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CVE-2025-23145

Published: May 3, 2025Last modified: May 3, 2025

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix NULL pointer in can_accept_new_subflow When testing valkey benchmark tool with MPTCP, the kernel panics in 'mptcp_can_accept_new_subflow' because subflow_req->msk is NULL. Call trace: mptcp_can_accept_new_subflow (./net/mptcp/subflow.c:63 (discriminator 4)) (P) subflow_syn_recv_sock (./net/mptcp/subflow.c:854) tcp_check_req (./net/ipv4/tcp_minisocks.c:863) tcp_v4_rcv (./net/ipv4/tcp_ipv4.c:2268) ip_protocol_deliver_rcu (./net/ipv4/ip_input.c:207) ip_local_deliver_finish (./net/ipv4/ip_input.c:234) ip_local_deliver (./net/ipv4/ip_input.c:254) ip_rcv_finish (./net/ipv4/ip_input.c:449) ... According to the debug log, the same req received two SYN-ACK in a very short time, very likely because the client retransmits the syn ack due to multiple reasons. Even if the packets are transmitted with a relevant time interval, they can be processed by the server on different CPUs concurrently). The 'subflow_req->msk' ownership is transferred to the subflow the first, and there will be a risk of a null pointer dereference here. This patch fixes this issue by moving the 'subflow_req->msk' under the `own_req == true` conditional. Note that the !msk check in subflow_hmac_valid() can be dropped, because the same check already exists under the own_req mpj branch where the code has been moved to.

Severity score breakdown

ParameterValue
Base score5.5
Attack VectorLOCAL
Attack complexityLOW
Privileges requiredLOW
User interactionNONE
ScopeUNCHANGED
ConfidentialityNONE
Integrity impactNONE
Availability impactHIGH
VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Status

ProductReleasePackageStatus
Alpaquita Linux23 LTSlinux-ltsFixed (6.1.140-r0)
25 LTSlinux-ltsFixed (6.12.41-r0)
Streamlinux-ltsFixed (6.12.41-r0)

References

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