make the following change to find_pmd_or_thp_or_none():
- if (!pmd_present(pmde))
- return SCAN_PMD_NULL;
+ if (pmd_none(pmde))
+ return SCAN_PMD_NONE;
This was for-use by MADV_COLLAPSE file/shmem codepaths, where
MADV_COLLAPSE might identify a pte-mapped hugepage, only to have
khugepaged race-in, free the pte table, and clear the pmd. Such codepaths
include:
A) If we find a suitably-aligned compound page of order HPAGE_PMD_ORDER
already in the pagecache.
B) In retract_page_tables(), if we fail to grab mmap_lock for the target
mm/address.
In these cases, collapse_pte_mapped_thp() really does expect a none (not
just !present) pmd, and we want to suitably identify that case separate
from the case where no pmd is found, or it's a bad-pmd (of course, many
things could happen once we drop mmap_lock, and the pmd could plausibly
undergo multiple transitions due to intervening fault, split, etc).
Regardless, the code is prepared install a huge-pmd only when the existing
pmd entry is either a genuine pte-table-mapping-pmd, or the none-pmd.
However, the commit introduces a logical hole; namely, that we've allowed
!none- && !huge- && !bad-pmds to be classified as genuine
pte-table-mapping-pmds. One such example that could leak through are swap
entries. The pmd values aren't checked again before use in
pte_offset_map_lock(), which is expecting nothing less than a genuine
pte-table-mapping-pmd.
We want to put back the !pmd_present() check (below the pmd_none() check),
but need to be careful to deal with subtleties in pmd transitions and
treatments by various arch.
The issue is that __split_huge_pmd_locked() temporarily clears the present
bit (or otherwise marks the entry as invalid), but pmd_present() and
pmd_trans_huge() still need to return true while the pmd is in this
transitory state. For example, x86's pmd_present() also checks the
_PAGE_PSE , riscv's version also checks the _PAGE_LEAF bit, and arm64 also
checks a PMD_PRESENT_INVALID bit.
Covering all 4 cases for x86 (all checks done on the same pmd value):
1) pmd_present() && pmd_trans_huge()
All we actually know here is that the PSE bit is set. Either:
a) We aren't racing with __split_huge_page(), and PRESENT or PROTNONE
is set.
=> huge-pmd
b) We are currently racing with __split_huge_page(). The danger here
is that we proceed as-if we have a huge-pmd, but really we are
looking at a pte-mapping-pmd. So, what is the risk of this
danger?
The only relevant path is:
madvise_collapse() -> collapse_pte_mapped_thp()
Where we might just incorrectly report back "success", when really
the memory isn't pmd-backed. This is fine, since split could
happen immediately after (actually) successful madvise_collapse().
So, it should be safe to just assume huge-pmd here.
2) pmd_present() && !pmd_trans_huge()
Either:
a) PSE not set and either PRESENT or PROTNONE is.
=> pte-table-mapping pmd (or PROT_NONE)
b) devmap. This routine can be called immediately after
unlocking/locking mmap_lock -- or called with no locks held (see
khugepaged_scan_mm_slot()), so previous VMA checks have since been
invalidated.
3) !pmd_present() && pmd_trans_huge()
Not possible.
4) !pmd_present() && !pmd_trans_huge()
Neither PRESENT nor PROTNONE set
=> not present
I've checked all archs that implement pmd_trans_huge() (arm64, riscv,
powerpc, longarch, x86, mips, s390) and this logic roughly translates
(though devmap treatment is unique to x86 and powerpc, and (3) doesn't
necessarily hold in general -- but that doesn't matter since
!pmd_present() always takes failure path).
Also, add a comment above find_pmd_or_thp_or_none()
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
tty: n_gsm: fix race condition in status line change on dead connections
gsm_cleanup_mux() cleans up the gsm by closing all DLCIs, stopping all
timers, removing the virtual tty devices and clearing the data queues.
This procedure, however, may cause subsequent changes of the virtual modem
status lines of a DLCI. More data is being added the outgoing data queue
and the deleted kick timer is restarted to handle this. At this point many
resources have already been removed by the cleanup procedure. Thus, a
kernel panic occurs.
Fix this by proving in gsm_modem_update() that the cleanup procedure has
not been started and the mux is still alive.
