Linux: >> Linux Kernel >> 4.14.185 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: fix dereferencing invalid pmd migration entry
When migrating a THP, concurrent access to the PMD migration entry during
a deferred split scan can lead to an invalid address access, as
illustrated below. To prevent this invalid access, it is necessary to
check the PMD migration entry and return early. In this context, there is
no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the
equality of the target folio. Since the PMD migration entry is locked, it
cannot be served as the target.
Mailing list discussion and explanation from Hugh Dickins: "An anon_vma
lookup points to a location which may contain the folio of interest, but
might instead contain another folio: and weeding out those other folios is
precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of
replacing the wrong folio" comment a few lines above it) is for."
BUG: unable to handle page fault for address: ffffea60001db008
CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60
Call Trace:
<TASK>
try_to_migrate_one+0x28c/0x3730
rmap_walk_anon+0x4f6/0x770
unmap_folio+0x196/0x1f0
split_huge_page_to_list_to_order+0x9f6/0x1560
deferred_split_scan+0xac5/0x12a0
shrinker_debugfs_scan_write+0x376/0x470
full_proxy_write+0x15c/0x220
vfs_write+0x2fc/0xcb0
ksys_write+0x146/0x250
do_syscall_64+0x6a/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The bug is found by syzkaller on an internal kernel, then confirmed on
upstream.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
ipvs: fix uninit-value for saddr in do_output_route4
syzbot reports for uninit-value for the saddr argument [1].
commit 4754957f04f5 ("ipvs: do not use random local source address for
tunnels") already implies that the input value of saddr
should be ignored but the code is still reading it which can prevent
to connect the route. Fix it by changing the argument to ret_saddr.
[1]
BUG: KMSAN: uninit-value in do_output_route4+0x42c/0x4d0 net/netfilter/ipvs/ip_vs_xmit.c:147
do_output_route4+0x42c/0x4d0 net/netfilter/ipvs/ip_vs_xmit.c:147
__ip_vs_get_out_rt+0x403/0x21d0 net/netfilter/ipvs/ip_vs_xmit.c:330
ip_vs_tunnel_xmit+0x205/0x2380 net/netfilter/ipvs/ip_vs_xmit.c:1136
ip_vs_in_hook+0x1aa5/0x35b0 net/netfilter/ipvs/ip_vs_core.c:2063
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xf7/0x400 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:269 [inline]
__ip_local_out+0x758/0x7e0 net/ipv4/ip_output.c:118
ip_local_out net/ipv4/ip_output.c:127 [inline]
ip_send_skb+0x6a/0x3c0 net/ipv4/ip_output.c:1501
udp_send_skb+0xfda/0x1b70 net/ipv4/udp.c:1195
udp_sendmsg+0x2fe3/0x33c0 net/ipv4/udp.c:1483
inet_sendmsg+0x1fc/0x280 net/ipv4/af_inet.c:851
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x267/0x380 net/socket.c:727
____sys_sendmsg+0x91b/0xda0 net/socket.c:2566
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2620
__sys_sendmmsg+0x41d/0x880 net/socket.c:2702
__compat_sys_sendmmsg net/compat.c:360 [inline]
__do_compat_sys_sendmmsg net/compat.c:367 [inline]
__se_compat_sys_sendmmsg net/compat.c:364 [inline]
__ia32_compat_sys_sendmmsg+0xc8/0x140 net/compat.c:364
ia32_sys_call+0x3ffa/0x41f0 arch/x86/include/generated/asm/syscalls_32.h:346
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xb0/0x110 arch/x86/entry/syscall_32.c:306
do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
Uninit was created at:
slab_post_alloc_hook mm/slub.c:4167 [inline]
slab_alloc_node mm/slub.c:4210 [inline]
__kmalloc_cache_noprof+0x8fa/0xe00 mm/slub.c:4367
kmalloc_noprof include/linux/slab.h:905 [inline]
ip_vs_dest_dst_alloc net/netfilter/ipvs/ip_vs_xmit.c:61 [inline]
__ip_vs_get_out_rt+0x35d/0x21d0 net/netfilter/ipvs/ip_vs_xmit.c:323
ip_vs_tunnel_xmit+0x205/0x2380 net/netfilter/ipvs/ip_vs_xmit.c:1136
ip_vs_in_hook+0x1aa5/0x35b0 net/netfilter/ipvs/ip_vs_core.c:2063
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xf7/0x400 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:269 [inline]
__ip_local_out+0x758/0x7e0 net/ipv4/ip_output.c:118
ip_local_out net/ipv4/ip_output.c:127 [inline]
ip_send_skb+0x6a/0x3c0 net/ipv4/ip_output.c:1501
udp_send_skb+0xfda/0x1b70 net/ipv4/udp.c:1195
