Commit 460cf341 authored Sep 14, 2010 by Jeff Layton Committed by Steve French Sep 14, 2010

cifs: fix potential double put of TCP session reference



cifs_get_smb_ses must be called on a server pointer on which it holds an
active reference. It first does a search for an existing SMB session. If
it finds one, it'll put the server reference and then try to ensure that
the negprot is done, etc.

If it encounters an error at that point then it'll return an error.
There's a potential problem here though. When cifs_get_smb_ses returns
an error, the caller will also put the TCP server reference leading to a
double-put.

Fix this by having cifs_get_smb_ses only put the server reference if
it found an existing session that it could use and isn't returning an
error.

Cc: stable@kernel.org
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

parent bfa88ea7

fs/cifs/connect.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1706,9 +1706,6 @@ cifs_get_smb_ses(struct TCP_Server_Info server, struct smb_vol volume_info)
		if (ses) {
		cFYI(1, "Existing smb sess found (status=%d)", ses->status);

		/* existing SMB ses has a server reference already */
		cifs_put_tcp_session(server);

		mutex_lock(&ses->session_mutex);
		rc = cifs_negotiate_protocol(xid, ses);
		if (rc) {
		@@ -1731,6 +1728,9 @@ cifs_get_smb_ses(struct TCP_Server_Info server, struct smb_vol volume_info)
		}
		}
		mutex_unlock(&ses->session_mutex);

		/* existing SMB ses has a server reference already */
		cifs_put_tcp_session(server);
		FreeXid(xid);
		return ses;
		}

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