[PATCH AUTOSEL 3.18 01/29] crypto: skcipher - Fix -Wstringop-truncation warnings

[Sasha Levin]

From: Stafford Horne <shorne@xxxxxxxxx>

[ Upstream commit cefd769fd0192c84d638f66da202459ed8ad63ba ]

As of GCC 9.0.0 the build is reporting warnings like:

    crypto/ablkcipher.c: In function âcrypto_ablkcipher_reportâ:
    crypto/ablkcipher.c:374:2: warning: âstrncpyâ 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 <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Eric Biggers <ebiggers3@xxxxxxxxx>
Cc: Nick Desaulniers <nick.desaulniers@xxxxxxxxx>
Signed-off-by: Stafford Horne <shorne@xxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 crypto/ablkcipher.c | 2 ++
 crypto/blkcipher.c  | 1 +
 2 files changed, 3 insertions(+)

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index 5061d7ad33e4..cad66af5a1ae 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -382,6 +382,7 @@ 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;
@@ -463,6 +464,7 @@ 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 5ebfdd0d4543..5ba9916a33c8 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -514,6 +514,7 @@ 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