Note that writing to a virtual tty is already protected by checks against
the DLCI specific connection state. |
| In the Linux kernel, the following vulnerability has been resolved:
media: bttv: fix use after free error due to btv->timeout timer
There may be some a race condition between timer function
bttv_irq_timeout and bttv_remove. The timer is setup in
probe and there is no timer_delete operation in remove
function. When it hit kfree btv, the function might still be
invoked, which will cause use after free bug.
This bug is found by static analysis, it may be false positive.
Fix it by adding del_timer_sync invoking to the remove function.
cpu0 cpu1
bttv_probe
->timer_setup
->bttv_set_dma
->mod_timer;
bttv_remove
->kfree(btv);
->bttv_irq_timeout
->USE btv |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix a race condition of vram buffer unref in svm code
prange->svm_bo unref can happen in both mmu callback and a callback after
migrate to system ram. Both are async call in different tasks. Sync svm_bo
unref operation to avoid random "use-after-free". |
| In the Linux kernel, the following vulnerability has been resolved:
Fix page corruption caused by racy check in __free_pages
When we upgraded our kernel, we started seeing some page corruption like
the following consistently:
BUG: Bad page state in process ganesha.nfsd pfn:1304ca
page:0000000022261c55 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1304ca
flags: 0x17ffffc0000000()
raw: 0017ffffc0000000 ffff8a513ffd4c98 ffffeee24b35ec08 0000000000000000
raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000
page dumped because: nonzero mapcount
CPU: 0 PID: 15567 Comm: ganesha.nfsd Kdump: loaded Tainted: P B O 5.10.158-1.nutanix.20221209.el7.x86_64 #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016
Call Trace:
dump_stack+0x74/0x96
bad_page.cold+0x63/0x94
check_new_page_bad+0x6d/0x80
rmqueue+0x46e/0x970
get_page_from_freelist+0xcb/0x3f0
? _cond_resched+0x19/0x40
__alloc_pages_nodemask+0x164/0x300
alloc_pages_current+0x87/0xf0
skb_page_frag_refill+0x84/0x110
...
Sometimes, it would also show up as corruption in the free list pointer
and cause crashes.
After bisecting the issue, we found the issue started from commit
e320d3012d25 ("mm/page_alloc.c: fix freeing non-compound pages"):
if (put_page_testzero(page))
free_the_page(page, order);
else if (!PageHead(page))
while (order-- > 0)
free_the_page(page + (1 << order), order);
So the problem is the check PageHead is racy because at this point we
already dropped our reference to the page. So even if we came in with
compound page, the page can already be freed and PageHead can return
false and we will end up freeing all the tail pages causing double free. |
| In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Fix a suspicious RCU usage warning
I received the following warning while running cthon against an ontap
server running pNFS:
[ 57.202521] =============================
[ 57.202522] WARNING: suspicious RCU usage
[ 57.202523] 6.7.0-rc3-g2cc14f52aeb7 #41492 Not tainted
[ 57.202525] -----------------------------
[ 57.202525] net/sunrpc/xprtmultipath.c:349 RCU-list traversed in non-reader section!!
[ 57.202527]
other info that might help us debug this:
[ 57.202528]
rcu_scheduler_active = 2, debug_locks = 1
[ 57.202529] no locks held by test5/3567.
