Security Vulnerabilities - CVEs Published In April 2025
In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Fix flush_tlb_range() when used for zapping normal PMDs
On the following path, flush_tlb_range() can be used for zapping normal
PMD entries (PMD entries that point to page tables) together with the PTE
entries in the pointed-to page table:
collapse_pte_mapped_thp
pmdp_collapse_flush
flush_tlb_range
The arm64 version of flush_tlb_range() has a comment describing that it can
be used for page table removal, and does not use any last-level
invalidation optimizations. Fix the X86 version by making it behave the
same way.
Currently, X86 only uses this information for the following two purposes,
which I think means the issue doesn't have much impact:
- In native_flush_tlb_multi() for checking if lazy TLB CPUs need to be
IPI'd to avoid issues with speculative page table walks.
- In Hyper-V TLB paravirtualization, again for lazy TLB stuff.
The patch "x86/mm: only invalidate final translations with INVLPGB" which
is currently under review (see
<https://lore.kernel.org/all/20241230175550.4046587-13-riel@surriel.com/>)
would probably be making the impact of this a lot worse.
CVSS Score
5.5
EPSS Score
0.002
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
mm/gup: reject FOLL_SPLIT_PMD with hugetlb VMAs
Patch series "mm: fixes for device-exclusive entries (hmm)", v2.
Discussing the PageTail() call in make_device_exclusive_range() with
Willy, I recently discovered [1] that device-exclusive handling does not
properly work with THP, making the hmm-tests selftests fail if THPs are
enabled on the system.
Looking into more details, I found that hugetlb is not properly fenced,
and I realized that something that was bugging me for longer -- how
device-exclusive entries interact with mapcounts -- completely breaks
migration/swapout/split/hwpoison handling of these folios while they have
device-exclusive PTEs.
The program below can be used to allocate 1 GiB worth of pages and making
them device-exclusive on a kernel with CONFIG_TEST_HMM.
Once they are device-exclusive, these folios cannot get swapped out
(proc$pid/smaps_rollup will always indicate 1 GiB RSS no matter how much
one forces memory reclaim), and when having a memory block onlined to
ZONE_MOVABLE, trying to offline it will loop forever and complain about
failed migration of a page that should be movable.
# echo offline > /sys/devices/system/memory/memory136/state
# echo online_movable > /sys/devices/system/memory/memory136/state
# ./hmm-swap &
... wait until everything is device-exclusive
# echo offline > /sys/devices/system/memory/memory136/state
[ 285.193431][T14882] page: refcount:2 mapcount:0 mapping:0000000000000000
index:0x7f20671f7 pfn:0x442b6a
[ 285.196618][T14882] memcg:ffff888179298000
[ 285.198085][T14882] anon flags: 0x5fff0000002091c(referenced|uptodate|
dirty|active|owner_2|swapbacked|node=1|zone=3|lastcpupid=0x7ff)
[ 285.201734][T14882] raw: ...
[ 285.204464][T14882] raw: ...
[ 285.207196][T14882] page dumped because: migration failure
[ 285.209072][T14882] page_owner tracks the page as allocated
[ 285.210915][T14882] page last allocated via order 0, migratetype
Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO),
id 14926, tgid 14926 (hmm-swap), ts 254506295376, free_ts 227402023774
[ 285.216765][T14882] post_alloc_hook+0x197/0x1b0
[ 285.218874][T14882] get_page_from_freelist+0x76e/0x3280
[ 285.220864][T14882] __alloc_frozen_pages_noprof+0x38e/0x2740
[ 285.223302][T14882] alloc_pages_mpol+0x1fc/0x540
[ 285.225130][T14882] folio_alloc_mpol_noprof+0x36/0x340
[ 285.227222][T14882] vma_alloc_folio_noprof+0xee/0x1a0
[ 285.229074][T14882] __handle_mm_fault+0x2b38/0x56a0
[ 285.230822][T14882] handle_mm_fault+0x368/0x9f0
...
This series fixes all issues I found so far. There is no easy way to fix
without a bigger rework/cleanup. I have a bunch of cleanups on top (some
previous sent, some the result of the discussion in v1) that I will send
out separately once this landed and I get to it.
I wish we could just use some special present PROT_NONE PTEs instead of
these (non-present, non-none) fake-swap entries; but that just results in
the same problem we keep having (lack of spare PTE bits), and staring at
other similar fake-swap entries, that ship has sailed.
