crypto: drbg - set freed buffers to NULL

commit eea0d3ea75 upstream.

During freeing of the internal buffers used by the DRBG, set the pointer
to NULL. It is possible that the context with the freed buffers is
reused. In case of an error during initialization where the pointers
do not yet point to allocated memory, the NULL value prevents a double
free.

Cc: stable@vger.kernel.org
Fixes: 3cfc3b9721 ("crypto: drbg - use aligned buffers")
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Reported-by: syzbot+75397ee3df5c70164154@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stephan Mueller 2018-04-12 08:40:55 +02:00 committed by Greg Kroah-Hartman
parent 8970c12ac9
commit 2e2d6f1e78
1 changed files with 2 additions and 0 deletions

View File

@ -1134,8 +1134,10 @@ static inline void drbg_dealloc_state(struct drbg_state *drbg)
if (!drbg)
return;
kzfree(drbg->Vbuf);
drbg->Vbuf = NULL;
drbg->V = NULL;
kzfree(drbg->Cbuf);
drbg->Cbuf = NULL;
drbg->C = NULL;
kzfree(drbg->scratchpadbuf);
drbg->scratchpadbuf = NULL;