CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's handling of TLS 1.3 optimistic retries, where the message iterator can become misaligned, potentially allowing a TLS peer to manipulate the data being written to user buffers. This could lead to unintended data exposure or corruption, particularly when the receiver has TLS_RX_EXPECT_NO_PAD enabled. Organizations using Linux in environments that implement TLS 1.3 should prioritize addressing this issue to mitigate risks associated with data integrity and confidentiality.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: tls: rx: restore msg_iter before TLS 1.3 optimistic retry tls_decrypt_sg() 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, tls_decrypt_sw() 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 TLS_RX_EXPECT_NO_PAD. 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 TLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not overwrite later iovecs beyond the returned length.