Security Vulnerabilities
- CVEs Published In May 2024
In the Linux kernel, the following vulnerability has been resolved:
of: module: prevent NULL pointer dereference in vsnprintf()
In of_modalias(), we can get passed the str and len parameters which would
cause a kernel oops in vsnprintf() since it only allows passing a NULL ptr
when the length is also 0. Also, we need to filter out the negative values
of the len parameter as these will result in a really huge buffer since
snprintf() takes size_t parameter while ours is ssize_t...
Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.
In the Linux kernel, the following vulnerability has been resolved:
of: dynamic: Synchronize of_changeset_destroy() with the devlink removals
In the following sequence:
1) of_platform_depopulate()
2) of_overlay_remove()
During the step 1, devices are destroyed and devlinks are removed.
During the step 2, OF nodes are destroyed but
__of_changeset_entry_destroy() can raise warnings related to missing
of_node_put():
ERROR: memory leak, expected refcount 1 instead of 2 ...
Indeed, during the devlink removals performed at step 1, the removal
itself releasing the device (and the attached of_node) is done by a job
queued in a workqueue and so, it is done asynchronously with respect to
function calls.
When the warning is present, of_node_put() will be called but wrongly
too late from the workqueue job.
In order to be sure that any ongoing devlink removals are done before
the of_node destruction, synchronize the of_changeset_destroy() with the
devlink removals.
In the Linux kernel, the following vulnerability has been resolved:
io_uring/kbuf: hold io_buffer_list reference over mmap
If we look up the kbuf, ensure that it doesn't get unregistered until
after we're done with it. Since we're inside mmap, we cannot safely use
the io_uring lock. Rely on the fact that we can lookup the buffer list
under RCU now and grab a reference to it, preventing it from being
unregistered until we're done with it. The lookup returns the
io_buffer_list directly with it referenced.
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP
Jan Schunk reports that his small NFS servers suffer from memory
exhaustion after just a few days. A bisect shows that commit
e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single
sock_sendmsg() call") is the first bad commit.
That commit assumed that sock_sendmsg() releases all the pages in
the underlying bio_vec array, but the reality is that it doesn't.
svc_xprt_release() releases the rqst's response pages, but the
record marker page fragment isn't one of those, so it is never
released.
This is a narrow fix that can be applied to stable kernels. A
more extensive fix is in the works.
In the Linux kernel, the following vulnerability has been resolved:
spi: mchp-pci1xxx: Fix a possible null pointer dereference in pci1xxx_spi_probe
In function pci1xxxx_spi_probe, there is a potential null pointer that
may be caused by a failed memory allocation by the function devm_kzalloc.
Hence, a null pointer check needs to be added to prevent null pointer
dereferencing later in the code.
To fix this issue, spi_bus->spi_int[iter] should be checked. The memory
allocated by devm_kzalloc will be automatically released, so just directly
return -ENOMEM without worrying about memory leaks.
In the Linux kernel, the following vulnerability has been resolved:
udp: do not accept non-tunnel GSO skbs landing in a tunnel
When rx-udp-gro-forwarding is enabled UDP packets might be GROed when
being forwarded. If such packets might land in a tunnel this can cause
various issues and udp_gro_receive makes sure this isn't the case by
looking for a matching socket. This is performed in
udp4/6_gro_lookup_skb but only in the current netns. This is an issue
with tunneled packets when the endpoint is in another netns. In such
cases the packets will be GROed at the UDP level, which leads to various
issues later on. The same thing can happen with rx-gro-list.
We saw this with geneve packets being GROed at the UDP level. In such
case gso_size is set; later the packet goes through the geneve rx path,
the geneve header is pulled, the offset are adjusted and frag_list skbs
are not adjusted with regard to geneve. When those skbs hit
skb_fragment, it will misbehave. Different outcomes are possible
depending on what the GROed skbs look like; from corrupted packets to
kernel crashes.
