Linux: >> Linux Kernel >> 5.7.7 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix kmemleak warning for percpu hashmap
Vlad Poenaru reported the following kmemleak issue:
unreferenced object 0x606fd7c44ac8 (size 32):
backtrace (crc 0):
pcpu_alloc_noprof+0x730/0xeb0
bpf_map_alloc_percpu+0x69/0xc0
prealloc_init+0x9d/0x1b0
htab_map_alloc+0x363/0x510
map_create+0x215/0x3a0
__sys_bpf+0x16b/0x3e0
__x64_sys_bpf+0x18/0x20
do_syscall_64+0x7b/0x150
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Further investigation shows the reason is due to not 8-byte aligned
store of percpu pointer in htab_elem_set_ptr():
*(void __percpu **)(l->key + key_size) = pptr;
Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size
is 4, that means pptr is stored in a location which is 4 byte aligned but
not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based
on 8 byte stride, so it won't detect above pptr, hence reporting the memory
leak.
In htab_map_alloc(), we already have
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
if (percpu)
htab->elem_size += sizeof(void *);
else
htab->elem_size += round_up(htab->map.value_size, 8);
So storing pptr with 8-byte alignment won't cause any problem and can fix
kmemleak too.
The issue can be reproduced with bpf selftest as well:
1. Enable CONFIG_DEBUG_KMEMLEAK config
2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.
The purpose is to keep map available so kmemleak can be detected.
3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-08
In the Linux kernel, the following vulnerability has been resolved:
crypto: null - Use spin lock instead of mutex
As the null algorithm may be freed in softirq context through
af_alg, use spin locks instead of mutexes to protect the default
null algorithm.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-08
In the Linux kernel, the following vulnerability has been resolved:
driver core: fix potential NULL pointer dereference in dev_uevent()
If userspace reads "uevent" device attribute at the same time as another
threads unbinds the device from its driver, change to dev->driver from a
valid pointer to NULL may result in crash. Fix this by using READ_ONCE()
when fetching the pointer, and take bus' drivers klist lock to make sure
driver instance will not disappear while we access it.
Use WRITE_ONCE() when setting the driver pointer to ensure there is no
tearing.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-08
In the Linux kernel, the following vulnerability has been resolved:
bpf: consider that tail calls invalidate packet pointers
Tail-called programs could execute any of the helpers that invalidate
packet pointers. Hence, conservatively assume that each tail call
invalidates packet pointers.
Making the change in bpf_helper_changes_pkt_data() automatically makes
use of check_cfg() logic that computes 'changes_pkt_data' effect for
global sub-programs, such that the following program could be
rejected:
int tail_call(struct __sk_buff *sk)
{
bpf_tail_call_static(sk, &jmp_table, 0);
return 0;
}
SEC("tc")
int not_safe(struct __sk_buff *sk)
{
int *p = (void *)(long)sk->data;
... make p valid ...
tail_call(sk);
*p = 42; /* this is unsafe */
...
}
The tc_bpf2bpf.c:subprog_tc() needs change: mark it as a function that
can invalidate packet pointers. Otherwise, it can't be freplaced with
tailcall_freplace.c:entry_freplace() that does a tail call.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-05
In the Linux kernel, the following vulnerability has been resolved:
bpf: track changes_pkt_data property for global functions
When processing calls to certain helpers, verifier invalidates all
packet pointers in a current state. For example, consider the
following program:
__attribute__((__noinline__))
long skb_pull_data(struct __sk_buff *sk, __u32 len)
{
return bpf_skb_pull_data(sk, len);
}
SEC("tc")
int test_invalidate_checks(struct __sk_buff *sk)
{
int *p = (void *)(long)sk->data;
if ((void *)(p + 1) > (void *)(long)sk->data_end) return TCX_DROP;
skb_pull_data(sk, 0);
*p = 42;
return TCX_PASS;
}
After a call to bpf_skb_pull_data() the pointer 'p' can't be used
safely. See function filter.c:bpf_helper_changes_pkt_data() for a list
of such helpers.