[ 57.202530]
stack backtrace:
[ 57.202532] CPU: 0 PID: 3567 Comm: test5 Not tainted 6.7.0-rc3-g2cc14f52aeb7 #41492 5b09971b4965c0aceba19f3eea324a4a806e227e
[ 57.202534] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022
[ 57.202536] Call Trace:
[ 57.202537] <TASK>
[ 57.202540] dump_stack_lvl+0x77/0xb0
[ 57.202551] lockdep_rcu_suspicious+0x154/0x1a0
[ 57.202556] rpc_xprt_switch_has_addr+0x17c/0x190 [sunrpc ebe02571b9a8ceebf7d98e71675af20c19bdb1f6]
[ 57.202596] rpc_clnt_setup_test_and_add_xprt+0x50/0x180 [sunrpc ebe02571b9a8ceebf7d98e71675af20c19bdb1f6]
[ 57.202621] ? rpc_clnt_add_xprt+0x254/0x300 [sunrpc ebe02571b9a8ceebf7d98e71675af20c19bdb1f6]
[ 57.202646] rpc_clnt_add_xprt+0x27a/0x300 [sunrpc ebe02571b9a8ceebf7d98e71675af20c19bdb1f6]
[ 57.202671] ? __pfx_rpc_clnt_setup_test_and_add_xprt+0x10/0x10 [sunrpc ebe02571b9a8ceebf7d98e71675af20c19bdb1f6]
[ 57.202696] nfs4_pnfs_ds_connect+0x345/0x760 [nfsv4 c716d88496ded0ea6d289bbea684fa996f9b57a9]
[ 57.202728] ? __pfx_nfs4_test_session_trunk+0x10/0x10 [nfsv4 c716d88496ded0ea6d289bbea684fa996f9b57a9]
[ 57.202754] nfs4_fl_prepare_ds+0x75/0xc0 [nfs_layout_nfsv41_files e3a4187f18ae8a27b630f9feae6831b584a9360a]
[ 57.202760] filelayout_write_pagelist+0x4a/0x200 [nfs_layout_nfsv41_files e3a4187f18ae8a27b630f9feae6831b584a9360a]
[ 57.202765] pnfs_generic_pg_writepages+0xbe/0x230 [nfsv4 c716d88496ded0ea6d289bbea684fa996f9b57a9]
[ 57.202788] __nfs_pageio_add_request+0x3fd/0x520 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202813] nfs_pageio_add_request+0x18b/0x390 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202831] nfs_do_writepage+0x116/0x1e0 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202849] nfs_writepages_callback+0x13/0x30 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202866] write_cache_pages+0x265/0x450
[ 57.202870] ? __pfx_nfs_writepages_callback+0x10/0x10 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202891] nfs_writepages+0x141/0x230 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202913] do_writepages+0xd2/0x230
[ 57.202917] ? filemap_fdatawrite_wbc+0x5c/0x80
[ 57.202921] filemap_fdatawrite_wbc+0x67/0x80
[ 57.202924] filemap_write_and_wait_range+0xd9/0x170
[ 57.202930] nfs_wb_all+0x49/0x180 [nfs 6c976fa593a7c2976f5a0aeb4965514a828e6902]
[ 57.202947] nfs4_file_flush+0x72/0xb0 [nfsv4 c716d88496ded0ea6d289bbea684fa996f9b57a9]
[ 57.202969] __se_sys_close+0x46/0xd0
[ 57.202972] do_syscall_64+0x68/0x100
[ 57.202975] ? do_syscall_64+0x77/0x100
[ 57.202976] ? do_syscall_64+0x77/0x100
[ 57.202979] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 57.202982] RIP: 0033:0x7fe2b12e4a94
[ 57.202985] Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 80 3d d5 18 0e 00 00 74 13 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 44 c3 0f 1f 00 48 83 ec 18 89 7c 24 0c e8 c3
[ 57.202987] RSP: 002b:00007ffe857ddb38 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
[ 57.202989] RAX: ffffffffffffffda RBX: 00007ffe857dfd68 RCX: 00007fe2b12e4a94
[ 57.202991] RDX: 0000000000002000 RSI: 00007ffe857ddc40 RDI: 0000000000000003
[ 57.202992] RBP: 00007ffe857dfc50 R08: 7fffffffffffffff R09: 0000000065650f49
[ 57.202993] R10: 00007f
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
drm/msm/dpu: Add mutex lock in control vblank irq
Add a mutex lock to control vblank irq to synchronize vblank
enable/disable operations happening from different threads to prevent
race conditions while registering/unregistering the vblank irq callback.
v4: -Removed vblank_ctl_lock from dpu_encoder_virt, so it is only a
parameter of dpu_encoder_phys.
-Switch from atomic refcnt to a simple int counter as mutex has
now been added
v3: Mistakenly did not change wording in last version. It is done now.
v2: Slightly changed wording of commit message
Patchwork: https://patchwork.freedesktop.org/patch/571854/ |
| In the Linux kernel, the following vulnerability has been resolved:
spi: sun6i: fix race between DMA RX transfer completion and RX FIFO drain
Previously the transfer complete IRQ immediately drained to RX FIFO to
read any data remaining in FIFO to the RX buffer. This behaviour is
correct when dealing with SPI in interrupt mode. However in DMA mode the
transfer complete interrupt still fires as soon as all bytes to be
transferred have been stored in the FIFO. At that point data in the FIFO
still needs to be picked up by the DMA engine. Thus the drain procedure
and DMA engine end up racing to read from RX FIFO, corrupting any data
read. Additionally the RX buffer pointer is never adjusted according to
DMA progress in DMA mode, thus calling the RX FIFO drain procedure in DMA
mode is a bug.