One example is a BUG_ON[1] triggered in skb_segment while processing the
frag_list. Because gso_size is wrong (geneve header was pulled)
skb_segment thinks there is "geneve header size" of data in frag_list,
although it's in fact the next packet. The BUG_ON itself has nothing to
do with the issue. This is only one of the potential issues.
Looking up for a matching socket in udp_gro_receive is fragile: the
lookup could be extended to all netns (not speaking about performances)
but nothing prevents those packets from being modified in between and we
could still not find a matching socket. It's OK to keep the current
logic there as it should cover most cases but we also need to make sure
we handle tunnel packets being GROed too early.
This is done by extending the checks in udp_unexpected_gso: GSO packets
lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits and landing in a tunnel must
be segmented.
[1] kernel BUG at net/core/skbuff.c:4408!
RIP: 0010:skb_segment+0xd2a/0xf70
__udp_gso_segment+0xaa/0x560
In the Linux kernel, the following vulnerability has been resolved:
mlxbf_gige: stop interface during shutdown
The mlxbf_gige driver intermittantly encounters a NULL pointer
exception while the system is shutting down via "reboot" command.
The mlxbf_driver will experience an exception right after executing
its shutdown() method. One example of this exception is:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=000000011d373000
[0000000000000070] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 96000004 [#1] SMP
CPU: 0 PID: 13 Comm: ksoftirqd/0 Tainted: G S OE 5.15.0-bf.6.gef6992a #1
Hardware name: https://www.mellanox.com BlueField SoC/BlueField SoC, BIOS 4.0.2.12669 Apr 21 2023
pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : mlxbf_gige_handle_tx_complete+0xc8/0x170 [mlxbf_gige]
lr : mlxbf_gige_poll+0x54/0x160 [mlxbf_gige]
sp : ffff8000080d3c10
x29: ffff8000080d3c10 x28: ffffcce72cbb7000 x27: ffff8000080d3d58
x26: ffff0000814e7340 x25: ffff331cd1a05000 x24: ffffcce72c4ea008
x23: ffff0000814e4b40 x22: ffff0000814e4d10 x21: ffff0000814e4128
x20: 0000000000000000 x19: ffff0000814e4a80 x18: ffffffffffffffff
x17: 000000000000001c x16: ffffcce72b4553f4 x15: ffff80008805b8a7
x14: 0000000000000000 x13: 0000000000000030 x12: 0101010101010101
x11: 7f7f7f7f7f7f7f7f x10: c2ac898b17576267 x9 : ffffcce720fa5404
x8 : ffff000080812138 x7 : 0000000000002e9a x6 : 0000000000000080
x5 : ffff00008de3b000 x4 : 0000000000000000 x3 : 0000000000000001
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
mlxbf_gige_handle_tx_complete+0xc8/0x170 [mlxbf_gige]
mlxbf_gige_poll+0x54/0x160 [mlxbf_gige]
__napi_poll+0x40/0x1c8
net_rx_action+0x314/0x3a0
__do_softirq+0x128/0x334
run_ksoftirqd+0x54/0x6c
smpboot_thread_fn+0x14c/0x190
kthread+0x10c/0x110
ret_from_fork+0x10/0x20
Code: 8b070000 f9000ea0 f95056c0 f86178a1 (b9407002)
---[ end trace 7cc3941aa0d8e6a4 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt
Kernel Offset: 0x4ce722520000 from 0xffff800008000000
PHYS_OFFSET: 0x80000000
CPU features: 0x000005c1,a3330e5a
Memory Limit: none
---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
During system shutdown, the mlxbf_gige driver's shutdown() is always executed.
However, the driver's stop() method will only execute if networking interface
configuration logic within the Linux distribution has been setup to do so.
If shutdown() executes but stop() does not execute, NAPI remains enabled
and this can lead to an exception if NAPI is scheduled while the hardware
interface has only been partially deinitialized.
The networking interface managed by the mlxbf_gige driver must be properly
stopped during system shutdown so that IFF_UP is cleared, the hardware
interface is put into a clean state, and NAPI is fully deinitialized.
