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lcd_putsxyofs 16 bit lcd_mono_bitmap_part [AS]

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'Bugfix' mono_bitmap_part reads ahead in the buffer,
if the height is <= char bit pixels other memory gets read
found with [Address Sanitizer]

also g#3332 since this is clearly a problem across the code
instead place the check for height < 8 in the lcd_mono_bitmap_part function

Change-Id: I917cbbd568fd5474b76a98c8919467e2538e0f0c
This commit is contained in:
William Wilgus 2021-04-30 15:10:15 -04:00
parent 20cd89908d
commit 49edfc237b
1 changed files with 8 additions and 9 deletions
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17
firmware/drivers/lcd-16bit-common.c
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@ -341,12 +341,18 @@ void ICODE_ATTR lcd_mono_bitmap_part(const unsigned char *src, int src_x,
if (y + height > LCD_HEIGHT)
height = LCD_HEIGHT - y;
#endif
src += stride * (src_y >> 3) + src_x; /* move starting point */
src_y &= 7;
src_end = src + width;
dst_col = FBADDR(x, y);
/* 'Bugfix' mono_bitmap_part reads ahead in the buffer,
* if the height is <= char bit pixels other memory gets read
* the other option is to check in the hot code path but this appears
* sufficient
*/
if (height <= CHAR_BIT)
stride = 0;
if (drmode & DRMODE_INVERSEVID)
{
@ -462,14 +468,7 @@ void ICODE_ATTR lcd_mono_bitmap_part(const unsigned char *src, int src_x,
/* Draw a full monochrome bitmap */
void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int height)
{
int stride = width;
/* 'Bugfix' mono_bitmap_part reads ahead in the buffer,
* if the height is <= char bit pixels other memory gets read
*/
if (height <= CHAR_BIT)
stride = 0;
lcd_mono_bitmap_part(src, 0, 0, stride, x, y, width, height);
lcd_mono_bitmap_part(src, 0, 0, width, x, y, width, height);
}