48 lines
1.6 KiB
Diff
48 lines
1.6 KiB
Diff
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From f958c48ee431bef8d4d466b40c9cb2d4dbcb7791 Mon Sep 17 00:00:00 2001
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From: Werner Lemberg <wl@gnu.org>
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Date: Fri, 24 Mar 2017 09:15:10 +0100
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Subject: [PATCH] [psaux] Better protect `flex' handling.
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Reported as
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https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=935
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* src/psaux/t1decode.c (t1_decoder_parse_charstrings)
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<callothersubr>: Since there is not a single flex operator but a
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series of subroutine calls, malformed fonts can call arbitrary other
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operators after the start of a flex, possibly adding points. For
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this reason we have to check the available number of points before
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inserting a point.
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Fixes CVE-2017-8105
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Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
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---
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diff --git a/src/psaux/t1decode.c b/src/psaux/t1decode.c
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index af7b465e..7dd45135 100644
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--- a/src/psaux/t1decode.c
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+++ b/src/psaux/t1decode.c
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@@ -780,10 +780,19 @@
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/* point without adding any point to the outline */
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idx = decoder->num_flex_vectors++;
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if ( idx > 0 && idx < 7 )
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+ {
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+ /* in malformed fonts it is possible to have other */
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+ /* opcodes in the middle of a flex (which don't */
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+ /* increase `num_flex_vectors'); we thus have to */
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+ /* check whether we can add a point */
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+ if ( FT_SET_ERROR( t1_builder_check_points( builder, 1 ) ) )
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+ goto Syntax_Error;
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+
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t1_builder_add_point( builder,
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x,
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y,
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(FT_Byte)( idx == 3 || idx == 6 ) );
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+ }
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}
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break;
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--
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2.11.0
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