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[oCERT-2009-001] Pango integer overflow in heap allocation size calculations
May 07 2009 05:42PM
Will Drewry (redpig ocert org)
#2009-001 Pango integer overflow in heap allocation size calculations
Pango is a library for laying out and rendering text, with an emphasis
on internationalization. Pango suffers from a multiplicative integer
overflow which may lead to a potentially exploitable, heap overflow
depending on the calling conditions. For example, this vulnerability is
remotely reachable in Firefox by creating an overly large
document.location value but only results in a process-terminating,
allocation error (denial of service).
The affected function is pango_glyph_string_set_size. An overflow check
when doubling the size neglects the overflow possible on the subsequent
string->glyphs = g_realloc (string->glyphs, string->space *
Note that other font rendering subsystems suffer from similar issues and
should be cross-checked by maintainers.
Pango < 1.24
Pango >= 1.24
(check with your package maintainer for backports)
Credit: Will Drewry, oCERT Team | Google Security Team.
Special thanks to Karl Tomlinson for extended analysis of the
impact on Firefox.
2009-02-22: attempted to contact upstream via gtk-i18n-list (at) gnome (dot) org [email concealed]
2009-02-25: bug filed with Mozilla against firefox
2009-03-02: Behdad Esfahbod patched Pango upstream for 1.24
2009-04-13: vendor-sec alerted regarding backporting the silent pango fix
2009-04-23: embargo date and CVE assigned (thanks Josh Bressers!)
2009-05-07: advisory released
Will Drewry <redpig (at) ocert (dot) org [email concealed]>
oCERT Team :: http://ocert.org
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