In the Linux kernel, the following vulnerability has been resolved:
wifi: libertas: fix some memleaks in lbs_allocate_cmd_buffer()
In the for statement of lbs_allocate_cmd_buffer(), if the allocation of
cmdarray[i].cmdbuf fails, both cmdarray and cmdarray[i].cmdbuf needs to
be freed. Otherwise, there will be memleaks in lbs_allocate_cmd_buffer().
In the Linux kernel, the following vulnerability has been resolved:
x86/efistub: Call mixed mode boot services on the firmware's stack
Normally, the EFI stub calls into the EFI boot services using the stack
that was live when the stub was entered. According to the UEFI spec,
this stack needs to be at least 128k in size - this might seem large but
all asynchronous processing and event handling in EFI runs from the same
stack and so quite a lot of space may be used in practice.
In mixed mode, the situation is a bit different: the bootloader calls
the 32-bit EFI stub entry point, which calls the decompressor's 32-bit
entry point, where the boot stack is set up, using a fixed allocation
of 16k. This stack is still in use when the EFI stub is started in
64-bit mode, and so all calls back into the EFI firmware will be using
the decompressor's limited boot stack.
Due to the placement of the boot stack right after the boot heap, any
stack overruns have gone unnoticed. However, commit
5c4feadb0011983b ("x86/decompressor: Move global symbol references to C code")
moved the definition of the boot heap into C code, and now the boot
stack is placed right at the base of BSS, where any overruns will
corrupt the end of the .data section.
While it would be possible to work around this by increasing the size of
the boot stack, doing so would affect all x86 systems, and mixed mode
systems are a tiny (and shrinking) fraction of the x86 installed base.
So instead, record the firmware stack pointer value when entering from
the 32-bit firmware, and switch to this stack every time a EFI boot
service call is made.
In the Linux kernel, the following vulnerability has been resolved:
net: atlantic: eliminate double free in error handling logic
Driver has a logic leak in ring data allocation/free,
where aq_ring_free could be called multiple times on same ring,
if system is under stress and got memory allocation error.
Ring pointer was used as an indicator of failure, but this is
not correct since only ring data is allocated/deallocated.
Ring itself is an array member.
Changing ring allocation functions to return error code directly.
This simplifies error handling and eliminates aq_ring_free
on higher layer.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock with fiemap and extent locking
While working on the patchset to remove extent locking I got a lockdep
splat with fiemap and pagefaulting with my new extent lock replacement
lock.
This deadlock exists with our normal code, we just don't have lockdep
annotations with the extent locking so we've never noticed it.
Since we're copying the fiemap extent to user space on every iteration
we have the chance of pagefaulting. Because we hold the extent lock for
the entire range we could mkwrite into a range in the file that we have
mmap'ed. This would deadlock with the following stack trace
[<0>] lock_extent+0x28d/0x2f0
[<0>] btrfs_page_mkwrite+0x273/0x8a0
[<0>] do_page_mkwrite+0x50/0xb0
[<0>] do_fault+0xc1/0x7b0
[<0>] __handle_mm_fault+0x2fa/0x460
[<0>] handle_mm_fault+0xa4/0x330
[<0>] do_user_addr_fault+0x1f4/0x800
[<0>] exc_page_fault+0x7c/0x1e0
[<0>] asm_exc_page_fault+0x26/0x30
[<0>] rep_movs_alternative+0x33/0x70
[<0>] _copy_to_user+0x49/0x70
[<0>] fiemap_fill_next_extent+0xc8/0x120
[<0>] emit_fiemap_extent+0x4d/0xa0
[<0>] extent_fiemap+0x7f8/0xad0
[<0>] btrfs_fiemap+0x49/0x80
[<0>] __x64_sys_ioctl+0x3e1/0xb50
[<0>] do_syscall_64+0x94/0x1a0
[<0>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
I wrote an fstest to reproduce this deadlock without my replacement lock
and verified that the deadlock exists with our existing locking.
To fix this simply don't take the extent lock for the entire duration of
the fiemap. This is safe in general because we keep track of where we
are when we're searching the tree, so if an ordered extent updates in
the middle of our fiemap call we'll still emit the correct extents
because we know what offset we were on before.
The only place we maintain the lock is searching delalloc. Since the
delalloc stuff can change during writeback we want to lock the extent
range so we have a consistent view of delalloc at the time we're
checking to see if we need to set the delalloc flag.
With this patch applied we no longer deadlock with my testcase.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: bridge: confirm multicast packets before passing them up the stack
conntrack nf_confirm logic cannot handle cloned skbs referencing
the same nf_conn entry, which will happen for multicast (broadcast)
frames on bridges.
Example:
macvlan0
|
br0
/ \
ethX ethY
ethX (or Y) receives a L2 multicast or broadcast packet containing
an IP packet, flow is not yet in conntrack table.
1. skb passes through bridge and fake-ip (br_netfilter)Prerouting.
-> skb->_nfct now references a unconfirmed entry
2. skb is broad/mcast packet. bridge now passes clones out on each bridge
interface.
3. skb gets passed up the stack.
4. In macvlan case, macvlan driver retains clone(s) of the mcast skb
and schedules a work queue to send them out on the lower devices.
The clone skb->_nfct is not a copy, it is the same entry as the
original skb. The macvlan rx handler then returns RX_HANDLER_PASS.
5. Normal conntrack hooks (in NF_INET_LOCAL_IN) confirm the orig skb.
The Macvlan broadcast worker and normal confirm path will race.
