Commit 543a3b939df50e02e52b948f4c9c8ba63bf38059
2019-09-01T23:03:09
* src/sfnt/sfwoff2.c (woff2_open_font): Add sanity check. Don't trust `totalSfntSize' unconditionally. Reported as https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=16893
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diff --git a/ChangeLog b/ChangeLog
index 3904020..a6d7cb4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2019-09-01 Werner Lemberg <wl@gnu.org>
+
+ * src/sfnt/sfwoff2.c (woff2_open_font): Add sanity check.
+
+ Don't trust `totalSfntSize' unconditionally.
+
+ Reported as
+
+ https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=16893
+
2019-08-27 Dominik Röttsches <drott@chromium.org>
[woff2] Don't use `FT_UInt64' (#56815).
diff --git a/src/sfnt/sfwoff2.c b/src/sfnt/sfwoff2.c
index a599ae5..6e2ff04 100644
--- a/src/sfnt/sfwoff2.c
+++ b/src/sfnt/sfwoff2.c
@@ -2092,7 +2092,22 @@
/* This is what we normally expect. */
/* Initially trust `totalSfntSize' and change later as required. */
if ( woff2.totalSfntSize > sfnt_size )
- sfnt_size = woff2.totalSfntSize;
+ {
+ /* However, adjust the value to something reasonable. */
+
+ /* Factor 64 is heuristic. */
+ if ( ( woff2.totalSfntSize >> 6 ) > sfnt_size )
+ sfnt_size <<= 6;
+ else
+ sfnt_size = woff2.totalSfntSize;
+
+ /* Value 1<<26 = 67108864 is heuristic. */
+ if (sfnt_size >= (1 << 26))
+ sfnt_size = 1 << 26;
+
+ FT_TRACE4(( "adjusting estimate of uncompressed font size to %lu\n",
+ sfnt_size ));
+ }
/* Write sfnt header. */
if ( FT_ALLOC( sfnt, sfnt_size ) ||