With this series, make_device_exclusive() doesn't actually belong into
mm/rmap.c anymore, but I'll leave moving that for another day.
I only tested this series with the hmm-tests selftests due to lack of HW,
so I'd appreciate some testing, especially if the interaction between two
GPUs wanting a device-exclusive entry works as expected.
<program>
#include <stdio.h>
#include <fcntl.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/ioctl.h>
#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
struct hmm_dmirror_cmd {
__u64 addr;
__u64 ptr;
__u64 npages;
__u64 cpages;
__u64 faults;
};
const size_t size = 1 * 1024 * 1024 * 1024ul;
const size_t chunk_size = 2 * 1024 * 1024ul;
int m
---truncated---
CVSS Score
5.5
EPSS Score
0.002
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix use-after-free in print_graph_function_flags during tracer switching
Kairui reported a UAF issue in print_graph_function_flags() during
ftrace stress testing [1]. This issue can be reproduced if puting a
'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(),
and executing the following script:
$ echo function_graph > current_tracer
$ cat trace > /dev/null &
$ sleep 5 # Ensure the 'cat' reaches the 'mdelay(10)' point
$ echo timerlat > current_tracer
The root cause lies in the two calls to print_graph_function_flags
within print_trace_line during each s_show():
* One through 'iter->trace->print_line()';
* Another through 'event->funcs->trace()', which is hidden in
print_trace_fmt() before print_trace_line returns.
Tracer switching only updates the former, while the latter continues
to use the print_line function of the old tracer, which in the script
above is print_graph_function_flags.
Moreover, when switching from the 'function_graph' tracer to the
'timerlat' tracer, s_start only calls graph_trace_close of the
'function_graph' tracer to free 'iter->private', but does not set
it to NULL. This provides an opportunity for 'event->funcs->trace()'
to use an invalid 'iter->private'.
To fix this issue, set 'iter->private' to NULL immediately after
freeing it in graph_trace_close(), ensuring that an invalid pointer
is not passed to other tracers. Additionally, clean up the unnecessary
'iter->private = NULL' during each 'cat trace' when using wakeup and
irqsoff tracers.
[1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/
CVSS Score
7.8
EPSS Score
0.002
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
exfat: fix random stack corruption after get_block
When get_block is called with a buffer_head allocated on the stack, such
as do_mpage_readpage, stack corruption due to buffer_head UAF may occur in
the following race condition situation.
<CPU 0> <CPU 1>
mpage_read_folio
<<bh on stack>>
do_mpage_readpage
exfat_get_block
bh_read
__bh_read
get_bh(bh)
submit_bh
wait_on_buffer
...
end_buffer_read_sync
__end_buffer_read_notouch
unlock_buffer
<<keep going>>
...
...
...
...
<<bh is not valid out of mpage_read_folio>>
.
.
another_function
<<variable A on stack>>
put_bh(bh)
atomic_dec(bh->b_count)
* stack corruption here *
This patch returns -EAGAIN if a folio does not have buffers when bh_read
needs to be called. By doing this, the caller can fallback to functions
like block_read_full_folio(), create a buffer_head in the folio, and then
call get_block again.
Let's do not call bh_read() with on-stack buffer_head.
CVSS Score
7.0
EPSS Score
0.002
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix null pointer dereference in alloc_preauth_hash()
The Client send malformed smb2 negotiate request. ksmbd return error
response. Subsequently, the client can send smb2 session setup even
thought conn->preauth_info is not allocated.
This patch add KSMBD_SESS_NEED_SETUP status of connection to ignore
session setup request if smb2 negotiate phase is not complete.
CVSS Score
5.5
EPSS Score
0.282
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate zero num_subauth before sub_auth is accessed
Access psid->sub_auth[psid->num_subauth - 1] without checking
if num_subauth is non-zero leads to an out-of-bounds read.
This patch adds a validation step to ensure num_subauth != 0
before sub_auth is accessed.
CVSS Score
7.1
EPSS Score
0.002
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix overflow in dacloffset bounds check
The dacloffset field was originally typed as int and used in an
unchecked addition, which could overflow and bypass the existing
bounds check in both smb_check_perm_dacl() and smb_inherit_dacl().
This could result in out-of-bounds memory access and a kernel crash
when dereferencing the DACL pointer.
