From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: mszeredi@redhat.com, Daniel Berrange <berrange@redhat.com>,
slp@redhat.com, "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Greg Kurz <groug@kaod.org>,
virtio-fs@redhat.com, Stefan Hajnoczi <stefanha@redhat.com>,
P J P <ppandit@redhat.com>, Laszlo Ersek <lersek@redhat.com>,
vgoyal@redhat.com
Subject: [PATCH v4 2/3] virtiofsd: optionally return inode pointer from lo_do_lookup()
Date: Wed, 3 Feb 2021 11:37:18 +0000 [thread overview]
Message-ID: <20210203113719.83633-3-stefanha@redhat.com> (raw)
In-Reply-To: <20210203113719.83633-1-stefanha@redhat.com>
lo_do_lookup() finds an existing inode or allocates a new one. It
increments nlookup so that the inode stays alive until the client
releases it.
Existing callers don't need the struct lo_inode so the function doesn't
return it. Extend the function to optionally return the inode. The next
commit will need it.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
tools/virtiofsd/passthrough_ll.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index e63cbd3fb7..c87a1f3d72 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -831,11 +831,13 @@ static int do_statx(struct lo_data *lo, int dirfd, const char *pathname,
}
/*
- * Increments nlookup and caller must release refcount using
- * lo_inode_put(&parent).
+ * Increments nlookup on the inode on success. unref_inode_lolocked() must be
+ * called eventually to decrement nlookup again. If inodep is non-NULL, the
+ * inode pointer is stored and the caller must call lo_inode_put().
*/
static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
- struct fuse_entry_param *e)
+ struct fuse_entry_param *e,
+ struct lo_inode **inodep)
{
int newfd;
int res;
@@ -845,6 +847,10 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
struct lo_inode *inode = NULL;
struct lo_inode *dir = lo_inode(req, parent);
+ if (inodep) {
+ *inodep = NULL;
+ }
+
/*
* name_to_handle_at() and open_by_handle_at() can reach here with fuse
* mount point in guest, but we don't have its inode info in the
@@ -913,7 +919,14 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
pthread_mutex_unlock(&lo->mutex);
}
e->ino = inode->fuse_ino;
- lo_inode_put(lo, &inode);
+
+ /* Transfer ownership of inode pointer to caller or drop it */
+ if (inodep) {
+ *inodep = inode;
+ } else {
+ lo_inode_put(lo, &inode);
+ }
+
lo_inode_put(lo, &dir);
fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n", (unsigned long long)parent,
@@ -948,7 +961,7 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)
return;
}
- err = lo_do_lookup(req, parent, name, &e);
+ err = lo_do_lookup(req, parent, name, &e, NULL);
if (err) {
fuse_reply_err(req, err);
} else {
@@ -1056,7 +1069,7 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent,
goto out;
}
- saverr = lo_do_lookup(req, parent, name, &e);
+ saverr = lo_do_lookup(req, parent, name, &e, NULL);
if (saverr) {
goto out;
}
@@ -1534,7 +1547,7 @@ static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
if (plus) {
if (!is_dot_or_dotdot(name)) {
- err = lo_do_lookup(req, ino, name, &e);
+ err = lo_do_lookup(req, ino, name, &e, NULL);
if (err) {
goto error;
}
@@ -1732,7 +1745,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
}
fi->fh = fh;
- err = lo_do_lookup(req, parent, name, &e);
+ err = lo_do_lookup(req, parent, name, &e, NULL);
}
if (lo->cache == CACHE_NONE) {
fi->direct_io = 1;
--
2.29.2
next prev parent reply other threads:[~2021-02-03 11:41 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
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 ` Stefan Hajnoczi [this message]
2021-02-03 14:20 ` [PATCH v4 2/3] virtiofsd: optionally return inode pointer from lo_do_lookup() 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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