DRBD: replace strcpy with strscpy

strcpy is deprecated due to lack of bounds checking. This patch replaces
strcpy with strscpy, the recommended alternative for null terminated
strings, to follow best practices.

I had to do a small refactor for __drbd_send_protocol since it uses
strlen anyways. so why not use that for strscpy.

V2:
 - I forgot about null termination so i fixed it.

Signed-off-by: Eslam Khafagy <[email protected]>

Author: eslammedhat

drivers/block/drbd/drbd_main.c

@@ -742,9 +742,9 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device)
 	}
 
 	if (apv >= 88)
-		strcpy(p->verify_alg, nc->verify_alg);
+		strscpy(p->verify_alg, nc->verify_alg);
 	if (apv >= 89)
-		strcpy(p->csums_alg, nc->csums_alg);
+		strscpy(p->csums_alg, nc->csums_alg);
 	rcu_read_unlock();
 
 	return drbd_send_command(peer_device, sock, cmd, size, NULL, 0);
@@ -771,10 +771,6 @@ int __drbd_send_protocol(struct drbd_connection *connection, enum drbd_packet cm
 		return -EOPNOTSUPP;
 	}
 
-	size = sizeof(*p);
-	if (connection->agreed_pro_version >= 87)
-		size += strlen(nc->integrity_alg) + 1;
-
 	p->protocol      = cpu_to_be32(nc->wire_protocol);
 	p->after_sb_0p   = cpu_to_be32(nc->after_sb_0p);
 	p->after_sb_1p   = cpu_to_be32(nc->after_sb_1p);
@@ -787,8 +783,13 @@ int __drbd_send_protocol(struct drbd_connection *connection, enum drbd_packet cm
 		cf |= CF_DRY_RUN;
 	p->conn_flags    = cpu_to_be32(cf);
 
-	if (connection->agreed_pro_version >= 87)
-		strcpy(p->integrity_alg, nc->integrity_alg);
+	size = sizeof(*p);
+	if (connection->agreed_pro_version >= 87) {
+		int integrity_len = strlen(nc->integrity_alg) + 1;
+		size += integrity_len;
+		strscpy(p->integrity_alg, nc->integrity_alg, integrity_len);
+	}
+
 	rcu_read_unlock();
 
 	return __conn_send_command(connection, sock, cmd, size, NULL, 0);

drivers/block/drbd/drbd_receiver.c

@@ -3985,14 +3985,14 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i
 			*new_net_conf = *old_net_conf;
 
 			if (verify_tfm) {
-				strcpy(new_net_conf->verify_alg, p->verify_alg);
+				strscpy(new_net_conf->verify_alg, p->verify_alg);
 				new_net_conf->verify_alg_len = strlen(p->verify_alg) + 1;
 				crypto_free_shash(peer_device->connection->verify_tfm);
 				peer_device->connection->verify_tfm = verify_tfm;
 				drbd_info(device, "using verify-alg: \"%s\"\n", p->verify_alg);
 			}
 			if (csums_tfm) {
-				strcpy(new_net_conf->csums_alg, p->csums_alg);
+				strscpy(new_net_conf->csums_alg, p->csums_alg);
 				new_net_conf->csums_alg_len = strlen(p->csums_alg) + 1;
 				crypto_free_shash(peer_device->connection->csums_tfm);
 				peer_device->connection->csums_tfm = csums_tfm;