From: Greg Kurz <groug@kaod.org>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: mszeredi@redhat.com, Daniel Berrange <berrange@redhat.com>,
slp@redhat.com, qemu-devel@nongnu.org,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
virtio-fs@redhat.com, P J P <ppandit@redhat.com>,
Laszlo Ersek <lersek@redhat.com>,
vgoyal@redhat.com
Subject: Re: [PATCH v4 1/3] virtiofsd: extract lo_do_open() from lo_open()
Date: Wed, 3 Feb 2021 15:20:35 +0100 [thread overview]
Message-ID: <20210203152035.374924b9@bahia.lan> (raw)
In-Reply-To: <20210203113719.83633-2-stefanha@redhat.com>
On Wed, 3 Feb 2021 11:37:17 +0000
Stefan Hajnoczi <stefanha@redhat.com> wrote:
> Both lo_open() and lo_create() have similar code to open a file. Extract
> a common lo_do_open() function from lo_open() that will be used by
> lo_create() in a later commit.
>
> Since lo_do_open() does not otherwise need fuse_req_t req, convert
> lo_add_fd_mapping() to use struct lo_data *lo instead.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
With the s/ENOMEM/-ENOMEM/ change in lo_do_open() suggested by patchew,
Reviewed-by: Greg Kurz <groug@kaod.org>
> tools/virtiofsd/passthrough_ll.c | 73 ++++++++++++++++++++------------
> 1 file changed, 46 insertions(+), 27 deletions(-)
>
> diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
> index 5fb36d9407..e63cbd3fb7 100644
> --- a/tools/virtiofsd/passthrough_ll.c
> +++ b/tools/virtiofsd/passthrough_ll.c
> @@ -459,17 +459,17 @@ static void lo_map_remove(struct lo_map *map, size_t key)
> }
>
> /* Assumes lo->mutex is held */
> -static ssize_t lo_add_fd_mapping(fuse_req_t req, int fd)
> +static ssize_t lo_add_fd_mapping(struct lo_data *lo, int fd)
> {
> struct lo_map_elem *elem;
>
> - elem = lo_map_alloc_elem(&lo_data(req)->fd_map);
> + elem = lo_map_alloc_elem(&lo->fd_map);
> if (!elem) {
> return -1;
> }
>
> elem->fd = fd;
> - return elem - lo_data(req)->fd_map.elems;
> + return elem - lo->fd_map.elems;
> }
>
> /* Assumes lo->mutex is held */
> @@ -1651,6 +1651,38 @@ static void update_open_flags(int writeback, int allow_direct_io,
> }
> }
>
> +static int lo_do_open(struct lo_data *lo, struct lo_inode *inode,
> + struct fuse_file_info *fi)
> +{
> + char buf[64];
> + ssize_t fh;
> + int fd;
> +
> + update_open_flags(lo->writeback, lo->allow_direct_io, fi);
> +
> + sprintf(buf, "%i", inode->fd);
> + fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
> + if (fd == -1) {
> + return -errno;
> + }
> +
> + pthread_mutex_lock(&lo->mutex);
> + fh = lo_add_fd_mapping(lo, fd);
> + pthread_mutex_unlock(&lo->mutex);
> + if (fh == -1) {
> + close(fd);
> + return ENOMEM;
> + }
> +
> + fi->fh = fh;
> + if (lo->cache == CACHE_NONE) {
> + fi->direct_io = 1;
> + } else if (lo->cache == CACHE_ALWAYS) {
> + fi->keep_cache = 1;
> + }
> + return 0;
> +}
> +
> static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
> mode_t mode, struct fuse_file_info *fi)
> {
> @@ -1691,7 +1723,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
> ssize_t fh;
>
> pthread_mutex_lock(&lo->mutex);
> - fh = lo_add_fd_mapping(req, fd);
> + fh = lo_add_fd_mapping(lo, fd);
> pthread_mutex_unlock(&lo->mutex);
> if (fh == -1) {
> close(fd);
> @@ -1892,38 +1924,25 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, 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 = lo_data(req);
> + struct lo_inode *inode = lo_inode(req, ino);
> + int err;
>
> fuse_log(FUSE_LOG_DEBUG, "lo_open(ino=%" PRIu64 ", flags=%d)\n", ino,
> fi->flags);
>
> - update_open_flags(lo->writeback, lo->allow_direct_io, fi);
> -
> - sprintf(buf, "%i", lo_fd(req, ino));
> - fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
> - if (fd == -1) {
> - return (void)fuse_reply_err(req, errno);
> - }
> -
> - pthread_mutex_lock(&lo->mutex);
> - fh = lo_add_fd_mapping(req, fd);
> - pthread_mutex_unlock(&lo->mutex);
> - if (fh == -1) {
> - close(fd);
> - fuse_reply_err(req, ENOMEM);
> + if (!inode) {
> + fuse_reply_err(req, EBADF);
> return;
> }
>
> - fi->fh = fh;
> - if (lo->cache == CACHE_NONE) {
> - fi->direct_io = 1;
> - } else if (lo->cache == CACHE_ALWAYS) {
> - fi->keep_cache = 1;
> + err = lo_do_open(lo, inode, fi);
> + lo_inode_put(lo, &inode);
> + if (err) {
> + fuse_reply_err(req, err);
> + } else {
> + fuse_reply_open(req, fi);
> }
> - fuse_reply_open(req, fi);
> }
>
> static void lo_release(fuse_req_t req, fuse_ino_t ino,
next prev parent reply other threads:[~2021-02-03 14:22 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 11:37 [PATCH v4 0/3] virtiofsd: prevent opening of special files (CVE-2020-35517) Stefan Hajnoczi
2021-02-03 11:37 ` [PATCH v4 1/3] virtiofsd: extract lo_do_open() from lo_open() Stefan Hajnoczi
2021-02-03 14:20 ` Greg Kurz [this message]
2021-02-03 14:47 ` Dr. David Alan Gilbert
2021-02-03 15:45 ` Greg Kurz
2021-02-03 17:47 ` Greg Kurz
2021-02-03 16:57 ` Stefan Hajnoczi
2021-02-03 11:37 ` [PATCH v4 2/3] virtiofsd: optionally return inode pointer from lo_do_lookup() Stefan Hajnoczi
2021-02-03 14:20 ` Greg Kurz
2021-02-03 17:00 ` Stefan Hajnoczi
2021-02-04 8:25 ` Greg Kurz
2021-02-04 9:45 ` Stefan Hajnoczi
2021-02-04 11:19 ` Greg Kurz
2021-02-03 11:37 ` [PATCH v4 3/3] virtiofsd: prevent opening of special files (CVE-2020-35517) Stefan Hajnoczi
2021-02-03 15:28 ` Vivek Goyal
2021-02-03 16:02 ` Greg Kurz
2021-02-03 16:08 ` Vivek Goyal
2021-02-03 17:05 ` Stefan Hajnoczi
2021-02-03 18:05 ` Dr. David Alan Gilbert
2021-02-03 21:14 ` Vivek Goyal
2021-02-04 9:47 ` Stefan Hajnoczi
2021-02-03 15:57 ` Greg Kurz
2021-02-03 17:06 ` Stefan Hajnoczi
2021-02-03 11:46 ` [PATCH v4 0/3] " no-reply
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