Fix corruptions in DMA RX mode by draining RX FIFO only in interrupt mode.
Also wait for completion of RX DMA when in DMA mode before returning to
ensure all data has been copied to the supplied memory buffer. |
| In the Linux kernel, the following vulnerability has been resolved:
net: nfc: fix races in nfc_llcp_sock_get() and nfc_llcp_sock_get_sn()
Sili Luo reported a race in nfc_llcp_sock_get(), leading to UAF.
Getting a reference on the socket found in a lookup while
holding a lock should happen before releasing the lock.
nfc_llcp_sock_get_sn() has a similar problem.
Finally nfc_llcp_recv_snl() needs to make sure the socket
found by nfc_llcp_sock_from_sn() does not disappear. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix race condition between session lookup and expire
Thread A + Thread B
ksmbd_session_lookup | smb2_sess_setup
sess = xa_load |
|
| xa_erase(&conn->sessions, sess->id);
|
| ksmbd_session_destroy(sess) --> kfree(sess)
|
// UAF! |
sess->last_active = jiffies |
+
This patch add rwsem to fix race condition between ksmbd_session_lookup
and ksmbd_expire_session. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: logitech-hidpp: Fix kernel crash on receiver USB disconnect
hidpp_connect_event() has *four* time-of-check vs time-of-use (TOCTOU)
races when it races with itself.
hidpp_connect_event() primarily runs from a workqueue but it also runs
on probe() and if a "device-connected" packet is received by the hw
when the thread running hidpp_connect_event() from probe() is waiting on
the hw, then a second thread running hidpp_connect_event() will be
started from the workqueue.
This opens the following races (note the below code is simplified):
1. Retrieving + printing the protocol (harmless race):
if (!hidpp->protocol_major) {
hidpp_root_get_protocol_version()
hidpp->protocol_major = response.rap.params[0];
}
We can actually see this race hit in the dmesg in the abrt output
attached to rhbz#2227968:
[ 3064.624215] logitech-hidpp-device 0003:046D:4071.0049: HID++ 4.5 device connected.
[ 3064.658184] logitech-hidpp-device 0003:046D:4071.0049: HID++ 4.5 device connected.
Testing with extra logging added has shown that after this the 2 threads
take turn grabbing the hw access mutex (send_mutex) so they ping-pong
through all the other TOCTOU cases managing to hit all of them:
2. Updating the name to the HIDPP name (harmless race):
if (hidpp->name == hdev->name) {
...
hidpp->name = new_name;
}
3. Initializing the power_supply class for the battery (problematic!):
hidpp_initialize_battery()
{
if (hidpp->battery.ps)
return 0;
probe_battery(); /* Blocks, threads take turns executing this */
hidpp->battery.desc.properties =
devm_kmemdup(dev, hidpp_battery_props, cnt, GFP_KERNEL);
hidpp->battery.ps =
devm_power_supply_register(&hidpp->hid_dev->dev,
&hidpp->battery.desc, cfg);
}
4. Creating delayed input_device (potentially problematic):
if (hidpp->delayed_input)
return;
hidpp->delayed_input = hidpp_allocate_input(hdev);
The really big problem here is 3. Hitting the race leads to the following
sequence:
hidpp->battery.desc.properties =
devm_kmemdup(dev, hidpp_battery_props, cnt, GFP_KERNEL);
hidpp->battery.ps =
devm_power_supply_register(&hidpp->hid_dev->dev,
&hidpp->battery.desc, cfg);
...
hidpp->battery.desc.properties =
devm_kmemdup(dev, hidpp_battery_props, cnt, GFP_KERNEL);
hidpp->battery.ps =
devm_power_supply_register(&hidpp->hid_dev->dev,
&hidpp->battery.desc, cfg);
So now we have registered 2 power supplies for the same battery,
which looks a bit weird from userspace's pov but this is not even
the really big problem.
