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netlink: introduce NLA_POLICY_MAX_BE

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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 <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal 2022-09-05 12:09:36 +02:00 committed by David S. Miller
parent 98ba81081b
commit 08724ef699
2 changed files with 36 additions and 4 deletions
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9
include/net/netlink.h
View File

@ -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) { \

31
lib/nlattr.c
View File

@ -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;