🚨 CVE-2021-46967
In the Linux kernel, the following vulnerability has been resolved:

vhost-vdpa: fix vm_flags for virtqueue doorbell mapping

The virtqueue doorbell is usually implemented via registeres but we
don't provide the necessary vma->flags like VM_PFNMAP. This may cause
several issues e.g when userspace tries to map the doorbell via vhost
IOTLB, kernel may panic due to the page is not backed by page
structure. This patch fixes this by setting the necessary
vm_flags. With this patch, try to map doorbell via IOTLB will fail
with bad address.

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🚨 CVE-2021-46969
In the Linux kernel, the following vulnerability has been resolved:

bus: mhi: core: Fix invalid error returning in mhi_queue

mhi_queue returns an error when the doorbell is not accessible in
the current state. This can happen when the device is in non M0
state, like M3, and needs to be waken-up prior ringing the DB. This
case is managed earlier by triggering an asynchronous M3 exit via
controller resume/suspend callbacks, that in turn will cause M0
transition and DB update.

So, since it's not an error but just delaying of doorbell update, there
is no reason to return an error.

This also fixes a use after free error for skb case, indeed a caller
queuing skb will try to free the skb if the queueing fails, but in
that case queueing has been done.

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🚨 CVE-2021-46973
In the Linux kernel, the following vulnerability has been resolved:

net: qrtr: Avoid potential use after free in MHI send

It is possible that the MHI ul_callback will be invoked immediately
following the queueing of the skb for transmission, leading to the
callback decrementing the refcount of the associated sk and freeing the
skb.

As such the dereference of skb and the increment of the sk refcount must
happen before the skb is queued, to avoid the skb to be used after free
and potentially the sk to drop its last refcount..

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🚨 CVE-2021-46974
In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix masking negation logic upon negative dst register

The negation logic for the case where the off_reg is sitting in the
dst register is not correct given then we cannot just invert the add
to a sub or vice versa. As a fix, perform the final bitwise and-op
unconditionally into AX from the off_reg, then move the pointer from
the src to dst and finally use AX as the source for the original
pointer arithmetic operation such that the inversion yields a correct
result. The single non-AX mov in between is possible given constant
blinding is retaining it as it's not an immediate based operation.

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🚨 CVE-2020-36785
In the Linux kernel, the following vulnerability has been resolved:

media: atomisp: Fix use after free in atomisp_alloc_css_stat_bufs()

The "s3a_buf" is freed along with all the other items on the
"asd->s3a_stats" list. It leads to a double free and a use after free.

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🚨 CVE-2020-36787
In the Linux kernel, the following vulnerability has been resolved:

media: aspeed: fix clock handling logic

Video engine uses eclk and vclk for its clock sources and its reset
control is coupled with eclk so the current clock enabling sequence works
like below.

Enable eclk
De-assert Video Engine reset
10ms delay
Enable vclk

It introduces improper reset on the Video Engine hardware and eventually
the hardware generates unexpected DMA memory transfers that can corrupt
memory region in random and sporadic patterns. This issue is observed
very rarely on some specific AST2500 SoCs but it causes a critical
kernel panic with making a various shape of signature so it's extremely
hard to debug. Moreover, the issue is observed even when the video
engine is not actively used because udevd turns on the video engine
hardware for a short time to make a query in every boot.

To fix this issue, this commit changes the clock handling logic to make
the reset de-assertion triggered after enabling both eclk and vclk. Also,
it adds clk_unprepare call for a case when probe fails.

clk: ast2600: fix reset settings for eclk and vclk
Video engine reset setting should be coupled with eclk to match it
with the setting for previous Aspeed SoCs which is defined in
clk-aspeed.c since all Aspeed SoCs are sharing a single video engine
driver. Also, reset bit 6 is defined as 'Video Engine' reset in
datasheet so it should be de-asserted when eclk is enabled. This
commit fixes the setting.

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🚨 CVE-2021-46977
In the Linux kernel, the following vulnerability has been resolved:

KVM: VMX: Disable preemption when probing user return MSRs

Disable preemption when probing a user return MSR via RDSMR/WRMSR. If
the MSR holds a different value per logical CPU, the WRMSR could corrupt
the host's value if KVM is preempted between the RDMSR and WRMSR, and
then rescheduled on a different CPU.

Opportunistically land the helper in common x86, SVM will use the helper
in a future commit.

