From 97e232e75bbc0032f4a309d248f383384612eafe Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Mon, 27 Jan 2020 19:01:25 +0100 Subject: [PATCH 054/116] virtiofsd: prevent ".." escape in lo_do_readdir() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Dr. David Alan Gilbert Message-id: <20200127190227.40942-51-dgilbert@redhat.com> Patchwork-id: 93507 O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 050/112] virtiofsd: prevent ".." escape in lo_do_readdir() Bugzilla: 1694164 RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Sergio Lopez Pascual From: Stefan Hajnoczi Construct a fake dirent for the root directory's ".." entry. This hides the parent directory from the FUSE client. Signed-off-by: Stefan Hajnoczi Reviewed-by: Sergio Lopez Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit 752272da2b68a2312f0e11fc5303015a6c3ee1ac) Signed-off-by: Miroslav Rezanina --- tools/virtiofsd/passthrough_ll.c | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 79d5966..e3d65c3 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -1149,19 +1149,25 @@ out_err: static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, off_t offset, struct fuse_file_info *fi, int plus) { + struct lo_data *lo = lo_data(req); struct lo_dirp *d; + struct lo_inode *dinode; char *buf = NULL; char *p; size_t rem = size; - int err = ENOMEM; + int err = EBADF; - (void)ino; + dinode = lo_inode(req, ino); + if (!dinode) { + goto error; + } d = lo_dirp(req, fi); if (!d) { goto error; } + err = ENOMEM; buf = calloc(1, size); if (!buf) { goto error; @@ -1192,15 +1198,21 @@ static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, } nextoff = d->entry->d_off; name = d->entry->d_name; + fuse_ino_t entry_ino = 0; + struct fuse_entry_param e = (struct fuse_entry_param){ + .attr.st_ino = d->entry->d_ino, + .attr.st_mode = d->entry->d_type << 12, + }; + + /* Hide root's parent directory */ + if (dinode == &lo->root && strcmp(name, "..") == 0) { + e.attr.st_ino = lo->root.ino; + e.attr.st_mode = DT_DIR << 12; + } + if (plus) { - struct fuse_entry_param e; - if (is_dot_or_dotdot(name)) { - e = (struct fuse_entry_param){ - .attr.st_ino = d->entry->d_ino, - .attr.st_mode = d->entry->d_type << 12, - }; - } else { + if (!is_dot_or_dotdot(name)) { err = lo_do_lookup(req, ino, name, &e); if (err) { goto error; @@ -1210,11 +1222,7 @@ static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, entsize = fuse_add_direntry_plus(req, p, rem, name, &e, nextoff); } else { - struct stat st = { - .st_ino = d->entry->d_ino, - .st_mode = d->entry->d_type << 12, - }; - entsize = fuse_add_direntry(req, p, rem, name, &st, nextoff); + entsize = fuse_add_direntry(req, p, rem, name, &e.attr, nextoff); } if (entsize > rem) { if (entry_ino != 0) { -- 1.8.3.1