udp_sendmsg+0x2fe3/0x33c0 net/ipv4/udp.c:1483
inet_sendmsg+0x1fc/0x280 net/ipv4/af_inet.c:851
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x267/0x380 net/socket.c:727
____sys_sendmsg+0x91b/0xda0 net/socket.c:2566
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2620
__sys_sendmmsg+0x41d/0x880 net/socket.c:2702
__compat_sys_sendmmsg net/compat.c:360 [inline]
__do_compat_sys_sendmmsg net/compat.c:367 [inline]
__se_compat_sys_sendmmsg net/compat.c:364 [inline]
__ia32_compat_sys_sendmmsg+0xc8/0x140 net/compat.c:364
ia32_sys_call+0x3ffa/0x41f0 arch/x86/include/generated/asm/syscalls_32.h:346
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xb0/0x110 arch/x86/entry/syscall_32.c:306
do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
CPU: 0 UID: 0 PID: 22408 Comm: syz.4.5165 Not tainted 6.15.0-rc3-syzkaller-00019-gbc3372351d0c #0 PREEMPT(undef)
Hardware name: Google Google Compute Engi
---truncated---
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
arm64: bpf: Only mitigate cBPF programs loaded by unprivileged users
Support for eBPF programs loaded by unprivileged users is typically
disabled. This means only cBPF programs need to be mitigated for BHB.
In addition, only mitigate cBPF programs that were loaded by an
unprivileged user. Privileged users can also load the same program
via eBPF, making the mitigation pointless.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
smb: client: Avoid race in open_cached_dir with lease breaks
A pre-existing valid cfid returned from find_or_create_cached_dir might
race with a lease break, meaning open_cached_dir doesn't consider it
valid, and thinks it's newly-constructed. This leaks a dentry reference
if the allocation occurs before the queued lease break work runs.
Avoid the race by extending holding the cfid_list_lock across
find_or_create_cached_dir and when the result is checked.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
arm64: bpf: Add BHB mitigation to the epilogue for cBPF programs
A malicious BPF program may manipulate the branch history to influence
what the hardware speculates will happen next.
On exit from a BPF program, emit the BHB mititgation sequence.
This is only applied for 'classic' cBPF programs that are loaded by
seccomp.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
xenbus: Use kref to track req lifetime
Marek reported seeing a NULL pointer fault in the xenbus_thread
callstack:
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: e030:__wake_up_common+0x4c/0x180
Call Trace:
<TASK>
__wake_up_common_lock+0x82/0xd0
process_msg+0x18e/0x2f0
xenbus_thread+0x165/0x1c0
process_msg+0x18e is req->cb(req). req->cb is set to xs_wake_up(), a
thin wrapper around wake_up(), or xenbus_dev_queue_reply(). It seems
like it was xs_wake_up() in this case.
It seems like req may have woken up the xs_wait_for_reply(), which
kfree()ed the req. When xenbus_thread resumes, it faults on the zero-ed
data.
Linux Device Drivers 2nd edition states:
"Normally, a wake_up call can cause an immediate reschedule to happen,
meaning that other processes might run before wake_up returns."
... which would match the behaviour observed.
Change to keeping two krefs on each request. One for the caller, and
one for xenbus_thread. Each will kref_put() when finished, and the last
will free it.
This use of kref matches the description in
Documentation/core-api/kref.rst
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
ftrace: Add cond_resched() to ftrace_graph_set_hash()
When the kernel contains a large number of functions that can be traced,
the loop in ftrace_graph_set_hash() may take a lot of time to execute.
This may trigger the softlockup watchdog.
Add cond_resched() within the loop to allow the kernel to remain
responsive even when processing a large number of functions.
This matches the cond_resched() that is used in other locations of the
code that iterates over all functions that can be traced.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
objtool, media: dib8000: Prevent divide-by-zero in dib8000_set_dds()
If dib8000_set_dds()'s call to dib8000_read32() returns zero, the result
is a divide-by-zero. Prevent that from happening.
