| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| 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:
btrfs: do not double complete bio on errors during compressed reads
I hit some weird panics while fixing up the error handling from
btrfs_lookup_bio_sums(). Turns out the compression path will complete
the bio we use if we set up any of the compression bios and then return
an error, and then btrfs_submit_data_bio() will also call bio_endio() on
the bio.
Fix this by making btrfs_submit_compressed_read() responsible for
calling bio_endio() on the bio if there are any errors. Currently it
was only doing it if we created the compression bios, otherwise it was
depending on btrfs_submit_data_bio() to do the right thing. This
creates the above problem, so fix up btrfs_submit_compressed_read() to
always call bio_endio() in case of an error, and then simply return from
btrfs_submit_data_bio() if we had to call
btrfs_submit_compressed_read(). |
| In the Linux kernel, the following vulnerability has been resolved:
video: fbdev: sm712fb: Fix crash in smtcfb_write()
When the sm712fb driver writes three bytes to the framebuffer, the
driver will crash:
BUG: unable to handle page fault for address: ffffc90001ffffff
RIP: 0010:smtcfb_write+0x454/0x5b0
Call Trace:
vfs_write+0x291/0xd60
? do_sys_openat2+0x27d/0x350
? __fget_light+0x54/0x340
ksys_write+0xce/0x190
do_syscall_64+0x43/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix it by removing the open-coded endianness fixup-code. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: revisit gc autotuning
as of commit 4608fdfc07e1
("netfilter: conntrack: collect all entries in one cycle")
conntrack gc was changed to run every 2 minutes.
On systems where conntrack hash table is set to large value, most evictions
happen from gc worker rather than the packet path due to hash table
distribution.
This causes netlink event overflows when events are collected.
This change collects average expiry of scanned entries and
reschedules to the average remaining value, within 1 to 60 second interval.
To avoid event overflows, reschedule after each bucket and add a
limit for both run time and number of evictions per run.
If more entries have to be evicted, reschedule and restart 1 jiffy
into the future. |
| In the Linux kernel, the following vulnerability has been resolved:
Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests
hv_panic_page might contain guest-sensitive information, do not dump it
over to Hyper-V by default in isolated guests.
While at it, update some comments in hyperv_{panic,die}_event(). |
| In the Linux kernel, the following vulnerability has been resolved:
mm: fix unexpected zeroed page mapping with zram swap
Two processes under CLONE_VM cloning, user process can be corrupted by
seeing zeroed page unexpectedly.
CPU A CPU B
do_swap_page do_swap_page
SWP_SYNCHRONOUS_IO path SWP_SYNCHRONOUS_IO path
swap_readpage valid data
swap_slot_free_notify
delete zram entry
swap_readpage zeroed(invalid) data
pte_lock
map the *zero data* to userspace
pte_unlock
pte_lock
if (!pte_same)
goto out_nomap;
pte_unlock
return and next refault will
read zeroed data
The swap_slot_free_notify is bogus for CLONE_VM case since it doesn't
increase the refcount of swap slot at copy_mm so it couldn't catch up
whether it's safe or not to discard data from backing device. In the
case, only the lock it could rely on to synchronize swap slot freeing is
page table lock. Thus, this patch gets rid of the swap_slot_free_notify
function. With this patch, CPU A will see correct data.
CPU A CPU B
do_swap_page do_swap_page
SWP_SYNCHRONOUS_IO path SWP_SYNCHRONOUS_IO path
swap_readpage original data
pte_lock
map the original data
swap_free
swap_range_free
bd_disk->fops->swap_slot_free_notify
swap_readpage read zeroed data
pte_unlock
pte_lock
if (!pte_same)
goto out_nomap;
pte_unlock
return
on next refault will see mapped data by CPU B
The concern of the patch would increase memory consumption since it
could keep wasted memory with compressed form in zram as well as
uncompressed form in address space. However, most of cases of zram uses
no readahead and do_swap_page is followed by swap_free so it will free
the compressed form from in zram quickly. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: fix panic when forwarding a pkt with no in6 dev
kongweibin reported a kernel panic in ip6_forward() when input interface
has no in6 dev associated.