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix infinite recursion in fib6_dump_done().
syzkaller reported infinite recursive calls of fib6_dump_done() during
netlink socket destruction. [1]
From the log, syzkaller sent an AF_UNSPEC RTM_GETROUTE message, and then
the response was generated. The following recvmmsg() resumed the dump
for IPv6, but the first call of inet6_dump_fib() failed at kzalloc() due
to the fault injection. [0]
12:01:34 executing program 3:
r0 = socket$nl_route(0x10, 0x3, 0x0)
sendmsg$nl_route(r0, ... snip ...)
recvmmsg(r0, ... snip ...) (fail_nth: 8)
Here, fib6_dump_done() was set to nlk_sk(sk)->cb.done, and the next call
of inet6_dump_fib() set it to nlk_sk(sk)->cb.args[3]. syzkaller stopped
receiving the response halfway through, and finally netlink_sock_destruct()
called nlk_sk(sk)->cb.done().
fib6_dump_done() calls fib6_dump_end() and nlk_sk(sk)->cb.done() if it
is still not NULL. fib6_dump_end() rewrites nlk_sk(sk)->cb.done() by
nlk_sk(sk)->cb.args[3], but it has the same function, not NULL, calling
itself recursively and hitting the stack guard page.
To avoid the issue, let's set the destructor after kzalloc().
[0]:
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 1 PID: 432110 Comm: syz-executor.3 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:117)
should_fail_ex (lib/fault-inject.c:52 lib/fault-inject.c:153)
should_failslab (mm/slub.c:3733)
kmalloc_trace (mm/slub.c:3748 mm/slub.c:3827 mm/slub.c:3992)
inet6_dump_fib (./include/linux/slab.h:628 ./include/linux/slab.h:749 net/ipv6/ip6_fib.c:662)
rtnl_dump_all (net/core/rtnetlink.c:4029)
netlink_dump (net/netlink/af_netlink.c:2269)
netlink_recvmsg (net/netlink/af_netlink.c:1988)
____sys_recvmsg (net/socket.c:1046 net/socket.c:2801)
___sys_recvmsg (net/socket.c:2846)
do_recvmmsg (net/socket.c:2943)
__x64_sys_recvmmsg (net/socket.c:3041 net/socket.c:3034 net/socket.c:3034)
[1]:
BUG: TASK stack guard page was hit at 00000000f2fa9af1 (stack is 00000000b7912430..000000009a436beb)
stack guard page: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 223719 Comm: kworker/1:3 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Workqueue: events netlink_sock_destruct_work
RIP: 0010:fib6_dump_done (net/ipv6/ip6_fib.c:570)
Code: 3c 24 e8 f3 e9 51 fd e9 28 fd ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 41 57 41 56 41 55 41 54 55 48 89 fd <53> 48 8d 5d 60 e8 b6 4d 07 fd 48 89 da 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000d980000 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffffff84405990 RCX: ffffffff844059d3
RDX: ffff8881028e0000 RSI: ffffffff84405ac2 RDI: ffff88810c02f358
RBP: ffff88810c02f358 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000224 R12: 0000000000000000
R13: ffff888007c82c78 R14: ffff888007c82c68 R15: ffff888007c82c68
FS: 0000000000000000(0000) GS:ffff88811b100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000d97fff8 CR3: 0000000102309002 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
<#DF>
</#DF>
<TASK>
fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))
fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))
...
fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))
fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1))
netlink_sock_destruct (net/netlink/af_netlink.c:401)
__sk_destruct (net/core/sock.c:2177 (discriminator 2))
sk_destruct (net/core/sock.c:2224)
__sk_free (net/core/sock.c:2235)
sk_free (net/core/sock.c:2246)
process_one_work (kernel/workqueue.c:3259)
worker_thread (kernel/workqueue.c:3329 kernel/workqueue.
