In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Fix race of snd_seq_timer_open()
The timer instance per queue is exclusive, and snd_seq_timer_open()
should have managed the concurrent accesses. It looks as if it's
checking the already existing timer instance at the beginning, but
it's not right, because there is no protection, hence any later
concurrent call of snd_seq_timer_open() may override the timer
instance easily. This may result in UAF, as the leftover timer
instance can keep running while the queue itself gets closed, as
spotted by syzkaller recently.
For avoiding the race, add a proper check at the assignment of
tmr->timeri again, and return -EBUSY if it's been already registered.
In the Linux kernel, the following vulnerability has been resolved:
net:sfc: fix non-freed irq in legacy irq mode
SFC driver can be configured via modparam to work using MSI-X, MSI or
legacy IRQ interrupts. In the last one, the interrupt was not properly
released on module remove.
It was not freed because the flag irqs_hooked was not set during
initialization in the case of using legacy IRQ.
Example of (trimmed) trace during module remove without this fix:
remove_proc_entry: removing non-empty directory 'irq/125', leaking at least '0000:3b:00.1'
WARNING: CPU: 39 PID: 3658 at fs/proc/generic.c:715 remove_proc_entry+0x15c/0x170
...trimmed...
Call Trace:
unregister_irq_proc+0xe3/0x100
free_desc+0x29/0x70
irq_free_descs+0x47/0x70
mp_unmap_irq+0x58/0x60
acpi_unregister_gsi_ioapic+0x2a/0x40
acpi_pci_irq_disable+0x78/0xb0
pci_disable_device+0xd1/0x100
efx_pci_remove+0xa1/0x1e0 [sfc]
pci_device_remove+0x38/0xa0
__device_release_driver+0x177/0x230
driver_detach+0xcb/0x110
bus_remove_driver+0x58/0xd0
pci_unregister_driver+0x2a/0xb0
efx_exit_module+0x24/0xf40 [sfc]
__do_sys_delete_module.constprop.0+0x171/0x280
? exit_to_user_mode_prepare+0x83/0x1d0
do_syscall_64+0x3d/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f9f9385800b
...trimmed...
In the Linux kernel, the following vulnerability has been resolved:
ACPI: fix NULL pointer dereference
Commit 71f642833284 ("ACPI: utils: Fix reference counting in
for_each_acpi_dev_match()") started doing "acpi_dev_put()" on a pointer
that was possibly NULL. That fails miserably, because that helper
inline function is not set up to handle that case.
Just make acpi_dev_put() silently accept a NULL pointer, rather than
calling down to put_device() with an invalid offset off that NULL
pointer.
In the Linux kernel, the following vulnerability has been resolved:
usb: fix various gadget panics on 10gbps cabling
usb_assign_descriptors() is called with 5 parameters,
the last 4 of which are the usb_descriptor_header for:
full-speed (USB1.1 - 12Mbps [including USB1.0 low-speed @ 1.5Mbps),
high-speed (USB2.0 - 480Mbps),
super-speed (USB3.0 - 5Gbps),
super-speed-plus (USB3.1 - 10Gbps).
The differences between full/high/super-speed descriptors are usually
substantial (due to changes in the maximum usb block size from 64 to 512
to 1024 bytes and other differences in the specs), while the difference
between 5 and 10Gbps descriptors may be as little as nothing
(in many cases the same tuning is simply good enough).
However if a gadget driver calls usb_assign_descriptors() with
a NULL descriptor for super-speed-plus and is then used on a max 10gbps
configuration, the kernel will crash with a null pointer dereference,
when a 10gbps capable device port + cable + host port combination shows up.
(This wouldn't happen if the gadget max-speed was set to 5gbps, but
it of course defaults to the maximum, and there's no real reason to
artificially limit it)
The fix is to simply use the 5gbps descriptor as the 10gbps descriptor,
if a 10gbps descriptor wasn't provided.
Obviously this won't fix the problem if the 5gbps descriptor is also
NULL, but such cases can't be so trivially solved (and any such gadgets
are unlikely to be used with USB3 ports any way).
In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: ep0: fix NULL pointer exception
There is no validation of the index from dwc3_wIndex_to_dep() and we might
be referring a non-existing ep and trigger a NULL pointer exception. In
certain configurations we might use fewer eps and the index might wrongly
indicate a larger ep index than existing.
By adding this validation from the patch we can actually report a wrong
index back to the caller.
In our usecase we are using a composite device on an older kernel, but
upstream might use this fix also. Unfortunately, I cannot describe the
hardware for others to reproduce the issue as it is a proprietary
implementation.
[ 82.958261] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a4
[ 82.966891] Mem abort info:
[ 82.969663] ESR = 0x96000006
[ 82.972703] Exception class = DABT (current EL), IL = 32 bits
[ 82.978603] SET = 0, FnV = 0
[ 82.981642] EA = 0, S1PTW = 0
[ 82.984765] Data abort info:
[ 82.987631] ISV = 0, ISS = 0x00000006
[ 82.991449] CM = 0, WnR = 0
[ 82.994409] user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c6210ccc
[ 83.000999] [00000000000000a4] pgd=0000000053aa5003, pud=0000000053aa5003, pmd=0000000000000000
[ 83.009685] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[ 83.026433] Process irq/62-dwc3 (pid: 303, stack limit = 0x000000003985154c)
[ 83.033470] CPU: 0 PID: 303 Comm: irq/62-dwc3 Not tainted 4.19.124 #1
[ 83.044836] pstate: 60000085 (nZCv daIf -PAN -UAO)
[ 83.049628] pc : dwc3_ep0_handle_feature+0x414/0x43c
[ 83.054558] lr : dwc3_ep0_interrupt+0x3b4/0xc94
...
