CVE-2025-37756 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: tls: explicitly disallow disconnect

syzbot discovered that it can disconnect a TLS socket and then run into all sort of unexpected corner cases. I have a vague recollection of Eric pointing this out to us a long time ago. Supporting disconnect is really hard for one thing if offload is enabled we’d need to wait for all packets to be acked. Disconnect is not commonly used disallow it.

The immediate problem syzbot run into is the warning in the strp but that’s just the easiest bug to trigger:

WARNING: CPU: 0 PID: 5834 at net/tls/tls_strp.c:486 tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486 RIP: 0010:tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486 Call Trace: tls_rx_rec_wait+0x280/0xa60 net/tls/tls_sw.c:1363 tls_sw_recvmsg+0x85c/0x1c30 net/tls/tls_sw.c:2043 inet6_recvmsg+0x2c9/0x730 net/ipv6/af_inet6.c:678 sock_recvmsg_nosec net/socket.c:1023 [inline] sock_recvmsg+0x109/0x280 net/socket.c:1045 __sys_recvfrom+0x202/0x380 net/socket.c:2237

Reference

https://git.kernel.org/stable/c/2bcad8fefcecdd5f005d8c550b25d703c063c34a https://git.kernel.org/stable/c/5071a1e606b30c0c11278d3c6620cd6a24724cf6 https://git.kernel.org/stable/c/8513411ec321942bd3cfed53d5bb700665c67d86 https://git.kernel.org/stable/c/9fcbca0f801580cbb583e9cb274e2c7fbe766ca6 https://git.kernel.org/stable/c/c665bef891e8972e1d3ce5bbc0d42a373346a2c3 https://git.kernel.org/stable/c/f3ce4d3f874ab7919edca364c147ac735f9f1d04