Commit 6caaf104 authored by Sabrina Dubroca's avatar Sabrina Dubroca Committed by Jakub Kicinski
Browse files

tls: fix peeking with sync+async decryption 



If we peek from 2 records with a currently empty rx_list, and the
first record is decrypted synchronously but the second record is
decrypted async, the following happens:
  1. decrypt record 1 (sync)
  2. copy from record 1 to the userspace's msg
  3. queue the decrypted record to rx_list for future read(!PEEK)
  4. decrypt record 2 (async)
  5. queue record 2 to rx_list
  6. call process_rx_list to copy data from the 2nd record

We currently pass copied=0 as skip offset to process_rx_list, so we
end up copying once again from the first record. We should skip over
the data we've already copied.

Seen with selftest tls.12_aes_gcm.recv_peek_large_buf_mult_recs

Fixes: 692d7b5d ("tls: Fix recvmsg() to be able to peek across multiple records")
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/1b132d2b2b99296bfde54e8a67672d90d6d16e71.1709132643.git.sd@queasysnail.net


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f7fa16d4

net/tls/tls_sw.c

+6 −3
Original line number Diff line number Diff line
@@ -1950,6 +1950,7 @@ int tls_sw_recvmsg(struct sock *sk, 
	struct strp_msg *rxm;

	struct tls_msg *tlm;

	ssize_t copied = 0;

	ssize_t peeked = 0;

	bool async = false;

	int target, err;

	bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
@@ -2097,8 +2098,10 @@ int tls_sw_recvmsg(struct sock *sk, 
			if (err < 0)

				goto put_on_rx_list_err;



			if (is_peek)

			if (is_peek) {

				peeked += chunk;

				goto put_on_rx_list;

			}



			if (partially_consumed) {

				rxm->offset += chunk;
@@ -2137,8 +2140,8 @@ int tls_sw_recvmsg(struct sock *sk, 


		/* Drain records from the rx_list & copy if required */

		if (is_peek || is_kvec)

			err = process_rx_list(ctx, msg, &control, copied,

					      decrypted, is_peek, NULL);

			err = process_rx_list(ctx, msg, &control, copied + peeked,

					      decrypted - peeked, is_peek, NULL);

		else

			err = process_rx_list(ctx, msg, &control, 0,

					      async_copy_bytes, is_peek, NULL);