[ 83.141788] Call trace:
[ 83.144227] dwc3_ep0_handle_feature+0x414/0x43c
[ 83.148823] dwc3_ep0_interrupt+0x3b4/0xc94
[ 83.181546] ---[ end trace aac6b5267d84c32f ]---
In the Linux kernel, the following vulnerability has been resolved:
bcache: avoid oversized read request in cache missing code path
In the cache missing code path of cached device, if a proper location
from the internal B+ tree is matched for a cache miss range, function
cached_dev_cache_miss() will be called in cache_lookup_fn() in the
following code block,
[code block 1]
526 unsigned int sectors = KEY_INODE(k) == s->iop.inode
527 ? min_t(uint64_t, INT_MAX,
528 KEY_START(k) - bio->bi_iter.bi_sector)
529 : INT_MAX;
530 int ret = s->d->cache_miss(b, s, bio, sectors);
Here s->d->cache_miss() is the call backfunction pointer initialized as
cached_dev_cache_miss(), the last parameter 'sectors' is an important
hint to calculate the size of read request to backing device of the
missing cache data.
Current calculation in above code block may generate oversized value of
'sectors', which consequently may trigger 2 different potential kernel
panics by BUG() or BUG_ON() as listed below,
1) BUG_ON() inside bch_btree_insert_key(),
[code block 2]
886 BUG_ON(b->ops->is_extents && !KEY_SIZE(k));
2) BUG() inside biovec_slab(),
[code block 3]
51 default:
52 BUG();
53 return NULL;
All the above panics are original from cached_dev_cache_miss() by the
oversized parameter 'sectors'.
Inside cached_dev_cache_miss(), parameter 'sectors' is used to calculate
the size of data read from backing device for the cache missing. This
size is stored in s->insert_bio_sectors by the following lines of code,
[code block 4]
909 s->insert_bio_sectors = min(sectors, bio_sectors(bio) + reada);
Then the actual key inserting to the internal B+ tree is generated and
stored in s->iop.replace_key by the following lines of code,
[code block 5]
911 s->iop.replace_key = KEY(s->iop.inode,
912 bio->bi_iter.bi_sector + s->insert_bio_sectors,
913 s->insert_bio_sectors);
The oversized parameter 'sectors' may trigger panic 1) by BUG_ON() from
the above code block.
And the bio sending to backing device for the missing data is allocated
with hint from s->insert_bio_sectors by the following lines of code,
[code block 6]
926 cache_bio = bio_alloc_bioset(GFP_NOWAIT,
927 DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS),
928 &dc->disk.bio_split);
The oversized parameter 'sectors' may trigger panic 2) by BUG() from the
agove code block.
Now let me explain how the panics happen with the oversized 'sectors'.
In code block 5, replace_key is generated by macro KEY(). From the
definition of macro KEY(),
[code block 7]
71 #define KEY(inode, offset, size) \
72 ((struct bkey) { \
73 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \
74 .low = (offset) \
75 })
Here 'size' is 16bits width embedded in 64bits member 'high' of struct
bkey. But in code block 1, if "KEY_START(k) - bio->bi_iter.bi_sector" is
very probably to be larger than (1<<16) - 1, which makes the bkey size
calculation in code block 5 is overflowed. In one bug report the value
of parameter 'sectors' is 131072 (= 1 << 17), the overflowed 'sectors'
results the overflowed s->insert_bio_sectors in code block 4, then makes
size field of s->iop.replace_key to be 0 in code block 5. Then the 0-
sized s->iop.replace_key is inserted into the internal B+ tree as cache
missing check key (a special key to detect and avoid a racing between
normal write request and cache missing read request) as,
[code block 8]
915 ret = bch_btree_insert_check_key(b, &s->op, &s->iop.replace_key);
Then the 0-sized s->iop.replace_key as 3rd parameter triggers the bkey
size check BUG_ON() in code block 2, and causes the kernel panic 1).
Another ke
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix potential memory leak in DMUB hw_init
[Why]
On resume we perform DMUB hw_init which allocates memory:
dm_resume->dm_dmub_hw_init->dc_dmub_srv_create->kzalloc
That results in memory leak in suspend/resume scenarios.
[How]
Allocate memory for the DC wrapper to DMUB only if it was not
allocated before.
No need to reallocate it on suspend/resume.
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Fix use-after-free in gfs2_glock_shrink_scan
The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to
remove the glock from the lru list in __gfs2_glock_put().
On the shrink scan path, the same flag is cleared under lru_lock but because
of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the
put side can be made without deleting the glock from the lru list.
Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to
ensure correct behavior on both sides - clear GLF_LRU after list_del under
lru_lock.
In the Linux kernel, the following vulnerability has been resolved:
net: ieee802154: fix null deref in parse dev addr
Fix a logic error that could result in a null deref if the user sets
the mode incorrectly for the given addr type.