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Thu, 24 Oct 2019 11:27:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571916471; 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=zmdeBxGXJeXKGEo7YlK7OvPYcpMZQjpGIwy7oqHxlkg=; b=hr9IPC/6Ls4y7udWpPdll8bv4DsZ4CRorzx28yqth1sfIS7jJl3KXRjoW0b7VTVNOwvaiG P0sRU/RWOgRAlx43plEXz+B0bH9WHn+QQED5nR2ZiBXvN869jyYYKI/c+lPJAak0M0NPEI tT6OnfgY0w1KikrbD/opba38wyTwVOE= 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 05/25] virtiofsd: passthrough_ll: add fd_map to hide file descriptors Date: Thu, 24 Oct 2019 12:26:58 +0100 Message-Id: <20191024112718.34657-6-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: i-rabJQhPwmiND5h1IXgng-1 X-Mimecast-Spam-Score: 0 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: 205.139.110.61 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: Stefan Hajnoczi Do not expose file descriptor numbers to clients. This prevents the abuse of internal file descriptors (like stdin/stdout). Signed-off-by: Stefan Hajnoczi --- contrib/virtiofsd/passthrough_ll.c | 113 +++++++++++++++++++++++------ 1 file changed, 92 insertions(+), 21 deletions(-) diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthr= ough_ll.c index 9f82166079..a71fbff143 100644 --- a/contrib/virtiofsd/passthrough_ll.c +++ b/contrib/virtiofsd/passthrough_ll.c @@ -60,6 +60,7 @@ struct lo_map_elem { union { struct lo_inode *inode; struct lo_dirp *dirp; + int fd; ssize_t freelist; }; bool in_use; @@ -107,6 +108,7 @@ struct lo_data { struct lo_inode root; /* protected by lo->mutex */ struct lo_map ino_map; /* protected by lo->mutex */ struct lo_map dirp_map; /* protected by lo->mutex */ + struct lo_map fd_map; /* protected by lo->mutex */ }; =20 static const struct fuse_opt lo_opts[] =3D { @@ -241,6 +243,19 @@ static void lo_map_remove(struct lo_map *map, size_t k= ey) map->freelist =3D key; } =20 +/* Assumes lo->mutex is held */ +static ssize_t lo_add_fd_mapping(fuse_req_t req, int fd) +{ + struct lo_map_elem *elem; + + elem =3D lo_map_alloc_elem(&lo_data(req)->fd_map); + if (!elem) + return -1; + + elem->fd =3D fd; + return elem - lo_data(req)->fd_map.elems; +} + /* Assumes lo->mutex is held */ static ssize_t lo_add_dirp_mapping(fuse_req_t req, struct lo_dirp *dirp) { @@ -350,6 +365,21 @@ static int utimensat_empty_nofollow(struct lo_inode *i= node, return utimensat(AT_FDCWD, procname, tv, 0); } =20 +static int lo_fi_fd(fuse_req_t req, struct fuse_file_info *fi) +{ + struct lo_data *lo =3D lo_data(req); + struct lo_map_elem *elem; + + pthread_mutex_lock(&lo->mutex); + elem =3D lo_map_get(&lo->fd_map, fi->fh); + pthread_mutex_unlock(&lo->mutex); + + if (!elem) + return -1; + + return elem->fd; +} + static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, int valid, struct fuse_file_info *fi) { @@ -358,6 +388,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, = struct stat *attr, struct lo_inode *inode; int ifd; int res; + int fd; =20 inode =3D lo_inode(req, ino); if (!inode) { @@ -367,9 +398,13 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino,= struct stat *attr, =20 ifd =3D inode->fd; =20 + /* If fi->fh is invalid we'll report EBADF later */ + if (fi) + fd =3D lo_fi_fd(req, fi); + if (valid & FUSE_SET_ATTR_MODE) { if (fi) { - res =3D fchmod(fi->fh, attr->st_mode); + res =3D fchmod(fd, attr->st_mode); } else { sprintf(procname, "/proc/self/fd/%i", ifd); res =3D chmod(procname, attr->st_mode); @@ -390,7 +425,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, = struct stat *attr, } if (valid & FUSE_SET_ATTR_SIZE) { if (fi) { - res =3D ftruncate(fi->fh, attr->st_size); + res =3D ftruncate(fd, attr->st_size); } else { sprintf(procname, "/proc/self/fd/%i", ifd); res =3D truncate(procname, attr->st_size); @@ -417,7 +452,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, = struct stat *attr, tv[1] =3D attr->st_mtim; =20 if (fi) - res =3D futimens(fi->fh, tv); + res =3D futimens(fd, tv); else res =3D utimensat_empty_nofollow(inode, tv); if (res =3D=3D -1) @@ -1041,7 +1076,18 @@ static void lo_create(fuse_req_t req, fuse_ino_t par= ent, const char *name, lo_restore_cred(&old); =20 if (!err) { - fi->fh =3D fd; + ssize_t fh; + + pthread_mutex_lock(&lo->mutex); + fh =3D lo_add_fd_mapping(req, fd); + pthread_mutex_unlock(&lo->mutex); + if (fh =3D=3D -1) { + close(fd); + fuse_reply_err(req, ENOMEM); + return; + } + + fi->fh =3D