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, 7 insertions, 7 deletions

diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
index 20a4f3c..d0f3b6d 100644
--- a/drivers/net/wireguard/netlink.c
+++ b/drivers/net/wireguard/netlink.c
@@ -22,8 +22,8 @@ static struct genl_family genl_family;
 static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = {
 	[WGDEVICE_A_IFINDEX]		= { .type = NLA_U32 },
 	[WGDEVICE_A_IFNAME]		= { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
-	[WGDEVICE_A_PRIVATE_KEY]	= { .type = NLA_EXACT_LEN, .len = NOISE_PUBLIC_KEY_LEN },
-	[WGDEVICE_A_PUBLIC_KEY]		= { .type = NLA_EXACT_LEN, .len = NOISE_PUBLIC_KEY_LEN },
+	[WGDEVICE_A_PRIVATE_KEY]	= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
+	[WGDEVICE_A_PUBLIC_KEY]		= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
 	[WGDEVICE_A_FLAGS]		= { .type = NLA_U32 },
 	[WGDEVICE_A_LISTEN_PORT]	= { .type = NLA_U16 },
 	[WGDEVICE_A_FWMARK]		= { .type = NLA_U32 },
@@ -31,12 +31,12 @@ static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = {
 };
 
 static const struct nla_policy peer_policy[WGPEER_A_MAX + 1] = {
-	[WGPEER_A_PUBLIC_KEY]				= { .type = NLA_EXACT_LEN, .len = NOISE_PUBLIC_KEY_LEN },
-	[WGPEER_A_PRESHARED_KEY]			= { .type = NLA_EXACT_LEN, .len = NOISE_SYMMETRIC_KEY_LEN },
+	[WGPEER_A_PUBLIC_KEY]				= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
+	[WGPEER_A_PRESHARED_KEY]			= NLA_POLICY_EXACT_LEN(NOISE_SYMMETRIC_KEY_LEN),
 	[WGPEER_A_FLAGS]				= { .type = NLA_U32 },
-	[WGPEER_A_ENDPOINT]				= { .type = NLA_MIN_LEN, .len = sizeof(struct sockaddr) },
+	[WGPEER_A_ENDPOINT]				= NLA_POLICY_MIN_LEN(sizeof(struct sockaddr)),
 	[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]	= { .type = NLA_U16 },
-	[WGPEER_A_LAST_HANDSHAKE_TIME]			= { .type = NLA_EXACT_LEN, .len = sizeof(struct __kernel_timespec) },
+	[WGPEER_A_LAST_HANDSHAKE_TIME]			= NLA_POLICY_EXACT_LEN(sizeof(struct __kernel_timespec)),
 	[WGPEER_A_RX_BYTES]				= { .type = NLA_U64 },
 	[WGPEER_A_TX_BYTES]				= { .type = NLA_U64 },
 	[WGPEER_A_ALLOWEDIPS]				= { .type = NLA_NESTED },
@@ -45,7 +45,7 @@ static const struct nla_policy peer_policy[WGPEER_A_MAX + 1] = {
 
 static const struct nla_policy allowedip_policy[WGALLOWEDIP_A_MAX + 1] = {
 	[WGALLOWEDIP_A_FAMILY]		= { .type = NLA_U16 },
-	[WGALLOWEDIP_A_IPADDR]		= { .type = NLA_MIN_LEN, .len = sizeof(struct in_addr) },
+	[WGALLOWEDIP_A_IPADDR]		= NLA_POLICY_MIN_LEN(sizeof(struct in_addr)),
 	[WGALLOWEDIP_A_CIDR_MASK]	= { .type = NLA_U8 }
 };