Date: Fri, 27 Nov 2009 17:53:49 +0000 (UTC) From: Tony Finch <fanf@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r199867 - head/usr.bin/unifdef Message-ID: <200911271753.nARHrn3Z026212@svn.freebsd.org>
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Author: fanf Date: Fri Nov 27 17:53:49 2009 New Revision: 199867 URL: http://svn.freebsd.org/changeset/base/199867 Log: unifdef: fix invalid array access when nesting limit exceeded If the number of nested #if blocks exceeds 64, nest() increments the nesting depth and then reports an error. The message includes the line number for the start of the current #if block, which is read from past the end of the relevant array. Avoid the out-of-bounds read by reporting the error and exiting before the nesting depth has a chance to increase. Submitted by: Jonathan Nieder <jrnieder@gmail.com> Modified: head/usr.bin/unifdef/unifdef.c Modified: head/usr.bin/unifdef/unifdef.c ============================================================================== --- head/usr.bin/unifdef/unifdef.c Fri Nov 27 17:25:19 2009 (r199866) +++ head/usr.bin/unifdef/unifdef.c Fri Nov 27 17:53:49 2009 (r199867) @@ -24,17 +24,19 @@ */ /* - * This code is derived from software contributed to Berkeley by Dave Yost. + * This code was derived from software contributed to Berkeley by Dave Yost. * It was rewritten to support ANSI C by Tony Finch. The original version * of unifdef carried the 4-clause BSD copyright licence. None of its code * remains in this version (though some of the names remain) so it now * carries a more liberal licence. + * + * The latest version is available from http://dotat.at/prog/unifdef */ #include <sys/cdefs.h> #ifdef __IDSTRING -__IDSTRING(dotat, "$dotat: unifdef/unifdef.c,v 1.188 2009/11/25 00:11:02 fanf2 Exp $"); +__IDSTRING(dotat, "$dotat: unifdef/unifdef.c,v 1.190 2009/11/27 17:21:26 fanf2 Exp $"); #endif #ifdef __FBSDID __FBSDID("$FreeBSD$"); @@ -460,9 +462,11 @@ keywordedit(const char *replacement) static void nest(void) { - depth += 1; - if (depth >= MAXDEPTH) + if (depth > MAXDEPTH-1) + abort(); /* bug */ + if (depth == MAXDEPTH-1) error("Too many levels of nesting"); + depth += 1; stifline[depth] = linenum; } static void
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