From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38C92CA9EAF for ; Thu, 24 Oct 2019 13:17:14 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E81212084C for ; Thu, 24 Oct 2019 13:17:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NsqTt+Un" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E81212084C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42284 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNczI-0005TT-Ke for qemu-devel@archiver.kernel.org; Thu, 24 Oct 2019 09:17:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39417) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNbID-0003oK-Ai for qemu-devel@nongnu.org; Thu, 24 Oct 2019 07:28:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iNbIB-00006i-An for qemu-devel@nongnu.org; Thu, 24 Oct 2019 07:28:37 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:27203 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iNbIB-00005C-5S for qemu-devel@nongnu.org; Thu, 24 Oct 2019 07:28:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571916510; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Zat1t+hKG0Zk8YyYdD8I3eOrGeDc/SeMU3HKQTfuqnA=; b=NsqTt+UndQeVu2T1BsDPz3mjbx8VLxBBcvM6YPAv+b4DjJr5Xig+nvVH8AA1BMM4etO5mr 80GkAukxPpZsah+JFconR6fucjV2FgGR1G/MZCrmmgUtCoiQvtCMr3ZfaUnQ3r64tuOLmI yxXdTkBKk8vviAGtOsk0qhqQqBqmLRw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-204-HpkeFZk8O3mtTFlMMPJkRQ-1; Thu, 24 Oct 2019 07:28:28 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 092FE107AD31; Thu, 24 Oct 2019 11:28:27 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-117-248.ams2.redhat.com [10.36.117.248]) by smtp.corp.redhat.com (Postfix) with ESMTP id 81FD44524; Thu, 24 Oct 2019 11:28:24 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, renzhen@linux.alibaba.com, eguan@linux.alibaba.com, ganesh.mahalingam@intel.com, m.mizuma@jp.fujitsu.com, mszeredi@redhat.com, misono.tomohiro@jp.fujitsu.com, tao.peng@linux.alibaba.com, piaojun@huawei.com, stefanha@redhat.com, vgoyal@redhat.com, mst@redhat.com, berrange@redhat.com Subject: [PATCH 15/25] virtiofsd: use /proc/self/fd/ O_PATH file descriptor Date: Thu, 24 Oct 2019 12:27:08 +0100 Message-Id: <20191024112718.34657-16-dgilbert@redhat.com> In-Reply-To: <20191024112718.34657-1-dgilbert@redhat.com> References: <20191024112718.34657-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: HpkeFZk8O3mtTFlMMPJkRQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Stefan Hajnoczi Sandboxing will remove /proc from the mount namespace so we can no longer build string paths into "/proc/self/fd/...". Keep an O_PATH file descriptor so we can still re-open fds via /proc/self/fd. Signed-off-by: Stefan Hajnoczi --- contrib/virtiofsd/passthrough_ll.c | 128 +++++++++++++++++++++++------ 1 file changed, 101 insertions(+), 27 deletions(-) diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthr= ough_ll.c index cb01e3f088..3ddf22d162 100644 --- a/contrib/virtiofsd/passthrough_ll.c +++ b/contrib/virtiofsd/passthrough_ll.c @@ -110,6 +110,9 @@ struct lo_data { =09struct lo_map ino_map; /* protected by lo->mutex */ =09struct lo_map dirp_map; /* protected by lo->mutex */ =09struct lo_map fd_map; /* protected by lo->mutex */ + +=09/* An O_PATH file descriptor