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	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: 692d7b5d1f ("tls: Fix recvmsg() to be able to peek across multiple records")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/1b132d2b2b99296bfde54e8a67672d90d6d16e71.1709132643.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
			
			
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					 1 changed files with 6 additions and 3 deletions
				
			
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			@ -1950,6 +1950,7 @@ int tls_sw_recvmsg(struct sock *sk,
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	struct strp_msg *rxm;
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	struct tls_msg *tlm;
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	ssize_t copied = 0;
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	ssize_t peeked = 0;
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	bool async = false;
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	int target, err;
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	bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
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			@ -2097,8 +2098,10 @@ int tls_sw_recvmsg(struct sock *sk,
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			if (err < 0)
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				goto put_on_rx_list_err;
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			if (is_peek)
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			if (is_peek) {
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				peeked += chunk;
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				goto put_on_rx_list;
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			}
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			if (partially_consumed) {
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				rxm->offset += chunk;
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			@ -2137,8 +2140,8 @@ int tls_sw_recvmsg(struct sock *sk,
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		/* Drain records from the rx_list & copy if required */
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		if (is_peek || is_kvec)
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			err = process_rx_list(ctx, msg, &control, copied,
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					      decrypted, is_peek, NULL);
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			err = process_rx_list(ctx, msg, &control, copied + peeked,
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					      decrypted - peeked, is_peek, NULL);
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		else
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			err = process_rx_list(ctx, msg, &control, 0,
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					      async_copy_bytes, is_peek, NULL);
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