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From f53f2474d5d33cca04c4c7744ecc50cec41ba94f Mon Sep 17 00:00:00 2001
From: Mike DePaulo <mikedep333@gmail.com>
Date: Sun, 8 Feb 2015 20:28:30 -0500
Subject: [PATCH 05/40] CVE-2014-0209: integer overflow of realloc() size in
FontFileAddEntry() from xorg/lib/libXfont commit
2f5e57317339c526e6eaee1010b0e2ab8089c42e
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
FontFileReadDirectory() opens a fonts.dir file, and reads over every
line in an fscanf loop. For each successful entry read (font name,
file name) a call is made to FontFileAddFontFile().
FontFileAddFontFile() will add a font file entry (for the font name
and file) each time it’s called, by calling FontFileAddEntry().
FontFileAddEntry() will do the actual adding. If the table it has
to add to is full, it will do a realloc, adding 100 more entries
to the table size without checking to see if that will overflow the
int used to store the size.
---
nx-X11/lib/font/fontfile/fontdir.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/nx-X11/lib/font/fontfile/fontdir.c b/nx-X11/lib/font/fontfile/fontdir.c
index 8f75d8b..899ff05 100644
--- a/nx-X11/lib/font/fontfile/fontdir.c
+++ b/nx-X11/lib/font/fontfile/fontdir.c
@@ -185,6 +185,11 @@ FontFileAddEntry(FontTablePtr table, FontEntryPtr prototype)
if (table->sorted)
return (FontEntryPtr) 0; /* "cannot" happen */
if (table->used == table->size) {
+ if (table->size >= ((INT32_MAX / sizeof(FontEntryRec)) - 100))
+ /* If we've read so many entries we're going to ask for 2gb
+ or more of memory, something is so wrong with this font
+ directory that we should just give up before we overflow. */
+ return NULL;
newsize = table->size + 100;
entry = (FontEntryPtr) xrealloc(table->entries,
newsize * sizeof(FontEntryRec));
--
2.1.4
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