CVE-2026-74611

In the Linux kernel, the following vulnerability has been resolved:

tls: rx: restore msg_iter before TLS 1.3 optimistic retry

tlsdecryptsg() advances msg->msg_iter when it maps user pages for

the optimistic TLS 1.3 zero-copy path. If the decrypted record turns

out not to be unpadded application data, tlsdecryptsw() retries into

a kernel skb, but leaves the iterator advanced.

The subsequent copy from the skb then writes decrypted bytes again at

a later point in the caller iovecs while recvmsg() reports only the

post-retry length. A TLS peer can trigger this after the receiver

enables TLSRXEXPECTNOPAD.

Revert the iterator by the number of bytes consumed by the optimistic

mapping before retrying without zero-copy.

Add a selftest which sends a TLS 1.3 control record with

TLSRXEXPECTNOPAD enabled and verifies that recvmsg() does not

overwrite later iovecs beyond the returned length.