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authorMike DePaulo <mikedep333@gmail.com>2015-02-08 22:27:47 -0500
committerMike Gabriel <mike.gabriel@das-netzwerkteam.de>2015-02-14 16:14:31 +0100
commitece51493f1d970f45e53588e33a700464a42fbab (patch)
treeadd4b33f526b0ff73a59bba3bafadf2ece8b79ba /nx-X11/lib/font
parentd2b96c5d59766f96181de95da1906fd6e32785ba (diff)
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CVE-2014-0210: unvalidated length fields in fs_read_glyphs() from xorg/lib/libXfont commit 520683652564c2a4e42328ae23eef9bb63271565
fs_read_glyphs() parses a reply from the font server. The reply contains embedded length fields, none of which are validated. This can cause out of bound reads when looping over the glyph bitmaps in the reply.
Diffstat (limited to 'nx-X11/lib/font')
-rw-r--r--nx-X11/lib/font/fc/fserve.c29
1 files changed, 28 insertions, 1 deletions
diff --git a/nx-X11/lib/font/fc/fserve.c b/nx-X11/lib/font/fc/fserve.c
index 79de4f352..26218e568 100644
--- a/nx-X11/lib/font/fc/fserve.c
+++ b/nx-X11/lib/font/fc/fserve.c
@@ -1916,6 +1916,7 @@ fs_read_glyphs(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
FontInfoPtr pfi = &pfont->info;
fsQueryXBitmaps16Reply *rep;
char *buf;
+ long bufleft; /* length of reply left to use */
fsOffset32 *ppbits;
fsOffset32 local_off;
char *off_adr;
@@ -1947,9 +1948,33 @@ fs_read_glyphs(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
buf = (char *) rep;
buf += SIZEOF (fsQueryXBitmaps16Reply);
+ bufleft = rep->length << 2;
+ bufleft -= SIZEOF (fsQueryXBitmaps16Reply);
+
+ if ((bufleft / SIZEOF (fsOffset32)) < rep->num_chars)
+ {
+#ifdef DEBUG
+ fprintf(stderr,
+ "fsQueryXBitmaps16: num_chars (%d) > bufleft (%ld) / %d\n",
+ rep->num_chars, bufleft, SIZEOF (fsOffset32));
+#endif
+ err = AllocError;
+ goto bail;
+ }
ppbits = (fsOffset32 *) buf;
buf += SIZEOF (fsOffset32) * (rep->num_chars);
+ bufleft -= SIZEOF (fsOffset32) * (rep->num_chars);
+ if (bufleft < rep->nbytes)
+ {
+#ifdef DEBUG
+ fprintf(stderr,
+ "fsQueryXBitmaps16: nbytes (%d) > bufleft (%ld)\n",
+ rep->nbytes, bufleft);
+#endif
+ err = AllocError;
+ goto bail;
+ }
pbitmaps = (pointer ) buf;
if (blockrec->type == FS_LOAD_GLYPHS)
@@ -2007,7 +2032,9 @@ fs_read_glyphs(FontPathElementPtr fpe, FSBlockDataPtr blockrec)
*/
if (NONZEROMETRICS(&fsdata->encoding[minchar].metrics))
{
- if (local_off.length)
+ if (local_off.length &&
+ (local_off.position < rep->nbytes) &&
+ (local_off.length <= (rep->nbytes - local_off.position)))
{
bits = allbits;
allbits += local_off.length;