[PATCH 02/06] 9p: fix fid refcount leak in v9fs_vfs_get_link

From: Dominique Martinet
Date: Sun Jun 12 2022 - 04:54:23 EST


we check for protocol version later than required, after a fid has
been obtained. Just move the version check earlier.

Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
---
fs/9p/vfs_inode.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 55367ecb9442..18c780ffd4b5 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1250,15 +1250,15 @@ static const char *v9fs_vfs_get_link(struct dentry *dentry,
return ERR_PTR(-ECHILD);

v9ses = v9fs_dentry2v9ses(dentry);
- fid = v9fs_fid_lookup(dentry);
+ if (!v9fs_proto_dotu(v9ses))
+ return ERR_PTR(-EBADF);
+
p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
+ fid = v9fs_fid_lookup(dentry);

if (IS_ERR(fid))
return ERR_CAST(fid);

- if (!v9fs_proto_dotu(v9ses))
- return ERR_PTR(-EBADF);
-
st = p9_client_stat(fid);
p9_client_clunk(fid);
if (IS_ERR(st))
--
2.35.1