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netlink: make NLA_BINARY validation more flexible

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Add range validation for NLA_BINARY, allowing validation of any
combination of combination minimum or maximum lengths, using the
existing NLA_POLICY_RANGE()/NLA_POLICY_FULL_RANGE() macros, just
like for integers where the value is checked.

Also make NLA_POLICY_EXACT_LEN(), NLA_POLICY_EXACT_LEN_WARN()
and NLA_POLICY_MIN_LEN() special cases of this, removing the old
types NLA_EXACT_LEN and NLA_MIN_LEN.

This allows us to save some code where both minimum and maximum
lengths are requires, currently the policy only allows maximum
(NLA_BINARY), minimum (NLA_MIN_LEN) or exact (NLA_EXACT_LEN), so
a range of lengths cannot be accepted and must be checked by the
code that consumes the attributes later.

Also, this allows advertising the correct ranges in the policy
export to userspace. Here, NLA_MIN_LEN and NLA_EXACT_LEN already
were special cases of NLA_BINARY with min and min/max length
respectively.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Johannes Berg
2020-08-18 10:17:33 +02:00
committed by David S. Miller
parent bc04358550
commit 8aa26c575f
3 changed files with 89 additions and 61 deletions
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32
net/netlink/policy.c
View File

@@ -251,12 +251,6 @@ send_attribute:
pt->bitfield32_valid))
goto nla_put_failure;
break;
case NLA_EXACT_LEN:
type = NL_ATTR_TYPE_BINARY;
if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH, pt->len) ||
nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH, pt->len))
goto nla_put_failure;
break;
case NLA_STRING:
case NLA_NUL_STRING:
case NLA_BINARY:
@@ -266,14 +260,26 @@ send_attribute:
type = NL_ATTR_TYPE_NUL_STRING;
else
type = NL_ATTR_TYPE_BINARY;
if (pt->len && nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH,
pt->len))
goto nla_put_failure;
break;
case NLA_MIN_LEN:
type = NL_ATTR_TYPE_BINARY;
if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH, pt->len))
if (pt->validation_type != NLA_VALIDATE_NONE) {
struct netlink_range_validation range;
nla_get_range_unsigned(pt, &range);
if (range.min &&
nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH,
range.min))
goto nla_put_failure;
if (range.max < U16_MAX &&
nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH,
range.max))
goto nla_put_failure;
} else if (pt->len &&
nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH,
pt->len)) {
goto nla_put_failure;
}
break;
case NLA_FLAG:
type = NL_ATTR_TYPE_FLAG;