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🚨 CVE-2021-46984
In the Linux kernel, the following vulnerability has been resolved:

kyber: fix out of bounds access when preempted

__blk_mq_sched_bio_merge() gets the ctx and hctx for the current CPU and
passes the hctx to ->bio_merge(). kyber_bio_merge() then gets the ctx
for the current CPU again and uses that to get the corresponding Kyber
context in the passed hctx. However, the thread may be preempted between
the two calls to blk_mq_get_ctx(), and the ctx returned the second time
may no longer correspond to the passed hctx. This "works" accidentally
most of the time, but it can cause us to read garbage if the second ctx
came from an hctx with more ctx's than the first one (i.e., if
ctx->index_hw[hctx->type] > hctx->nr_ctx).

This manifested as this UBSAN array index out of bounds error reported
by Jakub:

UBSAN: array-index-out-of-bounds in ../kernel/locking/qspinlock.c:130:9
index 13106 is out of range for type 'long unsigned int [128]'
Call Trace:
dump_stack+0xa4/0xe5
ubsan_epilogue+0x5/0x40
__ubsan_handle_out_of_bounds.cold.13+0x2a/0x34
queued_spin_lock_slowpath+0x476/0x480
do_raw_spin_lock+0x1c2/0x1d0
kyber_bio_merge+0x112/0x180
blk_mq_submit_bio+0x1f5/0x1100
submit_bio_noacct+0x7b0/0x870
submit_bio+0xc2/0x3a0
btrfs_map_bio+0x4f0/0x9d0
btrfs_submit_data_bio+0x24e/0x310
submit_one_bio+0x7f/0xb0
submit_extent_page+0xc4/0x440
__extent_writepage_io+0x2b8/0x5e0
__extent_writepage+0x28d/0x6e0
extent_write_cache_pages+0x4d7/0x7a0
extent_writepages+0xa2/0x110
do_writepages+0x8f/0x180
__writeback_single_inode+0x99/0x7f0
writeback_sb_inodes+0x34e/0x790
__writeback_inodes_wb+0x9e/0x120
wb_writeback+0x4d2/0x660
wb_workfn+0x64d/0xa10
process_one_work+0x53a/0xa80
worker_thread+0x69/0x5b0
kthread+0x20b/0x240
ret_from_fork+0x1f/0x30

Only Kyber uses the hctx, so fix it by passing the request_queue to
->bio_merge() instead. BFQ and mq-deadline just use that, and Kyber can
map the queues itself to avoid the mismatch.

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🚨 CVE-2021-46989
In the Linux kernel, the following vulnerability has been resolved:

hfsplus: prevent corruption in shrinking truncate

I believe there are some issues introduced by commit 31651c607151
("hfsplus: avoid deadlock on file truncation")

HFS+ has extent records which always contains 8 extents. In case the
first extent record in catalog file gets full, new ones are allocated from
extents overflow file.

In case shrinking truncate happens to middle of an extent record which
locates in extents overflow file, the logic in hfsplus_file_truncate() was
changed so that call to hfs_brec_remove() is not guarded any more.

Right action would be just freeing the extents that exceed the new size
inside extent record by calling hfsplus_free_extents(), and then check if
the whole extent record should be removed. However since the guard
(blk_cnt > start) is now after the call to hfs_brec_remove(), this has
unfortunate effect that the last matching extent record is removed
unconditionally.

To reproduce this issue, create a file which has at least 10 extents, and
then perform shrinking truncate into middle of the last extent record, so
that the number of remaining extents is not under or divisible by 8. This
causes the last extent record (8 extents) to be removed totally instead of
truncating into middle of it. Thus this causes corruption, and lost data.

Fix for this is simply checking if the new truncated end is below the
start of this extent record, making it safe to remove the full extent
record. However call to hfs_brec_remove() can't be moved to it's previous
place since we're dropping ->tree_lock and it can cause a race condition
and the cached info being invalidated possibly corrupting the node data.

Another issue is related to this one. When entering into the block
(blk_cnt > start) we are not holding the ->tree_lock. We break out from
the loop not holding the lock, but hfs_find_exit() does unlock it. Not
sure if it's possible for someone else to take the lock under our feet,
but it can cause hard to debug errors and premature unlocking. Even if
there's no real risk of it, the locking should still always be kept in
balance. Thus taking the lock now just before the check.

