In the Linux kernel, the following vulnerability has been resolved:
bpf: fix ktls panic with sockmap
[ 2172.936997] ------------[ cut here ]------------
[ 2172.936999] kernel BUG at lib/iov_iter.c:629!
......
[ 2172.944996] PKRU: 55555554
[ 2172.945155] Call Trace:
[ 2172.945299] <TASK>
[ 2172.945428] ? die+0x36/0x90
[ 2172.945601] ? do_trap+0xdd/0x100
[ 2172.945795] ? iov_iter_revert+0x178/0x180
[ 2172.946031] ? iov_iter_revert+0x178/0x180
[ 2172.946267] ? do_error_trap+0x7d/0x110
[ 2172.946499] ? iov_iter_revert+0x178/0x180
[ 2172.946736] ? exc_invalid_op+0x50/0x70
[ 2172.946961] ? iov_iter_revert+0x178/0x180
[ 2172.947197] ? asm_exc_invalid_op+0x1a/0x20
[ 2172.947446] ? iov_iter_revert+0x178/0x180
[ 2172.947683] ? iov_iter_revert+0x5c/0x180
[ 2172.947913] tls_sw_sendmsg_locked.isra.0+0x794/0x840
[ 2172.948206] tls_sw_sendmsg+0x52/0x80
[ 2172.948420] ? inet_sendmsg+0x1f/0x70
[ 2172.948634] __sys_sendto+0x1cd/0x200
[ 2172.948848] ? find_held_lock+0x2b/0x80
[ 2172.949072] ? syscall_trace_enter+0x140/0x270
[ 2172.949330] ? __lock_release.isra.0+0x5e/0x170
[ 2172.949595] ? find_held_lock+0x2b/0x80
[ 2172.949817] ? syscall_trace_enter+0x140/0x270
[ 2172.950211] ? lockdep_hardirqs_on_prepare+0xda/0x190
[ 2172.950632] ? ktime_get_coarse_real_ts64+0xc2/0xd0
[ 2172.951036] __x64_sys_sendto+0x24/0x30
[ 2172.951382] do_syscall_64+0x90/0x170
......
After calling bpf_exec_tx_verdict(), the size of msg_pl->sg may increase,
e.g., when the BPF program executes bpf_msg_push_data().
If the BPF program sets cork_bytes and sg.size is smaller than cork_bytes,
it will return -ENOSPC and attempt to roll back to the non-zero copy
logic. However, during rollback, msg->msg_iter is reset, but since
msg_pl->sg.size has been increased, subsequent executions will exceed the
actual size of msg_iter.
'''
iov_iter_revert(&msg->msg_iter, msg_pl->sg.size - orig_size);
'''
The changes in this commit are based on the following considerations:
1. When cork_bytes is set, rolling back to non-zero copy logic is
pointless and can directly go to zero-copy logic.
2. We can not calculate the correct number of bytes to revert msg_iter.
Assume the original data is "abcdefgh" (8 bytes), and after 3 pushes
by the BPF program, it becomes 11-byte data: "abc?de?fgh?".
Then, we set cork_bytes to 6, which means the first 6 bytes have been
processed, and the remaining 5 bytes "?fgh?" will be cached until the
length meets the cork_bytes requirement.
However, some data in "?fgh?" is not within 'sg->msg_iter'
(but in msg_pl instead), especially the data "?" we pushed.
So it doesn't seem as simple as just reverting through an offset of
msg_iter.
3. For non-TLS sockets in tcp_bpf_sendmsg, when a "cork" situation occurs,
the user-space send() doesn't return an error, and the returned length is
the same as the input length parameter, even if some data is cached.
Additionally, I saw that the current non-zero-copy logic for handling
corking is written as:
'''
line 1177
else if (ret != -EAGAIN) {
if (ret == -ENOSPC)
ret = 0;
goto send_end;
'''
So it's ok to just return 'copied' without error when a "cork" situation
occurs.
References
Configurations
History
18 Dec 2025, 20:51
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| CWE | NVD-CWE-noinfo | |
| First Time |
Linux
Debian Debian debian Linux Linux linux Kernel |
|
| CPE | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
|
| References | () https://git.kernel.org/stable/c/2e36a81d388ec9c3f78b6223f7eda2088cd40adb - Patch | |
| References | () https://git.kernel.org/stable/c/328cac3f9f8ae394748485e769a527518a9137c8 - Patch | |
| References | () https://git.kernel.org/stable/c/54a3ecaeeeae8176da8badbd7d72af1017032c39 - Patch | |
| References | () https://git.kernel.org/stable/c/57fbbe29e86042bbaa31c1a30d2afa16c427e3f7 - Patch | |
| References | () https://git.kernel.org/stable/c/603943f022a7fe5cc83ca7005faf34798fb7853f - Patch | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html - Third Party Advisory |
03 Nov 2025, 18:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
03 Jul 2025, 15:13
| Type | Values Removed | Values Added |
|---|---|---|
| Summary |
|
03 Jul 2025, 09:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-07-03 09:15
Updated : 2025-12-18 20:51
NVD link : CVE-2025-38166
Mitre link : CVE-2025-38166
CVE.ORG link : CVE-2025-38166
JSON object : View
Products Affected
debian
- debian_linux
linux
- linux_kernel
CWE
