In the Linux kernel, the following vulnerability has been resolved:
kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg().
syzkaller found a memory leak in kcm_sendmsg(), and commit c821a88bd720
("kcm: Fix memory leak in error path of kcm_sendmsg()") suppressed it by
updating kcm_tx_msg(head)->last_skb if partial data is copied so that the
following sendmsg() will resume from the skb.
However, we cannot know how many bytes were copied when we get the error.
Thus, we could mess up the MSG_MORE queue.
When kcm_sendmsg() fails for SOCK_DGRAM, we should purge the queue as we
do so for UDP by udp_flush_pending_frames().
Even without this change, when the error occurred, the following sendmsg()
resumed from a wrong skb and the queue was messed up. However, we have
yet to get such a report, and only syzkaller stumbled on it. So, this
can be changed safely.
Note this does not change SOCK_SEQPACKET behaviour.
Metrics
Affected Vendors & Products
References
History
Wed, 10 Dec 2025 00:15:00 +0000
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threat_severity
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cvssV3_1
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Tue, 09 Dec 2025 02:00:00 +0000
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| Description | In the Linux kernel, the following vulnerability has been resolved: kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg(). syzkaller found a memory leak in kcm_sendmsg(), and commit c821a88bd720 ("kcm: Fix memory leak in error path of kcm_sendmsg()") suppressed it by updating kcm_tx_msg(head)->last_skb if partial data is copied so that the following sendmsg() will resume from the skb. However, we cannot know how many bytes were copied when we get the error. Thus, we could mess up the MSG_MORE queue. When kcm_sendmsg() fails for SOCK_DGRAM, we should purge the queue as we do so for UDP by udp_flush_pending_frames(). Even without this change, when the error occurred, the following sendmsg() resumed from a wrong skb and the queue was messed up. However, we have yet to get such a report, and only syzkaller stumbled on it. So, this can be changed safely. Note this does not change SOCK_SEQPACKET behaviour. | |
| Title | kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg(). | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
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Status: PUBLISHED
Assigner: Linux
Published: 2025-12-09T01:29:38.539Z
Updated: 2025-12-09T01:29:38.539Z
Reserved: 2025-12-09T01:27:17.824Z
Link: CVE-2023-53825
No data.
Status : Awaiting Analysis
Published: 2025-12-09T16:17:21.337
Modified: 2025-12-09T18:37:13.640
Link: CVE-2023-53825