Coordinates passed to screen_write_char() did not have any checks to
ensure they are not out-of-bounds. This adds an if statement to prevent
out-of-bounds writes to the VGA text buffer.
Signed-off-by: Ryan Cohen <rcohenprogramm...@gmail.com>
---
grub-core/term/i386/pc/vga_text.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/grub-core/term/i386/pc/vga_text.c
b/grub-core/term/i386/pc/vga_text.c
index 669d06fad..b88fa9d2e 100644
--- a/grub-core/term/i386/pc/vga_text.c
+++ b/grub-core/term/i386/pc/vga_text.c
@@ -63,7 +63,8 @@ static grub_uint8_t cur_color = 0x7;
static void
screen_write_char (int x, int y, short c)
{
- VGA_TEXT_SCREEN[y * COLS + x] = grub_cpu_to_le16 (c);
+ if (x < COLS && y < ROWS && x >= 0 && y >= 0)
+ VGA_TEXT_SCREEN[y * COLS + x] = grub_cpu_to_le16 (c);
}
static short
--
2.38.1
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