net: vrf: correct FRA_L3MDEV encode type

FRA_L3MDEV is defined as U8, but is being added as a U32 attribute. On
big endian architecture, this results in the l3mdev entry not being
added to the FIB rules.

Fixes: 1aa6c4f6b8cd8 ("net: vrf: Add l3mdev rules on first device create")
Signed-off-by: Jeff Barnhill <0xeffeff@gmail.com>
---
 drivers/net/vrf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

On 11/1/17 8:58 AM, Jeff Barnhill wrote:
> FRA_L3MDEV is defined as U8, but is being added as a U32 attribute. On
> big endian architecture, this results in the l3mdev entry not being
> added to the FIB rules.
> 
> Fixes: 1aa6c4f6b8cd8 ("net: vrf: Add l3mdev rules on first device create")
> Signed-off-by: Jeff Barnhill <0xeffeff@gmail.com>
> ---
>  drivers/net/vrf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
> index 9b243e6f3008..7dc3bcac3506 100644
> --- a/drivers/net/vrf.c
> +++ b/drivers/net/vrf.c
> @@ -1165,7 +1165,7 @@ static int vrf_fib_rule(const struct net_device *dev, __u8 family, bool add_it)
>  	frh->family = family;
>  	frh->action = FR_ACT_TO_TBL;
>  
> -	if (nla_put_u32(skb, FRA_L3MDEV, 1))
> +	if (nla_put_u8(skb, FRA_L3MDEV, 1))
>  		goto nla_put_failure;
>  
>  	if (nla_put_u32(skb, FRA_PRIORITY, FIB_RULE_PREF))
> 

Acked-by: David Ahern <dsahern@gmail.com>

From: Jeff Barnhill <0xeffeff@gmail.com>
Date: Wed,  1 Nov 2017 14:58:09 +0000

> FRA_L3MDEV is defined as U8, but is being added as a U32 attribute. On
> big endian architecture, this results in the l3mdev entry not being
> added to the FIB rules.
> 
> Fixes: 1aa6c4f6b8cd8 ("net: vrf: Add l3mdev rules on first device create")
> Signed-off-by: Jeff Barnhill <0xeffeff@gmail.com>

Applied and queued up for -stable, thank you.

I wish we could trap things like this using the policy,
enforcing an exact size access for attributes such as
these.

Thanks again.

On 11/2/17 12:22 AM, David Miller wrote:
> I wish we could trap things like this using the policy,
> enforcing an exact size access for attributes such as
> these.
From feae5aa9dd7a26b7fbf33582738c7c89f068d81b Mon Sep 17 00:00:00 2001
From: David Ahern <dsahern@gmail.com>
Date: Thu, 2 Nov 2017 12:18:02 -0700
Subject: [PATCH net-next] net: netlink: Update attr validation to require
 exact length for some types

Attributes using NLA_U* and NLA_S* (where * is 8, 16,32 and 64) are
expected to be an exact length. Spliti these data types from
nla_attr_minlen into nla_attr_len and update validate_nla to require
the attribute to have exact length for them.

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 lib/nlattr.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/lib/nlattr.c b/lib/nlattr.c
index 927c2f19f119..b5e360e7dfc8 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -14,19 +14,23 @@
 #include <linux/types.h>
 #include <net/netlink.h>
 
-static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
+/* for these data types attribute length must be exactly given size */
+static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {
 	[NLA_U8]	= sizeof(u8),
 	[NLA_U16]	= sizeof(u16),
 	[NLA_U32]	= sizeof(u32),
 	[NLA_U64]	= sizeof(u64),
-	[NLA_MSECS]	= sizeof(u64),
-	[NLA_NESTED]	= NLA_HDRLEN,
 	[NLA_S8]	= sizeof(s8),
 	[NLA_S16]	= sizeof(s16),
 	[NLA_S32]	= sizeof(s32),
 	[NLA_S64]	= sizeof(s64),
 };
 
+static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
+	[NLA_MSECS]	= sizeof(u64),
+	[NLA_NESTED]	= NLA_HDRLEN,
+};
+
 static int validate_nla_bitfield32(const struct nlattr *nla,
 				   u32 *valid_flags_allowed)
 {
@@ -64,6 +68,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
 
 	BUG_ON(pt->type > NLA_TYPE_MAX);
 
+	/* for data types NLA_U* and NLA_S* require exact length */
+	if (nla_attr_len[pt->type]) {
+		if (attrlen != nla_attr_len[pt->type])
+			return -ERANGE;
+		return 0;
+	}
+
 	switch (pt->type) {
 	case NLA_FLAG:
 		if (attrlen > 0)