ncpfs: make sure server connection survives a kill

Use internal buffers instead of the ones supplied by the caller
so that a caller can be interrupted without having to abort the
entire ncp connection.

Signed-off-by: Pierre Ossman <ossman@cendio.se>
Acked-by: Petr Vandrovec <petr@vandrovec.name>

1 files changed, 89 insertions, 62 deletions

diff --git a/fs/ncpfs/sock.c b/fs/ncpfs/sock.c
index e496d8b65e9..e37df8d5fe7 100644
--- a/fs/ncpfs/sock.c
+++ b/fs/ncpfs/sock.c
@@ -14,6 +14,7 @@
 #include <linux/socket.h>
 #include <linux/fcntl.h>
 #include <linux/stat.h>
+#include <linux/string.h>
 #include <asm/uaccess.h>
 #include <linux/in.h>
 #include <linux/net.h>
@@ -55,10 +56,11 @@ static int _send(struct socket *sock, const void *buff, int len)
 struct ncp_request_reply {
 	struct list_head req;
 	wait_queue_head_t wq;
-	struct ncp_reply_header* reply_buf;
+	atomic_t refs;
+	unsigned char* reply_buf;
 	size_t datalen;
 	int result;
-	enum { RQ_DONE, RQ_INPROGRESS, RQ_QUEUED, RQ_IDLE } status;
+	enum { RQ_DONE, RQ_INPROGRESS, RQ_QUEUED, RQ_IDLE, RQ_ABANDONED } status;
 	struct kvec* tx_ciov;
 	size_t tx_totallen;
 	size_t tx_iovlen;
@@ -67,6 +69,32 @@ struct ncp_request_reply {
 	u_int32_t sign[6];
 };
 
+static inline struct ncp_request_reply* ncp_alloc_req(void)
+{
+	struct ncp_request_reply *req;
+
+	req = kmalloc(sizeof(struct ncp_request_reply), GFP_KERNEL);
+	if (!req)
+		return NULL;
+
+	init_waitqueue_head(&req->wq);
+	atomic_set(&req->refs, (1));
+	req->status = RQ_IDLE;
+
+	return req;
+}
+
+static void ncp_req_get(struct ncp_request_reply *req)
+{
+	atomic_inc(&req->refs);
+}
+
+static void ncp_req_put(struct ncp_request_reply *req)
+{
+	if (atomic_dec_and_test(&req->refs))
+		kfree(req);
+}
+
 void ncp_tcp_data_ready(struct sock *sk, int len)
 {
 	struct ncp_server *server = sk->sk_user_data;
@@ -101,14 +129,17 @@ void ncpdgram_timeout_call(unsigned long v)
 	schedule_work(&server->timeout_tq);
 }
 
-static inline void ncp_finish_request(struct ncp_request_reply *req, int result)
+static inline void ncp_finish_request(struct ncp_server *server, struct ncp_request_reply *req, int result)
 {
 	req->result = result;
+	if (req->status != RQ_ABANDONED)
+		memcpy(req->reply_buf, server->rxbuf, req->datalen);
 	req->status = RQ_DONE;
 	wake_up_all(&req->wq);
+	ncp_req_put(req);
 }
 
-static void __abort_ncp_connection(struct ncp_server *server, struct ncp_request_reply *aborted, int err)
+static void __abort_ncp_connection(struct ncp_server *server)
 {
 	struct ncp_request_reply *req;
 
@@ -118,31 +149,19 @@ static void __abort_ncp_connection(struct ncp_server *server, struct ncp_request
 		req = list_entry(server->tx.requests.next, struct ncp_request_reply, req);
 		
 		list_del_init(&req->req);
-		if (req == aborted) {
-			ncp_finish_request(req, err);
-		} else {
-			ncp_finish_request(req, -EIO);
-		}
+		ncp_finish_request(server, req, -EIO);
 	}
 	req = server->rcv.creq;
 	if (req) {
 		server->rcv.creq = NULL;
-		if (req == aborted) {
-			ncp_finish_request(req, err);
-		} else {
-			ncp_finish_request(req, -EIO);
-		}
+		ncp_finish_request(server, req, -EIO);
 		server->rcv.ptr = NULL;
 		server->rcv.state = 0;
 	}
 	req = server->tx.creq;
 	if (req) {
 		server->tx.creq = NULL;
-		if (req == aborted) {
-			ncp_finish_request(req, err);
-		} else {
-			ncp_finish_request(req, -EIO);
-		}
+		ncp_finish_request(server, req, -EIO);
 	}
 }
 
