From: John F Carr <jfc@mit.edu>
To: 20156@debbugs.gnu.org
Subject: bug#20156: Emacs 24 stack corruption in fontset.c:fontset_pattern_regexp
Date: Sat, 21 Mar 2015 12:06:16 +0000 [thread overview]
Message-ID: <F8A72762-CE59-4EEA-B06B-5E71E5FE1A04@exchange.mit.edu> (raw)
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Emacs crashes on Mac Yosemite (native window system) when I use set-frame-font with certain font patterns. The cause is writing past the end of an alloca buffer in fontset.c:fontset_pattern_regexp. This triggers a stack check assertion. Alloca is used to allocate space for a regexp, but the size neglects to consider the ^$ around the regexp. “+1” should be “+3”.
To reproduce:
(set-frame-font "-adobe-courier-medium-r-normal--24-*-75-75-m-150-iso8859-1”)
without X installed.
Bug in 24.3 and "GNU Emacs 24.4.2 (x86_64-apple-darwin14.1.0, NS apple-appkit-1344.72)”.
[-- Attachment #2: fontset.diff --]
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--- fontset.c.orig 2014-08-09 16:41:01.000000000 -0400
+++ fontset.c 2015-03-21 07:55:48.000000000 -0400
@@ -1097,9 +1097,9 @@
we convert "*" to "[^-]*" which is much faster in regular
expression matching. */
if (ndashes < 14)
- p1 = regex = alloca (SBYTES (pattern) + 2 * nstars + 2 * nescs + 1);
+ p1 = regex = alloca (SBYTES (pattern) + 2 * nstars + 2 * nescs + 3);
else
- p1 = regex = alloca (SBYTES (pattern) + 5 * nstars + 2 * nescs + 1);
+ p1 = regex = alloca (SBYTES (pattern) + 5 * nstars + 2 * nescs + 3);
*p1++ = '^';
for (p0 = SDATA (pattern); *p0; p0++)
next reply other threads:[~2015-03-21 12:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-21 12:06 John F Carr [this message]
2015-03-22 9:23 ` bug#20156: Emacs 24 stack corruption in fontset.c:fontset_pattern_regexp Jan D.
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