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-rw-r--r--include/net/netlink.h67
1 files changed, 64 insertions, 3 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 3698ca8ff92c..d34ceeba82a8 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -188,9 +188,19 @@ enum {
#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
+enum nla_policy_validation {
+ NLA_VALIDATE_NONE,
+ NLA_VALIDATE_RANGE,
+ NLA_VALIDATE_MIN,
+ NLA_VALIDATE_MAX,
+};
+
/**
* struct nla_policy - attribute validation policy
* @type: Type of attribute or NLA_UNSPEC
+ * @validation_type: type of attribute validation done in addition to
+ * type-specific validation (e.g. range), see
+ * &enum nla_policy_validation
* @len: Type specific length of payload
*
* Policies are defined as arrays of this struct, the array must be
@@ -238,7 +248,26 @@ enum {
* nested attributes directly inside, while an array has
* the nested attributes at another level down and the
* attributes directly in the nesting don't matter.
- * All other Unused
+ * All other Unused - but note that it's a union
+ *
+ * Meaning of `min' and `max' fields, use via NLA_POLICY_MIN, NLA_POLICY_MAX
+ * and NLA_POLICY_RANGE:
+ * NLA_U8,
+ * NLA_U16,
+ * NLA_U32,
+ * NLA_U64,
+ * NLA_S8,
+ * NLA_S16,
+ * NLA_S32,
+ * NLA_S64 These are used depending on the validation_type
+ * field, if that is min/max/range then the minimum,
+ * maximum and both are used (respectively) to check
+ * the value of the integer attribute.
+ * Note that in the interest of code simplicity and
+ * struct size both limits are s16, so you cannot
+ * enforce a range that doesn't fall within the range
+ * of s16 - do that as usual in the code instead.
+ * All other Unused - but note that it's a union
*
* Example:
* static const struct nla_policy my_policy[ATTR_MAX+1] = {
@@ -249,9 +278,15 @@ enum {
* };
*/
struct nla_policy {
- u16 type;
+ u8 type;
+ u8 validation_type;
u16 len;
- const void *validation_data;
+ union {
+ const void *validation_data;
+ struct {
+ s16 min, max;
+ };
+ };
};
#define NLA_POLICY_EXACT_LEN(_len) { .type = NLA_EXACT_LEN, .len = _len }
@@ -266,6 +301,32 @@ struct nla_policy {
#define NLA_POLICY_NESTED_ARRAY(maxattr, policy) \
{ .type = NLA_NESTED_ARRAY, .validation_data = policy, .len = maxattr }
+#define __NLA_ENSURE(condition) (sizeof(char[1 - 2*!(condition)]) - 1)
+#define NLA_ENSURE_INT_TYPE(tp) \
+ (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 || \
+ tp == NLA_S16 || tp == NLA_U16 || \
+ tp == NLA_S32 || tp == NLA_U32 || \
+ tp == NLA_S64 || tp == NLA_U64) + tp)
+
+#define NLA_POLICY_RANGE(tp, _min, _max) { \
+ .type = NLA_ENSURE_INT_TYPE(tp), \
+ .validation_type = NLA_VALIDATE_RANGE, \
+ .min = _min, \
+ .max = _max \
+}
+
+#define NLA_POLICY_MIN(tp, _min) { \
+ .type = NLA_ENSURE_INT_TYPE(tp), \
+ .validation_type = NLA_VALIDATE_MIN, \
+ .min = _min, \
+}
+
+#define NLA_POLICY_MAX(tp, _max) { \
+ .type = NLA_ENSURE_INT_TYPE(tp), \
+ .validation_type = NLA_VALIDATE_MAX, \
+ .max = _max, \
+}
+
/**
* struct nl_info - netlink source information
* @nlh: Netlink message header of original request