From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46640) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cYAr6-0000Wc-Tj for qemu-devel@nongnu.org; Mon, 30 Jan 2017 07:14:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cYAr3-00016X-Pz for qemu-devel@nongnu.org; Mon, 30 Jan 2017 07:14:44 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:37381 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 1cYAr3-00016L-Je for qemu-devel@nongnu.org; Mon, 30 Jan 2017 07:14:41 -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 v0UCEYB3171830 for ; Mon, 30 Jan 2017 07:14:41 -0500 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0b-001b2d01.pphosted.com with ESMTP id 289954wvjr-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 30 Jan 2017 07:14:36 -0500 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 30 Jan 2017 05:14:02 -0700 From: Greg Kurz Date: Mon, 30 Jan 2017 13:13:56 +0100 In-Reply-To: <148577817618.10533.9740628265078537215.stgit@bahia.lan> References: <148577817618.10533.9740628265078537215.stgit@bahia.lan> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <148577843680.10533.18024708307122210366.stgit@bahia.lan> Subject: [Qemu-devel] [PATCH RFC 34/36] 9pfs: local: llistxattr: don't follow symlinks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: ppandit@redhat.com, jannh@google.com, Eric Blake , Greg Kurz , "Aneesh Kumar K.V" This fixes CVE-2016-9602 for all security models. Signed-off-by: Greg Kurz --- hw/9pfs/9p-xattr.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c index 29f4f940a23f..08df02e0bab2 100644 --- a/hw/9pfs/9p-xattr.c +++ b/hw/9pfs/9p-xattr.c @@ -214,6 +214,11 @@ ssize_t pt_listxattr(FsContext *ctx, const char *path, return name_size; } +static ssize_t flistxattrat(int dirfd, const char *path, char *list, + size_t size) +{ + return do_xattrat_op(XATTRAT_OP_LIST, dirfd, path, NULL, list, size, 0); +} /* * Get the list and pass to each layer to find out whether @@ -223,24 +228,37 @@ ssize_t v9fs_list_xattr(FsContext *ctx, const char *path, void *value, size_t vsize) { ssize_t size = 0; - char *buffer; void *ovalue = value; XattrOperations *xops; char *orig_value, *orig_value_start; ssize_t xattr_len, parsed_len = 0, attr_len; + char *dirpath, *name; + int dirfd; /* Get the actual len */ - buffer = rpath(ctx, path); - xattr_len = llistxattr(buffer, value, 0); + dirpath = local_dirname(path); + dirfd = local_opendir_nofollow(ctx, dirpath); + g_free(dirpath); + if (dirfd == -1) { + return -1; + } + + name = local_basename(path); + xattr_len = flistxattrat(dirfd, name, value, 0); if (xattr_len <= 0) { - g_free(buffer); + g_free(name); + close_preserve_errno(dirfd); return xattr_len; } /* Now fetch the xattr and find the actual size */ orig_value = g_malloc(xattr_len); - xattr_len = llistxattr(buffer, orig_value, xattr_len); - g_free(buffer); + xattr_len = flistxattrat(dirfd, name, orig_value, xattr_len); + g_free(name); + close_preserve_errno(dirfd); + if (xattr_len < 0) { + return -1; + } /* store the orig pointer */ orig_value_start = orig_value;