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From 94c6de0649cd295044b1e4ff7265949c9c787519 Mon Sep 17 00:00:00 2001
From: Mike DePaulo <mikedep333@gmail.com>
Date: Sun, 8 Feb 2015 21:03:33 -0500
Subject: [PATCH 07/40] CVE-2014-0210: unvalidated length in
_fs_recv_conn_setup() from xorg/lib/libXfont commit
891e084b26837162b12f841060086a105edde86d
The connection setup reply from the font server can include a list
of alternate servers to contact if this font server stops working.
The reply specifies a total size of all the font server names, and
then provides a list of names. _fs_recv_conn_setup() allocated the
specified total size for copying the names to, but didn't check to
make sure it wasn't copying more data to that buffer than the size
it had allocated.
---
nx-X11/lib/font/fc/fserve.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/nx-X11/lib/font/fc/fserve.c b/nx-X11/lib/font/fc/fserve.c
index bac0b8e..0fdcc1d 100644
--- a/nx-X11/lib/font/fc/fserve.c
+++ b/nx-X11/lib/font/fc/fserve.c
@@ -2782,7 +2782,7 @@ _fs_recv_conn_setup (FSFpePtr conn)
int ret;
fsConnSetup *setup;
FSFpeAltPtr alts;
- int i, alt_len;
+ unsigned int i, alt_len;
int setup_len;
char *alt_save, *alt_names;
@@ -2809,9 +2809,9 @@ _fs_recv_conn_setup (FSFpePtr conn)
}
if (setup->num_alternates)
{
+ size_t alt_name_len = setup->alternate_len << 2;
alts = (FSFpeAltPtr) xalloc (setup->num_alternates *
- sizeof (FSFpeAltRec) +
- (setup->alternate_len << 2));
+ sizeof (FSFpeAltRec) + alt_name_len);
if (alts)
{
alt_names = (char *) (setup + 1);
@@ -2820,10 +2820,25 @@ _fs_recv_conn_setup (FSFpePtr conn)
{
alts[i].subset = alt_names[0];
alt_len = alt_names[1];
+ if (alt_len >= alt_name_len) {
+ /*
+ * Length is longer than setup->alternate_len
+ * told us to allocate room for, assume entire
+ * alternate list is corrupted.
+ */
+#ifdef DEBUG
+ fprintf (stderr,
+ "invalid alt list (length %lx >= %lx)\n",
+ (long) alt_len, (long) alt_name_len);
+#endif
+ free(alts);
+ return FSIO_ERROR;
+ }
alts[i].name = alt_save;
memcpy (alt_save, alt_names + 2, alt_len);
alt_save[alt_len] = '\0';
alt_save += alt_len + 1;
+ alt_name_len -= alt_len + 1;
alt_names += _fs_pad_length (alt_len + 2);
}
conn->numAlts = setup->num_alternates;
--
2.1.4
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