fh; err =3D lo_do_lookup(req, parent, name, &e); } if (lo->cache =3D=3D CACHE_NEVER) @@ -1082,6 +1128,7 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t in= o, int datasync, static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info = *fi) { int fd; + ssize_t fh; char buf[64]; struct lo_data *lo =3D lo_data(req); =20 @@ -1110,7 +1157,16 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, = struct fuse_file_info *fi) if (fd =3D=3D -1) return (void) fuse_reply_err(req, errno); =20 - fi->fh =3D fd; + pthread_mutex_lock(&lo->mutex); + fh =3D lo_add_fd_mapping(req, fd); + pthread_mutex_unlock(&lo->mutex); + if (fh =3D=3D -1) { + close(fd); + fuse_reply_err(req, ENOMEM); + return; + } + + fi->fh =3D fh; if (lo->cache =3D=3D CACHE_NEVER) fi->direct_io =3D 1; else if (lo->cache =3D=3D CACHE_ALWAYS) @@ -1120,9 +1176,18 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, = struct fuse_file_info *fi) =20 static void lo_release(fuse_req_t req, fuse_ino_t ino, struct fuse_file_in= fo *fi) { + struct lo_data *lo =3D lo_data(req); + int fd; + (void) ino; =20 - close(fi->fh); + fd =3D lo_fi_fd(req, fi); + + pthread_mutex_lock(&lo->mutex); + lo_map_remove(&lo->fd_map, fi->fh); + pthread_mutex_unlock(&lo->mutex); + + close(fd); fuse_reply_err(req, 0); } =20 @@ -1130,7 +1195,7 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, = struct fuse_file_info *fi) { int res; (void) ino; - res =3D close(dup(fi->fh)); + res =3D close(dup(lo_fi_fd(req, fi))); fuse_reply_err(req, res =3D=3D -1 ? errno : 0); } =20 @@ -1155,7 +1220,7 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, = int datasync, if (fd =3D=3D -1) return (void) fuse_reply_err(req, errno); } else - fd =3D fi->fh; + fd =3D lo_fi_fd(req, fi); =20 if (datasync) res =3D fdatasync(fd); @@ -1176,7 +1241,7 @@ static void lo_read(fuse_req_t req, fuse_ino_t ino, s= ize_t size, "off=3D%lu)\n", ino, size, (unsigned long) offset); =20 buf.buf[0].flags =3D FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK; - buf.buf[0].fd =3D fi->fh; + buf.buf[0].fd =3D lo_fi_fd(req, fi); buf.buf[0].pos =3D offset; =20 fuse_reply_data(req, &buf, FUSE_BUF_SPLICE_MOVE); @@ -1191,7 +1256,7 @@ static void lo_write_buf(fuse_req_t req, fuse_ino_t i= no, struct fuse_bufvec out_buf =3D FUSE_BUFVEC_INIT(fuse_buf_size(in_buf)); =20 out_buf.buf[0].flags =3D FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK; - out_buf.buf[0].fd =3D fi->fh; + out_buf.buf[0].fd =3D lo_fi_fd(req, fi); out_buf.buf[0].pos =3D off; =20 if (lo_debug(req)) @@ -1234,7 +1299,8 @@ static void lo_fallocate(fuse_req_t req, fuse_ino_t i= no, int mode, return; } =20 - err =3D posix_fallocate(fi->fh, offset, length); + err =3D posix_fallocate(lo_fi_fd(req, fi), offset, + length); #endif =20 fuse_reply_err(req, err); @@ -1246,7 +1312,7 @@ static void lo_flock(fuse_req_t req, fuse_ino_t ino, = struct fuse_file_info *fi, int res; (void) ino; =20 - res =3D flock(fi->fh, op); + res =3D flock(lo_fi_fd(req, fi), op); =20 fuse_reply_err(req, res =3D=3D -1 ? errno : 0); } @@ -1458,17 +1524,20 @@ static void lo_copy_file_range(fuse_req_t req, fuse= _ino_t ino_in, off_t off_in, struct fuse_file_info *fi_out, size_t len, int flags) { + int in_fd, out_fd; ssize_t res; =20 - if (lo_debug(req)) - fuse_log(FUSE_LOG_DEBUG, "lo_copy_file_range(ino=3D%" PRIu64 "/fd=3D%lu,= " - "off=3D%lu, ino=3D%" PRIu64 "/fd=3D%lu, " - "off=3D%lu, size=3D%zd, flags=3D0x%x)\n", - ino_in, fi_in->fh, off_in, ino_out, fi_out->fh, off_out, - len, flags); - - res =3D copy_file_range(fi_in->fh, &off_in, fi_out->fh, &off_out, len, - flags); + in_fd =3D lo_fi_fd(req, fi_in); + out_fd =3D lo_fi_fd(req, fi_out); + + fuse_log(FUSE_LOG_DEBUG, + "lo_copy_file_range(ino=3D%" PRIu64 "/fd=3D%d, " + "off=3D%lu, ino=3D%" PRIu64 "/fd=3D%d, " + "off=3D%lu, size=3D%zd, flags=3D0x%x)\n", + ino_in, in_fd, off_in, ino_out, out_fd, off_out, len, + flags); + + res =3D copy_file_range(in_fd, &off_in, out_fd, &off_out, len, flags); if (res < 0) fuse_reply_err(req, -errno); else @@ -1552,6 +1621,7 @@ int main(int argc, char *argv[]) root_elem->inode =3D &lo.root; =20 lo_map_init(&lo.dirp_map); + lo_map_init(&lo.fd_map); =20 if (fuse_parse_cmdline(&args, &opts) !=3D 0) return 1; @@ -1646,6 +1716,7 @@ err_out2: err_out1: fuse_opt_free_args(&args); =20 + lo_map_destroy(&lo.fd_map); lo_map_destroy(&lo.dirp_map); lo_map_destroy(&lo.ino_map); =20 --=20 2.23.0