From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37677) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cif3l-0001IK-Sp for qemu-devel@nongnu.org; Tue, 28 Feb 2017 05:31:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cif3i-0007zH-Id for qemu-devel@nongnu.org; Tue, 28 Feb 2017 05:31:09 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53689 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cif3i-0007z5-B5 for qemu-devel@nongnu.org; Tue, 28 Feb 2017 05:31:06 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1SASjh2043844 for ; Tue, 28 Feb 2017 05:31:05 -0500 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0b-001b2d01.pphosted.com with ESMTP id 28vn6ar6j1-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 28 Feb 2017 05:31:05 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 28 Feb 2017 10:31:02 -0000 From: Greg Kurz Date: Tue, 28 Feb 2017 11:30:26 +0100 In-Reply-To: <1488277840-18608-1-git-send-email-groug@kaod.org> References: <1488277840-18608-1-git-send-email-groug@kaod.org> Message-Id: <1488277840-18608-15-git-send-email-groug@kaod.org> Subject: [Qemu-devel] [PULL 14/28] 9pfs: local: statfs: don't follow symlinks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , "Aneesh Kumar K.V" , Greg Kurz The local_statfs() callback is vulnerable to symlink attacks because it calls statfs() which follows symbolic links in all path elements. This patch converts local_statfs() to rely on open_nofollow() and fstatfs() instead. This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz Reviewed-by: Stefan Hajnoczi --- hw/9pfs/9p-local.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index a6dd77d7b895..95b2c1c34172 100644 --- a/hw/9pfs/9p-local.c +++ b/hw/9pfs/9p-local.c @@ -1077,13 +1077,11 @@ static int local_fsync(FsContext *ctx, int fid_type, static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) { - char *buffer; - int ret; - char *path = fs_path->data; + int fd, ret; - buffer = rpath(s, path); - ret = statfs(buffer, stbuf); - g_free(buffer); + fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0); + ret = fstatfs(fd, stbuf); + close_preserve_errno(fd); return ret; } -- 2.7.4