@@ -160,10 +179,12 @@ static inline void __ncp_abort_request(struct ncp_server *server, struct ncp_req
 			break;
 		case RQ_QUEUED:
 			list_del_init(&req->req);
-			ncp_finish_request(req, err);
+			ncp_finish_request(server, req, err);
 			break;
 		case RQ_INPROGRESS:
-			__abort_ncp_connection(server, req, err);
+			req->status = RQ_ABANDONED;
+			break;
+		case RQ_ABANDONED:
 			break;
 	}
 }
@@ -177,7 +198,7 @@ static inline void ncp_abort_request(struct ncp_server *server, struct ncp_reque
 
 static inline void __ncptcp_abort(struct ncp_server *server)
 {
-	__abort_ncp_connection(server, NULL, 0);
+	__abort_ncp_connection(server);
 }
 
 static int ncpdgram_send(struct socket *sock, struct ncp_request_reply *req)
@@ -294,6 +315,11 @@ static void ncptcp_start_request(struct ncp_server *server, struct ncp_request_r
 
 static inline void __ncp_start_request(struct ncp_server *server, struct ncp_request_reply *req)
 {
+	/* we copy the data so that we do not depend on the caller
+	   staying alive */
+	memcpy(server->txbuf, req->tx_iov[1].iov_base, req->tx_iov[1].iov_len);
+	req->tx_iov[1].iov_base = server->txbuf;
+
 	if (server->ncp_sock->type == SOCK_STREAM)
 		ncptcp_start_request(server, req);
 	else
@@ -308,6 +334,7 @@ static int ncp_add_request(struct ncp_server *server, struct ncp_request_reply *
 		printk(KERN_ERR "ncpfs: tcp: Server died\n");
 		return -EIO;
 	}
+	ncp_req_get(req);
 	if (server->tx.creq || server->rcv.creq) {
 		req->status = RQ_QUEUED;
 		list_add_tail(&req->req, &server->tx.requests);
@@ -409,7 +436,7 @@ void ncpdgram_rcv_proc(struct work_struct *work)
 					server->timeout_last = NCP_MAX_RPC_TIMEOUT;
 					mod_timer(&server->timeout_tm, jiffies + NCP_MAX_RPC_TIMEOUT);
 				} else if (reply.type == NCP_REPLY) {
-					result = _recv(sock, (void*)req->reply_buf, req->datalen, MSG_DONTWAIT);
+					result = _recv(sock, server->rxbuf, req->datalen, MSG_DONTWAIT);
 #ifdef CONFIG_NCPFS_PACKET_SIGNING
 					if (result >= 0 && server->sign_active && req->tx_type != NCP_DEALLOC_SLOT_REQUEST) {
 						if (result < 8 + 8) {
@@ -419,7 +446,7 @@ void ncpdgram_rcv_proc(struct work_struct *work)
 							
 							result -= 8;
 							hdrl = sock->sk->sk_family == AF_INET ? 8 : 6;
-							if (sign_verify_reply(server, ((char*)req->reply_buf) + hdrl, result - hdrl, cpu_to_le32(result), ((char*)req->reply_buf) + result)) {
+							if (sign_verify_reply(server, server->rxbuf + hdrl, result - hdrl, cpu_to_le32(result), server->rxbuf + result)) {
 								printk(KERN_INFO "ncpfs: Signature violation\n");
 								result = -EIO;
 							}
@@ -428,7 +455,7 @@ void ncpdgram_rcv_proc(struct work_struct *work)
 #endif
 					del_timer(&server->timeout_tm);
 				     	server->rcv.creq = NULL;
-					ncp_finish_request(req, result);
+					ncp_finish_request(server, req, result);
 					__ncp_next_request(server);
 					mutex_unlock(&server->rcv.creq_mutex);
 					continue;
@@ -478,12 +505,6 @@ void ncpdgram_timeout_proc(struct work_struct *work)
 	mutex_unlock(&server->rcv.creq_mutex);
 }
 