to /proc/self/fd/ */ +=09int proc_self_fd; }; =20 static const struct fuse_opt lo_opts[] =3D { @@ -378,9 +381,9 @@ static int lo_parent_and_name(struct lo_data *lo, struc= t lo_inode *inode, =09int res; =20 retry: -=09sprintf(procname, "/proc/self/fd/%i", inode->fd); +=09sprintf(procname, "%i", inode->fd); =20 -=09res =3D readlink(procname, path, PATH_MAX); +=09res =3D readlinkat(lo->proc_self_fd, procname, path, PATH_MAX); =09if (res < 0) { =09=09fuse_log(FUSE_LOG_WARNING, "lo_parent_and_name: readlink failed: %m\= n"); =09=09goto fail_noretry; @@ -465,9 +468,9 @@ static int utimensat_empty(struct lo_data *lo, struct l= o_inode *inode, =09=09} =09=09return res; =09} -=09sprintf(path, "/proc/self/fd/%i", inode->fd); +=09sprintf(path, "%i", inode->fd); =20 -=09return utimensat(AT_FDCWD, path, tv, 0); +=09return utimensat(lo->proc_self_fd, path, tv, 0); =20 fallback: =09res =3D lo_parent_and_name(lo, inode, path, &parent); @@ -521,8 +524,9 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, = struct stat *attr, =09=09if (fi) { =09=09=09res =3D fchmod(fd, attr->st_mode); =09=09} else { -=09=09=09sprintf(procname, "/proc/self/fd/%i", ifd); -=09=09=09res =3D chmod(procname, attr->st_mode); +=09=09=09sprintf(procname, "%i", ifd); +=09=09=09res =3D fchmodat(lo->proc_self_fd, procname, +=09=09=09=09 attr->st_mode, 0); =09=09} =09=09if (res =3D=3D -1) =09=09=09goto out_err; @@ -539,11 +543,23 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino= , struct stat *attr, =09=09=09goto out_err; =09} =09if (valid & FUSE_SET_ATTR_SIZE) { +=09=09int truncfd; + =09=09if (fi) { -=09=09=09res =3D ftruncate(fd, attr->st_size); +=09=09=09truncfd =3D fd; =09=09} else { -=09=09=09sprintf(procname, "/proc/self/fd/%i", ifd); -=09=09=09res =3D truncate(procname, attr->st_size); +=09=09=09sprintf(procname, "%i", ifd); +=09=09=09truncfd =3D openat(lo->proc_self_fd, procname, O_RDWR); +=09=09=09if (truncfd < 0) { +=09=09=09=09goto out_err; +=09=09=09} +=09=09} + +=09=09res =3D ftruncate(truncfd, attr->st_size); +=09=09if (!fi) { +=09=09=09saverr =3D errno; +=09=09=09close(truncfd); +=09=09=09errno =3D saverr; =09=09} =09=09if (res =3D=3D -1) =09=09=09goto out_err; @@ -825,9 +841,9 @@ static int linkat_empty_nofollow(struct lo_data *lo, st= ruct lo_inode *inode, =09=09return res; =09} =20 -=09sprintf(path, "/proc/self/fd/%i", inode->fd); +=09sprintf(path, "%i", inode->fd); =20 -=09return linkat(AT_FDCWD, path, dfd, name, AT_SYMLINK_FOLLOW); +=09return linkat(lo->proc_self_fd, path, dfd, name, AT_SYMLINK_FOLLOW); =20 fallback: =09res =3D lo_parent_and_name(lo, inode, path, &parent); @@ -1325,8 +1341,8 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, s= truct fuse_file_info *fi) =09if (lo->writeback && (fi->flags & O_APPEND)) =09=09fi->flags &=3D ~O_APPEND; =20 -=09sprintf(buf, "/proc/self/fd/%i", lo_fd(req, ino)); -=09fd =3D open(buf, fi->flags & ~O_NOFOLLOW); +=09sprintf(buf, "%i", lo_fd(req, ino)); +=09fd =3D openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW); =09if (fd =3D=3D -1) =09=09return (void) fuse_reply_err(req, errno); =20 @@ -1375,8 +1391,8 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, = struct fuse_file_info *fi) static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync, =09=09 