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🚨 CVE-2021-46992
In the Linux kernel, the following vulnerability has been resolved:

netfilter: nftables: avoid overflows in nft_hash_buckets()

Number of buckets being stored in 32bit variables, we have to
ensure that no overflows occur in nft_hash_buckets()

syzbot injected a size == 0x40000000 and reported:

UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
shift exponent 64 is too large for 64-bit type 'long unsigned int'
CPU: 1 PID: 29539 Comm: syz-executor.4 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
__roundup_pow_of_two include/linux/log2.h:57 [inline]
nft_hash_buckets net/netfilter/nft_set_hash.c:411 [inline]
nft_hash_estimate.cold+0x19/0x1e net/netfilter/nft_set_hash.c:652
nft_select_set_ops net/netfilter/nf_tables_api.c:3586 [inline]
nf_tables_newset+0xe62/0x3110 net/netfilter/nf_tables_api.c:4322
nfnetlink_rcv_batch+0xa09/0x24b0 net/netfilter/nfnetlink.c:488
nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:612 [inline]
nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:630
netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:674
____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
___sys_sendmsg+0xf3/0x170 net/socket.c:2404
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2433
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46

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🚨 CVE-2021-46993
In the Linux kernel, the following vulnerability has been resolved:

sched: Fix out-of-bound access in uclamp

Util-clamp places tasks in different buckets based on their clamp values
for performance reasons. However, the size of buckets is currently
computed using a rounding division, which can lead to an off-by-one
error in some configurations.

For instance, with 20 buckets, the bucket size will be 1024/20=51. A
task with a clamp of 1024 will be mapped to bucket id 1024/51=20. Sadly,
correct indexes are in range [0,19], hence leading to an out of bound
memory access.

Clamp the bucket id to fix the issue.

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🚨 CVE-2021-46998
In the Linux kernel, the following vulnerability has been resolved:

ethernet:enic: Fix a use after free bug in enic_hard_start_xmit

In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside
enic_queue_wq_skb, if some error happens, the skb will be freed
by dev_kfree_skb(skb). But the freed skb is still used in
skb_tx_timestamp(skb).

My patch makes enic_queue_wq_skb() return error and goto spin_unlock()
incase of error. The solution is provided by Govind.
See https://lkml.org/lkml/2021/4/30/961.

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🚨 CVE-2021-46999
In the Linux kernel, the following vulnerability has been resolved:

sctp: do asoc update earlier in sctp_sf_do_dupcook_a

There's a panic that occurs in a few of envs, the call trace is as below:

[] general protection fault, ... 0x29acd70f1000a: 0000 [#1] SMP PTI
[] RIP: 0010:sctp_ulpevent_notify_peer_addr_change+0x4b/0x1fa [sctp]
[] sctp_assoc_control_transport+0x1b9/0x210 [sctp]
[] sctp_do_8_2_transport_strike.isra.16+0x15c/0x220 [sctp]
[] sctp_cmd_interpreter.isra.21+0x1231/0x1a10 [sctp]
[] sctp_do_sm+0xc3/0x2a0 [sctp]
[] sctp_generate_timeout_event+0x81/0xf0 [sctp]

This is caused by a transport use-after-free issue. When processing a
duplicate COOKIE-ECHO chunk in sctp_sf_do_dupcook_a(), both COOKIE-ACK
and SHUTDOWN chunks are allocated with the transort from the new asoc.
However, later in the sideeffect machine, the old asoc is used to send
them out and old asoc's shutdown_last_sent_to is set to the transport
that SHUTDOWN chunk attached to in sctp_cmd_setup_t2(), which actually
belongs to the new asoc. After the new_asoc is freed and the old asoc
T2 timeout, the old asoc's shutdown_last_sent_to that is already freed
would be accessed in sctp_sf_t2_timer_expire().

Thanks Alexander and Jere for helping dig into this issue.

To fix it, this patch is to do the asoc update first, then allocate
the COOKIE-ACK and SHUTDOWN chunks with the 'updated' old asoc. This
would make more sense, as a chunk from an asoc shouldn't be sent out
with another asoc. We had fixed quite a few issues caused by this.

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🚨 CVE-2021-47001
In the Linux kernel, the following vulnerability has been resolved:

xprtrdma: Fix cwnd update ordering

After a reconnect, the reply handler is opening the cwnd (and thus
enabling more RPC Calls to be sent) /before/ rpcrdma_post_recvs()
can post enough Receive WRs to receive their replies. This causes an
RNR and the new connection is lost immediately.