This patch converts dacloffset to unsigned int and uses
check_add_overflow() to validate access to the DACL.
CVSS Score
7.1
EPSS Score
0.003
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix session use-after-free in multichannel connection
There is a race condition between session setup and
ksmbd_sessions_deregister. The session can be freed before the connection
is added to channel list of session.
This patch check reference count of session before freeing it.
CVSS Score
8.8
EPSS Score
0.006
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free in ksmbd_sessions_deregister()
In multichannel mode, UAF issue can occur in session_deregister
when the second channel sets up a session through the connection of
the first channel. session that is freed through the global session
table can be accessed again through ->sessions of connection.
CVSS Score
8.8
EPSS Score
0.006
Published
2025-04-16
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix management of listener transports
Currently, when no active threads are running, a root user using nfsdctl
command can try to remove a particular listener from the list of previously
added ones, then start the server by increasing the number of threads,
it leads to the following problem:
[ 158.835354] refcount_t: addition on 0; use-after-free.
[ 158.835603] WARNING: CPU: 2 PID: 9145 at lib/refcount.c:25 refcount_warn_saturate+0x160/0x1a0
[ 158.836017] Modules linked in: rpcrdma rdma_cm iw_cm ib_cm ib_core nfsd auth_rpcgss nfs_acl lockd grace overlay isofs uinput snd_seq_dummy snd_hrtimer nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 rfkill ip_set nf_tables qrtr sunrpc vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops uvc videobuf2_v4l2 videodev videobuf2_common snd_hda_codec_generic mc e1000e snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore sg loop dm_multipath dm_mod nfnetlink vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vmw_vmci vsock xfs libcrc32c crct10dif_ce ghash_ce vmwgfx sha2_ce sha256_arm64 sr_mod sha1_ce cdrom nvme drm_client_lib drm_ttm_helper ttm nvme_core drm_kms_helper nvme_auth drm fuse
[ 158.840093] CPU: 2 UID: 0 PID: 9145 Comm: nfsd Kdump: loaded Tainted: G B W 6.13.0-rc6+ #7
[ 158.840624] Tainted: [B]=BAD_PAGE, [W]=WARN
[ 158.840802] Hardware name: VMware, Inc. VMware20,1/VBSA, BIOS VMW201.00V.24006586.BA64.2406042154 06/04/2024
[ 158.841220] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 158.841563] pc : refcount_warn_saturate+0x160/0x1a0
[ 158.841780] lr : refcount_warn_saturate+0x160/0x1a0
[ 158.842000] sp : ffff800089be7d80
[ 158.842147] x29: ffff800089be7d80 x28: ffff00008e68c148 x27: ffff00008e68c148
[ 158.842492] x26: ffff0002e3b5c000 x25: ffff600011cd1829 x24: ffff00008653c010
[ 158.842832] x23: ffff00008653c000 x22: 1fffe00011cd1829 x21: ffff00008653c028
[ 158.843175] x20: 0000000000000002 x19: ffff00008653c010 x18: 0000000000000000
[ 158.843505] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[ 158.843836] x14: 0000000000000000 x13: 0000000000000001 x12: ffff600050a26493
[ 158.844143] x11: 1fffe00050a26492 x10: ffff600050a26492 x9 : dfff800000000000
[ 158.844475] x8 : 00009fffaf5d9b6e x7 : ffff000285132493 x6 : 0000000000000001
[ 158.844823] x5 : ffff000285132490 x4 : ffff600050a26493 x3 : ffff8000805e72bc
[ 158.845174] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000098588000
[ 158.845528] Call trace:
[ 158.845658] refcount_warn_saturate+0x160/0x1a0 (P)
[ 158.845894] svc_recv+0x58c/0x680 [sunrpc]
[ 158.846183] nfsd+0x1fc/0x348 [nfsd]
[ 158.846390] kthread+0x274/0x2f8
[ 158.846546] ret_from_fork+0x10/0x20
[ 158.846714] ---[ end trace 0000000000000000 ]---
nfsd_nl_listener_set_doit() would manipulate the list of transports of
server's sv_permsocks and close the specified listener but the other
list of transports (server's sp_xprts list) would not be changed leading
to the problem above.
Instead, determined if the nfsdctl is trying to remove a listener, in
which case, delete all the existing listener transports and re-create
all-but-the-removed ones.
CVSS Score
5.5
EPSS Score
0.002
Published
2025-04-16