Linux: >> Linux Kernel >> 5.4.172 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
ftrace: Fix use-after-free for dynamic ftrace_ops
KASAN reported a use-after-free with ftrace ops [1]. It was found from
vmcore that perf had registered two ops with the same content
successively, both dynamic. After unregistering the second ops, a
use-after-free occurred.
In ftrace_shutdown(), when the second ops is unregistered, the
FTRACE_UPDATE_CALLS command is not set because there is another enabled
ops with the same content. Also, both ops are dynamic and the ftrace
callback function is ftrace_ops_list_func, so the
FTRACE_UPDATE_TRACE_FUNC command will not be set. Eventually the value
of 'command' will be 0 and ftrace_shutdown() will skip the rcu
synchronization.
However, ftrace may be activated. When the ops is released, another CPU
may be accessing the ops. Add the missing synchronization to fix this
problem.
[1]
BUG: KASAN: use-after-free in __ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
BUG: KASAN: use-after-free in ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
Read of size 8 at addr ffff56551965bbc8 by task syz-executor.2/14468
CPU: 1 PID: 14468 Comm: syz-executor.2 Not tainted 5.10.0 #7
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x40c arch/arm64/kernel/stacktrace.c:132
show_stack+0x30/0x40 arch/arm64/kernel/stacktrace.c:196
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b4/0x248 lib/dump_stack.c:118
print_address_description.constprop.0+0x28/0x48c mm/kasan/report.c:387
__kasan_report mm/kasan/report.c:547 [inline]
kasan_report+0x118/0x210 mm/kasan/report.c:564
check_memory_region_inline mm/kasan/generic.c:187 [inline]
__asan_load8+0x98/0xc0 mm/kasan/generic.c:253
__ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
ftrace_graph_call+0x0/0x4
__might_sleep+0x8/0x100 include/linux/perf_event.h:1170
__might_fault mm/memory.c:5183 [inline]
__might_fault+0x58/0x70 mm/memory.c:5171
do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
strncpy_from_user+0x1f4/0x4b0 lib/strncpy_from_user.c:139
getname_flags+0xb0/0x31c fs/namei.c:149
getname+0x2c/0x40 fs/namei.c:209
[...]
Allocated by task 14445:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc mm/kasan/common.c:479 [inline]
__kasan_kmalloc.constprop.0+0x110/0x13c mm/kasan/common.c:449
kasan_kmalloc+0xc/0x14 mm/kasan/common.c:493
kmem_cache_alloc_trace+0x440/0x924 mm/slub.c:2950
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:675 [inline]
perf_event_alloc.part.0+0xb4/0x1350 kernel/events/core.c:11230
perf_event_alloc kernel/events/core.c:11733 [inline]
__do_sys_perf_event_open kernel/events/core.c:11831 [inline]
__se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
__arm64_sys_perf_event_open+0x6c/0x80 kernel/events/core.c:11723
[...]
Freed by task 14445:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
kasan_set_track+0x24/0x34 mm/kasan/common.c:56
kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:358
__kasan_slab_free.part.0+0x11c/0x1b0 mm/kasan/common.c:437
__kasan_slab_free mm/kasan/common.c:445 [inline]
kasan_slab_free+0x2c/0x40 mm/kasan/common.c:446
slab_free_hook mm/slub.c:1569 [inline]
slab_free_freelist_hook mm/slub.c:1608 [inline]
slab_free mm/slub.c:3179 [inline]
kfree+0x12c/0xc10 mm/slub.c:4176
perf_event_alloc.part.0+0xa0c/0x1350 kernel/events/core.c:11434
perf_event_alloc kernel/events/core.c:11733 [inline]
__do_sys_perf_event_open kernel/events/core.c:11831 [inline]
__se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
[...]
CVSS Score
7.8
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix tree mod log mishandling of reallocated nodes
We have been seeing the following panic in production
kernel BUG at fs/btrfs/tree-mod-log.c:677!