The race is most clearly exposed when KASAN and disconnect injection
are enabled. This slows down rpcrdma_rep_create() enough to allow
the send side to post a bunch of RPC Calls before the Receive
completion handler can invoke ib_post_recv().

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🚨 CVE-2021-47004
In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to avoid touching checkpointed data in get_victim()

In CP disabling mode, there are two issues when using LFS or SSR | AT_SSR
mode to select victim:

1. LFS is set to find source section during GC, the victim should have
no checkpointed data, since after GC, section could not be set free for
reuse.

Previously, we only check valid chpt blocks in current segment rather
than section, fix it.

2. SSR | AT_SSR are set to find target segment for writes which can be
fully filled by checkpointed and newly written blocks, we should never
select such segment, otherwise it can cause panic or data corruption
during allocation, potential case is described as below:

a) target segment has 'n' (n < 512) ckpt valid blocks
b) GC migrates 'n' valid blocks to other segment (segment is still
in dirty list)
c) GC migrates '512 - n' blocks to target segment (segment has 'n'
cp_vblocks and '512 - n' vblocks)
d) If GC selects target segment via {AT,}SSR allocator, however there
is no free space in targe segment.

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🚨 CVE-2021-47011
In the Linux kernel, the following vulnerability has been resolved:

mm: memcontrol: slab: fix obtain a reference to a freeing memcg

Patch series "Use obj_cgroup APIs to charge kmem pages", v5.

Since Roman's series "The new cgroup slab memory controller" applied.
All slab objects are charged with the new APIs of obj_cgroup. The new
APIs introduce a struct obj_cgroup to charge slab objects. It prevents
long-living objects from pinning the original memory cgroup in the
memory. But there are still some corner objects (e.g. allocations
larger than order-1 page on SLUB) which are not charged with the new
APIs. Those objects (include the pages which are allocated from buddy
allocator directly) are charged as kmem pages which still hold a
reference to the memory cgroup.

E.g. We know that the kernel stack is charged as kmem pages because the
size of the kernel stack can be greater than 2 pages (e.g. 16KB on
x86_64 or arm64). If we create a thread (suppose the thread stack is
charged to memory cgroup A) and then move it from memory cgroup A to
memory cgroup B. Because the kernel stack of the thread hold a
reference to the memory cgroup A. The thread can pin the memory cgroup
A in the memory even if we remove the cgroup A. If we want to see this
scenario by using the following script. We can see that the system has
added 500 dying cgroups (This is not a real world issue, just a script
to show that the large kmallocs are charged as kmem pages which can pin
the memory cgroup in the memory).

#!/bin/bash

cat /proc/cgroups | grep memory

cd /sys/fs/cgroup/memory
echo 1 > memory.move_charge_at_immigrate

for i in range{1..500}
do
mkdir kmem_test
echo $$ > kmem_test/cgroup.procs
sleep 3600 &
echo $$ > cgroup.procs
echo `cat kmem_test/cgroup.procs` > cgroup.procs
rmdir kmem_test
done

cat /proc/cgroups | grep memory

This patchset aims to make those kmem pages to drop the reference to
memory cgroup by using the APIs of obj_cgroup. Finally, we can see that
the number of the dying cgroups will not increase if we run the above test
script.

This patch (of 7):

The rcu_read_lock/unlock only can guarantee that the memcg will not be
freed, but it cannot guarantee the success of css_get (which is in the
refill_stock when cached memcg changed) to memcg.

rcu_read_lock()
memcg = obj_cgroup_memcg(old)
__memcg_kmem_uncharge(memcg)
refill_stock(memcg)
if (stock->cached != memcg)
// css_get can change the ref counter from 0 back to 1.
css_get(&memcg->css)
rcu_read_unlock()

This fix is very like the commit:

eefbfa7fd678 ("mm: memcg/slab: fix use after free in obj_cgroup_charge")

Fix this by holding a reference to the memcg which is passed to the
__memcg_kmem_uncharge() before calling __memcg_kmem_uncharge().

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🚨 CVE-2021-47012
In the Linux kernel, the following vulnerability has been resolved:

RDMA/siw: Fix a use after free in siw_alloc_mr

Our code analyzer reported a UAF.

In siw_alloc_mr(), it calls siw_mr_add_mem(mr,..). In the implementation of
siw_mr_add_mem(), mem is assigned to mr->mem and then mem is freed via
kfree(mem) if xa_alloc_cyclic() failed. Here, mr->mem still point to a
freed object. After, the execution continue up to the err_out branch of
siw_alloc_mr, and the freed mr->mem is used in siw_mr_drop_mem(mr).

