From d338f81df1e188eb16e1d6aeea7f4800f89c1218 Mon Sep 17 00:00:00 2001

From: Alan Coopersmith <alan.coopersmith@oracle.com>

Date: Fri, 2 May 2014 19:24:17 -0700

Subject: [PATCH 12/12] CVE-2014-0210: unvalidated length fields in fs_read_list_info()

fs_read_list_info() parses a reply from the font server.  The reply

contains a number of additional data items with embedded length or

count fields, none of which are validated. This can cause out of

bound reads when looping over these items in the reply.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

---

 src/fc/fserve.c |   54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++

 1 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/src/fc/fserve.c b/src/fc/fserve.c

index 4dcdc04..c1cf9d6 100644

--- a/src/fc/fserve.c

+++ b/src/fc/fserve.c

@@ -2491,6 +2491,7 @@ fs_read_list_info(FontPathElementPtr fpe, FSBlockDataPtr blockrec)

     FSBlockedListInfoPtr	binfo = (FSBlockedListInfoPtr) blockrec->data;

     fsListFontsWithXInfoReply	*rep;

     char			*buf;

+    long			bufleft;

     FSFpePtr			conn = (FSFpePtr) fpe->private;

     fsPropInfo			*pi;

     fsPropOffset		*po;

@@ -2527,6 +2528,7 @@ fs_read_list_info(FontPathElementPtr fpe, FSBlockDataPtr blockrec)

     }

     buf = (char *) rep + SIZEOF (fsListFontsWithXInfoReply);

+    bufleft = (rep->length << 2) - SIZEOF (fsListFontsWithXInfoReply);

     /*

      * The original FS implementation didn't match

@@ -2535,19 +2537,71 @@ fs_read_list_info(FontPathElementPtr fpe, FSBlockDataPtr blockrec)

      */

     if (conn->fsMajorVersion <= 1)

     {

+	if (rep->nameLength > bufleft) {

+#ifdef DEBUG

+	    fprintf(stderr,

+		    "fsListFontsWithXInfo: name length (%d) > bufleft (%ld)\n",

+		    (int) rep->nameLength, bufleft);

+#endif

+	    err = AllocError;

+	    goto done;

+	}

+	/* binfo->name is a 256 char array, rep->nameLength is a CARD8 */

 	memcpy (binfo->name, buf, rep->nameLength);

 	buf += _fs_pad_length (rep->nameLength);

+	bufleft -= _fs_pad_length (rep->nameLength);

     }

     pi = (fsPropInfo *) buf;

+    if (SIZEOF (fsPropInfo) > bufleft) {

+#ifdef DEBUG

+	fprintf(stderr,

+		"fsListFontsWithXInfo: PropInfo length (%d) > bufleft (%ld)\n",

+		(int) SIZEOF (fsPropInfo), bufleft);

+#endif

+	err = AllocError;

+	goto done;

+    }

+    bufleft -= SIZEOF (fsPropInfo);

     buf += SIZEOF (fsPropInfo);

     po = (fsPropOffset *) buf;

+    if (pi->num_offsets > (bufleft / SIZEOF (fsPropOffset))) {

+#ifdef DEBUG

+	fprintf(stderr,

+		"fsListFontsWithXInfo: offset length (%d * %d) > bufleft (%ld)\n",

+		pi->num_offsets, (int) SIZEOF (fsPropOffset), bufleft);

+#endif

+	err = AllocError;

+	goto done;

+    }

+    bufleft -= pi->num_offsets * SIZEOF (fsPropOffset);

     buf += pi->num_offsets * SIZEOF (fsPropOffset);

     pd = (pointer) buf;

+    if (pi->data_len > bufleft) {

+#ifdef DEBUG

+	fprintf(stderr,

+		"fsListFontsWithXInfo: data length (%d) > bufleft (%ld)\n",

+		pi->data_len, bufleft);

+#endif

+	err = AllocError;

+	goto done;

+    }

+    bufleft -= pi->data_len;

     buf += pi->data_len;

     if (conn->fsMajorVersion > 1)

     {

+	if (rep->nameLength > bufleft) {

+#ifdef DEBUG

+	    fprintf(stderr,

+		    "fsListFontsWithXInfo: name length (%d) > bufleft (%ld)\n",

+		    (int) rep->nameLength, bufleft);

+#endif

+	    err = AllocError;

+	    goto done;

+	}

+	/* binfo->name is a 256 char array, rep->nameLength is a CARD8 */

 	memcpy (binfo->name, buf, rep->nameLength);

 	buf += _fs_pad_length (rep->nameLength);

+	bufleft -= _fs_pad_length (rep->nameLength);

     }

 #ifdef DEBUG

-- 

1.7.1