[RESEND] ASoC: wm_adsp: Fix validation of firmware and coeff lengths
diff mbox

Message ID 20171208161520.sxiz6s3qcms2jeis@xylophone.i.decadent.org.uk
State New
Headers show

Commit Message

Ben Hutchings Dec. 8, 2017, 4:15 p.m. UTC
The checks for whether another region/block header could be present
are subtracting the size from the current offset.  Obviously we should
instead subtract the offset from the size.

The checks for whether the region/block data fit in the file are
adding the data size to the current offset and header size, without
checking for integer overflow.  Rearrange these so that overflow is
impossible.

Cc: stable@vger.kernel.org
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 sound/soc/codecs/wm_adsp.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Comments

Mark Brown Dec. 8, 2017, 5:16 p.m. UTC | #1
On Fri, Dec 08, 2017 at 04:15:20PM +0000, Ben Hutchings wrote:
> The checks for whether another region/block header could be present
> are subtracting the size from the current offset.  Obviously we should
> instead subtract the offset from the size.

This is described as a resend but I checked and I've not been sent this
patch before :(

Patch
diff mbox

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 65c059b5ffd7..66e32f5d2917 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -1733,7 +1733,7 @@  static int wm_adsp_load(struct wm_adsp *dsp)
 		 le64_to_cpu(footer->timestamp));
 
 	while (pos < firmware->size &&
-	       pos - firmware->size > sizeof(*region)) {
+	       sizeof(*region) < firmware->size - pos) {
 		region = (void *)&(firmware->data[pos]);
 		region_name = "Unknown";
 		reg = 0;
@@ -1782,8 +1782,8 @@  static int wm_adsp_load(struct wm_adsp *dsp)
 			 regions, le32_to_cpu(region->len), offset,
 			 region_name);
 
-		if ((pos + le32_to_cpu(region->len) + sizeof(*region)) >
-		    firmware->size) {
+		if (le32_to_cpu(region->len) >
+		    firmware->size - pos - sizeof(*region)) {
 			adsp_err(dsp,
 				 "%s.%d: %s region len %d bytes exceeds file length %zu\n",
 				 file, regions, region_name,
@@ -2253,7 +2253,7 @@  static int wm_adsp_load_coeff(struct wm_adsp *dsp)
 
 	blocks = 0;
 	while (pos < firmware->size &&
-	       pos - firmware->size > sizeof(*blk)) {
+	       sizeof(*blk) < firmware->size - pos) {
 		blk = (void *)(&firmware->data[pos]);
 
 		type = le16_to_cpu(blk->type);
@@ -2327,8 +2327,8 @@  static int wm_adsp_load_coeff(struct wm_adsp *dsp)
 		}
 
 		if (reg) {
-			if ((pos + le32_to_cpu(blk->len) + sizeof(*blk)) >
-			    firmware->size) {
+			if (le32_to_cpu(blk->len) >
+			    firmware->size - pos - sizeof(*blk)) {
 				adsp_err(dsp,
 					 "%s.%d: %s region len %d bytes exceeds file length %zu\n",
 					 file, blocks, region_name,