From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Nieder Subject: [PATCH 2/4] vcs-svn: cap number of bytes read from sliding view Date: Fri, 27 May 2011 06:11:00 -0500 Message-ID: <20110527111059.GC7972@elie> References: <20110525235520.GA6971@elie> <20110527110828.GA7972@elie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org, Ramkumar Ramachandra , Dmitry Ivankov To: David Barr X-From: git-owner@vger.kernel.org Fri May 27 13:11:16 2011 Return-path: Envelope-to: gcvg-git-2@lo.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1QPuwl-0002wf-6U for gcvg-git-2@lo.gmane.org; Fri, 27 May 2011 13:11:15 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752476Ab1E0LLF (ORCPT ); Fri, 27 May 2011 07:11:05 -0400 Received: from mail-yi0-f46.google.com ([209.85.218.46]:35400 "EHLO mail-yi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751891Ab1E0LLE (ORCPT ); Fri, 27 May 2011 07:11:04 -0400 Received: by yia27 with SMTP id 27so638260yia.19 for ; Fri, 27 May 2011 04:11:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:date:from:to:cc:subject:message-id:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; bh=X/fgzOfi5EEPW8GpQub9ok5GX1xeEedL7B/CDSMMGS8=; b=J/zAMqCMoYh6MYuwEjduWPWbsAepKza7Dft0HatUo6e18dSLDLE3oczNI8ZEFBuuGA HoRuF2goVjOIBHeyCaa47gOpMfRPfylPCk1s35+E8Tcbh9rCRKtsBXsQZo2lCRN2cOic 6zYL6IwCZAnd8fpQ8yZAh5HqZy8SY3I91Vcmw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=ZbOmUVecJhWdwPz5+9oyxjfB8u4HiLgFVIn4wHKbuwKTViffB/ytoib9/+40XdzFVw w4J5BGUoRj3t41HMoc0xu8ni9fI3a6izXziu1QSlqlfWrv8+nwgFQvFH1VO5q4RVoWeF fQ5Tjo7yVBfktVsYH7jmqk84+AmhgcZbtqDqw= Received: by 10.236.77.227 with SMTP id d63mr2758728yhe.9.1306494663820; Fri, 27 May 2011 04:11:03 -0700 (PDT) Received: from elie (adsl-69-209-65-98.dsl.chcgil.ameritech.net [69.209.65.98]) by mx.google.com with ESMTPS id w70sm289694yhl.3.2011.05.27.04.11.02 (version=SSLv3 cipher=OTHER); Fri, 27 May 2011 04:11:03 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20110527110828.GA7972@elie> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Introduce a "max_off" field in struct sliding_view, roughly speaking representing a maximum number of bytes that can be read from "file". More precisely, if it is set to a nonnegative integer, a call to move_window() attempting to put the right endpoint beyond that offset will return an error instead. A value of -1 disables the check. The idea is to use this when applying Subversion-format deltas to prevent reads past the end of the preimage (which has known length). Without such a check, corrupt deltas would cause svn-fe to block indefinitely when data in the input pipe is exhausted. Inspired-by: Ramkumar Ramachandra Signed-off-by: Jonathan Nieder --- test-svn-fe.c | 2 +- vcs-svn/sliding_window.c | 2 ++ vcs-svn/sliding_window.h | 3 ++- 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/test-svn-fe.c b/test-svn-fe.c index a027626..332a5f7 100644 --- a/test-svn-fe.c +++ b/test-svn-fe.c @@ -15,7 +15,7 @@ static int apply_delta(int argc, char *argv[]) { struct line_buffer preimage = LINE_BUFFER_INIT; struct line_buffer delta = LINE_BUFFER_INIT; - struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage); + struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage, -1); if (argc != 5) usage(test_svnfe_usage); diff --git a/vcs-svn/sliding_window.c b/vcs-svn/sliding_window.c index 1b8d987..1bac7a4 100644 --- a/vcs-svn/sliding_window.c +++ b/vcs-svn/sliding_window.c @@ -54,6 +54,8 @@ int move_window(struct sliding_view *view, off_t off, size_t width) return -1; if (off < view->off || off + width < view->off + view->width) return error("invalid delta: window slides left"); + if (view->max_off >= 0 && view->max_off < off + width) + return error("delta preimage ends early"); file_offset = view->off + view->buf.len; if (off < file_offset) { diff --git a/vcs-svn/sliding_window.h b/vcs-svn/sliding_window.h index ed0bfdd..b43a825 100644 --- a/vcs-svn/sliding_window.h +++ b/vcs-svn/sliding_window.h @@ -7,10 +7,11 @@ struct sliding_view { struct line_buffer *file; off_t off; size_t width; + off_t max_off; /* -1 means unlimited */ struct strbuf buf; }; -#define SLIDING_VIEW_INIT(input) { (input), 0, 0, STRBUF_INIT } +#define SLIDING_VIEW_INIT(input, len) { (input), 0, 0, (len), STRBUF_INIT } extern int move_window(struct sliding_view *view, off_t off, size_t width); -- 1.7.5.1