The following tc commands were used to reproduce this panic:
tc qdisc del dev vxlan100 root
tc qdisc add dev vxlan100 root netem corrupt 5% |
| In the Linux kernel, the following vulnerability has been resolved:
mm/gup: fix gup_pud_range() for dax
For dax pud, pud_huge() returns true on x86. So the function works as long
as hugetlb is configured. However, dax doesn't depend on hugetlb.
Commit 414fd080d125 ("mm/gup: fix gup_pmd_range() for dax") fixed
devmap-backed huge PMDs, but missed devmap-backed huge PUDs. Fix this as
well.
This fixes the below kernel panic:
general protection fault, probably for non-canonical address 0x69e7c000cc478: 0000 [#1] SMP
< snip >
Call Trace:
<TASK>
get_user_pages_fast+0x1f/0x40
iov_iter_get_pages+0xc6/0x3b0
? mempool_alloc+0x5d/0x170
bio_iov_iter_get_pages+0x82/0x4e0
? bvec_alloc+0x91/0xc0
? bio_alloc_bioset+0x19a/0x2a0
blkdev_direct_IO+0x282/0x480
? __io_complete_rw_common+0xc0/0xc0
? filemap_range_has_page+0x82/0xc0
generic_file_direct_write+0x9d/0x1a0
? inode_update_time+0x24/0x30
__generic_file_write_iter+0xbd/0x1e0
blkdev_write_iter+0xb4/0x150
? io_import_iovec+0x8d/0x340
io_write+0xf9/0x300
io_issue_sqe+0x3c3/0x1d30
? sysvec_reschedule_ipi+0x6c/0x80
__io_queue_sqe+0x33/0x240
? fget+0x76/0xa0
io_submit_sqes+0xe6a/0x18d0
? __fget_light+0xd1/0x100
__x64_sys_io_uring_enter+0x199/0x880
? __context_tracking_enter+0x1f/0x70
? irqentry_exit_to_user_mode+0x24/0x30
? irqentry_exit+0x1d/0x30
? __context_tracking_exit+0xe/0x70
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc97c11a7be
< snip >
</TASK>
---[ end trace 48b2e0e67debcaeb ]---
RIP: 0010:internal_get_user_pages_fast+0x340/0x990
< snip >
Kernel panic - not syncing: Fatal exception
Kernel Offset: disabled |
| In the Linux kernel, the following vulnerability has been resolved:
net: mana: Fix race on per-CQ variable napi work_done
After calling napi_complete_done(), the NAPIF_STATE_SCHED bit may be
cleared, and another CPU can start napi thread and access per-CQ variable,
cq->work_done. If the other thread (for example, from busy_poll) sets
it to a value >= budget, this thread will continue to run when it should
stop, and cause memory corruption and panic.
To fix this issue, save the per-CQ work_done variable in a local variable
before napi_complete_done(), so it won't be corrupted by a possible
concurrent thread after napi_complete_done().
Also, add a flag bit to advertise to the NIC firmware: the NAPI work_done
variable race is fixed, so the driver is able to reliably support features
like busy_poll. |
| In the Linux kernel, the following vulnerability has been resolved:
media: vivid: fix compose size exceed boundary
syzkaller found a bug:
BUG: unable to handle page fault for address: ffffc9000a3b1000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 100000067 P4D 100000067 PUD 10015f067 PMD 1121ca067 PTE 0
Oops: 0002 [#1] PREEMPT SMP
CPU: 0 PID: 23489 Comm: vivid-000-vid-c Not tainted 6.1.0-rc1+ #512
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:memcpy_erms+0x6/0x10
[...]
Call Trace:
<TASK>
? tpg_fill_plane_buffer+0x856/0x15b0
vivid_fillbuff+0x8ac/0x1110
vivid_thread_vid_cap_tick+0x361/0xc90
vivid_thread_vid_cap+0x21a/0x3a0
kthread+0x143/0x180
ret_from_fork+0x1f/0x30
</TASK>
This is because we forget to check boundary after adjust compose->height
int V4L2_SEL_TGT_CROP case. Add v4l2_rect_map_inside() to fix this problem
for this case. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: make apf token non-zero to fix bug
In current async pagefault logic, when a page is ready, KVM relies on
kvm_arch_can_dequeue_async_page_present() to determine whether to deliver
a READY event to the Guest. This function test token value of struct
kvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a
READY event is finished by Guest. If value is zero meaning that a READY
event is done, so the KVM can deliver another.
