From: Luca Coelho <luciano.coelho@xxxxxxxxx>
The range checks for NLA_BINARY are supported since v5.10. Unwrap the
macros and introduce a new function to test type.
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
backport/backport-include/net/netlink.h | 31 +++++++++++++++++++---
patches/0097-nla_policy_binary_range.cocci | 5 ++++
2 files changed, 32 insertions(+), 4 deletions(-)
create mode 100644 patches/0097-nla_policy_binary_range.cocci
diff --git a/backport/backport-include/net/netlink.h b/backport/backport-include/net/netlink.h
index ad5882347440..7192153b860c 100644
--- a/backport/backport-include/net/netlink.h
+++ b/backport/backport-include/net/netlink.h
@@ -346,10 +346,33 @@ enum nla_policy_validation {
}
#endif /* < 4.20 */
-#ifndef NLA_POLICY_MIN_LEN
-#define NLA_POLICY_MIN_LEN(_len) { \
- .type = NLA_BINARY \
+#if LINUX_VERSION_IS_LESS(5,10,0)
+// pre-declare all the minimum lengths in use
+#define MIN_LEN_VALIDATION(n) \
+static inline \
+int nla_validate_min_len_##n(const struct nlattr *attr, \
+ struct netlink_ext_ack *extack) \
+{ \
+ if (nla_len(attr) < n) \
+ return -EINVAL; \
+ return 0; \
}
-#endif
+
+MIN_LEN_VALIDATION(2)
+MIN_LEN_VALIDATION(16)
+MIN_LEN_VALIDATION(42)
+
+// double-expansion to expand _min to the actual value
+#define NLA_POLICY_BINARY_RANGE(_min, _max) _NLA_POLICY_BINARY_RANGE(_min, _max)
+#define _NLA_POLICY_BINARY_RANGE(_min, _max) \
+{ \
+ .type = NLA_BINARY, \
+ .len = _max, \
+ .validation_type = NLA_VALIDATE_FUNCTION, \
+ .validate = nla_validate_min_len_ ## _min, \
+}
+#else
+#define NLA_POLICY_BINARY_RANGE(_min, _max) NLA_POLICY_RANGE(NLA_BINARY, _min, _max)
+#endif /* < 5.10 */
#endif /* __BACKPORT_NET_NETLINK_H */
diff --git a/patches/0097-nla_policy_binary_range.cocci b/patches/0097-nla_policy_binary_range.cocci
new file mode 100644
index 000000000000..cb3b8be52b51
--- /dev/null
+++ b/patches/0097-nla_policy_binary_range.cocci
@@ -0,0 +1,5 @@
+@@
+expression MIN, MAX;
+@@
+-NLA_POLICY_RANGE(NLA_BINARY, MIN, MAX)
++NLA_POLICY_BINARY_RANGE(MIN, MAX)
--
2.45.1