-static inline void ncp_init_req(struct ncp_request_reply* req)
-{
-	init_waitqueue_head(&req->wq);
-	req->status = RQ_IDLE;
-}
-
 static int do_tcp_rcv(struct ncp_server *server, void *buffer, size_t len)
 {
 	int result;
@@ -601,8 +622,8 @@ skipdata:;
 					goto skipdata;
 				}
 				req->datalen = datalen - 8;
-				req->reply_buf->type = NCP_REPLY;
-				server->rcv.ptr = (unsigned char*)(req->reply_buf) + 2;
+				((struct ncp_reply_header*)server->rxbuf)->type = NCP_REPLY;
+				server->rcv.ptr = server->rxbuf + 2;
 				server->rcv.len = datalen - 10;
 				server->rcv.state = 1;
 				break;
@@ -615,12 +636,12 @@ skipdata:;
 			case 1:
 				req = server->rcv.creq;
 				if (req->tx_type != NCP_ALLOC_SLOT_REQUEST) {
-					if (req->reply_buf->sequence != server->sequence) {
+					if (((struct ncp_reply_header*)server->rxbuf)->sequence != server->sequence) {
 						printk(KERN_ERR "ncpfs: tcp: Bad sequence number\n");
 						__ncp_abort_request(server, req, -EIO);
 						return -EIO;
 					}
-					if ((req->reply_buf->conn_low | (req->reply_buf->conn_high << 8)) != server->connection) {
+					if ((((struct ncp_reply_header*)server->rxbuf)->conn_low | (((struct ncp_reply_header*)server->rxbuf)->conn_high << 8)) != server->connection) {
 						printk(KERN_ERR "ncpfs: tcp: Connection number mismatch\n");
 						__ncp_abort_request(server, req, -EIO);
 						return -EIO;
@@ -628,14 +649,14 @@ skipdata:;
 				}
 #ifdef CONFIG_NCPFS_PACKET_SIGNING				
 				if (server->sign_active && req->tx_type != NCP_DEALLOC_SLOT_REQUEST) {
-					if (sign_verify_reply(server, (unsigned char*)(req->reply_buf) + 6, req->datalen - 6, cpu_to_be32(req->datalen + 16), &server->rcv.buf.type)) {
+					if (sign_verify_reply(server, server->rxbuf + 6, req->datalen - 6, cpu_to_be32(req->datalen + 16), &server->rcv.buf.type)) {
 						printk(KERN_ERR "ncpfs: tcp: Signature violation\n");
 						__ncp_abort_request(server, req, -EIO);
 						return -EIO;
 					}
 				}
 #endif				
-				ncp_finish_request(req, req->datalen);
+				ncp_finish_request(server, req, req->datalen);
 			nextreq:;
 				__ncp_next_request(server);
 			case 2:
@@ -645,7 +666,7 @@ skipdata:;
 				server->rcv.state = 0;
 				break;
 			case 3:
-				ncp_finish_request(server->rcv.creq, -EIO);
+				ncp_finish_request(server, server->rcv.creq, -EIO);
 				goto nextreq;
 			case 5:
 				info_server(server, 0, server->unexpected_packet.data, server->unexpected_packet.len);
@@ -675,28 +696,39 @@ void ncp_tcp_tx_proc(struct work_struct *work)
 }
 
 static int do_ncp_rpc_call(struct ncp_server *server, int size,
-		struct ncp_reply_header* reply_buf, int max_reply_size)
+		unsigned char* reply_buf, int max_reply_size)
 {
 	int result;
-	struct ncp_request_reply req;
-
-	ncp_init_req(&req);
-	req.reply_buf = reply_buf;
-	req.datalen = max_reply_size;
-	req.tx_iov[1].iov_base = server->packet;
-	req.tx_iov[1].iov_len = size;
-	req.tx_iovlen = 1;
-	req.tx_totallen = size;
-	req.tx_type = *(u_int16_t*)server->packet;
-
-	result = ncp_add_request(server, &req);
-	if (result < 0) {
-		return result;
-	}
-	if (wait_event_interruptible(req.wq, req.status == RQ_DONE)) {
-		ncp_abort_request(server, &req, -EIO);
+	struct ncp_request_reply *req;
+
+	req = ncp_alloc_req();
+	if (!req)
+		return -ENOMEM;
+
+	req->reply_buf = reply_buf;
+	req->datalen = max_reply_size;
+	req->tx_iov[1].iov_base = server->packet;
+	req->tx_iov[1].iov_len = size;
+	req->tx_iovlen = 1;
+	req->tx_totallen = size;
+	req->tx_type = *(u_int16_t*)server->packet;
+
+	result = ncp_add_request(server, req);
+	if (result < 0)
+		goto out;
+
+	if (wait_event_interruptible(req->wq, req->status == RQ_DONE)) {
+		ncp_abort_request(server, req, -EINTR);
+		result = -EINTR;
+		goto out;
 	}
-	return req.result;
+
+	result = req->result;
+
+out:
+	ncp_req_put(req);
+
+	return result;
 }
 
 /*
@@ -751,11 +783,6 @@ static int ncp_do_request(struct ncp_server *server, int size,
 
 	DDPRINTK("do_ncp_rpc_call returned %d\n", result);
 
-	if (result < 0) {
-		/* There was a problem with I/O, so the connections is
-		 * no longer usable. */
-		ncp_invalidate_conn(server);
-	}
 	return result;
 }