Security Vulnerabilities
- CVEs Published In May 2025
In the Linux kernel, the following vulnerability has been resolved:
memblock: Accept allocated memory before use in memblock_double_array()
When increasing the array size in memblock_double_array() and the slab
is not yet available, a call to memblock_find_in_range() is used to
reserve/allocate memory. However, the range returned may not have been
accepted, which can result in a crash when booting an SNP guest:
RIP: 0010:memcpy_orig+0x68/0x130
Code: ...
RSP: 0000:ffffffff9cc03ce8 EFLAGS: 00010006
RAX: ff11001ff83e5000 RBX: 0000000000000000 RCX: fffffffffffff000
RDX: 0000000000000bc0 RSI: ffffffff9dba8860 RDI: ff11001ff83e5c00
RBP: 0000000000002000 R08: 0000000000000000 R09: 0000000000002000
R10: 000000207fffe000 R11: 0000040000000000 R12: ffffffff9d06ef78
R13: ff11001ff83e5000 R14: ffffffff9dba7c60 R15: 0000000000000c00
memblock_double_array+0xff/0x310
memblock_add_range+0x1fb/0x2f0
memblock_reserve+0x4f/0xa0
memblock_alloc_range_nid+0xac/0x130
memblock_alloc_internal+0x53/0xc0
memblock_alloc_try_nid+0x3d/0xa0
swiotlb_init_remap+0x149/0x2f0
mem_init+0xb/0xb0
mm_core_init+0x8f/0x350
start_kernel+0x17e/0x5d0
x86_64_start_reservations+0x14/0x30
x86_64_start_kernel+0x92/0xa0
secondary_startup_64_no_verify+0x194/0x19b
Mitigate this by calling accept_memory() on the memory range returned
before the slab is available.
Prior to v6.12, the accept_memory() interface used a 'start' and 'end'
parameter instead of 'start' and 'size', therefore the accept_memory()
call must be adjusted to specify 'start + size' for 'end' when applying
to kernels prior to v6.12.
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---
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix memory leak in parse_lease_state()
The previous patch that added bounds check for create lease context
introduced a memory leak. When the bounds check fails, the function
returns NULL without freeing the previously allocated lease_ctx_info
structure.
This patch fixes the issue by adding kfree(lreq) before returning NULL
in both boundary check cases.
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.
In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Eliminate window where TLB flushes may be inadvertently skipped
tl;dr: There is a window in the mm switching code where the new CR3 is
set and the CPU should be getting TLB flushes for the new mm. But
should_flush_tlb() has a bug and suppresses the flush. Fix it by
widening the window where should_flush_tlb() sends an IPI.
Long Version:
=== History ===
There were a few things leading up to this.
First, updating mm_cpumask() was observed to be too expensive, so it was
made lazier. But being lazy caused too many unnecessary IPIs to CPUs
due to the now-lazy mm_cpumask(). So code was added to cull
mm_cpumask() periodically[2]. But that culling was a bit too aggressive
and skipped sending TLB flushes to CPUs that need them. So here we are
again.
=== Problem ===
The too-aggressive code in should_flush_tlb() strikes in this window:
// Turn on IPIs for this CPU/mm combination, but only
// if should_flush_tlb() agrees:
cpumask_set_cpu(cpu, mm_cpumask(next));
next_tlb_gen = atomic64_read(&next->context.tlb_gen);
choose_new_asid(next, next_tlb_gen, &new_asid, &need_flush);
load_new_mm_cr3(need_flush);
// ^ After 'need_flush' is set to false, IPIs *MUST*
// be sent to this CPU and not be ignored.
this_cpu_write(cpu_tlbstate.loaded_mm, next);
// ^ Not until this point does should_flush_tlb()
// become true!
should_flush_tlb() will suppress TLB flushes between load_new_mm_cr3()
and writing to 'loaded_mm', which is a window where they should not be
suppressed. Whoops.
=== Solution ===
Thankfully, the fuzzy "just about to write CR3" window is already marked
with loaded_mm==LOADED_MM_SWITCHING. Simply checking for that state in
should_flush_tlb() is sufficient to ensure that the CPU is targeted with
an IPI.
This will cause more TLB flush IPIs. But the window is relatively small
and I do not expect this to cause any kind of measurable performance
impact.
Update the comment where LOADED_MM_SWITCHING is written since it grew
yet another user.
Peter Z also raised a concern that should_flush_tlb() might not observe
'loaded_mm' and 'is_lazy' in the same order that switch_mm_irqs_off()
writes them. Add a barrier to ensure that they are observed in the
order they are written.
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix panic in failed foilio allocation
commit 7e119cff9d0a ("ocfs2: convert w_pages to w_folios") and commit
9a5e08652dc4b ("ocfs2: use an array of folios instead of an array of
pages") save -ENOMEM in the folio array upon allocation failure and call
the folio array free code.
The folio array free code expects either valid folio pointers or NULL.
Finding the -ENOMEM will result in a panic. Fix by NULLing the error
folio entry.
In the Linux kernel, the following vulnerability has been resolved:
drm/v3d: Add job to pending list if the reset was skipped
When a CL/CSD job times out, we check if the GPU has made any progress
since the last timeout. If so, instead of resetting the hardware, we skip
the reset and let the timer get rearmed. This gives long-running jobs a
chance to complete.
However, when `timedout_job()` is called, the job in question is removed
from the pending list, which means it won't be automatically freed through
`free_job()`. Consequently, when we skip the reset and keep the job
running, the job won't be freed when it finally completes.
This situation leads to a memory leak, as exposed in [1] and [2].
Similarly to commit 704d3d60fec4 ("drm/etnaviv: don't block scheduler when
GPU is still active"), this patch ensures the job is put back on the
pending list when extending the timeout.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: Fix UAF in __close_file_table_ids
A use-after-free is possible if one thread destroys the file
via __ksmbd_close_fd while another thread holds a reference to
it. The existing checks on fp->refcount are not sufficient to
prevent this.
The fix takes ft->lock around the section which removes the
file from the file table. This prevents two threads acquiring the
same file pointer via __close_file_table_ids, as well as the other
functions which retrieve a file from the IDR and which already use
this same lock.
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereference in htb_next_rb_node()
after we made htb_qlen_notify() idempotent.
It turns out in the following case it introduced some regression:
htb_dequeue_tree():
|-> fq_codel_dequeue()
|-> qdisc_tree_reduce_backlog()
|-> htb_qlen_notify()
|-> htb_deactivate()
|-> htb_next_rb_node()
|-> htb_deactivate()
For htb_next_rb_node(), after calling the 1st htb_deactivate(), the
clprio[prio]->ptr could be already set to NULL, which means
htb_next_rb_node() is vulnerable here.
For htb_deactivate(), although we checked qlen before calling it, in
case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again
which triggers the warning inside.
To fix the issues here, we need to:
1) Make htb_deactivate() idempotent, that is, simply return if we
already call it before.
2) Make htb_next_rb_node() safe against ptr==NULL.
Many thanks to Alan for testing and for the reproducer.
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.