From patchwork Wed Feb 19 16:50:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Schwab X-Patchwork-Id: 1240864 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=209.132.180.131; helo=sourceware.org; envelope-from=libc-alpha-return-109915-incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.a=rsa-sha1 header.s=default header.b=vdONq0er; dkim-atps=neutral Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48N3d074ftz9sR4 for ; Thu, 20 Feb 2020 03:50:44 +1100 (AEDT) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:subject:date:message-id:mime-version :content-type; q=dns; s=default; b=HjwlOKBIvvl+yeZuM/QYnEzkgwsnT Qd6QmTxpRLofYR2pwsIUMVbZDU35W3d1RxTsrG6HFDMcAOFy0+D2d26T6eehW2jQ HCJEoNl6LOb+YqSGu+hv2b6RliaGolfpmtWpZpyT9ybcR8kBeBctAbQ/nEzJ3Ff/ 5tKDyZkTFTw3mc= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:subject:date:message-id:mime-version :content-type; s=default; bh=BWpN5WtqLQgSUtQjafCrVmkuncw=; b=vdO Nq0ero9dh9zd+QV2O1qUVbokL58CSZTZFm9JQ1JRvvLStd2IYUWSiN9vpqVPOapS 3zurOxi4ktluuvCmX05n7D15C6IpctW4HqNsr9N4BWOAKGoJXQbsNb0Pc3/33jtb nURiZuqCrhIZZV4xX4jwEId90AlPSbE/6q0qpSXk= Received: (qmail 96713 invoked by alias); 19 Feb 2020 16:50:38 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 96699 invoked by uid 89); 19 Feb 2020 16:50:38 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-15.3 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, SPF_PASS autolearn=ham version=3.3.1 spammy= X-HELO: mx2.suse.de From: Andreas Schwab To: libc-alpha@sourceware.org Subject: [PATCH] Fix use-after-free in glob when expanding ~user (bug 25414) X-Yow: I'm sitting on my SPEED QUEEN.. To me, it's ENJOYABLE.. I'm WARM.. I'm VIBRATORY.. Date: Wed, 19 Feb 2020 17:50:34 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 The value of `end_name' points into the value of `dirname', thus don't deallocate the latter before the last use of the former. --- posix/glob.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/posix/glob.c b/posix/glob.c index cba9cd1819..0708ed5ee4 100644 --- a/posix/glob.c +++ b/posix/glob.c @@ -827,31 +827,32 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int), { size_t home_len = strlen (p->pw_dir); size_t rest_len = end_name == NULL ? 0 : strlen (end_name); - char *d; + char *d, *newp; + int use_alloca = glob_use_alloca (alloca_used, + home_len + rest_len + 1); - if (__glibc_unlikely (malloc_dirname)) - free (dirname); - malloc_dirname = 0; - - if (glob_use_alloca (alloca_used, home_len + rest_len + 1)) - dirname = alloca_account (home_len + rest_len + 1, - alloca_used); + if (use_alloca) + newp = alloca_account (home_len + rest_len + 1, alloca_used); else { - dirname = malloc (home_len + rest_len + 1); - if (dirname == NULL) + newp = malloc (home_len + rest_len + 1); + if (newp == NULL) { scratch_buffer_free (&pwtmpbuf); retval = GLOB_NOSPACE; goto out; } - malloc_dirname = 1; } - d = mempcpy (dirname, p->pw_dir, home_len); + d = mempcpy (newp, p->pw_dir, home_len); if (end_name != NULL) d = mempcpy (d, end_name, rest_len); *d = '\0'; + if (__glibc_unlikely (malloc_dirname)) + free (dirname); + dirname = newp; + malloc_dirname = !use_alloca; + dirlen = home_len + rest_len; dirname_modified = 1; }