From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stephan Mueller , syzbot+75397ee3df5c70164154@syzkaller.appspotmail.com, Herbert Xu Subject: [PATCH 4.16 083/113] crypto: drbg - set freed buffers to NULL Date: Mon, 30 Apr 2018 12:24:54 -0700 Message-Id: <20180430184018.696347574@linuxfoundation.org> In-Reply-To: <20180430184015.043892819@linuxfoundation.org> References: <20180430184015.043892819@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephan Mueller 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(+) --- a/crypto/drbg.c +++ b/crypto/drbg.c @@ -1134,8 +1134,10 @@ static inline void drbg_dealloc_state(st 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;