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Date:   Fri, 29 May 2020 23:18:11 +1000
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Stephan Mueller <smueller@chronox.de>
Subject: [PATCH] crypto: algif_aead - Only wake up when ctx->more is zero
Message-ID: <20200529131811.GA9137@gondor.apana.org.au>
References: <20200529045443.GA475@gondor.apana.org.au>
 <20200529124048.GA7283@gondor.apana.org.au>
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AEAD does not support partial requests so we must not wake up
while ctx->more is set.  While we're fixing this also change
algif_skcipher to only wake up when at least a block is available
as otherwise we'd just fail straight away with -EINVAL.

Fixes: 2d97591ef43d ("crypto: af_alg - consolidation of...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index b1cd3535c5256..474a9511f0ed4 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -738,9 +738,10 @@ EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
  *
  * @sk socket of connection to user space
  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
+ * @min Set to minimum request size if partial requests are allowed.
  * @return 0 when writable memory is available, < 0 upon error
  */
-int af_alg_wait_for_data(struct sock *sk, unsigned flags)
+int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
 {
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	struct alg_sock *ask = alg_sk(sk);
@@ -758,7 +759,8 @@ int af_alg_wait_for_data(struct sock *sk, unsigned flags)
 		if (signal_pending(current))
 			break;
 		timeout = MAX_SCHEDULE_TIMEOUT;
-		if (sk_wait_event(sk, &timeout, (ctx->used || !ctx->more),
+		if (sk_wait_event(sk, &timeout,
+				  (min && ctx->used >= min) || !ctx->more,
 				  &wait)) {
 			err = 0;
 			break;
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index eb1910b6d434c..efea00046be65 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -107,7 +107,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	size_t processed = 0;		/* [in]  TX bufs to be consumed */
 
 	if (!ctx->used) {
-		err = af_alg_wait_for_data(sk, flags);
+		err = af_alg_wait_for_data(sk, flags, 0);
 		if (err)
 			return err;
 	}
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 24dd2fc2431cc..5b334fd9432c0 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -62,7 +62,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 	size_t len = 0;
 
 	if (!ctx->used) {
-		err = af_alg_wait_for_data(sk, flags);
+		err = af_alg_wait_for_data(sk, flags, bs);
 		if (err)
 			return err;
 	}
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 56527c85d1222..e1e5525473e4c 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -226,7 +226,7 @@ unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 		      size_t dst_offset);
 void af_alg_wmem_wakeup(struct sock *sk);
-int af_alg_wait_for_data(struct sock *sk, unsigned flags);
+int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min);
 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		   unsigned int ivsize);
 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt