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, "Gustavo A. R. Silva" , Chanwoo Choi , MyungJoo Ham , Sasha Levin Subject: [PATCH 4.9 129/310] PM / devfreq: Fix potential NULL pointer dereference in governor_store Date: Wed, 11 Apr 2018 20:34:28 +0200 Message-Id: <20180411183628.020210084@linuxfoundation.org> In-Reply-To: <20180411183622.305902791@linuxfoundation.org> References: <20180411183622.305902791@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Gustavo A. R. Silva" [ Upstream commit 63f1e05f7fe9ca509c60154d6a833abf96eecdc9 ] df->governor is being dereferenced before it is null checked, hence there is a potential null pointer dereference. Notice that df->governor is being null checked at line 1004: if (df->governor) {, which implies it might be null. Fix this by null checking df->governor before dereferencing it. Addresses-Coverity-ID: 1401988 ("Dereference before null check") Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs") Signed-off-by: Gustavo A. R. Silva Reviewed-by: Chanwoo Choi Signed-off-by: MyungJoo Ham Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/devfreq/devfreq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -943,7 +943,8 @@ static ssize_t governor_store(struct dev if (df->governor == governor) { ret = 0; goto out; - } else if (df->governor->immutable || governor->immutable) { + } else if ((df->governor && df->governor->immutable) || + governor->immutable) { ret = -EINVAL; goto out; }