[PATCHv3 06/16] staging: usbip: Add proper error reporting

Dominik Paulus dominik.paulus at fau.de
Sat Sep 28 17:42:43 UTC 2013


This patch adds new error codes and features extended error reporting in
op_common packets.

Signed-off-by: Dominik Paulus <dominik.paulus at fau.de>
Signed-off-by: Tobias Polzer <tobias.polzer at fau.de>
---
 drivers/staging/usbip/userspace/src/usbip_attach.c |  4 +-
 drivers/staging/usbip/userspace/src/usbip_list.c   |  3 +-
 .../staging/usbip/userspace/src/usbip_network.c    | 50 ++++++++++++++++------
 .../staging/usbip/userspace/src/usbip_network.h    | 17 +++++++-
 drivers/staging/usbip/userspace/src/usbipd.c       | 29 +++++++------
 5 files changed, 74 insertions(+), 29 deletions(-)

diff --git a/drivers/staging/usbip/userspace/src/usbip_attach.c b/drivers/staging/usbip/userspace/src/usbip_attach.c
index 2363e56..2a3f313 100644
--- a/drivers/staging/usbip/userspace/src/usbip_attach.c
+++ b/drivers/staging/usbip/userspace/src/usbip_attach.c
@@ -147,7 +147,7 @@ static int query_import_device(int sockfd, char *busid)
 	/* receive a reply */
 	rc = usbip_net_recv_op_common(sockfd, &code);
 	if (rc < 0) {
-		err("recv op_common");
+		err("recv op_common: %s", usbip_net_strerror(rc));
 		return -1;
 	}
 
@@ -177,7 +177,7 @@ static int attach_device(char *host, char *busid)
 
 	sockfd = usbip_net_connect(host);
 	if (sockfd < 0) {
-		err("tcp connect");
+		err("connection attempt failed");
 		return -1;
 	}
 
diff --git a/drivers/staging/usbip/userspace/src/usbip_list.c b/drivers/staging/usbip/userspace/src/usbip_list.c
index e4fa5b8..ff7acf8 100644
--- a/drivers/staging/usbip/userspace/src/usbip_list.c
+++ b/drivers/staging/usbip/userspace/src/usbip_list.c
@@ -64,7 +64,8 @@ static int get_exported_devices(char *host, int sockfd)
 
 	rc = usbip_net_recv_op_common(sockfd, &code);
 	if (rc < 0) {
-		dbg("usbip_net_recv_op_common failed");
+		err("usbip_net_recv_op_common failed: %s",
+			usbip_net_strerror(rc));
 		return -1;
 	}
 
diff --git a/drivers/staging/usbip/userspace/src/usbip_network.c b/drivers/staging/usbip/userspace/src/usbip_network.c
index 9425cb6..e573cb2 100644
--- a/drivers/staging/usbip/userspace/src/usbip_network.c
+++ b/drivers/staging/usbip/userspace/src/usbip_network.c
@@ -181,7 +181,7 @@ int usbip_net_recv_op_common(int sockfd, uint16_t *code)
 	rc = usbip_net_recv(sockfd, &op_common, sizeof(op_common));
 	if (rc < 0) {
 		dbg("usbip_net_recv failed: %d", rc);
-		goto err;
+		return -ERR_SYSERR;
 	}
 
 	PACK_OP_COMMON(0, &op_common);
@@ -189,30 +189,48 @@ int usbip_net_recv_op_common(int sockfd, uint16_t *code)
 	if (op_common.version != USBIP_VERSION) {
 		dbg("version mismatch: %d %d", op_common.version,
 		    USBIP_VERSION);
-		goto err;
+		return -ERR_MISMATCH;
 	}
 
 	switch (*code) {
 	case OP_UNSPEC:
 		break;
 	default:
-		if (op_common.code != *code) {
+		/*
+		 * Only accept expected opcode. Exception: OP_REPLY
+		 * flag set may be sent as a reply to all requests,
+		 * if only used for status reporting.
+		 */
+		if (op_common.code != *code && op_common.code != OP_REPLY) {
 			dbg("unexpected pdu %#0x for %#0x", op_common.code,
 			    *code);
-			goto err;
+			return -ERR_UNEXPECTED;
 		}
 	}
 
