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gdi32: Limit line drawing coordinates to reasonable values to avoid overflows.

This commit is contained in:
Alexandre Julliard 2012-07-30 12:47:24 +02:00
parent 78d12e7fcc
commit a9151e5da3
1 changed files with 20 additions and 7 deletions
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27
dlls/gdi32/dibdrv/objects.c
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@ -300,6 +300,17 @@ static inline DWORD calc_outcode(const POINT *pt, const RECT *clip)
return out; return out;
} }
/* crop coordinates to a reasonable range to avoid overflows in calculations */
static inline POINT crop_coords( POINT pt )
{
if (pt.x >= 0x10000000 || pt.x <= -0x10000000 || pt.y >= 0x10000000 || pt.y <= -0x10000000)
{
pt.x /= 8;
pt.y /= 8;
}
return pt;
}
static void init_bres_params( const POINT *start, const POINT *end, bres_params *clip_params, static void init_bres_params( const POINT *start, const POINT *end, bres_params *clip_params,
struct line_params *line_params, RECT *rect ) struct line_params *line_params, RECT *rect )
{ {
@ -603,6 +614,7 @@ static BOOL solid_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end, DWORD
{ {
bres_params clip_params; bres_params clip_params;
struct line_params line_params; struct line_params line_params;
POINT p1 = crop_coords( *start ), p2 = crop_coords( *end );
init_bres_params( start, end, &clip_params, &line_params, &rect ); init_bres_params( start, end, &clip_params, &line_params, &rect );
if (!get_clipped_rects( &pdev->dib, &rect, pdev->clip, &clipped_rects )) return TRUE; if (!get_clipped_rects( &pdev->dib, &rect, pdev->clip, &clipped_rects )) return TRUE;
@ -611,11 +623,11 @@ static BOOL solid_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end, DWORD
POINT clipped_start, clipped_end; POINT clipped_start, clipped_end;
int clip_status; int clip_status;
clip_status = clip_line(start, end, clipped_rects.rects + i, &clip_params, &clipped_start, &clipped_end); clip_status = clip_line( &p1, &p2, clipped_rects.rects + i, &clip_params, &clipped_start, &clipped_end);
if(clip_status) if(clip_status)
{ {
int m = abs(clipped_start.x - start->x); int m = abs(clipped_start.x - p1.x);
int n = abs(clipped_start.y - start->y); int n = abs(clipped_start.y - p1.y);
if (line_params.x_major) if (line_params.x_major)
{ {
@ -630,7 +642,7 @@ static BOOL solid_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end, DWORD
line_params.length = abs( clipped_end.y - clipped_start.y ) + 1; line_params.length = abs( clipped_end.y - clipped_start.y ) + 1;
} }
if (clipped_end.x == end->x && clipped_end.y == end->y) line_params.length--; if (clipped_end.x == p2.x && clipped_end.y == p2.y) line_params.length--;
pdev->dib.funcs->solid_line( &pdev->dib, &clipped_start, &line_params, and, xor ); pdev->dib.funcs->solid_line( &pdev->dib, &clipped_start, &line_params, and, xor );
@ -987,6 +999,7 @@ static BOOL dashed_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end)
{ {
bres_params clip_params; bres_params clip_params;
struct line_params line_params; struct line_params line_params;
POINT p1 = crop_coords( *start ), p2 = crop_coords( *end );
init_bres_params( start, end, &clip_params, &line_params, &rect ); init_bres_params( start, end, &clip_params, &line_params, &rect );
get_clipped_rects( &pdev->dib, &rect, pdev->clip, &clipped_rects ); get_clipped_rects( &pdev->dib, &rect, pdev->clip, &clipped_rects );
@ -994,12 +1007,12 @@ static BOOL dashed_pen_line(dibdrv_physdev *pdev, POINT *start, POINT *end)
{ {
POINT clipped_start, clipped_end; POINT clipped_start, clipped_end;
int clip_status; int clip_status;
clip_status = clip_line(start, end, clipped_rects.rects + i, &clip_params, &clipped_start, &clipped_end); clip_status = clip_line(&p1, &p2, clipped_rects.rects + i, &clip_params, &clipped_start, &clipped_end);
if(clip_status) if(clip_status)
{ {
int m = abs(clipped_start.x - start->x); int m = abs(clipped_start.x - p1.x);
int n = abs(clipped_start.y - start->y); int n = abs(clipped_start.y - p1.y);
pdev->dash_pos = start_pos; pdev->dash_pos = start_pos;