On Fri, Jun 22, 2018 at 07:41:49PM -0700, Eric Biggers wrote: > On Sat, Jun 23, 2018 at 11:07:52AM +0900, Stafford Horne wrote: > > 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@xxxxxxxxxxxxxxxxxxx> > > Cc: Arnd Bergmann <arnd@xxxxxxxx> > > Signed-off-by: Stafford Horne <shorne@xxxxxxxxx> > > --- > > 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; > > Your "fix" introduces an information disclosure bug, as it results in > uninitialized memory being copied to userspace. This same broken patch was sent > by someone else too. > > Maybe it would be best to just memset() the crypto_report_* structs to 0 after > declaration and then replace the strncpy()'s with strscpy()'s, even if just to > stop people from sending broken "fixes". Do you want to do that? Right, I didnt realize that we were using strncpy to also init the whole buffer. I will do as suggest, and respic. -Stafford
