[PATCH AUTOSEL 4.9 01/57] crypto: skcipher - Fix -Wstringop-truncation warnings

[Sasha Levin]

From: Stafford Horne <sho...@gmail.com>

[ Upstream commit cefd769fd0192c84d638f66da202459ed8ad63ba ]

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
explicitly performing '\0' termination.

Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Max Filippov <jcmvb...@gmail.com>
Cc: Eric Biggers <ebigge...@gmail.com>
Cc: Nick Desaulniers <nick.desaulni...@gmail.com>
Signed-off-by: Stafford Horne <sho...@gmail.com>
Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 crypto/ablkcipher.c | 2 ++
 crypto/blkcipher.c  | 1 +
 2 files changed, 3 insertions(+)

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index 860c9e5dfd7a..3bc0e76eaaef 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -367,6 +367,7 @@ 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));
+       rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0';
 
        rblkcipher.blocksize = alg->cra_blocksize;
        rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
@@ -441,6 +442,7 @@ 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));
+       rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0';
 
        rblkcipher.blocksize = alg->cra_blocksize;
        rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 27f98666763a..59a0936ed8bc 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -510,6 +510,7 @@ 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));
+       rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0';
 
        rblkcipher.blocksize = alg->cra_blocksize;
        rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
-- 
2.17.1