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Subject[PATCH 3.16 065/346] cifs: Check for existing directory when opening file with O_CREAT
3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sachin Prabhu <sprabhu@redhat.com>

commit 8d9535b6efd86e6c07da59f97e68f44efb7fe080 upstream.

When opening a file with O_CREAT flag, check to see if the file opened
is an existing directory.

This prevents the directory from being opened which subsequently causes
a crash when the close function for directories cifs_closedir() is called
which frees up the file->private_data memory while the file is still
listed on the open file list for the tcon.

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/cifs/dir.c | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -229,6 +229,13 @@ cifs_do_create(struct inode *inode, stru
goto cifs_create_get_file_info;
}

+ if (S_ISDIR(newinode->i_mode)) {
+ CIFSSMBClose(xid, tcon, fid->netfid);
+ iput(newinode);
+ rc = -EISDIR;
+ goto out;
+ }
+
if (!S_ISREG(newinode->i_mode)) {
/*
* The server may allow us to open things like
@@ -399,10 +406,14 @@ cifs_create_set_dentry:
if (rc != 0) {
cifs_dbg(FYI, "Create worked, get_inode_info failed rc = %d\n",
rc);
- if (server->ops->close)
- server->ops->close(xid, tcon, fid);
- goto out;
+ goto out_err;
}
+
+ if (S_ISDIR(newinode->i_mode)) {
+ rc = -EISDIR;
+ goto out_err;
+ }
+
d_drop(direntry);
d_add(direntry, newinode);

@@ -410,6 +421,13 @@ out:
kfree(buf);
kfree(full_path);
return rc;
+
+out_err:
+ if (server->ops->close)
+ server->ops->close(xid, tcon, fid);
+ if (newinode)
+ iput(newinode);
+ goto out;
}

int
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