Do not try and crop glyphs from outside of source ImageFont image

radarhere · Dec 30, 2023 · 0870923 · 0870923
1 parent c9805df
commit 0870923
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diff --git a/docs/releasenotes/10.2.0.rst b/docs/releasenotes/10.2.0.rst
@@ -70,6 +70,15 @@ Restricted environment keys for ImageMath.eval
 arbitrary code. To prevent this, keys matching the names of builtins and keys
 containing double underscores will now raise a :py:exc:`ValueError`.
 
+Trim glyph size in ImageFont.getmask
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+:py:class:`PIL.ImageFont.ImageFont` now trims the size of individual glyphs so that
+they do not extend beyond the bitmap image.
+
+A decompression bomb check has been also been added to
+:py:meth:`PIL.ImageFont.ImageFont.getmask`.
+
 Other Changes
 =============
 

diff --git a/src/_imaging.c b/src/_imaging.c
@@ -2649,6 +2649,14 @@ _font_new(PyObject *self_, PyObject *args) {
         self->glyphs[i].sy0 = S16(B16(glyphdata, 14));
         self->glyphs[i].sx1 = S16(B16(glyphdata, 16));
         self->glyphs[i].sy1 = S16(B16(glyphdata, 18));
+        if (self->glyphs[i].sx1 > self->bitmap->xsize) {
+            self->glyphs[i].dx1 -= self->glyphs[i].sx1 - self->bitmap->xsize;
+            self->glyphs[i].sx1 = self->bitmap->xsize;
+        }
+        if (self->glyphs[i].sy1 > self->bitmap->ysize) {
+            self->glyphs[i].dy1 -= self->glyphs[i].sy1 - self->bitmap->ysize;
+            self->glyphs[i].sy1 = self->bitmap->ysize;
+        }
         if (self->glyphs[i].dy0 < y0) {
             y0 = self->glyphs[i].dy0;
         }