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
ax25: fix use-after-free bugs caused by ax25_ds_del_timer
When the ax25 device is detaching, the ax25_dev_device_down()
calls ax25_ds_del_timer() to cleanup the slave_timer. When
the timer handler is running, the ax25_ds_del_timer() that
calls del_timer() in it will return directly. As a result,
the use-after-free bugs could happen, one of the scenarios
is shown below:
(Thread 1) | (Thread 2)
| ax25_ds_timeout()
ax25_dev_device_down() |
ax25_ds_del_timer() |
del_timer() |
ax25_dev_put() //FREE |
| ax25_dev-> //USE
In order to mitigate bugs, when the device is detaching, use
timer_shutdown_sync() to stop the timer.
In the Linux kernel, the following vulnerability has been resolved:
erspan: make sure erspan_base_hdr is present in skb->head
syzbot reported a problem in ip6erspan_rcv() [1]
Issue is that ip6erspan_rcv() (and erspan_rcv()) no longer make
sure erspan_base_hdr is present in skb linear part (skb->head)
before getting @ver field from it.
Add the missing pskb_may_pull() calls.
v2: Reload iph pointer in erspan_rcv() after pskb_may_pull()
because skb->head might have changed.
[1]
BUG: KMSAN: uninit-value in pskb_may_pull_reason include/linux/skbuff.h:2742 [inline]
BUG: KMSAN: uninit-value in pskb_may_pull include/linux/skbuff.h:2756 [inline]
BUG: KMSAN: uninit-value in ip6erspan_rcv net/ipv6/ip6_gre.c:541 [inline]
BUG: KMSAN: uninit-value in gre_rcv+0x11f8/0x1930 net/ipv6/ip6_gre.c:610
pskb_may_pull_reason include/linux/skbuff.h:2742 [inline]
pskb_may_pull include/linux/skbuff.h:2756 [inline]
ip6erspan_rcv net/ipv6/ip6_gre.c:541 [inline]
gre_rcv+0x11f8/0x1930 net/ipv6/ip6_gre.c:610
ip6_protocol_deliver_rcu+0x1d4c/0x2ca0 net/ipv6/ip6_input.c:438
ip6_input_finish net/ipv6/ip6_input.c:483 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ip6_input+0x15d/0x430 net/ipv6/ip6_input.c:492
ip6_mc_input+0xa7e/0xc80 net/ipv6/ip6_input.c:586
dst_input include/net/dst.h:460 [inline]
ip6_rcv_finish+0x955/0x970 net/ipv6/ip6_input.c:79
NF_HOOK include/linux/netfilter.h:314 [inline]
ipv6_rcv+0xde/0x390 net/ipv6/ip6_input.c:310
__netif_receive_skb_one_core net/core/dev.c:5538 [inline]
__netif_receive_skb+0x1da/0xa00 net/core/dev.c:5652
netif_receive_skb_internal net/core/dev.c:5738 [inline]
netif_receive_skb+0x58/0x660 net/core/dev.c:5798
tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1549
tun_get_user+0x5566/0x69e0 drivers/net/tun.c:2002
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
call_write_iter include/linux/fs.h:2108 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xb63/0x1520 fs/read_write.c:590
ksys_write+0x20f/0x4c0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x93/0xe0 fs/read_write.c:652
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
Uninit was created at:
slab_post_alloc_hook mm/slub.c:3804 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
__alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668
alloc_skb include/linux/skbuff.h:1318 [inline]
alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504
sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795
tun_alloc_skb drivers/net/tun.c:1525 [inline]
tun_get_user+0x209a/0x69e0 drivers/net/tun.c:1846
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
call_write_iter include/linux/fs.h:2108 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xb63/0x1520 fs/read_write.c:590
ksys_write+0x20f/0x4c0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x93/0xe0 fs/read_write.c:652
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
CPU: 1 PID: 5045 Comm: syz-executor114 Not tainted 6.9.0-rc1-syzkaller-00021-g962490525cff #0