From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760178Ab2INW3u (ORCPT ); Fri, 14 Sep 2012 18:29:50 -0400 Received: from brettmacdonald.ca ([204.244.237.11]:52418 "HELO optimus.nome.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751372Ab2INW3r (ORCPT ); Fri, 14 Sep 2012 18:29:47 -0400 X-Greylist: delayed 400 seconds by postgrey-1.27 at vger.kernel.org; Fri, 14 Sep 2012 18:29:47 EDT Date: Sat, 15 Sep 2012 00:23:04 +0200 From: Markus Mayer To: linux-kernel@vger.kernel.org Subject: [PATCH] Fix segfault in dtc when empty input file is given. Message-ID: <20120914222304.GA2698@mmayer.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Operating-System: Linux 2.6.26-1-xen-amd64 x86_64 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Markus Mayer Date: Thu, 13 Sep 2012 14:46:28 -0700 Subject: [PATCH] Fix segfault in dtc when empty input file is given. Prior to this change, an empty input file would cause a segfault, because yylloc had never been initialized. There was never any characters for the lexer to match, so YY_USER_ACTION was never executed before the parse error was detected. When the parser printed the error message, it tried to include the name of the file, but the structure holding the file name (yylloc.file, referenced as pos->file) had never been initialized. Without the fix: $ ./dtc /dev/null DTC: dts->dts on file "/dev/null" Segmentation fault (core dumped) $ gdb dtc core Program terminated with signal 11, Segmentation fault. at scripts/dtc/srcpos.c:194 194 fname = pos->file->name; (gdb) bt at scripts/dtc/srcpos.c:194 fmt=0x40d769 "%s", va=0x7fffbf027148) at scripts/dtc/srcpos.c:220 at scripts/dtc/dtc-parser.tab.c:1920 at scripts/dtc/treesource.c:38 at scripts/dtc/dtc.c:203 (gdb) p *pos $1 = {first_line = 0, first_column = 0, last_line = 0, last_column = 0, file = 0x0} With the fix: $ ./dtc /dev/null DTC: dts->dts on file "/dev/null" Error: /dev/null:1.1 syntax error FATAL ERROR: Unable to parse input tree Signed-off-by: Markus Mayer --- scripts/dtc/treesource.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/scripts/dtc/treesource.c b/scripts/dtc/treesource.c index c09aafa..b461b88 100644 --- a/scripts/dtc/treesource.c +++ b/scripts/dtc/treesource.c @@ -29,11 +29,15 @@ int treesource_error; struct boot_info *dt_from_source(const char *fname) { + extern YYLTYPE yylloc; + the_boot_info = NULL; treesource_error = 0; srcfile_push(fname); yyin = current_srcfile->f; + /* Initialize yylloc->file to avoid segfault on empty input */ + srcpos_update(&yylloc, NULL, 0); if (yyparse() != 0) die("Unable to parse input tree\n"); -- 1.7.5.4