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From: Stafford Horne <shorne@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	arnd@arndb.de, linux-crypto@vger.kernel.org,
	Stafford Horne <shorne@gmail.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>
Subject: [RFC PATCH 1/2] crypto: Fix -Wstringop-truncation warnings
Date: Sat, 23 Jun 2018 11:07:52 +0900	[thread overview]
Message-ID: <20180623020753.27266-2-shorne@gmail.com> (raw)
In-Reply-To: <20180623020753.27266-1-shorne@gmail.com>

As of GCC 9.0.0 the build is reporting warnings like:

    crypto/ablkcipher.c: In function ‘crypto_ablkcipher_report’:
    crypto/ablkcipher.c:374:2: warning: ‘strncpy’ specified bound 64 equals destination size [-Wstringop-truncation]
      strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       sizeof(rblkcipher.geniv));
       ~~~~~~~~~~~~~~~~~~~~~~~~~

This means the strnycpy might create a non null terminated string.  Fix this by
limiting the size of the string copy to include the null terminator.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stafford Horne <shorne@gmail.com>
---
 crypto/ablkcipher.c | 4 ++--
 crypto/blkcipher.c  | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index d880a4897159..972cd7c879f6 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -372,7 +372,7 @@ static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 
 	strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
 	strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
-		sizeof(rblkcipher.geniv));
+		sizeof(rblkcipher.geniv) - 1);
 
 	rblkcipher.blocksize = alg->cra_blocksize;
 	rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
@@ -446,7 +446,7 @@ static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 
 	strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));
 	strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",
-		sizeof(rblkcipher.geniv));
+		sizeof(rblkcipher.geniv) - 1);
 
 	rblkcipher.blocksize = alg->cra_blocksize;
 	rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 01c0d4aa2563..f1644b5cf68c 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -511,7 +511,7 @@ static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 
 	strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
 	strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",
-		sizeof(rblkcipher.geniv));
+		sizeof(rblkcipher.geniv) - 1);
 
 	rblkcipher.blocksize = alg->cra_blocksize;
 	rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
-- 
2.17.0


  reply	other threads:[~2018-06-23  2:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-23  2:07 [RFC PATCH 0/2] Fix GCC -Wstringop-truncation warnings Stafford Horne
2018-06-23  2:07 ` Stafford Horne [this message]
2018-06-23  2:22   ` [RFC PATCH 1/2] crypto: Fix " Max Filippov
2018-06-23  2:41   ` Eric Biggers
2018-06-23  2:52     ` Stafford Horne
2018-06-23  6:46       ` Stafford Horne
2018-06-23  2:07 ` [RFC PATCH 2/2] kobject: Fix -Wstringop-truncation warning Stafford Horne
2018-06-23  2:31   ` Eric Biggers
2018-06-23  2:50     ` Stafford Horne

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