Merge branch 'devlink-param-type-string-fixes'

Moshe Shemesh says:

====================
devlink param type string fixes

This patchset fixes devlink param infrastructure for string param type.

The devlink param infrastructure doesn't handle copying the string data
correctly.  The first two patches fix it and the third patch adds helper
function to safely copy string value without exceeding
DEVLINK_PARAM_MAX_STRING_VALUE.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 6 deletions

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 8c0ed225e280..6bc42933be4a 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -2995,6 +2995,8 @@ devlink_param_value_get_from_info(const struct devlink_param *param,
 				  struct genl_info *info,
 				  union devlink_param_value *value)
 {
+	int len;
+
 	if (param->type != DEVLINK_PARAM_TYPE_BOOL &&
 	    !info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA])
 		return -EINVAL;
@@ -3010,10 +3012,13 @@ devlink_param_value_get_from_info(const struct devlink_param *param,
 		value->vu32 = nla_get_u32(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]);
 		break;
 	case DEVLINK_PARAM_TYPE_STRING:
-		if (nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]) >
-		    DEVLINK_PARAM_MAX_STRING_VALUE)
+		len = strnlen(nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]),
+			      nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]));
+		if (len == nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]) ||
+		    len >= __DEVLINK_PARAM_MAX_STRING_VALUE)
 			return -EINVAL;
-		value->vstr = nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]);
+		strcpy(value->vstr,
+		       nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]));
 		break;
 	case DEVLINK_PARAM_TYPE_BOOL:
 		value->vbool = info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA] ?
@@ -3100,7 +3105,10 @@ static int devlink_nl_cmd_param_set_doit(struct sk_buff *skb,
 		return -EOPNOTSUPP;
 
 	if (cmode == DEVLINK_PARAM_CMODE_DRIVERINIT) {
-		param_item->driverinit_value = value;
+		if (param->type == DEVLINK_PARAM_TYPE_STRING)
+			strcpy(param_item->driverinit_value.vstr, value.vstr);
+		else
+			param_item->driverinit_value = value;
 		param_item->driverinit_value_valid = true;
 	} else {
 		if (!param->set)
@@ -4540,7 +4548,10 @@ int devlink_param_driverinit_value_get(struct devlink *devlink, u32 param_id,
 					      DEVLINK_PARAM_CMODE_DRIVERINIT))
 		return -EOPNOTSUPP;
 
-	*init_val = param_item->driverinit_value;
+	if (param_item->param->type == DEVLINK_PARAM_TYPE_STRING)
+		strcpy(init_val->vstr, param_item->driverinit_value.vstr);
+	else
+		*init_val = param_item->driverinit_value;
 
 	return 0;
 }
@@ -4571,7 +4582,10 @@ int devlink_param_driverinit_value_set(struct devlink *devlink, u32 param_id,
 					      DEVLINK_PARAM_CMODE_DRIVERINIT))
 		return -EOPNOTSUPP;
 
-	param_item->driverinit_value = init_val;
+	if (param_item->param->type == DEVLINK_PARAM_TYPE_STRING)
+		strcpy(param_item->driverinit_value.vstr, init_val.vstr);
+	else
+		param_item->driverinit_value = init_val;
 	param_item->driverinit_value_valid = true;
 
 	devlink_param_notify(devlink, param_item, DEVLINK_CMD_PARAM_NEW);
@@ -4604,6 +4618,23 @@ void devlink_param_value_changed(struct devlink *devlink, u32 param_id)
 EXPORT_SYMBOL_GPL(devlink_param_value_changed);
 
 /**
+ *	devlink_param_value_str_fill - Safely fill-up the string preventing
+ *				       from overflow of the preallocated buffer
+ *
+ *	@dst_val: destination devlink_param_value
+ *	@src: source buffer
+ */
+void devlink_param_value_str_fill(union devlink_param_value *dst_val,
+				  const char *src)
+{
+	size_t len;
+
+	len = strlcpy(dst_val->vstr, src, __DEVLINK_PARAM_MAX_STRING_VALUE);
+	WARN_ON(len >= __DEVLINK_PARAM_MAX_STRING_VALUE);
+}
+EXPORT_SYMBOL_GPL(devlink_param_value_str_fill);
+
+/**
  *	devlink_region_create - create a new address region
  *
  *	@devlink: devlink