Notice how:
1. This is all devm-maganaged
2. The hidpp->battery.desc struct is shared between the 2 power supplies
3. hidpp->battery.desc.properties points to the result from the second
devm_kmemdup()
This causes a use after free scenario on USB disconnect of the receiver:
1. The last registered power supply class device gets unregistered
2. The memory from the last devm_kmemdup() call gets freed,
hidpp->battery.desc.properties now points to freed memory
3. The first registered power supply class device gets unregistered,
this involves sending a remove uevent to userspace which invokes
power_supply_uevent() to fill the uevent data
4. power_supply_uevent() uses hidpp->battery.desc.properties which
now points to freed memory leading to backtraces like this one:
Sep 22 20:01:35 eric kernel: BUG: unable to handle page fault for address: ffffb2140e017f08
...
Sep 22 20:01:35 eric kernel: Workqueue: usb_hub_wq hub_event
Sep 22 20:01:35 eric kernel: RIP: 0010:power_supply_uevent+0xee/0x1d0
...
Sep 22 20:01:35 eric kernel: ? asm_exc_page_fault+0x26/0x30
Sep 22 20:01:35 eric kernel: ? power_supply_uevent+0xee/0x1d0
Sep 22 20:01:35 eric kernel: ? power_supply_uevent+0x10d/0x1d0
Sep 22 20:01:35 eric kernel: dev_uevent+0x10f/0x2d0
Sep 22 20:01:35 eric kernel: kobject_uevent_env+0x291/0x680
Sep 22 20:01:35 eric kernel:
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
fs: dlm: fix race in lowcomms
This patch fixes a race between queue_work() in
_dlm_lowcomms_commit_msg() and srcu_read_unlock(). The queue_work() can
take the final reference of a dlm_msg and so msg->idx can contain
garbage which is signaled by the following warning:
[ 676.237050] ------------[ cut here ]------------
[ 676.237052] WARNING: CPU: 0 PID: 1060 at include/linux/srcu.h:189 dlm_lowcomms_commit_msg+0x41/0x50
[ 676.238945] Modules linked in: dlm_locktorture torture rpcsec_gss_krb5 intel_rapl_msr intel_rapl_common iTCO_wdt iTCO_vendor_support qxl kvm_intel drm_ttm_helper vmw_vsock_virtio_transport kvm vmw_vsock_virtio_transport_common ttm irqbypass crc32_pclmul joydev crc32c_intel serio_raw drm_kms_helper vsock virtio_scsi virtio_console virtio_balloon snd_pcm drm syscopyarea sysfillrect sysimgblt snd_timer fb_sys_fops i2c_i801 lpc_ich snd i2c_smbus soundcore pcspkr
[ 676.244227] CPU: 0 PID: 1060 Comm: lock_torture_wr Not tainted 5.19.0-rc3+ #1546
[ 676.245216] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.16.0-2.module+el8.7.0+15506+033991b0 04/01/2014
[ 676.246460] RIP: 0010:dlm_lowcomms_commit_msg+0x41/0x50
[ 676.247132] Code: fe ff ff ff 75 24 48 c7 c6 bd 0f 49 bb 48 c7 c7 38 7c 01 bd e8 00 e7 ca ff 89 de 48 c7 c7 60 78 01 bd e8 42 3d cd ff 5b 5d c3 <0f> 0b eb d8 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48
[ 676.249253] RSP: 0018:ffffa401c18ffc68 EFLAGS: 00010282
[ 676.249855] RAX: 0000000000000001 RBX: 00000000ffff8b76 RCX: 0000000000000006
[ 676.250713] RDX: 0000000000000000 RSI: ffffffffbccf3a10 RDI: ffffffffbcc7b62e
[ 676.251610] RBP: ffffa401c18ffc70 R08: 0000000000000001 R09: 0000000000000001
[ 676.252481] R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000005
[ 676.253421] R13: ffff8b76786ec370 R14: ffff8b76786ec370 R15: ffff8b76786ec480
[ 676.254257] FS: 0000000000000000(0000) GS:ffff8b7777800000(0000) knlGS:0000000000000000
[ 676.255239] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 676.255897] CR2: 00005590205d88b8 CR3: 000000017656c003 CR4: 0000000000770ee0
[ 676.256734] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 676.257567] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 676.258397] PKRU: 55555554
[ 676.258729] Call Trace:
[ 676.259063] <TASK>