But the kvm_arch_setup_async_pf() may produce a valid token with zero
value, which is confused with previous mention and may lead the loss of
this READY event.
This bug may cause task blocked forever in Guest:
INFO: task stress:7532 blocked for more than 1254 seconds.
Not tainted 5.10.0 #16
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:stress state:D stack: 0 pid: 7532 ppid: 1409
flags:0x00000080
Call Trace:
__schedule+0x1e7/0x650
schedule+0x46/0xb0
kvm_async_pf_task_wait_schedule+0xad/0xe0
? exit_to_user_mode_prepare+0x60/0x70
__kvm_handle_async_pf+0x4f/0xb0
? asm_exc_page_fault+0x8/0x30
exc_page_fault+0x6f/0x110
? asm_exc_page_fault+0x8/0x30
asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x402d00
RSP: 002b:00007ffd31912500 EFLAGS: 00010206
RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0
RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0
RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086
R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000 |
| In the Linux kernel, the following vulnerability has been resolved:
drm/vmwgfx: Remove rcu locks from user resources
User resource lookups used rcu to avoid two extra atomics. Unfortunately
the rcu paths were buggy and it was easy to make the driver crash by
submitting command buffers from two different threads. Because the
lookups never show up in performance profiles replace them with a
regular spin lock which fixes the races in accesses to those shared
resources.
Fixes kernel oops'es in IGT's vmwgfx execution_buffer stress test and
seen crashes with apps using shared resources. |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: Fix NFSv3 SETATTR/CREATE's handling of large file sizes
iattr::ia_size is a loff_t, so these NFSv3 procedures must be
careful to deal with incoming client size values that are larger
than s64_max without corrupting the value.
Silently capping the value results in storing a different value
than the client passed in which is unexpected behavior, so remove
the min_t() check in decode_sattr3().
Note that RFC 1813 permits only the WRITE procedure to return
NFS3ERR_FBIG. We believe that NFSv3 reference implementations
also return NFS3ERR_FBIG when ia_size is too large. |
| In the Linux kernel, the following vulnerability has been resolved:
mm: don't try to NUMA-migrate COW pages that have other uses
Oded Gabbay reports that enabling NUMA balancing causes corruption with
his Gaudi accelerator test load:
"All the details are in the bug, but the bottom line is that somehow,
this patch causes corruption when the numa balancing feature is
enabled AND we don't use process affinity AND we use GUP to pin pages
so our accelerator can DMA to/from system memory.
Either disabling numa balancing, using process affinity to bind to
specific numa-node or reverting this patch causes the bug to
disappear"
and Oded bisected the issue to commit 09854ba94c6a ("mm: do_wp_page()
simplification").
Now, the NUMA balancing shouldn't actually be changing the writability
of a page, and as such shouldn't matter for COW. But it appears it
does. Suspicious.
However, regardless of that, the condition for enabling NUMA faults in
change_pte_range() is nonsensical. It uses "page_mapcount(page)" to
decide if a COW page should be NUMA-protected or not, and that makes
absolutely no sense.
The number of mappings a page has is irrelevant: not only does GUP get a
reference to a page as in Oded's case, but the other mappings migth be
paged out and the only reference to them would be in the page count.
Since we should never try to NUMA-balance a page that we can't move
anyway due to other references, just fix the code to use 'page_count()'.
Oded confirms that that fixes his issue.
Now, this does imply that something in NUMA balancing ends up changing
page protections (other than the obvious one of making the page
inaccessible to get the NUMA faulting information). Otherwise the COW
simplification wouldn't matter - since doing the GUP on the page would
make sure it's writable.