invalid opcode: 0000 [#1] SMP
RIP: 0010:tree_mod_log_rewind+0x1b4/0x200
RSP: 0000:ffffc9002c02f890 EFLAGS: 00010293
RAX: 0000000000000003 RBX: ffff8882b448c700 RCX: 0000000000000000
RDX: 0000000000008000 RSI: 00000000000000a7 RDI: ffff88877d831c00
RBP: 0000000000000002 R08: 000000000000009f R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000100c40 R12: 0000000000000001
R13: ffff8886c26d6a00 R14: ffff88829f5424f8 R15: ffff88877d831a00
FS: 00007fee1d80c780(0000) GS:ffff8890400c0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fee1963a020 CR3: 0000000434f33002 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
btrfs_get_old_root+0x12b/0x420
btrfs_search_old_slot+0x64/0x2f0
? tree_mod_log_oldest_root+0x3d/0xf0
resolve_indirect_ref+0xfd/0x660
? ulist_alloc+0x31/0x60
? kmem_cache_alloc_trace+0x114/0x2c0
find_parent_nodes+0x97a/0x17e0
? ulist_alloc+0x30/0x60
btrfs_find_all_roots_safe+0x97/0x150
iterate_extent_inodes+0x154/0x370
? btrfs_search_path_in_tree+0x240/0x240
iterate_inodes_from_logical+0x98/0xd0
? btrfs_search_path_in_tree+0x240/0x240
btrfs_ioctl_logical_to_ino+0xd9/0x180
btrfs_ioctl+0xe2/0x2ec0
? __mod_memcg_lruvec_state+0x3d/0x280
? do_sys_openat2+0x6d/0x140
? kretprobe_dispatcher+0x47/0x70
? kretprobe_rethook_handler+0x38/0x50
? rethook_trampoline_handler+0x82/0x140
? arch_rethook_trampoline_callback+0x3b/0x50
? kmem_cache_free+0xfb/0x270
? do_sys_openat2+0xd5/0x140
__x64_sys_ioctl+0x71/0xb0
do_syscall_64+0x2d/0x40
Which is this code in tree_mod_log_rewind()
switch (tm->op) {
case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING:
BUG_ON(tm->slot < n);
This occurs because we replay the nodes in order that they happened, and
when we do a REPLACE we will log a REMOVE_WHILE_FREEING for every slot,
starting at 0. 'n' here is the number of items in this block, which in
this case was 1, but we had 2 REMOVE_WHILE_FREEING operations.
The actual root cause of this was that we were replaying operations for
a block that shouldn't have been replayed. Consider the following
sequence of events
1. We have an already modified root, and we do a btrfs_get_tree_mod_seq().
2. We begin removing items from this root, triggering KEY_REPLACE for
it's child slots.
3. We remove one of the 2 children this root node points to, thus triggering
the root node promotion of the remaining child, and freeing this node.
4. We modify a new root, and re-allocate the above node to the root node of
this other root.
The tree mod log looks something like this
logical 0 op KEY_REPLACE (slot 1) seq 2
logical 0 op KEY_REMOVE (slot 1) seq 3
logical 0 op KEY_REMOVE_WHILE_FREEING (slot 0) seq 4
logical 4096 op LOG_ROOT_REPLACE (old logical 0) seq 5
logical 8192 op KEY_REMOVE_WHILE_FREEING (slot 1) seq 6
logical 8192 op KEY_REMOVE_WHILE_FREEING (slot 0) seq 7
logical 0 op LOG_ROOT_REPLACE (old logical 8192) seq 8
>From here the bug is triggered by the following steps
1. Call btrfs_get_old_root() on the new_root.
2. We call tree_mod_log_oldest_root(btrfs_root_node(new_root)), which is
currently logical 0.
3. tree_mod_log_oldest_root() calls tree_mod_log_search_oldest(), which
gives us the KEY_REPLACE seq 2, and since that's not a
LOG_ROOT_REPLACE we incorrectly believe that we don't have an old
root, because we expect that the most recent change should be a
LOG_ROOT_REPLACE.
4. Back in tree_mod_log_oldest_root() we don't have a LOG_ROOT_REPLACE,
so we don't set old_root, we simply use our e
---truncated---
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
fscrypt: stop using keyrings subsystem for fscrypt_master_key
The approach of fs/crypto/ internally managing the fscrypt_master_key
structs as the payloads of "struct key" objects contained in a
"struct key" keyring has outlived its usefulness. The original idea was
to simplify the code by reusing code from the keyrings subsystem.
However, several issues have arisen that can't easily be resolved:
- When a master key struct is destroyed, blk_crypto_evict_key() must be
called on any per-mode keys embedded in it. (This started being the
case when inline encryption support was added.) Yet, the keyrings
subsystem can arbitrarily delay the destruction of keys, even past the
time the filesystem was unmounted. Therefore, currently there is no
easy way to call blk_crypto_evict_key() when a master key is
destroyed. Currently, this is worked around by holding an extra
reference to the filesystem's request_queue(s). But it was overlooked
that the request_queue reference is *not* guaranteed to pin the
corresponding blk_crypto_profile too; for device-mapper devices that
support inline crypto, it doesn't. This can cause a use-after-free.