This race will not happen if step 2 already confirmed a clone. In that
case later steps perform skb_clone() with skb->_nfct already confirmed (in
hash table). This works fine.
But such confirmation won't happen when eb/ip/nftables rules dropped the
packets before they reached the nf_confirm step in postrouting.
Pablo points out that nf_conntrack_bridge doesn't allow use of stateful
nat, so we can safely discard the nf_conn entry and let inet call
conntrack again.
This doesn't work for bridge netfilter: skb could have a nat
transformation. Also bridge nf prevents re-invocation of inet prerouting
via 'sabotage_in' hook.
Work around this problem by explicit confirmation of the entry at LOCAL_IN
time, before upper layer has a chance to clone the unconfirmed entry.
The downside is that this disables NAT and conntrack helpers.
Alternative fix would be to add locking to all code parts that deal with
unconfirmed packets, but even if that could be done in a sane way this
opens up other problems, for example:
-m physdev --physdev-out eth0 -j SNAT --snat-to 1.2.3.4
-m physdev --physdev-out eth1 -j SNAT --snat-to 1.2.3.5
For multicast case, only one of such conflicting mappings will be
created, conntrack only handles 1:1 NAT mappings.
Users should set create a setup that explicitly marks such traffic
NOTRACK (conntrack bypass) to avoid this, but we cannot auto-bypass
them, ruleset might have accept rules for untracked traffic already,
so user-visible behaviour would change.
In the Linux kernel, the following vulnerability has been resolved:
phonet/pep: fix racy skb_queue_empty() use
The receive queues are protected by their respective spin-lock, not
the socket lock. This could lead to skb_peek() unexpectedly
returning NULL or a pointer to an already dequeued socket buffer.
In the Linux kernel, the following vulnerability has been resolved:
usb: aqc111: check packet for fixup for true limit
If a device sends a packet that is inbetween 0
and sizeof(u64) the value passed to skb_trim()
as length will wrap around ending up as some very
large value.
The driver will then proceed to parse the header
located at that position, which will either oops or
process some random value.
The fix is to check against sizeof(u64) rather than
0, which the driver currently does. The issue exists
since the introduction of the driver.
Linux Kernel Bluetooth CMTP Module Double Free Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within the CMTP module. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel. Was ZDI-CAN-11977.
In the Linux kernel, the following vulnerability has been resolved:
scsi: mpt3sas: Fix use-after-free warning
Fix the following use-after-free warning which is observed during
controller reset:
refcount_t: underflow; use-after-free.
WARNING: CPU: 23 PID: 5399 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0
In the Linux kernel, the following vulnerability has been resolved:
drm/radeon: add a force flush to delay work when radeon
Although radeon card fence and wait for gpu to finish processing current batch rings,
there is still a corner case that radeon lockup work queue may not be fully flushed,
and meanwhile the radeon_suspend_kms() function has called pci_set_power_state() to
put device in D3hot state.
Per PCI spec rev 4.0 on 5.3.1.4.1 D3hot State.
> Configuration and Message requests are the only TLPs accepted by a Function in
> the D3hot state. All other received Requests must be handled as Unsupported Requests,
> and all received Completions may optionally be handled as Unexpected Completions.
This issue will happen in following logs:
Unable to handle kernel paging request at virtual address 00008800e0008010
CPU 0 kworker/0:3(131): Oops 0
pc = [<ffffffff811bea5c>] ra = [<ffffffff81240844>] ps = 0000 Tainted: G W
pc is at si_gpu_check_soft_reset+0x3c/0x240
ra is at si_dma_is_lockup+0x34/0xd0
v0 = 0000000000000000 t0 = fff08800e0008010 t1 = 0000000000010000
t2 = 0000000000008010 t3 = fff00007e3c00000 t4 = fff00007e3c00258
t5 = 000000000000ffff t6 = 0000000000000001 t7 = fff00007ef078000
s0 = fff00007e3c016e8 s1 = fff00007e3c00000 s2 = fff00007e3c00018
s3 = fff00007e3c00000 s4 = fff00007fff59d80 s5 = 0000000000000000
s6 = fff00007ef07bd98
a0 = fff00007e3c00000 a1 = fff00007e3c016e8 a2 = 0000000000000008
a3 = 0000000000000001 a4 = 8f5c28f5c28f5c29 a5 = ffffffff810f4338
t8 = 0000000000000275 t9 = ffffffff809b66f8 t10 = ff6769c5d964b800
t11= 000000000000b886 pv = ffffffff811bea20 at = 0000000000000000
gp = ffffffff81d89690 sp = 00000000aa814126
Disabling lock debugging due to kernel taint
Trace:
[<ffffffff81240844>] si_dma_is_lockup+0x34/0xd0
[<ffffffff81119610>] radeon_fence_check_lockup+0xd0/0x290
[<ffffffff80977010>] process_one_work+0x280/0x550
[<ffffffff80977350>] worker_thread+0x70/0x7c0
[<ffffffff80977410>] worker_thread+0x130/0x7c0
[<ffffffff80982040>] kthread+0x200/0x210
[<ffffffff809772e0>] worker_thread+0x0/0x7c0
[<ffffffff80981f8c>] kthread+0x14c/0x210
[<ffffffff80911658>] ret_from_kernel_thread+0x18/0x20
[<ffffffff80981e40>] kthread+0x0/0x210
Code: ad3e0008 43f0074a ad7e0018 ad9e0020 8c3001e8 40230101
<88210000> 4821ed21
So force lockup work queue flush to fix this problem.