-	if (op_common.status != ST_OK) {
-		dbg("request failed at peer: %d", op_common.status);
-		goto err;
-	}
-
 	*code = op_common.code;
 
-	return 0;
-err:
-	return -1;
+	return -op_common.status;
+}
+
+const char *usbip_net_strerror(int status)
+{
+	static const char *const errs[] = {
+		/* ERR_OK */ "Success",
+		/* ERR_NA */ "Command failed",
+		/* ERR_MISMATCH */ "Protocol version mismatch",
+		/* ERR_SYSERR */ "System error",
+		/* ERR_UNEXPECTED */ "Unexpected opcode received",
+		/* ERR_AUTHREQ */ "Server requires authentication",
+		/* ERR_PERM */ "Permission denied",
+		/* ERR_NOTFOUND */ "Requested device not found",
+		/* ERR_NOAUTH */ "Server doesn't support authentication"
+	};
+	if (status < 0)
+		status = -status;
+	if (status >= (int) (sizeof(errs) / sizeof(*errs)))
+		return "Invalid";
+	return errs[status];
 }
 
 int usbip_net_set_reuseaddr(int sockfd)
@@ -363,6 +381,7 @@ int usbip_net_connect(char *hostname)
 #ifdef HAVE_GNUTLS
 	if (usbip_srp_password) {
 		int rc;
+		uint16_t code = OP_REP_STARTTLS;
 
 		rc = usbip_net_send_op_common(sockfd, OP_REQ_STARTTLS, 0);
 		if (rc < 0) {
@@ -370,6 +389,13 @@ int usbip_net_connect(char *hostname)
 			return EAI_SYSTEM;
 		}
 
+		rc = usbip_net_recv_op_common(sockfd, &code);
+		if (rc < 0) {
+			err("STARTTLS attempt failed: %s",
+				usbip_net_strerror(rc));
+			return -1;
+		}
+
 		rc = usbip_net_srp_handshake(sockfd);
 		if (rc < 0) {
 			err("Unable to perform TLS handshake (wrong password?): %s",
diff --git a/drivers/staging/usbip/userspace/src/usbip_network.h b/drivers/staging/usbip/userspace/src/usbip_network.h
index 758656b..d3c1b71 100644
--- a/drivers/staging/usbip/userspace/src/usbip_network.h
+++ b/drivers/staging/usbip/userspace/src/usbip_network.h
@@ -29,8 +29,15 @@ struct op_common {
 	uint16_t code;
 
 	/* add more error code */
-#define ST_OK	0x00
-#define ST_NA	0x01
+#define ERR_OK         0x00
+#define ERR_NA         0x01
+#define ERR_MISMATCH   0x02
+#define ERR_SYSERR     0x03
+#define ERR_UNEXPECTED 0x04
+#define ERR_AUTHREQ    0x05
+#define ERR_PERM       0x06
+#define ERR_NOTFOUND   0x07
+#define ERR_NOAUTH     0x08
 	uint32_t status; /* op_code status (for reply) */
 
 } __attribute__((packed));
@@ -179,10 +186,16 @@ void usbip_net_pack_uint32_t(int pack, uint32_t *num);
 void usbip_net_pack_uint16_t(int pack, uint16_t *num);
 void usbip_net_pack_usb_device(int pack, struct usbip_usb_device *udev);
 void usbip_net_pack_usb_interface(int pack, struct usbip_usb_interface *uinf);
+const char *usbip_net_strerror(int status);
 
 ssize_t usbip_net_recv(int sockfd, void *buff, size_t bufflen);
 ssize_t usbip_net_send(int sockfd, void *buff, size_t bufflen);
 int usbip_net_send_op_common(int sockfd, uint32_t code, uint32_t status);
+/*
+ * Receive opcode.
+ * Returns: 0 on success, negative error code (that may be passed to
+ * usbip_net_strerror) on failure.
+ */
 int usbip_net_recv_op_common(int sockfd, uint16_t *code);
 int usbip_net_set_reuseaddr(int sockfd);
 int usbip_net_set_nodelay(int sockfd);
diff --git a/drivers/staging/usbip/userspace/src/usbipd.c b/drivers/staging/usbip/userspace/src/usbipd.c
index bc1fd19..ae572c6 100644
--- a/drivers/staging/usbip/userspace/src/usbipd.c
+++ b/drivers/staging/usbip/userspace/src/usbipd.c
@@ -234,7 +234,7 @@ static int recv_request_import(int sockfd)
 	struct sysfs_attribute *usbip_acl;
 	char ip_attr_path[SYSFS_PATH_MAX];
 	int found = 0;
-	int error = 0;
+	int error = ERR_OK;
 	int rc;
 
