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, 5 insertions, 7 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c04fc6cf6583..e45b95446ea0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -654,10 +654,8 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_RECEIVE_MULTICAST] = { .type = NLA_FLAG },
 	[NL80211_ATTR_WIPHY_FREQ_OFFSET] = NLA_POLICY_RANGE(NLA_U32, 0, 999),
 	[NL80211_ATTR_SCAN_FREQ_KHZ] = { .type = NLA_NESTED },
-	[NL80211_ATTR_HE_6GHZ_CAPABILITY] = {
-		.type = NLA_EXACT_LEN,
-		.len = sizeof(struct ieee80211_he_6ghz_capa),
-	},
+	[NL80211_ATTR_HE_6GHZ_CAPABILITY] =
+		NLA_POLICY_EXACT_LEN(sizeof(struct ieee80211_he_6ghz_capa)),
 };
 
 /* policy for the key attributes */
@@ -703,7 +701,7 @@ nl80211_wowlan_tcp_policy[NUM_NL80211_WOWLAN_TCP] = {
 	[NL80211_WOWLAN_TCP_DST_MAC] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN),
 	[NL80211_WOWLAN_TCP_SRC_PORT] = { .type = NLA_U16 },
 	[NL80211_WOWLAN_TCP_DST_PORT] = { .type = NLA_U16 },
-	[NL80211_WOWLAN_TCP_DATA_PAYLOAD] = { .type = NLA_MIN_LEN, .len = 1 },
+	[NL80211_WOWLAN_TCP_DATA_PAYLOAD] = NLA_POLICY_MIN_LEN(1),
 	[NL80211_WOWLAN_TCP_DATA_PAYLOAD_SEQ] = {
 		.len = sizeof(struct nl80211_wowlan_tcp_data_seq)
 	},
@@ -711,8 +709,8 @@ nl80211_wowlan_tcp_policy[NUM_NL80211_WOWLAN_TCP] = {
 		.len = sizeof(struct nl80211_wowlan_tcp_data_token)
 	},
 	[NL80211_WOWLAN_TCP_DATA_INTERVAL] = { .type = NLA_U32 },
-	[NL80211_WOWLAN_TCP_WAKE_PAYLOAD] = { .type = NLA_MIN_LEN, .len = 1 },
-	[NL80211_WOWLAN_TCP_WAKE_MASK] = { .type = NLA_MIN_LEN, .len = 1 },
+	[NL80211_WOWLAN_TCP_WAKE_PAYLOAD] = NLA_POLICY_MIN_LEN(1),
+	[NL80211_WOWLAN_TCP_WAKE_MASK] = NLA_POLICY_MIN_LEN(1),
 };
 #endif /* CONFIG_PM */