[PATCH 5.15.y] tls: separate no-async decryption request handling from async

From: Sabrina Dubroca <[email protected]>

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.

CVE: CVE-2024-58240
Signed-off-by: Sabrina Dubroca <[email protected]>
Link: https://lore.kernel.org/r/47bde5f649707610eaef9f0d679519966fc31061.1709132643.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <[email protected]>
(cherry picked from commit 41532b785e9d79636b3815a64ddf6a096647d011)
Signed-off-by: Wengang Wang <[email protected]>
---
 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 389597bd7ae5..0cdc9131aff2 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -278,9 +278,15 @@ static int tls_do_decryption(struct sock *sk,
 		BUILD_BUG_ON_INVALID(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);
@@ -289,10 +295,7 @@ 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);
 	}
-- 
2.50.1 (Apple Git-155)