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tls: fix peeking with sync+async decryption

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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>
This commit is contained in:
Sabrina Dubroca 2024-02-28 23:43:58 +01:00 committed by Jakub Kicinski
parent f7fa16d498
commit 6caaf10442
1 changed files with 6 additions and 3 deletions
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9
net/tls/tls_sw.c
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@ -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);