struct fuse_file_info *fi) { +=09struct lo_data *lo =3D lo_data(req); =09int res; -=09(void) ino; =09int fd; =09char *buf; =20 @@ -1384,11 +1400,11 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino= , int datasync, =09=09 (void *)fi); =20 =09if (!fi) { -=09=09res =3D asprintf(&buf, "/proc/self/fd/%i", lo_fd(req, ino)); +=09=09res =3D asprintf(&buf, "%i", lo_fd(req, ino)); =09=09if (res =3D=3D -1) =09=09=09return (void) fuse_reply_err(req, errno); =20 -=09=09fd =3D open(buf, O_RDWR); +=09=09fd =3D openat(lo->proc_self_fd, buf, O_RDWR); =09=09free(buf); =09=09if (fd =3D=3D -1) =09=09=09return (void) fuse_reply_err(req, errno); @@ -1493,11 +1509,13 @@ static void lo_flock(fuse_req_t req, fuse_ino_t ino= , struct fuse_file_info *fi, static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, =09=09=09size_t size) { +=09struct lo_data *lo =3D lo_data(req); =09char *value =3D NULL; =09char procname[64]; =09struct lo_inode *inode; =09ssize_t ret; =09int saverr; +=09int fd =3D -1; =20 =09inode =3D lo_inode(req, ino); =09if (!inode) { @@ -1520,14 +1538,18 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t = ino, const char *name, =09=09goto out; =09} =20 -=09sprintf(procname, "/proc/self/fd/%i", inode->fd); +=09sprintf(procname, "%i", inode->fd); +=09fd =3D openat(lo->proc_self_fd, procname, O_RDONLY); +=09if (fd < 0) { +=09=09goto out_err; +=09} =20 =09if (size) { =09=09value =3D malloc(size); =09=09if (!value) =09=09=09goto out_err; =20 -=09=09ret =3D getxattr(procname, name, value, size); +=09=09ret =3D fgetxattr(fd, name, value, size); =09=09if (ret =3D=3D -1) =09=09=09goto out_err; =09=09saverr =3D 0; @@ -1536,7 +1558,7 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t in= o, const char *name, =20 =09=09fuse_reply_buf(req, value, ret); =09} else { -=09=09ret =3D getxattr(procname, name, NULL, 0); +=09=09ret =3D fgetxattr(fd, name, NULL, 0); =09=09if (ret =3D=3D -1) =09=09=09goto out_err; =20 @@ -1544,6 +1566,10 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t i= no, const char *name, =09} out_free: =09free(value); + +=09if (fd >=3D 0) { +=09=09close(fd); +=09} =09return; =20 out_err: @@ -1555,11 +1581,13 @@ out: =20 static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) { +=09struct lo_data *lo =3D lo_data(req); =09char *value =3D NULL; =09char procname[64]; =09struct lo_inode *inode; =09ssize_t ret; =09int saverr; +=09int fd =3D -1; =20 =09inode =3D lo_inode(req, ino); =09if (!inode) { @@ -1582,14 +1610,18 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t= ino, size_t size) =09=09goto out; =09} =20 -=09sprintf(procname, "/proc/self/fd/%i", inode->fd); +=09sprintf(procname, "%i", inode->fd); +=09fd =3D openat(lo->proc_self_fd, procname, O_RDONLY); +=09if (fd < 0) { +=09=09goto out_err; +=09} =20 =09if (size) { =09=09value =3D malloc(size); =09=09if (!value) =09=09=09goto out_err; =20 -=09=09ret =3D listxattr(procname, value, size); +=09=09ret =3D flistxattr(fd, value, size); =09=09if (ret =3D=3D -1) =09=09=09goto out_err; =09=09saverr =3D 0; @@ -1598,7 +1630,7 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t i= no, size_t size) =20 =09=09fuse_reply_buf(req, value, ret); =09} else { -=09=09ret =3D listxattr(procname, NULL, 