[PATCH v2] video/logo: protect against divide by zero when reading image

[Yiyuan GUO]

In video/logo/pnmtologo.c, the function read_image can read from the
image file an integer 0 and pass it to function get_number255, leading
to a divide by zero problem.

Signed-off-by: Yiyuan GUO <yguoaz at gmail.com>
---
 drivers/video/logo/pnmtologo.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/video/logo/pnmtologo.c b/drivers/video/logo/pnmtologo.c
index 4718d7895..d9e8d1d5b 100644
--- a/drivers/video/logo/pnmtologo.c
+++ b/drivers/video/logo/pnmtologo.c
@@ -116,6 +116,16 @@ static unsigned int get_number(FILE *fp)
     return val;
 }
 
+static unsigned int get_maxval(FILE *fp)
+{
+    unsigned int maxval = get_number(fp);
+
+    if (!maxval)
+	die("%s: invalid maxval zero\n", filename);
+
+    return maxval;
+}
+
 static unsigned int get_number255(FILE *fp, unsigned int maxval)
 {
     unsigned int val = get_number(fp);
@@ -182,7 +192,7 @@ static void read_image(void)
 
 	case '2':
 	    /* Plain PGM */
-	    maxval = get_number(fp);
+	    maxval = get_maxval(fp);
 	    for (i = 0; i < logo_height; i++)
 		for (j = 0; j < logo_width; j++)
 		    logo_data[i][j].red = logo_data[i][j].green =
@@ -191,7 +201,7 @@ static void read_image(void)
 
 	case '3':
 	    /* Plain PPM */
-	    maxval = get_number(fp);
+	    maxval = get_maxval(fp);
 	    for (i = 0; i < logo_height; i++)
 		for (j = 0; j < logo_width; j++) {
 		    logo_data[i][j].red = get_number255(fp, maxval);
-- 
2.25.1