The cause of that permission change would be good to figure out too,
since it clearly results in spurious COW events - but fixing the
nonsensical test that just happened to work before is obviously the
CorrectThing(tm) to do regardless. |
| In the Linux kernel, the following vulnerability has been resolved:
IB/hfi1: Fix panic with larger ipoib send_queue_size
When the ipoib send_queue_size is increased from the default the following
panic happens:
RIP: 0010:hfi1_ipoib_drain_tx_ring+0x45/0xf0 [hfi1]
Code: 31 e4 eb 0f 8b 85 c8 02 00 00 41 83 c4 01 44 39 e0 76 60 8b 8d cc 02 00 00 44 89 e3 be 01 00 00 00 d3 e3 48 03 9d c0 02 00 00 <c7> 83 18 01 00 00 00 00 00 00 48 8b bb 30 01 00 00 e8 25 af a7 e0
RSP: 0018:ffffc9000798f4a0 EFLAGS: 00010286
RAX: 0000000000008000 RBX: ffffc9000aa0f000 RCX: 000000000000000f
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88810ff08000 R08: ffff88889476d900 R09: 0000000000000101
R10: 0000000000000000 R11: ffffc90006590ff8 R12: 0000000000000200
R13: ffffc9000798fba8 R14: 0000000000000000 R15: 0000000000000001
FS: 00007fd0f79cc3c0(0000) GS:ffff88885fb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000aa0f118 CR3: 0000000889c84001 CR4: 00000000001706e0
Call Trace:
<TASK>
hfi1_ipoib_napi_tx_disable+0x45/0x60 [hfi1]
hfi1_ipoib_dev_stop+0x18/0x80 [hfi1]
ipoib_ib_dev_stop+0x1d/0x40 [ib_ipoib]
ipoib_stop+0x48/0xc0 [ib_ipoib]
__dev_close_many+0x9e/0x110
__dev_change_flags+0xd9/0x210
dev_change_flags+0x21/0x60
do_setlink+0x31c/0x10f0
? __nla_validate_parse+0x12d/0x1a0
? __nla_parse+0x21/0x30
? inet6_validate_link_af+0x5e/0xf0
? cpumask_next+0x1f/0x20
? __snmp6_fill_stats64.isra.53+0xbb/0x140
? __nla_validate_parse+0x47/0x1a0
__rtnl_newlink+0x530/0x910
? pskb_expand_head+0x73/0x300
? __kmalloc_node_track_caller+0x109/0x280
? __nla_put+0xc/0x20
? cpumask_next_and+0x20/0x30
? update_sd_lb_stats.constprop.144+0xd3/0x820
? _raw_spin_unlock_irqrestore+0x25/0x37
? __wake_up_common_lock+0x87/0xc0
? kmem_cache_alloc_trace+0x3d/0x3d0
rtnl_newlink+0x43/0x60
The issue happens when the shift that should have been a function of the
txq item size mistakenly used the ring size.
Fix by using the item size. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Avoid consuming a stale esr value when SError occur
When any exception other than an IRQ occurs, the CPU updates the ESR_EL2
register with the exception syndrome. An SError may also become pending,
and will be synchronised by KVM. KVM notes the exception type, and whether
an SError was synchronised in exit_code.
When an exception other than an IRQ occurs, fixup_guest_exit() updates
vcpu->arch.fault.esr_el2 from the hardware register. When an SError was
synchronised, the vcpu esr value is used to determine if the exception
was due to an HVC. If so, ELR_EL2 is moved back one instruction. This
is so that KVM can process the SError first, and re-execute the HVC if
the guest survives the SError.
But if an IRQ synchronises an SError, the vcpu's esr value is stale.
If the previous non-IRQ exception was an HVC, KVM will corrupt ELR_EL2,
causing an unrelated guest instruction to be executed twice.
Check ARM_EXCEPTION_CODE() before messing with ELR_EL2, IRQs don't
update this register so don't need to check. |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: Forward wakeup to smc socket waitqueue after fallback
When we replace TCP with SMC and a fallback occurs, there may be
some socket waitqueue entries remaining in smc socket->wq, such
as eppoll_entries inserted by userspace applications.
After the fallback, data flows over TCP/IP and only clcsocket->wq
will be woken up. Applications can't be notified by the entries
which were inserted in smc socket->wq before fallback. So we need
a mechanism to wake up smc socket->wq at the same time if some
entries remaining in it.
The current workaround is to transfer the entries from smc socket->wq
to clcsock->wq during the fallback. But this may cause a crash
like this:
general protection fault, probably for non-canonical address 0xdead000000000100: 0000 [#1] PREEMPT SMP PTI
CPU: 3 PID: 0 Comm: swapper/3 Kdump: loaded Tainted: G E 5.16.0+ #107
RIP: 0010:__wake_up_common+0x65/0x170
Call Trace:
<IRQ>
__wake_up_common_lock+0x7a/0xc0
sock_def_readable+0x3c/0x70
tcp_data_queue+0x4a7/0xc40
tcp_rcv_established+0x32f/0x660
? sk_filter_trim_cap+0xcb/0x2e0
tcp_v4_do_rcv+0x10b/0x260
tcp_v4_rcv+0xd2a/0xde0
ip_protocol_deliver_rcu+0x3b/0x1d0
ip_local_deliver_finish+0x54/0x60
ip_local_deliver+0x6a/0x110
? tcp_v4_early_demux+0xa2/0x140
? tcp_v4_early_demux+0x10d/0x140
ip_sublist_rcv_finish+0x49/0x60
ip_sublist_rcv+0x19d/0x230
ip_list_rcv+0x13e/0x170
__netif_receive_skb_list_core+0x1c2/0x240
netif_receive_skb_list_internal+0x1e6/0x320
napi_complete_done+0x11d/0x190
mlx5e_napi_poll+0x163/0x6b0 [mlx5_core]
__napi_poll+0x3c/0x1b0
net_rx_action+0x27c/0x300
__do_softirq+0x114/0x2d2
irq_exit_rcu+0xb4/0xe0
common_interrupt+0xba/0xe0
</IRQ>
<TASK>
The crash is caused by privately transferring waitqueue entries from
smc socket->wq to clcsock->wq. The owners of these entries, such as
epoll, have no idea that the entries have been transferred to a
different socket wait queue and still use original waitqueue spinlock
(smc socket->wq.wait.lock) to make the entries operation exclusive,
but it doesn't work. The operations to the entries, such as removing
from the waitqueue (now is clcsock->wq after fallback), may cause a
crash when clcsock waitqueue is being iterated over at the moment.
This patch tries to fix this by no longer transferring wait queue
entries privately, but introducing own implementations of clcsock's
callback functions in fallback situation. The callback functions will
forward the wakeup to smc socket->wq if clcsock->wq is actually woken
up and smc socket->wq has remaining entries. |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/irdma: Fix drain SQ hang with no completion
SW generated completions for outstanding WRs posted on SQ
after QP is in error target the wrong CQ. This causes the
ib_drain_sq to hang with no completion.
Fix this to generate completions on the right CQ.
[ 863.969340] INFO: task kworker/u52:2:671 blocked for more than 122 seconds.
[ 863.979224] Not tainted 5.14.0-130.el9.x86_64 #1
[ 863.986588] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 863.996997] task:kworker/u52:2 state:D stack: 0 pid: 671 ppid: 2 flags:0x00004000
[ 864.007272] Workqueue: xprtiod xprt_autoclose [sunrpc]
[ 864.014056] Call Trace:
[ 864.017575] __schedule+0x206/0x580
[ 864.022296] schedule+0x43/0xa0
[ 864.026736] schedule_timeout+0x115/0x150
[ 864.032185] __wait_for_common+0x93/0x1d0
[ 864.037717] ? usleep_range_state+0x90/0x90
[ 864.043368] __ib_drain_sq+0xf6/0x170 [ib_core]
[ 864.049371] ? __rdma_block_iter_next+0x80/0x80 [ib_core]
[ 864.056240] ib_drain_sq+0x66/0x70 [ib_core]
[ 864.062003] rpcrdma_xprt_disconnect+0x82/0x3b0 [rpcrdma]
[ 864.069365] ? xprt_prepare_transmit+0x5d/0xc0 [sunrpc]
[ 864.076386] xprt_rdma_close+0xe/0x30 [rpcrdma]
[ 864.082593] xprt_autoclose+0x52/0x100 [sunrpc]
[ 864.088718] process_one_work+0x1e8/0x3c0
[ 864.094170] worker_thread+0x50/0x3b0
[ 864.099109] ? rescuer_thread+0x370/0x370
[ 864.104473] kthread+0x149/0x170
[ 864.109022] ? set_kthread_struct+0x40/0x40
[ 864.114713] ret_from_fork+0x22/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context.
