src/hb-ot-kern-table.hh | 9
+++++----
test/shaping/fonts/sha1sum/243798dd281c1c77c065958e1ff467420faa9bde.ttf |binary
test/shaping/tests/fuzzed.tests | 1
+
3 files changed, 6 insertions(+), 4 deletions(-)
New commits:
commit 8eed9cb11e28728a58e265fde5c13f519ccbdb4e
Author: Behdad Esfahbod <beh...@behdad.org>
Date: Thu Nov 9 18:09:40 2017 -0800
[kern] Fix invalid memory access if offset is zero
If offset is zero, we return Null() object. Wasn't prepared for that.
Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4088
diff --git a/src/hb-ot-kern-table.hh b/src/hb-ot-kern-table.hh
index 074eba32..5fd2e20e 100644
--- a/src/hb-ot-kern-table.hh
+++ b/src/hb-ot-kern-table.hh
@@ -117,10 +117,11 @@ struct KernSubTableFormat2
unsigned int l = (this+leftClassTable).get_class (left);
unsigned int r = (this+leftClassTable).get_class (left);
unsigned int offset = l * rowWidth + r * sizeof (FWORD);
- const FWORD *v = &StructAtOffset<FWORD> (&(this+array), offset);
- /* Untested code, as I have not been able to find ANY kern table format-2
yet. */
- assert (&(this+array) <= v);
- if (unlikely (v + 1 > (const FWORD *) end))
+ const FWORD *arr = &(this+array);
+ if (unlikely ((const void *) arr < (const void *) this || (const void *)
arr >= (const void *) end))
+ return 0;
+ const FWORD *v = &StructAtOffset<FWORD> (arr, offset);
+ if (unlikely ((const void *) v < (const void *) arr || (const void *) (v +
1) > (const void *) end))
return 0;
return *v;
}
diff --git
a/test/shaping/fonts/sha1sum/243798dd281c1c77c065958e1ff467420faa9bde.ttf
b/test/shaping/fonts/sha1sum/243798dd281c1c77c065958e1ff467420faa9bde.ttf
new file mode 100644
index 00000000..dd8506ef
Binary files /dev/null and
b/test/shaping/fonts/sha1sum/243798dd281c1c77c065958e1ff467420faa9bde.ttf differ
diff --git a/test/shaping/tests/fuzzed.tests b/test/shaping/tests/fuzzed.tests
index 1f51e441..53e9187e 100644
--- a/test/shaping/tests/fuzzed.tests
+++ b/test/shaping/tests/fuzzed.tests
@@ -15,3 +15,4 @@
fonts/sha1sum/a34a9191d9376bda419836effeef7e75c1386016.ttf:--font-funcs=ot:U+004
fonts/sha1sum/a69118c2c2ada48ff803d9149daa54c9ebdae30e.ttf:--font-funcs=ot:U+0041:[gid0=0+1229]
fonts/sha1sum/b6acef662e0beb8d5fcf5b61c6b0ca69537b7402.ttf:--font-funcs=ot:U+0041:[gid0=0+1000]
fonts/sha1sum/e88c339237f52d21e01c55f01b9c1b4cc14a0467.ttf:--font-funcs=ot:U+0041:[gid0=0+1000]
+fonts/sha1sum/243798dd281c1c77c065958e1ff467420faa9bde.ttf:--font-funcs=ot:U+0041:[gid0=0+1000]
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