0); +=09=09ret =3D flistxattr(fd, NULL, 0); =09=09if (ret =3D=3D -1) =09=09=09goto out_err; =20 @@ -1606,6 +1638,10 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t = ino, size_t size) =09} out_free: =09free(value); + +=09if (fd >=3D 0) { +=09=09close(fd); +=09} =09return; =20 out_err: @@ -1619,9 +1655,11 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t i= no, const char *name, =09=09=09const char *value, size_t size, int flags) { =09char procname[64]; +=09struct lo_data *lo =3D lo_data(req); =09struct lo_inode *inode; =09ssize_t ret; =09int saverr; +=09int fd =3D -1; =20 =09inode =3D lo_inode(req, ino); =09if (!inode) { @@ -1644,21 +1682,31 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t = ino, const char *name, =09=09goto out; =09} =20 -=09sprintf(procname, "/proc/self/fd/%i", inode->fd); +=09sprintf(procname, "%i", inode->fd); +=09fd =3D openat(lo->proc_self_fd, procname, O_RDWR); +=09if (fd < 0) { +=09=09saverr =3D errno; +=09=09goto out; +=09} =20 -=09ret =3D setxattr(procname, name, value, size, flags); +=09ret =3D fsetxattr(fd, name, value, size, flags); =09saverr =3D ret =3D=3D -1 ? errno : 0; =20 out: +=09if (fd >=3D 0) { +=09=09close(fd); +=09} =09fuse_reply_err(req, saverr); } =20 static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *nam= e) { =09char procname[64]; +=09struct lo_data *lo =3D lo_data(req); =09struct lo_inode *inode; =09ssize_t ret; =09int saverr; +=09int fd =3D -1; =20 =09inode =3D lo_inode(req, ino); =09if (!inode) { @@ -1681,12 +1729,20 @@ static void lo_removexattr(fuse_req_t req, fuse_ino= _t ino, const char *name) =09=09goto out; =09} =20 -=09sprintf(procname, "/proc/self/fd/%i", inode->fd); +=09sprintf(procname, "%i", inode->fd); +=09fd =3D openat(lo->proc_self_fd, procname, O_RDWR); +=09if (fd < 0) { +=09=09saverr =3D errno; +=09=09goto out; +=09} =20 -=09ret =3D removexattr(procname, name); +=09ret =3D fremovexattr(fd, name); =09saverr =3D ret =3D=3D -1 ? errno : 0; =20 out: +=09if (fd >=3D 0) { +=09=09close(fd); +=09} =09fuse_reply_err(req, saverr); } =20 @@ -1765,13 +1821,24 @@ static void print_capabilities(void) =09printf("}\n"); } =20 +static void setup_proc_self_fd(struct lo_data *lo) +{ +=09lo->proc_self_fd =3D open("/proc/self/fd", O_PATH); +=09if (lo->proc_self_fd =3D=3D -1) { +=09=09fuse_log(FUSE_LOG_ERR, "open(/proc/self/fd, O_PATH): %m\n"); +=09=09exit(1); +=09} +} + int main(int argc, char *argv[]) { =09struct fuse_args args =3D FUSE_ARGS_INIT(argc, argv); =09struct fuse_session *se; =09struct fuse_cmdline_opts opts; =09struct lo_data lo =3D { .debug =3D 0, -=09 .writeback =3D 0 }; +=09 .writeback =3D 0, +=09 .proc_self_fd =3D -1, +=09}; =09struct lo_map_elem *root_elem; =09int ret =3D -1; =20 @@ -1878,6 +1945,9 @@ int main(int argc, char *argv[]) =20 =09fuse_daemonize(opts.foreground); =20 +=09/* Must be after daemonize to get the right /proc/self/fd */ +=09setup_proc_self_fd(&lo); + =09/* Block until ctrl+c or fusermount -u */ =09ret =3D virtio_loop(se); =20 @@ -1893,6 +1963,10 @@ err_out1: =09lo_map_destroy(&lo.dirp_map); =09lo_map_destroy(&lo.ino_map); =20 +=09if (lo.proc_self_fd >=3D 0) { +=09=09close(lo.proc_self_fd); +=09} + =09if (lo.root.fd >=3D 0) =09=09close(lo.root.fd); =20 --=20 2.23.0