diff options
| author | Alan Coopersmith <alan.coopersmith@oracle.com> | 2014-04-25 23:03:24 -0700 |
|---|---|---|
| committer | Alan Coopersmith <alan.coopersmith@oracle.com> | 2014-05-12 23:32:15 -0700 |
| commit | 520683652564c2a4e42328ae23eef9bb63271565 (patch) | |
| tree | 33d3d64a01403e47eddab17321e76b7cfaa794e7 | |
| parent | a3f21421537620fc4e1f844a594a4bcd9f7e2bd8 (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>
| -rw-r--r-- | src/fc/fserve.c | 29 |
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; |