My patch moves "mr->mem = mem" behind the if (xa_alloc_cyclic(..)<0) {}
section, to avoid the uaf.

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🚨 CVE-2021-47013
In the Linux kernel, the following vulnerability has been resolved:

net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..).
If some error happens in emac_tx_fill_tpd(), the skb will be freed via
dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd().
But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len).

As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len,
thus my patch assigns skb->len to 'len' before the possible free and
use 'len' instead of skb->len later.

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🚨 CVE-2021-47014
In the Linux kernel, the following vulnerability has been resolved:

net/sched: act_ct: fix wild memory access when clearing fragments

while testing re-assembly/re-fragmentation using act_ct, it's possible to
observe a crash like the following one:

KASAN: maybe wild-memory-access in range [0x0001000000000448-0x000100000000044f]
CPU: 50 PID: 0 Comm: swapper/50 Tainted: G S 5.12.0-rc7+ #424
Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.4.3 01/17/2017
RIP: 0010:inet_frag_rbtree_purge+0x50/0xc0
Code: 00 fc ff df 48 89 c3 31 ed 48 89 df e8 a9 7a 38 ff 4c 89 fe 48 89 df 49 89 c6 e8 5b 3a 38 ff 48 8d 7b 40 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 75 59 48 8d bb d0 00 00 00 4c 8b 6b 40 48 89 f8 48
RSP: 0018:ffff888c31449db8 EFLAGS: 00010203
RAX: 0000200000000089 RBX: 000100000000040e RCX: ffffffff989eb960
RDX: 0000000000000140 RSI: ffffffff97cfb977 RDI: 000100000000044e
RBP: 0000000000000900 R08: 0000000000000000 R09: ffffed1186289350
R10: 0000000000000003 R11: ffffed1186289350 R12: dffffc0000000000
R13: 000100000000040e R14: 0000000000000000 R15: ffff888155e02160
FS: 0000000000000000(0000) GS:ffff888c31440000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005600cb70a5b8 CR3: 0000000a2c014005 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
inet_frag_destroy+0xa9/0x150
call_timer_fn+0x2d/0x180
run_timer_softirq+0x4fe/0xe70
__do_softirq+0x197/0x5a0
irq_exit_rcu+0x1de/0x200
sysvec_apic_timer_interrupt+0x6b/0x80
</IRQ>

when act_ct temporarily stores an IP fragment, restoring the skb qdisc cb
results in putting random data in FRAG_CB(), and this causes those "wild"
memory accesses later, when the rbtree is purged. Never overwrite the skb
cb in case tcf_ct_handle_fragments() returns -EINPROGRESS.

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🚨 CVE-2021-47017
In the Linux kernel, the following vulnerability has been resolved:

ath10k: Fix a use after free in ath10k_htc_send_bundle

In ath10k_htc_send_bundle, the bundle_skb could be freed by
dev_kfree_skb_any(bundle_skb). But the bundle_skb is used later
by bundle_skb->len.

As skb_len = bundle_skb->len, my patch replaces bundle_skb->len to
skb_len after the bundle_skb was freed.

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🚨 CVE-2021-47028
In the Linux kernel, the following vulnerability has been resolved:

mt76: mt7915: fix txrate reporting

Properly check rate_info to fix unexpected reporting.

[ 1215.161863] Call trace:
[ 1215.164307] cfg80211_calculate_bitrate+0x124/0x200 [cfg80211]
[ 1215.170139] ieee80211s_update_metric+0x80/0xc0 [mac80211]
[ 1215.175624] ieee80211_tx_status_ext+0x508/0x838 [mac80211]
[ 1215.181190] mt7915_mcu_get_rx_rate+0x28c/0x8d0 [mt7915e]
[ 1215.186580] mt7915_mac_tx_free+0x324/0x7c0 [mt7915e]
[ 1215.191623] mt7915_queue_rx_skb+0xa8/0xd0 [mt7915e]
[ 1215.196582] mt76_dma_cleanup+0x7b0/0x11d0 [mt76]
[ 1215.201276] __napi_poll+0x38/0xf8
[ 1215.204668] napi_workfn+0x40/0x80
[ 1215.208062] process_one_work+0x1fc/0x390
[ 1215.212062] worker_thread+0x48/0x4d0
[ 1215.215715] kthread+0x120/0x128
[ 1215.218935] ret_from_fork+0x10/0x1c

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