 	memset(&req, 0, sizeof(req));
@@ -263,7 +263,7 @@ static int recv_request_import(int sockfd)
 		/* export device needs a TCP/IP socket descriptor */
 		rc = usbip_host_export_device(edev, sockfd);
 		if (rc < 0)
-			error = 1;
+			error = ERR_SYSERR;
 
 		/* check for allowed IPs */
 		snprintf(ip_attr_path, sizeof(ip_attr_path), "%s/%s:%d.%d/%s",
@@ -275,11 +275,11 @@ static int recv_request_import(int sockfd)
 			rc = sysfs_read_attribute(usbip_acl);
 			if (rc < 0) {
 				err("Unable to open sysfs");
-				error = 1;
+				error = ERR_SYSERR;
 			} else if (check_allowed(usbip_acl->value, sockfd) != 1) {
 				info("Access denied to device %s",
 					edev->udev.busid);
-				error = 1;
+				error = ERR_PERM;
 			}
 			sysfs_close_attribute(usbip_acl);
 		} else {
@@ -287,17 +287,16 @@ static int recv_request_import(int sockfd)
 		}
 	} else {
 		info("requested device not found: %s", req.busid);
-		error = 1;
+		error = ERR_NOTFOUND;
 	}
 
-	rc = usbip_net_send_op_common(sockfd, OP_REP_IMPORT,
-				      (!error ? ST_OK : ST_NA));
+	rc = usbip_net_send_op_common(sockfd, OP_REP_IMPORT, error);
 	if (rc < 0) {
 		dbg("usbip_net_send_op_common failed: %#0x", OP_REP_IMPORT);
 		return -1;
 	}
 
-	if (error) {
+	if (error != 0) {
 		dbg("import request busid %s: failed", req.busid);
 		return -1;
 	}
@@ -333,7 +332,7 @@ static int send_reply_devlist(int connfd)
 	}
 	info("exportable devices: %d", reply.ndev);
 
-	rc = usbip_net_send_op_common(connfd, OP_REP_DEVLIST, ST_OK);
+	rc = usbip_net_send_op_common(connfd, OP_REP_DEVLIST, ERR_OK);
 	if (rc < 0) {
 		dbg("usbip_net_send_op_common failed: %#0x", OP_REP_DEVLIST);
 		return -1;
@@ -416,7 +415,8 @@ static int recv_pdu(int connfd)
 
 		ret = usbip_net_recv_op_common(connfd, &code);
 		if (ret < 0) {
-			dbg("could not receive opcode: %#0x", code);
+			dbg("could not receive opcode: %#0x: %s", code,
+				usbip_net_strerror(ret));
 			return -1;
 		}
 
@@ -424,7 +424,8 @@ static int recv_pdu(int connfd)
 
 		/* We require an authenticated encryption */
 		if (!auth && code != OP_REQ_STARTTLS) {
-			usbip_net_send_op_common(connfd, OP_REPLY, ST_NA);
+			info("Unauthenticated connection attempt");
+			usbip_net_send_op_common(connfd, OP_REPLY, ERR_AUTHREQ);
 			return -1;
 		}
 
@@ -432,10 +433,14 @@ static int recv_pdu(int connfd)
 #ifdef HAVE_GNUTLS
 		case OP_REQ_STARTTLS:
 			if (!need_auth) {
-				ret = -1;
+				usbip_net_send_op_common(connfd, OP_REPLY,
+					ERR_NOAUTH);
 				err("Unexpected TLS handshake attempt (client "
 					"uses password, server doesn't)");
+				ret = -1;
 			} else {
+				usbip_net_send_op_common(connfd, OP_REPLY,
+					ERR_OK);
 				ret = net_srp_server_handshake(connfd);
 				if (ret != 0)
 					err("TLS handshake failed");
-- 
1.8.4



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