From: Darren Kenny <darren.ke...@oracle.com>
The multiplication of 2 unsigned 32-bit integers may overflow before
promotion to unsigned 64-bit. We should ensure that the multiplication
is done with overflow detection. Additionally, use grub_sub() for
subtraction.
Fixes: CID 73640, CID 73697, CID 73702, CID 73823
Signed-off-by: Darren Kenny <darren.ke...@oracle.com>
Signed-off-by: Marco A Benatto <mbena...@redhat.com>
Reviewed-by: Daniel Kiper <daniel.ki...@oracle.com>
---
grub-core/video/fb/fbfill.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/grub-core/video/fb/fbfill.c b/grub-core/video/fb/fbfill.c
index 11816d07a..a37acd1e2 100644
--- a/grub-core/video/fb/fbfill.c
+++ b/grub-core/video/fb/fbfill.c
@@ -31,6 +31,7 @@
#include <grub/fbfill.h>
#include <grub/fbutil.h>
#include <grub/types.h>
+#include <grub/safemath.h>
#include <grub/video.h>
/* Generic filler that works for every supported mode. */
@@ -61,7 +62,9 @@ grub_video_fbfill_direct32 (struct grub_video_fbblit_info
*dst,
/* Calculate the number of bytes to advance from the end of one line
to the beginning of the next line. */
- rowskip = dst->mode_info->pitch - dst->mode_info->bytes_per_pixel * width;
+ if (grub_mul (dst->mode_info->bytes_per_pixel, width, &rowskip) ||
+ grub_sub (dst->mode_info->pitch, rowskip, &rowskip))
+ return;
/* Get the start address. */
dstptr = grub_video_fb_get_video_ptr (dst, x, y);
@@ -98,7 +101,9 @@ grub_video_fbfill_direct24 (struct grub_video_fbblit_info
*dst,
#endif
/* Calculate the number of bytes to advance from the end of one line
to the beginning of the next line. */
- rowskip = dst->mode_info->pitch - dst->mode_info->bytes_per_pixel * width;
+ if (grub_mul (dst->mode_info->bytes_per_pixel, width, &rowskip) ||
+ grub_sub (dst->mode_info->pitch, rowskip, &rowskip))
+ return;
/* Get the start address. */
dstptr = grub_video_fb_get_video_ptr (dst, x, y);
@@ -131,7 +136,9 @@ grub_video_fbfill_direct16 (struct grub_video_fbblit_info
*dst,
/* Calculate the number of bytes to advance from the end of one line
to the beginning of the next line. */
- rowskip = (dst->mode_info->pitch - dst->mode_info->bytes_per_pixel * width);
+ if (grub_mul (dst->mode_info->bytes_per_pixel, width, &rowskip) ||
+ grub_sub (dst->mode_info->pitch, rowskip, &rowskip))
+ return;
/* Get the start address. */
dstptr = grub_video_fb_get_video_ptr (dst, x, y);
@@ -161,7 +168,9 @@ grub_video_fbfill_direct8 (struct grub_video_fbblit_info
*dst,
/* Calculate the number of bytes to advance from the end of one line
to the beginning of the next line. */
- rowskip = dst->mode_info->pitch - dst->mode_info->bytes_per_pixel * width;
+ if (grub_mul (dst->mode_info->bytes_per_pixel, width, &rowskip) ||
+ grub_sub (dst->mode_info->pitch, rowskip, &rowskip))
+ return;
/* Get the start address. */
dstptr = grub_video_fb_get_video_ptr (dst, x, y);
--
2.11.0
_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