At the moment verifier invalidates packet pointers when processing
helper function calls, and does not traverse global sub-programs when
processing calls to global sub-programs. This means that calls to
helpers done from global sub-programs do not invalidate pointers in
the caller state. E.g. the program above is unsafe, but is not
rejected by verifier.
This commit fixes the omission by computing field
bpf_subprog_info->changes_pkt_data for each sub-program before main
verification pass.
changes_pkt_data should be set if:
- subprogram calls helper for which bpf_helper_changes_pkt_data
returns true;
- subprogram calls a global function,
for which bpf_subprog_info->changes_pkt_data should be set.
The verifier.c:check_cfg() pass is modified to compute this
information. The commit relies on depth first instruction traversal
done by check_cfg() and absence of recursive function calls:
- check_cfg() would eventually visit every call to subprogram S in a
state when S is fully explored;
- when S is fully explored:
- every direct helper call within S is explored
(and thus changes_pkt_data is set if needed);
- every call to subprogram S1 called by S was visited with S1 fully
explored (and thus S inherits changes_pkt_data from S1).
The downside of such approach is that dead code elimination is not
taken into account: if a helper call inside global function is dead
because of current configuration, verifier would conservatively assume
that the call occurs for the purpose of the changes_pkt_data
computation.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-05
In the Linux kernel, the following vulnerability has been resolved:
bpf: check changes_pkt_data property for extension programs
When processing calls to global sub-programs, verifier decides whether
to invalidate all packet pointers in current state depending on the
changes_pkt_data property of the global sub-program.
Because of this, an extension program replacing a global sub-program
must be compatible with changes_pkt_data property of the sub-program
being replaced.
This commit:
- adds changes_pkt_data flag to struct bpf_prog_aux:
- this flag is set in check_cfg() for main sub-program;
- in jit_subprogs() for other sub-programs;
- modifies bpf_check_attach_btf_id() to check changes_pkt_data flag;
- moves call to check_attach_btf_id() after the call to check_cfg(),
because it needs changes_pkt_data flag to be set:
bpf_check:
... ...
- check_attach_btf_id resolve_pseudo_ldimm64
resolve_pseudo_ldimm64 --> bpf_prog_is_offloaded
bpf_prog_is_offloaded check_cfg
check_cfg + check_attach_btf_id
... ...
The following fields are set by check_attach_btf_id():
- env->ops
- prog->aux->attach_btf_trace
- prog->aux->attach_func_name
- prog->aux->attach_func_proto
- prog->aux->dst_trampoline
- prog->aux->mod
- prog->aux->saved_dst_attach_type
- prog->aux->saved_dst_prog_type
- prog->expected_attach_type
Neither of these fields are used by resolve_pseudo_ldimm64() or
bpf_prog_offload_verifier_prep() (for netronome and netdevsim
drivers), so the reordering is safe.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-05
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Fix WRITE_SAME No Data Buffer crash
In newer version of the SBC specs, we have a NDOB bit that indicates there
is no data buffer that gets written out. If this bit is set using commands
like "sg_write_same --ndob" we will crash in target_core_iblock/file's
execute_write_same handlers when we go to access the se_cmd->t_data_sg
because its NULL.
This patch adds a check for the NDOB bit in the common WRITE SAME code
because we don't support it. And, it adds a check for zero SG elements in
each handler in case the initiator tries to send a normal WRITE SAME with
no data buffer.
CVSS Score
7.8
EPSS Score
0.001
Published
2025-05-02
In the Linux kernel, the following vulnerability has been resolved:
ila: do not generate empty messages in ila_xlat_nl_cmd_get_mapping()
ila_xlat_nl_cmd_get_mapping() generates an empty skb,
triggerring a recent sanity check [1].