[ 676.259354] dlm_midcomms_commit_mhandle+0xcc/0x110
[ 676.259964] queue_bast+0x8b/0xb0
[ 676.260423] grant_pending_locks+0x166/0x1b0
[ 676.261007] _unlock_lock+0x75/0x90
[ 676.261469] unlock_lock.isra.57+0x62/0xa0
[ 676.262009] dlm_unlock+0x21e/0x330
[ 676.262457] ? lock_torture_stats+0x80/0x80 [dlm_locktorture]
[ 676.263183] torture_unlock+0x5a/0x90 [dlm_locktorture]
[ 676.263815] ? preempt_count_sub+0xba/0x100
[ 676.264361] ? complete+0x1d/0x60
[ 676.264777] lock_torture_writer+0xb8/0x150 [dlm_locktorture]
[ 676.265555] kthread+0x10a/0x130
[ 676.266007] ? kthread_complete_and_exit+0x20/0x20
[ 676.266616] ret_from_fork+0x22/0x30
[ 676.267097] </TASK>
[ 676.267381] irq event stamp: 9579855
[ 676.267824] hardirqs last enabled at (9579863): [<ffffffffbb14e6f8>] __up_console_sem+0x58/0x60
[ 676.268896] hardirqs last disabled at (9579872): [<ffffffffbb14e6dd>] __up_console_sem+0x3d/0x60
[ 676.270008] softirqs last enabled at (9579798): [<ffffffffbc200349>] __do_softirq+0x349/0x4c7
[ 676.271438] softirqs last disabled at (9579897): [<ffffffffbb0d54c0>] irq_exit_rcu+0xb0/0xf0
[ 676.272796] ---[ end trace 0000000000000000 ]---
I reproduced this warning with dlm_locktorture test which is currently
not upstream. However this patch fix the issue by make a additional
refcount between dlm_lowcomms_new_msg() and dlm_lowcomms_commit_msg().
In case of the race the kref_put() in dlm_lowcomms_commit_msg() will be
the final put. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: target: iscsi: Fix a race condition between login_work and the login thread
In case a malicious initiator sends some random data immediately after a
login PDU; the iscsi_target_sk_data_ready() callback will schedule the
login_work and, at the same time, the negotiation may end without clearing
the LOGIN_FLAGS_INITIAL_PDU flag (because no additional PDU exchanges are
required to complete the login).
The login has been completed but the login_work function will find the
LOGIN_FLAGS_INITIAL_PDU flag set and will never stop from rescheduling
itself; at this point, if the initiator drops the connection, the
iscsit_conn structure will be freed, login_work will dereference a released
socket structure and the kernel crashes.
BUG: kernel NULL pointer dereference, address: 0000000000000230
PF: supervisor write access in kernel mode
PF: error_code(0x0002) - not-present page
Workqueue: events iscsi_target_do_login_rx [iscsi_target_mod]
RIP: 0010:_raw_read_lock_bh+0x15/0x30
Call trace:
iscsi_target_do_login_rx+0x75/0x3f0 [iscsi_target_mod]
process_one_work+0x1e8/0x3c0
Fix this bug by forcing login_work to stop after the login has been
completed and the socket callbacks have been restored.
Add a comment to clearify the return values of iscsi_target_do_login() |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: avoid hci_dev_test_and_set_flag() in mgmt_init_hdev()
syzbot is again reporting attempt to cancel uninitialized work
at mgmt_index_removed() [1], for setting of HCI_MGMT flag from
mgmt_init_hdev() from hci_mgmt_cmd() from hci_sock_sendmsg() can
race with testing of HCI_MGMT flag from mgmt_index_removed() from
hci_sock_bind() due to lack of serialization via hci_dev_lock().
Since mgmt_init_hdev() is called with mgmt_chan_list_lock held, we can
safely split hci_dev_test_and_set_flag() into hci_dev_test_flag() and
hci_dev_set_flag(). Thus, in order to close this race, set HCI_MGMT flag
after INIT_DELAYED_WORK() completed.
This is a local fix based on mgmt_chan_list_lock. Lack of serialization
via hci_dev_lock() might be causing different race conditions somewhere
else. But a global fix based on hci_dev_lock() should deserve a future
patch. |
