crypto: drbg - set freed buffers to NULL
diff mbox

Message ID 2295196.9WStPcntd3@positron.chronox.de
State Accepted
Delegated to: Herbert Xu
Headers show

Commit Message

Stephan Mueller April 12, 2018, 6:40 a.m. UTC
Add the Fixes, CC stable tags.

---8<---

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: 3cfc3b9721123 ("crypto: drbg - use aligned buffers")
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Reported-by: syzbot+75397ee3df5c70164154@syzkaller.appspotmail.com
---
 crypto/drbg.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Herbert Xu April 20, 2018, 4:54 p.m. UTC | #1
On Thu, Apr 12, 2018 at 08:40:55AM +0200, Stephan Müller wrote:
> Add the Fixes, CC stable tags.
> 
> ---8<---
> 
> 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: 3cfc3b9721123 ("crypto: drbg - use aligned buffers")
> Signed-off-by: Stephan Mueller <smueller@chronox.de>
> Reported-by: syzbot+75397ee3df5c70164154@syzkaller.appspotmail.com

Patch applied.  Thanks.

Patch
diff mbox

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 4faa2781c964..466a112a4446 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -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;