- When the last inode that was using an incompletely-removed master key
is evicted, the master key removal is completed by removing the key
struct from the keyring. Currently this is done via key_invalidate().
Yet, key_invalidate() takes the key semaphore. This can deadlock when
called from the shrinker, since in fscrypt_ioctl_add_key(), memory is
allocated with GFP_KERNEL under the same semaphore.
- More generally, the fact that the keyrings subsystem can arbitrarily
delay the destruction of keys (via garbage collection delay, or via
random processes getting temporary key references) is undesirable, as
it means we can't strictly guarantee that all secrets are ever wiped.
- Doing the master key lookups via the keyrings subsystem results in the
key_permission LSM hook being called. fscrypt doesn't want this, as
all access control for encrypted files is designed to happen via the
files themselves, like any other files. The workaround which SELinux
users are using is to change their SELinux policy to grant key search
access to all domains. This works, but it is an odd extra step that
shouldn't really have to be done.
The fix for all these issues is to change the implementation to what I
should have done originally: don't use the keyrings subsystem to keep
track of the filesystem's fscrypt_master_key structs. Instead, just
store them in a regular kernel data structure, and rework the reference
counting, locking, and lifetime accordingly. Retain support for
RCU-mode key lookups by using a hash table. Replace fscrypt_sb_free()
with fscrypt_sb_delete(), which releases the keys synchronously and runs
a bit earlier during unmount, so that block devices are still available.
A side effect of this patch is that neither the master keys themselves
nor the filesystem keyrings will be listed in /proc/keys anymore.
("Master key users" and the master key users keyrings will still be
listed.) However, this was mostly an implementation detail, and it was
intended just for debugging purposes. I don't know of anyone using it.
This patch does *not* change how "master key users" (->mk_users) works;
that still uses the keyrings subsystem. That is still needed for key
quotas, and changing that isn't necessary to solve the issues listed
above. If we decide to change that too, it would be a separate patch.
I've marked this as fixing the original commit that added the fscrypt
keyring, but as noted above the most important issue that this patch
fixes wasn't introduced until the addition of inline encryption support.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: fix memory leak in query_regdb_file()
In the function query_regdb_file() the alpha2 parameter is duplicated
using kmemdup() and subsequently freed in regdb_fw_cb(). However,
request_firmware_nowait() can fail without calling regdb_fw_cb() and
thus leak memory.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
ACPI: APEI: Fix integer overflow in ghes_estatus_pool_init()
Change num_ghes from int to unsigned int, preventing an overflow
and causing subsequent vmalloc() to fail.
The overflow happens in ghes_estatus_pool_init() when calculating
len during execution of the statement below as both multiplication
operands here are signed int:
len += (num_ghes * GHES_ESOURCE_PREALLOC_MAX_SIZE);
The following call trace is observed because of this bug:
[ 9.317108] swapper/0: vmalloc error: size 18446744071562596352, exceeds total pages, mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0-1
[ 9.317131] Call Trace:
[ 9.317134] <TASK>
[ 9.317137] dump_stack_lvl+0x49/0x5f
[ 9.317145] dump_stack+0x10/0x12
[ 9.317146] warn_alloc.cold+0x7b/0xdf
[ 9.317150] ? __device_attach+0x16a/0x1b0
[ 9.317155] __vmalloc_node_range+0x702/0x740
[ 9.317160] ? device_add+0x17f/0x920
[ 9.317164] ? dev_set_name+0x53/0x70
[ 9.317166] ? platform_device_add+0xf9/0x240
[ 9.317168] __vmalloc_node+0x49/0x50
[ 9.317170] ? ghes_estatus_pool_init+0x43/0xa0
[ 9.317176] vmalloc+0x21/0x30
[ 9.317177] ghes_estatus_pool_init+0x43/0xa0
[ 9.317179] acpi_hest_init+0x129/0x19c
[ 9.317185] acpi_init+0x434/0x4a4
[ 9.317188] ? acpi_sleep_proc_init+0x2a/0x2a
[ 9.317190] do_one_initcall+0x48/0x200
[ 9.317195] kernel_init_freeable+0x221/0x284
[ 9.317200] ? rest_init+0xe0/0xe0
[ 9.317204] kernel_init+0x1a/0x130
[ 9.317205] ret_from_fork+0x22/0x30
[ 9.317208] </TASK>
[ rjw: Subject and changelog edits ]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
media: meson: vdec: fix possible refcount leak in vdec_probe()
v4l2_device_unregister need to be called to put the refcount got by
v4l2_device_register when vdec_probe fails or vdec_remove is called.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: tun: Fix memory leaks of napi_get_frags
kmemleak reports after running test_progs:
unreferenced object 0xffff8881b1672dc0 (size 232):
comm "test_progs", pid 394388, jiffies 4354712116 (age 841.975s)
hex dump (first 32 bytes):
e0 84 d7 a8 81 88 ff ff 80 2c 67 b1 81 88 ff ff .........,g.....
