From 2e2d6f1e783fc6d827ca32a6ca41ebdda855cfd8 Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Thu, 12 Apr 2018 08:40:55 +0200 Subject: [PATCH] crypto: drbg - set freed buffers to NULL commit eea0d3ea7546961f69f55b26714ac8fd71c7c020 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: 3cfc3b9721123 ("crypto: drbg - use aligned buffers") Signed-off-by: Stephan Mueller Reported-by: syzbot+75397ee3df5c70164154@syzkaller.appspotmail.com Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/drbg.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/crypto/drbg.c b/crypto/drbg.c index 942ddff68408..4bb5f93c94cd 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; -- 2.20.1