Commit 5bccda0e authored Feb 23, 2012 by Jeff Layton Committed by Steve French Feb 26, 2012

cifs: fix dentry refcount leak when opening a FIFO on lookup



The cifs code will attempt to open files on lookup under certain
circumstances. What happens though if we find that the file we opened
was actually a FIFO or other special file?

Currently, the open filehandle just ends up being leaked leading to
a dentry refcount mismatch and oops on umount. Fix this by having the
code close the filehandle on the server if it turns out not to be a
regular file. While we're at it, change this spaghetti if statement
into a switch too.

Cc: stable@vger.kernel.org
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

parent 6de2ce42

fs/cifs/dir.c

+18 −2

Original line number	Diff line number	Diff line
		@@ -584,11 +584,27 @@ cifs_lookup(struct inode parent_dir_inode, struct dentry direntry,
		* If either that or op not supported returned, follow
		* the normal lookup.
		*/
		if ((rc == 0) \|\| (rc == -ENOENT))
		switch (rc) {
		case 0:
		/*
		* The server may allow us to open things like
		* FIFOs, but the client isn't set up to deal
		* with that. If it's not a regular file, just
		* close it and proceed as if it were a normal
		* lookup.
		*/
		if (newInode && !S_ISREG(newInode->i_mode)) {
		CIFSSMBClose(xid, pTcon, fileHandle);
		break;
		}
		case -ENOENT:
		posix_open = true;
		else if ((rc == -EINVAL) \|\| (rc != -EOPNOTSUPP))
		case -EOPNOTSUPP:
		break;
		default:
		pTcon->broken_posix_open = true;
		}
		}
		if (!posix_open)
		rc = cifs_get_inode_info_unix(&newInode, full_path,
		parent_dir_inode->i_sb, xid);