00 40 c5 9b 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............
backtrace:
[<00000000c8f01748>] napi_skb_cache_get+0xd4/0x150
[<0000000041c7fc09>] __napi_build_skb+0x15/0x50
[<00000000431c7079>] __napi_alloc_skb+0x26e/0x540
[<000000003ecfa30e>] napi_get_frags+0x59/0x140
[<0000000099b2199e>] tun_get_user+0x183d/0x3bb0 [tun]
[<000000008a5adef0>] tun_chr_write_iter+0xc0/0x1b1 [tun]
[<0000000049993ff4>] do_iter_readv_writev+0x19f/0x320
[<000000008f338ea2>] do_iter_write+0x135/0x630
[<000000008a3377a4>] vfs_writev+0x12e/0x440
[<00000000a6b5639a>] do_writev+0x104/0x280
[<00000000ccf065d8>] do_syscall_64+0x3b/0x90
[<00000000d776e329>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
The issue occurs in the following scenarios:
tun_get_user()
napi_gro_frags()
napi_frags_finish()
case GRO_NORMAL:
gro_normal_one()
list_add_tail(&skb->list, &napi->rx_list);
<-- While napi->rx_count < READ_ONCE(gro_normal_batch),
<-- gro_normal_list() is not called, napi->rx_list is not empty
<-- not ask to complete the gro work, will cause memory leaks in
<-- following tun_napi_del()
...
tun_napi_del()
netif_napi_del()
__netif_napi_del()
<-- &napi->rx_list is not empty, which caused memory leaks
To fix, add napi_complete() after napi_gro_frags().
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: gso: fix panic on frag_list with mixed head alloc types
Since commit 3dcbdb134f32 ("net: gso: Fix skb_segment splat when
splitting gso_size mangled skb having linear-headed frag_list"), it is
allowed to change gso_size of a GRO packet. However, that commit assumes
that "checking the first list_skb member suffices; i.e if either of the
list_skb members have non head_frag head, then the first one has too".
It turns out this assumption does not hold. We've seen BUG_ON being hit
in skb_segment when skbs on the frag_list had differing head_frag with
the vmxnet3 driver. This happens because __netdev_alloc_skb and
__napi_alloc_skb can return a skb that is page backed or kmalloced
depending on the requested size. As the result, the last small skb in
the GRO packet can be kmalloced.
There are three different locations where this can be fixed:
(1) We could check head_frag in GRO and not allow GROing skbs with
different head_frag. However, that would lead to performance
regression on normal forward paths with unmodified gso_size, where
!head_frag in the last packet is not a problem.
(2) Set a flag in bpf_skb_net_grow and bpf_skb_net_shrink indicating
that NETIF_F_SG is undesirable. That would need to eat a bit in
sk_buff. Furthermore, that flag can be unset when all skbs on the
frag_list are page backed. To retain good performance,
bpf_skb_net_grow/shrink would have to walk the frag_list.
(3) Walk the frag_list in skb_segment when determining whether
NETIF_F_SG should be cleared. This of course slows things down.
This patch implements (3). To limit the performance impact in
skb_segment, the list is walked only for skbs with SKB_GSO_DODGY set
that have gso_size changed. Normal paths thus will not hit it.
We could check only the last skb but since we need to walk the whole
list anyway, let's stay on the safe side.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix wrong reg type conversion in release_reference()
Some helper functions will allocate memory. To avoid memory leaks, the
verifier requires the eBPF program to release these memories by calling
the corresponding helper functions.
When a resource is released, all pointer registers corresponding to the
resource should be invalidated. The verifier use release_references() to
do this job, by apply __mark_reg_unknown() to each relevant register.
It will give these registers the type of SCALAR_VALUE. A register that
will contain a pointer value at runtime, but of type SCALAR_VALUE, which
may allow the unprivileged user to get a kernel pointer by storing this
register into a map.
Using __mark_reg_not_init() while NOT allow_ptr_leaks can mitigate this
problem.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
HID: hyperv: fix possible memory leak in mousevsc_probe()
If hid_add_device() returns error, it should call hid_destroy_device()
to free hid_dev which is allocated in hid_allocate_device().
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01