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net/tls: fix no wakeup on partial reads 

When tls_sw_recvmsg() partially copies a record it pops that
record from ctx->recv_pkt and places it on rx_list.

Next iteration of tls_sw_recvmsg() reads from rx_list via
process_rx_list() before it enters the decryption loop.
If there is no more records to be read tls_wait_data()
will put the process on the wait queue and got to sleep.
This is incorrect, because some data was already copied
in process_rx_list().

In case of RPC connections process may never get woken up,
because peer also simply blocks in read().

I think this may also fix a similar issue when BPF is at
play, because after __tcp_bpf_recvmsg() returns some data
we subtract it from len and use continue to restart the
loop, but len could have just reached 0, so again we'd
sleep unnecessarily. That's added by:
commit d3b18ad31f ("tls: add bpf support to sk_msg handling")

Fixes: 692d7b5d1f ("tls: Fix recvmsg() to be able to peek across multiple records")
Reported-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Tested-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2019-05-24 10:34:32 -07:00 committed by David S. Miller
parent 7718a855cd
commit 04b25a5411
1 changed files with 2 additions and 6 deletions
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8
net/tls/tls_sw.c
View File

@ -1719,7 +1719,7 @@ int tls_sw_recvmsg(struct sock *sk,
len = len - copied;
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
do {
while (len && (decrypted + copied < target || ctx->recv_pkt)) {
bool retain_skb = false;
bool zc = false;
int to_decrypt;
@ -1850,11 +1850,7 @@ pick_next_record:
} else {
break;
}
/* If we have a new message from strparser, continue now. */
if (decrypted + copied >= target && !ctx->recv_pkt)
break;
} while (len);
}
recv_end:
if (num_async) {