Fixes the following warning with an UBSAN kernel:
drivers/media/dvb-frontends/dib8000.o: warning: objtool: dib8000_tune() falls through to next function dib8096p_cfg_DibRx()
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
iommu/amd: Fix potential buffer overflow in parse_ivrs_acpihid
There is a string parsing logic error which can lead to an overflow of hid
or uid buffers. Comparing ACPIID_LEN against a total string length doesn't
take into account the lengths of individual hid and uid buffers so the
check is insufficient in some cases. For example if the length of hid
string is 4 and the length of the uid string is 260, the length of str
will be equal to ACPIID_LEN + 1 but uid string will overflow uid buffer
which size is 256.
The same applies to the hid string with length 13 and uid string with
length 250.
Check the length of hid and uid strings separately to prevent
buffer overflow.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
dm-bufio: don't schedule in atomic context
A BUG was reported as below when CONFIG_DEBUG_ATOMIC_SLEEP and
try_verify_in_tasklet are enabled.
[ 129.444685][ T934] BUG: sleeping function called from invalid context at drivers/md/dm-bufio.c:2421
[ 129.444723][ T934] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 934, name: kworker/1:4
[ 129.444740][ T934] preempt_count: 201, expected: 0
[ 129.444756][ T934] RCU nest depth: 0, expected: 0
[ 129.444781][ T934] Preemption disabled at:
[ 129.444789][ T934] [<ffffffd816231900>] shrink_work+0x21c/0x248
[ 129.445167][ T934] kernel BUG at kernel/sched/walt/walt_debug.c:16!
[ 129.445183][ T934] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
[ 129.445204][ T934] Skip md ftrace buffer dump for: 0x1609e0
[ 129.447348][ T934] CPU: 1 PID: 934 Comm: kworker/1:4 Tainted: G W OE 6.6.56-android15-8-o-g6f82312b30b9-debug #1 1400000003000000474e5500b3187743670464e8
[ 129.447362][ T934] Hardware name: Qualcomm Technologies, Inc. Parrot QRD, Alpha-M (DT)
[ 129.447373][ T934] Workqueue: dm_bufio_cache shrink_work
[ 129.447394][ T934] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 129.447406][ T934] pc : android_rvh_schedule_bug+0x0/0x8 [sched_walt_debug]
[ 129.447435][ T934] lr : __traceiter_android_rvh_schedule_bug+0x44/0x6c
[ 129.447451][ T934] sp : ffffffc0843dbc90
[ 129.447459][ T934] x29: ffffffc0843dbc90 x28: ffffffffffffffff x27: 0000000000000c8b
[ 129.447479][ T934] x26: 0000000000000040 x25: ffffff804b3d6260 x24: ffffffd816232b68
[ 129.447497][ T934] x23: ffffff805171c5b4 x22: 0000000000000000 x21: ffffffd816231900
[ 129.447517][ T934] x20: ffffff80306ba898 x19: 0000000000000000 x18: ffffffc084159030
[ 129.447535][ T934] x17: 00000000d2b5dd1f x16: 00000000d2b5dd1f x15: ffffffd816720358
[ 129.447554][ T934] x14: 0000000000000004 x13: ffffff89ef978000 x12: 0000000000000003
[ 129.447572][ T934] x11: ffffffd817a823c4 x10: 0000000000000202 x9 : 7e779c5735de9400
[ 129.447591][ T934] x8 : ffffffd81560d004 x7 : 205b5d3938373434 x6 : ffffffd8167397c8
[ 129.447610][ T934] x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffffffc0843db9e0
[ 129.447629][ T934] x2 : 0000000000002f15 x1 : 0000000000000000 x0 : 0000000000000000
[ 129.447647][ T934] Call trace:
[ 129.447655][ T934] android_rvh_schedule_bug+0x0/0x8 [sched_walt_debug 1400000003000000474e550080cce8a8a78606b6]
[ 129.447681][ T934] __might_resched+0x190/0x1a8
[ 129.447694][ T934] shrink_work+0x180/0x248
[ 129.447706][ T934] process_one_work+0x260/0x624
[ 129.447718][ T934] worker_thread+0x28c/0x454
[ 129.447729][ T934] kthread+0x118/0x158
[ 129.447742][ T934] ret_from_fork+0x10/0x20
[ 129.447761][ T934] Code: ???????? ???????? ???????? d2b5dd1f (d4210000)
[ 129.447772][ T934] ---[ end trace 0000000000000000 ]---
dm_bufio_lock will call spin_lock_bh when try_verify_in_tasklet
is enabled, and __scan will be called in atomic context.
CVSS Score
7.8
EPSS Score
0.003
Published
2025-05-20