linux-kernel - [PATCH 4.4 166/241] media: wl128x: prevent two potential buffer overflows

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sun,  9 Jun 2019 18:41:48 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.4 166/241] media: wl128x: prevent two potential buffer overflows

[ Upstream commit 9c2ccc324b3a6cbc865ab8b3e1a09e93d3c8ade9 ]

Smatch marks skb->data as untrusted so it warns that "evt_hdr->dlen"
can copy up to 255 bytes and we only have room for two bytes.  Even
if this comes from the firmware and we trust it, the new policy
generally is just to fix it as kernel hardenning.

I can't test this code so I tried to be very conservative.  I considered
not allowing "evt_hdr->dlen == 1" because it doesn't initialize the
whole variable but in the end I decided to allow it and manually
initialized "asic_id" and "asic_ver" to zero.

Fixes: e8454ff7b9a4 ("[media] drivers:media:radio: wl128x: FM Driver Common sources")

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/radio/wl128x/fmdrv_common.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/media/radio/wl128x/fmdrv_common.c b/drivers/media/radio/wl128x/fmdrv_common.c
index ebc73b0342496..51639a3f7abe4 100644
--- a/drivers/media/radio/wl128x/fmdrv_common.c
+++ b/drivers/media/radio/wl128x/fmdrv_common.c
@@ -494,7 +494,8 @@ int fmc_send_cmd(struct fmdev *fmdev, u8 fm_op, u16 type, void *payload,
 		return -EIO;
 	}
 	/* Send response data to caller */
-	if (response != NULL && response_len != NULL && evt_hdr->dlen) {
+	if (response != NULL && response_len != NULL && evt_hdr->dlen &&
+	    evt_hdr->dlen <= payload_len) {
 		/* Skip header info and copy only response data */
 		skb_pull(skb, sizeof(struct fm_event_msg_hdr));
 		memcpy(response, skb->data, evt_hdr->dlen);
@@ -590,6 +591,8 @@ static void fm_irq_handle_flag_getcmd_resp(struct fmdev *fmdev)
 		return;
 
 	fm_evt_hdr = (void *)skb->data;
+	if (fm_evt_hdr->dlen > sizeof(fmdev->irq_info.flag))
+		return;
 
 	/* Skip header info and copy only response data */
 	skb_pull(skb, sizeof(struct fm_event_msg_hdr));
@@ -1315,7 +1318,7 @@ static int load_default_rx_configuration(struct fmdev *fmdev)
 static int fm_power_up(struct fmdev *fmdev, u8 mode)
 {
 	u16 payload;
-	__be16 asic_id, asic_ver;
+	__be16 asic_id = 0, asic_ver = 0;
 	int resp_len, ret;
 	u8 fw_name[50];
 
-- 
2.20.1