In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix races among concurrent hw_params and hw_free calls
Currently we have neither proper check nor protection against the
concurrent calls of PCM hw_params and hw_free ioctls, which may result
in a UAF. Since the existing PCM stream lock can't be used for
protecting the whole ioctl operations, we need a new mutex to protect
those racy calls.
This patch introduced a new mutex, runtime->buffer_mutex, and applies
it to both hw_params and hw_free ioctl code paths. Along with it, the
both functions are slightly modified (the mmap_count check is moved
into the state-check block) for code simplicity.
In the Linux kernel, the following vulnerability has been resolved:
NFSD: prevent integer overflow on 32 bit systems
On a 32 bit system, the "len * sizeof(*p)" operation can have an
integer overflow.
In the Linux kernel, the following vulnerability has been resolved:
NFSD: prevent underflow in nfssvc_decode_writeargs()
Smatch complains:
fs/nfsd/nfsxdr.c:341 nfssvc_decode_writeargs()
warn: no lower bound on 'args->len'
Change the type to unsigned to prevent this issue.
In the Linux kernel, the following vulnerability has been resolved:
ext4: don't BUG if someone dirty pages without asking ext4 first
[un]pin_user_pages_remote is dirtying pages without properly warning
the file system in advance. A related race was noted by Jan Kara in
2018[1]; however, more recently instead of it being a very hard-to-hit
race, it could be reliably triggered by process_vm_writev(2) which was
discovered by Syzbot[2].
This is technically a bug in mm/gup.c, but arguably ext4 is fragile in
that if some other kernel subsystem dirty pages without properly
notifying the file system using page_mkwrite(), ext4 will BUG, while
other file systems will not BUG (although data will still be lost).
So instead of crashing with a BUG, issue a warning (since there may be
potential data loss) and just mark the page as clean to avoid
unprivileged denial of service attacks until the problem can be
properly fixed. More discussion and background can be found in the
thread starting at [2].
[1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
[2] https://lore.kernel.org/r/Yg0m6IjcNmfaSokM@google.com
In the Linux kernel, the following vulnerability has been resolved:
parisc: Fix non-access data TLB cache flush faults
When a page is not present, we get non-access data TLB faults from
the fdc and fic instructions in flush_user_dcache_range_asm and
flush_user_icache_range_asm. When these occur, the cache line is
not invalidated and potentially we get memory corruption. The
problem was hidden by the nullification of the flush instructions.
These faults also affect performance. With pa8800/pa8900 processors,
there will be 32 faults per 4 KB page since the cache line is 128
bytes. There will be more faults with earlier processors.
The problem is fixed by using flush_cache_pages(). It does the flush
using a tmp alias mapping.
The flush_cache_pages() call in flush_cache_range() flushed too
large a range.
V2: Remove unnecessary preempt_disable() and preempt_enable() calls.
In the Linux kernel, the following vulnerability has been resolved:
hwrng: cavium - fix NULL but dereferenced coccicheck error
Fix following coccicheck warning:
./drivers/char/hw_random/cavium-rng-vf.c:182:17-20: ERROR:
pdev is NULL but dereferenced.
In the Linux kernel, the following vulnerability has been resolved:
memstick/mspro_block: fix handling of read-only devices
Use set_disk_ro to propagate the read-only state to the block layer
instead of checking for it in ->open and leaking a reference in case
of a read-only device.