[PATCH] video: fbdev: metronomefb: fix some off by one bugs

[PATCH] video: fbdev: metronomefb: fix some off by one bugs

[Dan Carpenter]

The "mem" buffer has "size" bytes.  The ">" should be ">=" to prevent
reading one character beyond the end of the array.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Not tested.

diff --git a/drivers/video/fbdev/metronomefb.c b/drivers/video/fbdev/metronomefb.c
index 9085e9525341..bb4fee52e501 100644
--- a/drivers/video/fbdev/metronomefb.c
+++ b/drivers/video/fbdev/metronomefb.c
@@ -233,7 +233,7 @@ static int load_waveform(u8 *mem, size_t size, int m, int t,
 
 	/* check temperature range table checksum */
 	cksum_idx = sizeof(*wfm_hdr) + wfm_hdr->trc + 1;
-	if (cksum_idx > size)
+	if (cksum_idx >= size)
 		return -EINVAL;
 	cksum = calc_cksum(sizeof(*wfm_hdr), cksum_idx, mem);
 	if (cksum != mem[cksum_idx]) {
@@ -245,7 +245,7 @@ static int load_waveform(u8 *mem, size_t size, int m, int t,
 	/* check waveform mode table address checksum */
 	wmta = get_unaligned_le32(wfm_hdr->wmta) & 0x00FFFFFF;
 	cksum_idx = wmta + m*4 + 3;
-	if (cksum_idx > size)
+	if (cksum_idx >= size)
 		return -EINVAL;
 	cksum = calc_cksum(cksum_idx - 3, cksum_idx, mem);
 	if (cksum != mem[cksum_idx]) {
@@ -257,7 +257,7 @@ static int load_waveform(u8 *mem, size_t size, int m, int t,
 	/* check waveform temperature table address checksum */
 	tta = get_unaligned_le32(mem + wmta + m * 4) & 0x00FFFFFF;
 	cksum_idx = tta + trn*4 + 3;
-	if (cksum_idx > size)
+	if (cksum_idx >= size)
 		return -EINVAL;
 	cksum = calc_cksum(cksum_idx - 3, cksum_idx, mem);
 	if (cksum != mem[cksum_idx]) {
@@ -270,7 +270,7 @@ static int load_waveform(u8 *mem, size_t size, int m, int t,
 	metromem buffer. this does runlength decoding of the waveform */
 	wfm_idx = get_unaligned_le32(mem + tta + trn * 4) & 0x00FFFFFF;
 	owfm_idx = wfm_idx;
-	if (wfm_idx > size)
+	if (wfm_idx >= size)
 		return -EINVAL;
 	while (wfm_idx < size) {
 		unsigned char rl;
@@ -292,7 +292,7 @@ static int load_waveform(u8 *mem, size_t size, int m, int t,
 	}
 
 	cksum_idx = wfm_idx;
-	if (cksum_idx > size)
+	if (cksum_idx >= size)
 		return -EINVAL;
 	cksum = calc_cksum(owfm_idx, cksum_idx, mem);
 	if (cksum != mem[cksum_idx]) {

Re: [PATCH] video: fbdev: metronomefb: fix some off by one bugs

[Bartlomiej Zolnierkiewicz]

On Tuesday, July 03, 2018 03:28:13 PM Dan Carpenter wrote:
> The "mem" buffer has "size" bytes.  The ">" should be ">=" to prevent
> reading one character beyond the end of the array.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Patch queued for 4.19, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics