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| author | Robin Watts <robin.watts@artifex.com> | 2012-12-18 19:28:39 +0000 |
|---|---|---|
| committer | Robin Watts <robin.watts@artifex.com> | 2012-12-19 12:43:15 +0000 |
| commit | 956945485624f0df0ffdfbd471a4ec095bd145c9 (patch) | |
| tree | 8718dbab2e6267550e971ee3011ddd7ac16f6609 /draw | |
| parent | 1f39afecc00df83ff3306f81716483d843e3f70e (diff) | |
| download | mupdf-956945485624f0df0ffdfbd471a4ec095bd145c9.tar.xz | |
Bug 693503: Fix potential SEGV in bitmap scalers.
With a small dst_w (e.g. 1e-23) the floating point maths governing
scales can go wrong in the weight calculations. MSVC in particular
seems to return 1<<31 for the result of the max_len calculation.
It makes no real sense to scale bitmaps to < 1 pixel, so simply clamp
width and height as required.
Problem found in 2923.pdf.asan.22.2139, a test file supplied by
Mateusz "j00ru" Jurczyk and Gynvael Coldwind of the Google Security
Team using Address Sanitizer. Many thanks!
Diffstat (limited to 'draw')
| -rw-r--r-- | draw/draw_simple_scale.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/draw/draw_simple_scale.c b/draw/draw_simple_scale.c index aa00a916..55c981b4 100644 --- a/draw/draw_simple_scale.c +++ b/draw/draw_simple_scale.c @@ -1241,6 +1241,30 @@ fz_scale_pixmap_cached(fz_context *ctx, fz_pixmap *src, float x, float y, float if (w > (1<<24) || h > (1<<24) || w < -(1<<24) || h < -(1<<24)) return NULL; + /* Clamp small ranges of w and h */ + if (w <= -1) + { + } + else if (w < 0) + { + w = -1; + } + else if (w < 1) + { + w = 1; + } + if (h <= -1) + { + } + else if (h < 0) + { + h = -1; + } + else if (h < 1) + { + h = 1; + } + /* Find the destination bbox, width/height, and sub pixel offset, * allowing for whether we're flipping or not. */ /* The (x,y) position given describes where the top left corner of the |