[PATCH net 3/4] tls: separate no-async decryption request handling from async

[Sabrina Dubroca <sd@queasysnail.net>]

If we're not doing async, the handling is much simpler. There's no
reference counting, we just need to wait for the completion to wake us
up and return its result.

We should preferably also use a separate crypto_wait. I'm not seeing a
UAF as I did in the past, I think aec7961916f3 ("tls: fix race between
async notify and socket close") took care of it.

This will make the next fix easier.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
 net/tls/tls_sw.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 1394fc44f378..1fd37fe13ffd 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -274,9 +274,15 @@ static int tls_do_decryption(struct sock *sk,
 		DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->decrypt_pending) < 1);
 		atomic_inc(&ctx->decrypt_pending);
 	} else {
+		DECLARE_CRYPTO_WAIT(wait);
+
 		aead_request_set_callback(aead_req,
 					  CRYPTO_TFM_REQ_MAY_BACKLOG,
-					  crypto_req_done, &ctx->async_wait);
+					  crypto_req_done, &wait);
+		ret = crypto_aead_decrypt(aead_req);
+		if (ret == -EINPROGRESS || ret == -EBUSY)
+			ret = crypto_wait_req(ret, &wait);
+		return ret;
 	}
 
 	ret = crypto_aead_decrypt(aead_req);
@@ -285,10 +291,7 @@ static int tls_do_decryption(struct sock *sk,
 		ret = ret ?: -EINPROGRESS;
 	}
 	if (ret == -EINPROGRESS) {
-		if (darg->async)
-			return 0;
-
-		ret = crypto_wait_req(ret, &ctx->async_wait);
+		return 0;
 	} else if (darg->async) {
 		atomic_dec(&ctx->decrypt_pending);
 	}
-- 
2.43.0