Messages in this thread | | | Subject | Re: [PATCH v2 1/2] crypto: Fix -Wstringop-truncation warnings | From | Christophe LEROY <> | Date | Mon, 25 Jun 2018 14:59:58 +0200 |
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Le 25/06/2018 à 14:45, Stafford Horne a écrit : > 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 <gregkh@linuxfoundation.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Max Filippov <jcmvbkbc@gmail.com> > Cc: Eric Biggers <ebiggers3@gmail.com> > Cc: Nick Desaulniers <nick.desaulniers@gmail.com> > Signed-off-by: Stafford Horne <shorne@gmail.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 d880a4897159..1edb5000d783 100644 > --- a/crypto/ablkcipher.c > +++ b/crypto/ablkcipher.c > @@ -373,6 +373,7 @@ 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));
Is it worth copying something we are going to discard at the following line ? Shouldn't you limit the copy to sizeof(rblkcipher.geniv) - 1 ?
> + rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0'; > > rblkcipher.blocksize = alg->cra_blocksize; > rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize; > @@ -447,6 +448,7 @@ 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));
Same comment here.
Christophe
> + 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 01c0d4aa2563..dd4dcab3766a 100644 > --- a/crypto/blkcipher.c > +++ b/crypto/blkcipher.c > @@ -512,6 +512,7 @@ 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; >
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