Commit 5a836bf6b09f ("mm: slub: move flush_cpu_slab() invocations
__free_slab() invocations out of IRQ context") moved all flush_cpu_slab()
invocations to the global workqueue to avoid a problem related
with deactivate_slab()/__free_slab() being called from an IRQ context
on PREEMPT_RT kernels.
When the flush_all_cpu_locked() function is called from a task context
it may happen that a workqueue with WQ_MEM_RECLAIM bit set ends up
flushing the global workqueue, this will cause a dependency issue.
workqueue: WQ_MEM_RECLAIM nvme-delete-wq:nvme_delete_ctrl_work [nvme_core]
is flushing !WQ_MEM_RECLAIM events:flush_cpu_slab
WARNING: CPU: 37 PID: 410 at kernel/workqueue.c:2637
check_flush_dependency+0x10a/0x120
Workqueue: nvme-delete-wq nvme_delete_ctrl_work [nvme_core]
RIP: 0010:check_flush_dependency+0x10a/0x120[ 453.262125] Call Trace:
__flush_work.isra.0+0xbf/0x220
? __queue_work+0x1dc/0x420
flush_all_cpus_locked+0xfb/0x120
__kmem_cache_shutdown+0x2b/0x320
kmem_cache_destroy+0x49/0x100
bioset_exit+0x143/0x190
blk_release_queue+0xb9/0x100
kobject_cleanup+0x37/0x130
nvme_fc_ctrl_free+0xc6/0x150 [nvme_fc]
nvme_free_ctrl+0x1ac/0x2b0 [nvme_core]
Fix this bug by creating a workqueue for the flush operation with
the WQ_MEM_RECLAIM bit set. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: qcom-rng - ensure buffer for generate is completely filled
The generate function in struct rng_alg expects that the destination
buffer is completely filled if the function returns 0. qcom_rng_read()
can run into a situation where the buffer is partially filled with
randomness and the remaining part of the buffer is zeroed since
qcom_rng_generate() doesn't check the return value. This issue can
be reproduced by running the following from libkcapi:
kcapi-rng -b 9000000 > OUTFILE
The generated OUTFILE will have three huge sections that contain all
zeros, and this is caused by the code where the test
'val & PRNG_STATUS_DATA_AVAIL' fails.
Let's fix this issue by ensuring that qcom_rng_read() always returns
with a full buffer if the function returns success. Let's also have
qcom_rng_generate() return the correct value.
Here's some statistics from the ent project
(https://www.fourmilab.ch/random/) that shows information about the
quality of the generated numbers:
$ ent -c qcom-random-before
Value Char Occurrences Fraction
0 606748 0.067416
1 33104 0.003678
2 33001 0.003667
...
253 � 32883 0.003654
254 � 33035 0.003671
255 � 33239 0.003693
Total: 9000000 1.000000
Entropy = 7.811590 bits per byte.
Optimum compression would reduce the size
of this 9000000 byte file by 2 percent.
Chi square distribution for 9000000 samples is 9329962.81, and
randomly would exceed this value less than 0.01 percent of the
times.
Arithmetic mean value of data bytes is 119.3731 (127.5 = random).
Monte Carlo value for Pi is 3.197293333 (error 1.77 percent).
Serial correlation coefficient is 0.159130 (totally uncorrelated =
0.0).
Without this patch, the results of the chi-square test is 0.01%, and
the numbers are certainly not random according to ent's project page.
The results improve with this patch:
$ ent -c qcom-random-after
Value Char Occurrences Fraction
0 35432 0.003937
1 35127 0.003903
2 35424 0.003936
...
253 � 35201 0.003911
254 � 34835 0.003871
255 � 35368 0.003930
Total: 9000000 1.000000
Entropy = 7.999979 bits per byte.
Optimum compression would reduce the size
of this 9000000 byte file by 0 percent.
Chi square distribution for 9000000 samples is 258.77, and randomly
would exceed this value 42.24 percent of the times.
Arithmetic mean value of data bytes is 127.5006 (127.5 = random).
Monte Carlo value for Pi is 3.141277333 (error 0.01 percent).
Serial correlation coefficient is 0.000468 (totally uncorrelated =
0.0).
This change was tested on a Nexus 5 phone (msm8974 SoC). |