Instead, return an error code, so that user space
can get it.
[1]
skb_assert_len
WARNING: CPU: 0 PID: 5923 at include/linux/skbuff.h:2527 skb_assert_len include/linux/skbuff.h:2527 [inline]
WARNING: CPU: 0 PID: 5923 at include/linux/skbuff.h:2527 __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156
Modules linked in:
CPU: 0 PID: 5923 Comm: syz-executor269 Not tainted 6.2.0-syzkaller-18300-g2ebd1fbb946d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : skb_assert_len include/linux/skbuff.h:2527 [inline]
pc : __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156
lr : skb_assert_len include/linux/skbuff.h:2527 [inline]
lr : __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156
sp : ffff80001e0d6c40
x29: ffff80001e0d6e60 x28: dfff800000000000 x27: ffff0000c86328c0
x26: dfff800000000000 x25: ffff0000c8632990 x24: ffff0000c8632a00
x23: 0000000000000000 x22: 1fffe000190c6542 x21: ffff0000c8632a10
x20: ffff0000c8632a00 x19: ffff80001856e000 x18: ffff80001e0d5fc0
x17: 0000000000000000 x16: ffff80001235d16c x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001
x11: ff80800008353a30 x10: 0000000000000000 x9 : 21567eaf25bfb600
x8 : 21567eaf25bfb600 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80001e0d6558 x4 : ffff800015c74760 x3 : ffff800008596744
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000000e
Call trace:
skb_assert_len include/linux/skbuff.h:2527 [inline]
__dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156
dev_queue_xmit include/linux/netdevice.h:3033 [inline]
__netlink_deliver_tap_skb net/netlink/af_netlink.c:307 [inline]
__netlink_deliver_tap+0x45c/0x6f8 net/netlink/af_netlink.c:325
netlink_deliver_tap+0xf4/0x174 net/netlink/af_netlink.c:338
__netlink_sendskb net/netlink/af_netlink.c:1283 [inline]
netlink_sendskb+0x6c/0x154 net/netlink/af_netlink.c:1292
netlink_unicast+0x334/0x8d4 net/netlink/af_netlink.c:1380
nlmsg_unicast include/net/netlink.h:1099 [inline]
genlmsg_unicast include/net/genetlink.h:433 [inline]
genlmsg_reply include/net/genetlink.h:443 [inline]
ila_xlat_nl_cmd_get_mapping+0x620/0x7d0 net/ipv6/ila/ila_xlat.c:493
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x938/0xc1c net/netlink/genetlink.c:1065
netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2574
genl_rcv+0x38/0x50 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x800/0xae0 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0x558/0x844 net/socket.c:2479
___sys_sendmsg net/socket.c:2533 [inline]
__sys_sendmsg+0x26c/0x33c net/socket.c:2562
__do_sys_sendmsg net/socket.c:2571 [inline]
__se_sys_sendmsg net/socket.c:2569 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2569
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
irq event stamp: 136484
hardirqs last enabled at (136483): [<ffff800008350244>] __up_console_sem+0x60/0xb4 kernel/printk/printk.c:345
hardirqs last disabled at (136484): [<ffff800012358d60>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (136418): [<ffff800008020ea8>] softirq_ha
---truncated---
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-02
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix another off-by-one fsmap error on 1k block filesystems
Apparently syzbot figured out that issuing this FSMAP call:
struct fsmap_head cmd = {
.fmh_count = ...;
.fmh_keys = {
{ .fmr_device = /* ext4 dev */, .fmr_physical = 0, },
{ .fmr_device = /* ext4 dev */, .fmr_physical = 0, },
},
...
