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Fix CVE-2017-13722.
Copied from upstream source repository:
<https://cgit.freedesktop.org/xorg/lib/libXfont/commit/?id=672bb944311392e2415b39c0d63b1e1902905bcd>
From 672bb944311392e2415b39c0d63b1e1902905bcd Mon Sep 17 00:00:00 2001
From: Michal Srb <msrb@suse.com>
Date: Thu, 20 Jul 2017 17:05:23 +0200
Subject: pcfGetProperties: Check string boundaries (CVE-2017-13722)
Without the checks a malformed PCF file can cause the library to make
atom from random heap memory that was behind the `strings` buffer.
This may crash the process or leak information.
Signed-off-by: Julien Cristau <jcristau@debian.org>
diff --git a/src/bitmap/pcfread.c b/src/bitmap/pcfread.c
index dab1c44..ae34c28 100644
--- a/src/bitmap/pcfread.c
+++ b/src/bitmap/pcfread.c
@@ -45,6 +45,7 @@ from The Open Group.
#include <stdarg.h>
#include <stdint.h>
+#include <string.h>
void
pcfError(const char* message, ...)
@@ -311,11 +312,19 @@ pcfGetProperties(FontInfoPtr pFontInfo, FontFilePtr file,
if (IS_EOF(file)) goto Bail;
position += string_size;
for (i = 0; i < nprops; i++) {
+ if (props[i].name >= string_size) {
+ pcfError("pcfGetProperties(): String starts out of bounds (%ld/%d)\n", props[i].name, string_size);
+ goto Bail;
+ }
props[i].name = MakeAtom(strings + props[i].name,
- strlen(strings + props[i].name), TRUE);
+ strnlen(strings + props[i].name, string_size - props[i].name), TRUE);
if (isStringProp[i]) {
+ if (props[i].value >= string_size) {
+ pcfError("pcfGetProperties(): String starts out of bounds (%ld/%d)\n", props[i].value, string_size);
+ goto Bail;
+ }
props[i].value = MakeAtom(strings + props[i].value,
- strlen(strings + props[i].value), TRUE);
+ strnlen(strings + props[i].value, string_size - props[i].value), TRUE);
}
}
free(strings);
--
cgit v0.10.2
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