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authorAlan Coopersmith <alan.coopersmith@oracle.com>2014-04-25 23:03:24 -0700
committerAlan Coopersmith <alan.coopersmith@oracle.com>2014-05-12 23:32:15 -0700
commit520683652564c2a4e42328ae23eef9bb63271565 (patch)
tree33d3d64a01403e47eddab17321e76b7cfaa794e7 /src/fc/fserve.c
parenta3f21421537620fc4e1f844a594a4bcd9f7e2bd8 (diff)
CVE-2014-0210: unvalidated length fields in fs_read_glyphs()
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. Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com> Reviewed-by: Adam Jackson <ajax@redhat.com> Reviewed-by: Matthieu Herrb <matthieu@herrb.eu>
Diffstat (limited to 'src/fc/fserve.c')
-rw-r--r--src/fc/fserve.c29
1 files changed, 28 insertions, 1 deletions
diff --git a/src/fc/fserve.c b/src/fc/fserve.c
index 232e969..581bb1b 100644
--- a/src/fc/fserve.c
+++ b/src/fc/fserve.c
@@ -1907,6 +1907,7 @@ 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;
@@ -1938,9 +1939,33 @@ 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)
@@ -1998,7 +2023,9 @@ 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;