From 08724ef69907214ce622344fe4945412e38368f0 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 5 Sep 2022 12:09:36 +0200 Subject: [PATCH] netlink: introduce NLA_POLICY_MAX_BE netlink allows to specify allowed ranges for integer types. Unfortunately, nfnetlink passes integers in big endian, so the existing NLA_POLICY_MAX() cannot be used. At the moment, nfnetlink users, such as nf_tables, need to resort to programmatic checking via helpers such as nft_parse_u32_check(). This is both cumbersome and error prone. This adds NLA_POLICY_MAX_BE which adds range check support for BE16, BE32 and BE64 integers. Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- include/net/netlink.h | 9 +++++++++ lib/nlattr.c | 31 +++++++++++++++++++++++++++---- 2 files changed, 36 insertions(+), 4 deletions(-) diff --git a/include/net/netlink.h b/include/net/netlink.h index e658d18a..4418b19 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -325,6 +325,7 @@ struct nla_policy { struct netlink_range_validation_signed *range_signed; struct { s16 min, max; + u8 network_byte_order:1; }; int (*validate)(const struct nlattr *attr, struct netlink_ext_ack *extack); @@ -418,6 +419,14 @@ struct nla_policy { .type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp), \ .validation_type = NLA_VALIDATE_MAX, \ .max = _max, \ + .network_byte_order = 0, \ +} + +#define NLA_POLICY_MAX_BE(tp, _max) { \ + .type = NLA_ENSURE_UINT_TYPE(tp), \ + .validation_type = NLA_VALIDATE_MAX, \ + .max = _max, \ + .network_byte_order = 1, \ } #define NLA_POLICY_MASK(tp, _mask) { \ diff --git a/lib/nlattr.c b/lib/nlattr.c index 86029ad..40f22b1 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -159,6 +159,31 @@ void nla_get_range_unsigned(const struct nla_policy *pt, } } +static u64 nla_get_attr_bo(const struct nla_policy *pt, + const struct nlattr *nla) +{ + switch (pt->type) { + case NLA_U16: + if (pt->network_byte_order) + return ntohs(nla_get_be16(nla)); + + return nla_get_u16(nla); + case NLA_U32: + if (pt->network_byte_order) + return ntohl(nla_get_be32(nla)); + + return nla_get_u32(nla); + case NLA_U64: + if (pt->network_byte_order) + return be64_to_cpu(nla_get_be64(nla)); + + return nla_get_u64(nla); + } + + WARN_ON_ONCE(1); + return 0; +} + static int nla_validate_range_unsigned(const struct nla_policy *pt, const struct nlattr *nla, struct netlink_ext_ack *extack, @@ -172,12 +197,10 @@ static int nla_validate_range_unsigned(const struct nla_policy *pt, value = nla_get_u8(nla); break; case NLA_U16: - value = nla_get_u16(nla); - break; case NLA_U32: - value = nla_get_u32(nla); - break; case NLA_U64: + value = nla_get_attr_bo(pt, nla); + break; case NLA_MSECS: value = nla_get_u64(nla); break; -- 2.7.4