Merge branch 'netlink-allow-NLA_BINARY-length-range-validation'

Johannes Berg says:

====================
netlink: allow NLA_BINARY length range validation

In quite a few places (perhaps particularly in wireless) we need to
validation an NLA_BINARY attribute with both a minimum and a maximum
length. Currently, we can do either of the two, but not both, given
that we have NLA_MIN_LEN (minimum length) and NLA_BINARY (maximum).

Extend the range mechanisms that we use for integer validation to
apply to NLA_BINARY as well.

After converting everything to use NLA_POLICY_MIN_LEN() we can thus
get rid of the NLA_MIN_LEN type since that's now a special case of
NLA_BINARY with a minimum length validation. Similarly, NLA_EXACT_LEN
can be specified using NLA_POLICY_EXACT_LEN() and also maps to the
new NLA_BINARY validation (min == max == desired length).

Finally, NLA_POLICY_EXACT_LEN_WARN() also gets to be a somewhat
special case of this.

I haven't included the patch here now that converts nl82011 to use
this because it doesn't apply without another cleanup patch, but
we can remove a number of hand-coded min/max length checks and get
better error messages from the general validation code while doing
that.

As I had originally built the netlink policy export to userspace in
a way that has min/max length for NLA_BINARY (for the types that we
used to call NLA_MIN_LEN, NLA_BINARY and NLA_EXACT_LEN) anyway, it
doesn't really change anything there except that now there's a chance
that userspace sees min length < max length, which previously wasn't
possible.

v2:
 * fix the min<max comment to correctly say min<=max
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 5 deletions

diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
index e6ad42b11835..db25a0dc0f57 100644
--- a/net/sched/act_ct.c
+++ b/net/sched/act_ct.c
@@ -1039,7 +1039,7 @@ drop:
 
 static const struct nla_policy ct_policy[TCA_CT_MAX + 1] = {
 	[TCA_CT_ACTION] = { .type = NLA_U16 },
-	[TCA_CT_PARMS] = { .type = NLA_EXACT_LEN, .len = sizeof(struct tc_ct) },
+	[TCA_CT_PARMS] = NLA_POLICY_EXACT_LEN(sizeof(struct tc_ct)),
 	[TCA_CT_ZONE] = { .type = NLA_U16 },
 	[TCA_CT_MARK] = { .type = NLA_U32 },
 	[TCA_CT_MARK_MASK] = { .type = NLA_U32 },
@@ -1049,10 +1049,8 @@ static const struct nla_policy ct_policy[TCA_CT_MAX + 1] = {
 				 .len = 128 / BITS_PER_BYTE },
 	[TCA_CT_NAT_IPV4_MIN] = { .type = NLA_U32 },
 	[TCA_CT_NAT_IPV4_MAX] = { .type = NLA_U32 },
-	[TCA_CT_NAT_IPV6_MIN] = { .type = NLA_EXACT_LEN,
-				  .len = sizeof(struct in6_addr) },
-	[TCA_CT_NAT_IPV6_MAX] = { .type = NLA_EXACT_LEN,
-				   .len = sizeof(struct in6_addr) },
+	[TCA_CT_NAT_IPV6_MIN] = NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
+	[TCA_CT_NAT_IPV6_MAX] = NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
 	[TCA_CT_NAT_PORT_MIN] = { .type = NLA_U16 },
 	[TCA_CT_NAT_PORT_MAX] = { .type = NLA_U16 },
 };