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Date:   Fri, 29 May 2020 22:40:48 +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_skcipher - Do not perform zero-length ops
Message-ID: <20200529124048.GA7283@gondor.apana.org.au>
References: <20200529045443.GA475@gondor.apana.org.au>
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If a read(2) of less than a full block size is attempted we will
end up doing a zero-length operation.  This patch makes that return
-EINVAL instead, which is what we did originally.

Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 4c3bdffe0c3a5..24dd2fc2431cc 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -85,6 +85,10 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 	if (ctx->more || len < ctx->used)
 		len -= len % bs;
 
+	err = -EINVAL;
+	if (!len)
+		goto free;
+
 	/*
 	 * Create a per request TX SGL for this request which tracks the
 	 * SG entries from the global TX SGL.
-- 
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