Subject: [PATCH nf-next 1/2] netlink: allow be16 and be32 types in all uint policy checks

From: Florian Westphal <[email-masked]>
Date: Tue, 18 Jul 2023 09:52:29 +0200

__NLA_IS_BEINT_TYPE(tp) isn't useful.  NLA_BE16/32 are identical to
NLA_U16/32, the only difference is that it tells the netlink validation
functions that byteorder conversion might be needed before comparing
the value to the policy min/max ones.

After this change all policy macros that can be used with UINT types,
such as NLA_POLICY_MASK() can also be used with NLA_BE16/32.

This will be used to validate nf_tables flag attributes which
are in bigendian byte order.

Signed-off-by: Florian Westphal <[email-masked]>
---
 include/net/netlink.h | 10 +++-------
 lib/nlattr.c          |  6 ++++++
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/net/netlink.h b/include/net/netlink.h
index b12cd957abb4..8a7cd1170e1f 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -375,12 +375,11 @@ struct nla_policy {
 #define NLA_POLICY_BITFIELD32(valid) \
 	{ .type = NLA_BITFIELD32, .bitfield32_valid = valid }
 
-#define __NLA_IS_UINT_TYPE(tp)						\
-	(tp == NLA_U8 || tp == NLA_U16 || tp == NLA_U32 || tp == NLA_U64)
+#define __NLA_IS_UINT_TYPE(tp)					\
+	(tp == NLA_U8 || tp == NLA_U16 || tp == NLA_U32 ||	\
+	 tp == NLA_U64 || tp == NLA_BE16 || tp == NLA_BE32)
 #define __NLA_IS_SINT_TYPE(tp)						\
 	(tp == NLA_S8 || tp == NLA_S16 || tp == NLA_S32 || tp == NLA_S64)
-#define __NLA_IS_BEINT_TYPE(tp)						\
-	(tp == NLA_BE16 || tp == NLA_BE32)
 
 #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
 #define NLA_ENSURE_UINT_TYPE(tp)			\
@@ -394,7 +393,6 @@ struct nla_policy {
 #define NLA_ENSURE_INT_OR_BINARY_TYPE(tp)		\
 	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||		\
 		      __NLA_IS_SINT_TYPE(tp) ||		\
-		      __NLA_IS_BEINT_TYPE(tp) ||	\
 		      tp == NLA_MSECS ||		\
 		      tp == NLA_BINARY) + tp)
 #define NLA_ENSURE_NO_VALIDATION_PTR(tp)		\
@@ -402,8 +400,6 @@ struct nla_policy {
 		      tp != NLA_REJECT &&		\
 		      tp != NLA_NESTED &&		\
 		      tp != NLA_NESTED_ARRAY) + tp)
-#define NLA_ENSURE_BEINT_TYPE(tp)			\
-	(__NLA_ENSURE(__NLA_IS_BEINT_TYPE(tp)) + tp)
 
 #define NLA_POLICY_RANGE(tp, _min, _max) {		\
 	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 489e15bde5c1..7a2b6c38fd59 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -355,6 +355,12 @@ static int nla_validate_mask(const struct nla_policy *pt,
 	case NLA_U64:
 		value = nla_get_u64(nla);
 		break;
+	case NLA_BE16:
+		value = ntohs(nla_get_be16(nla));
+		break;
+	case NLA_BE32:
+		value = ntohl(nla_get_be32(nla));
+		break;
 	default:
 		return -EINVAL;
 	}
-- 
2.41.0