From 042421e9e3d266ad0bb7805132041ef51ad3234d Mon Sep 17 00:00:00 2001 From: Adrian Johnson Date: Wed, 16 Aug 2017 22:52:35 -0400 Subject: [PATCH] cairo: Fix CVE-2017-9814 The bug happens because in some scenarios the variable size can have a value of 0 at line 1288. And malloc(0) is not returning NULL as some people could expect: https://stackoverflow.com/questions/1073157/zero-size-malloc malloc(0) returns the smallest chunk possible. So the line 1290 with the return is not execute. And the execution continues with an invalid map. Since the size is 0 the variable map is not initialized correctly at load_trutype_table. So, later when the variable map is accessed previous values from a freed chunk are used. This could allows an attacker to control the variable map. This patch have not merge in upstream now. Upstream-Status: Backport [https://bugs.freedesktop.org/show_bug.cgi?id=101547] CVE: CVE-2017-9814 Signed-off-by: Dengke Du --- src/cairo-truetype-subset.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/cairo-truetype-subset.c b/src/cairo-truetype-subset.c index e3449a0..f77d11c 100644 --- a/src/cairo-truetype-subset.c +++ b/src/cairo-truetype-subset.c @@ -1285,7 +1285,7 @@ _cairo_truetype_reverse_cmap (cairo_scaled_font_t *scaled_font, return CAIRO_INT_STATUS_UNSUPPORTED; size = be16_to_cpu (map->length); - map = malloc (size); + map = _cairo_malloc (size); if (unlikely (map == NULL)) return _cairo_error (CAIRO_STATUS_NO_MEMORY); -- 2.8.1