};
ret = ioctl(fd, FS_IOC_GETFSMAP, &cmd);
Produces this crash if the underlying filesystem is a 1k-block ext4
filesystem:
kernel BUG at fs/ext4/ext4.h:3331!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU: 3 PID: 3227965 Comm: xfs_io Tainted: G W O 6.2.0-rc8-achx
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:ext4_mb_load_buddy_gfp+0x47c/0x570 [ext4]
RSP: 0018:ffffc90007c03998 EFLAGS: 00010246
RAX: ffff888004978000 RBX: ffffc90007c03a20 RCX: ffff888041618000
RDX: 0000000000000000 RSI: 00000000000005a4 RDI: ffffffffa0c99b11
RBP: ffff888012330000 R08: ffffffffa0c2b7d0 R09: 0000000000000400
R10: ffffc90007c03950 R11: 0000000000000000 R12: 0000000000000001
R13: 00000000ffffffff R14: 0000000000000c40 R15: ffff88802678c398
FS: 00007fdf2020c880(0000) GS:ffff88807e100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd318a5fe8 CR3: 000000007f80f001 CR4: 00000000001706e0
Call Trace:
<TASK>
ext4_mballoc_query_range+0x4b/0x210 [ext4 dfa189daddffe8fecd3cdfd00564e0f265a8ab80]
ext4_getfsmap_datadev+0x713/0x890 [ext4 dfa189daddffe8fecd3cdfd00564e0f265a8ab80]
ext4_getfsmap+0x2b7/0x330 [ext4 dfa189daddffe8fecd3cdfd00564e0f265a8ab80]
ext4_ioc_getfsmap+0x153/0x2b0 [ext4 dfa189daddffe8fecd3cdfd00564e0f265a8ab80]
__ext4_ioctl+0x2a7/0x17e0 [ext4 dfa189daddffe8fecd3cdfd00564e0f265a8ab80]
__x64_sys_ioctl+0x82/0xa0
do_syscall_64+0x2b/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fdf20558aff
RSP: 002b:00007ffd318a9e30 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000000200c0 RCX: 00007fdf20558aff
RDX: 00007fdf1feb2010 RSI: 00000000c0c0583b RDI: 0000000000000003
RBP: 00005625c0634be0 R08: 00005625c0634c40 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdf1feb2010
R13: 00005625be70d994 R14: 0000000000000800 R15: 0000000000000000
For GETFSMAP calls, the caller selects a physical block device by
writing its block number into fsmap_head.fmh_keys[01].fmr_device.
To query mappings for a subrange of the device, the starting byte of the
range is written to fsmap_head.fmh_keys[0].fmr_physical and the last
byte of the range goes in fsmap_head.fmh_keys[1].fmr_physical.
IOWs, to query what mappings overlap with bytes 3-14 of /dev/sda, you'd
set the inputs as follows:
fmh_keys[0] = { .fmr_device = major(8, 0), .fmr_physical = 3},
fmh_keys[1] = { .fmr_device = major(8, 0), .fmr_physical = 14},
Which would return you whatever is mapped in the 12 bytes starting at
physical offset 3.
The crash is due to insufficient range validation of keys[1] in
ext4_getfsmap_datadev. On 1k-block filesystems, block 0 is not part of
the filesystem, which means that s_first_data_block is nonzero.
ext4_get_group_no_and_offset subtracts this quantity from the blocknr
argument before cracking it into a group number and a block number
within a group. IOWs, block group 0 spans blocks 1-8192 (1-based)
instead of 0-8191 (0-based) like what happens with larger blocksizes.
The net result of this encoding is that blocknr < s_first_data_block is
not a valid input to this function. The end_fsb variable is set from
the keys that are copied from userspace, which means that in the above
example, its value is zero. That leads to an underflow here:
blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
The division then operates on -1:
offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
EXT4_SB(sb)->s_cluster_bits;
Leaving an impossibly large group number (2^32-1) in blocknr.
ext4_getfsmap_check_keys checked that keys[0
---truncated---
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-02
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Fix a server shutdown leak
Fix a race where kthread_stop() may prevent the threadfn from ever getting
called. If that happens the svc_rqst will not be cleaned up.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-02