SMB: fix leak of validate negotiate info response buffer

Fixes: ff1c038a ("Check SMB3 dialects against downgrade attacks")
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/smb2pdu.c

@@ -648,7 +648,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 {
 	int rc = 0;
 	struct validate_negotiate_info_req vneg_inbuf;
-	struct validate_negotiate_info_rsp *pneg_rsp;
+	struct validate_negotiate_info_rsp *pneg_rsp = NULL;
 	u32 rsplen;
 	u32 inbuflen; /* max of 4 dialects */
 
@@ -728,7 +728,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 
 		/* relax check since Mac returns max bufsize allowed on ioctl */
 		if (rsplen > CIFSMaxBufSize)
-			return -EIO;
+			goto err_rsp_free;
 	}
 
 	/* check validate negotiate info response matches what we got earlier */
@@ -747,10 +747,13 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 
 	/* validate negotiate successful */
 	cifs_dbg(FYI, "validate negotiate info successful\n");
+	kfree(pneg_rsp);
 	return 0;
 
 vneg_out:
 	cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
+err_rsp_free:
+	kfree(pneg_rsp);
 	return -EIO;
 }