vxlan: fix incorrect initializer in union vxlan_addr

PATCH Superseded Gerhard Stenzel 3 participants 5 messages Aug 15, 2014 – Aug 22, 2014 1 message not in the archive

Subsystems (2)

Networking Network drivers

lore

Share & tools

lore

A message that is not in the archive (sent off-list or not yet received): [email protected]

Gerhard Stenzel

author

2014-08-15 09:04 UTC #1 lore raw

PATCH 1/1 vxlan: fix incorrect initializer in union vxlan_addr

The first initializer in the following

		union vxlan_addr ipa = {
			.sin.sin_addr.s_addr = tip,
			.sa.sa_family = AF_INET,
		};

is optimised away by the compiler, due to the second initializer,
therefore initialising .sin.sin_addr.s_addr always to 0.
This results in netlink messages indicating a L3 miss never contain the
missed IP address. This was observed with GCC 4.8 and 4.9. I do not know about previous versions. The problem affects user space programs relying on an IP address being
sent as part of a netlink message indicating a L3 miss.

Changing
.sa.sa_family = AF_INET,
to
.sin.sin_family = AF_INET,
fixes the problem.

Signed-off-by Gerhard Stenzel <[email protected]>

---

drivers/net/vxlan.c +0 -0

index 1fb7b37..beb377b 100644
@@ -1327,7 +1327,7 @@ static int arp_reduce(struct net_device *dev,

struct sk_buff *skb)
} else if (vxlan->flags & VXLAN_F_L3MISS) {
union vxlan_addr ipa = {
.sin.sin_addr.s_addr = tip,
- .sa.sa_family = AF_INET,
+ .sin.sin_family = AF_INET,
};

vxlan_ip_miss(dev, &ipa);
@@ -1488,7 +1488,7 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb)
} else if (vxlan->flags & VXLAN_F_L3MISS) {
union vxlan_addr ipa = {
.sin6.sin6_addr = msg->target,
- .sa.sa_family = AF_INET6,
+ .sin6.sin6_family = AF_INET6,
};

vxlan_ip_miss(dev, &ipa);
@@ -1521,7 +1521,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
union vxlan_addr ipa = {
.sin.sin_addr.s_addr = pip->daddr,
- .sa.sa_family = AF_INET,
+ .sin.sin_family = AF_INET,
};

vxlan_ip_miss(dev, &ipa);
@@ -1542,7 +1542,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
union vxlan_addr ipa = {
.sin6.sin6_addr = pip6->daddr,
- .sa.sa_family = AF_INET6,
+ .sin6.sin6_family = AF_INET6,
};

vxlan_ip_miss(dev, &ipa);

Cong Wang

Acked-by on v1 1/1

2014-08-16 22:48 UTC #2 lore raw

Quoted 16 lines · Gerhard Stenzel

The first initializer in the following
                union vxlan_addr ipa = {
                        .sin.sin_addr.s_addr = tip,
                        .sa.sa_family = AF_INET,
                };
is optimised away by the compiler, due to the second initializer, therefore initialising .sin.sin_addr.s_addr always to 0. This results in netlink messages indicating a L3 miss never contain the missed IP address. This was observed with GCC 4.8 and 4.9. I do not know about previous versions.
The problem affects user space programs relying on an IP address being sent as part of a netlink message indicating a L3 miss.

Quoted 5 lines

Changing
.sa.sa_family = AF_INET,
to
.sin.sin_family = AF_INET,
fixes the problem.

So GCC can't figure out we are initializing different parts of this union through
different members... Or maybe we should not use initializer at all.

Anyway,

Acked-by Cong Wang <[email protected]>

David Miller

maintainer

2014-08-18 17:11 UTC #3 lore raw

In reply to Gerhard Stenzel

From: Gerhard Stenzel <[email protected]>
Date: Fri, 15 Aug 2014 11:03:58 +0200

Quoted 17 lines

The first initializer in the following
		union vxlan_addr ipa = {
			.sin.sin_addr.s_addr = tip,
			.sa.sa_family = AF_INET,
		};
is optimised away by the compiler, due to the second initializer, therefore initialising .sin.sin_addr.s_addr always to 0. This results in netlink messages indicating a L3 miss never contain the
missed IP address. This was observed with GCC 4.8 and 4.9. I do not know about previous versions.
The problem affects user space programs relying on an IP address being sent as part of a netlink message indicating a L3 miss.

Quoted 7 lines

Changing
.sa.sa_family = AF_INET,
to
.sin.sin_family = AF_INET,
fixes the problem.
Signed-off-by Gerhard Stenzel <[email protected]>

Your patch was corrupted by your email client, also please do not indent your signoff.

THanks.

Gerhard Stenzel

author

2014-08-19 20:36 UTC #4 lore raw

Trying again ...

On 08/18/2014 07:11 PM, David Miller wrote:
...

Quoted 6 lines

Your patch was corrupted by your email client, also please do not indent your signoff.
THanks.

The first initializer in the following

        union vxlan_addr ipa = {
            .sin.sin_addr.s_addr = tip,
            .sa.sa_family = AF_INET,
        };

Changing
.sa.sa_family = AF_INET,
to
.sin.sin_family = AF_INET,
fixes the problem.

Signed-off-by Gerhard Stenzel <[email protected]>

---

drivers/net/vxlan.c +4 -4

index 1fb7b37..beb377b 100644
@@ -1327,7 +1327,7 @@ static int arp_reduce(struct net_device *dev, struct sk_buff *skb)
 	} else if (vxlan->flags & VXLAN_F_L3MISS) {
 		union vxlan_addr ipa = {
 			.sin.sin_addr.s_addr = tip,
-			.sa.sa_family = AF_INET,
+			.sin.sin_family = AF_INET,
 		};
 
 		vxlan_ip_miss(dev, &ipa);

@@ -1488,7 +1488,7 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb)
 	} else if (vxlan->flags & VXLAN_F_L3MISS) {
 		union vxlan_addr ipa = {
 			.sin6.sin6_addr = msg->target,
-			.sa.sa_family = AF_INET6,
+			.sin6.sin6_family = AF_INET6,
 		};
 
 		vxlan_ip_miss(dev, &ipa);

@@ -1521,7 +1521,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
 		if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
 			union vxlan_addr ipa = {
 				.sin.sin_addr.s_addr = pip->daddr,
-				.sa.sa_family = AF_INET,
+				.sin.sin_family = AF_INET,
 			};
 
 			vxlan_ip_miss(dev, &ipa);

@@ -1542,7 +1542,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
 		if (!n && (vxlan->flags & VXLAN_F_L3MISS)) {
 			union vxlan_addr ipa = {
 				.sin6.sin6_addr = pip6->daddr,
-				.sa.sa_family = AF_INET6,
+				.sin6.sin6_family = AF_INET6,
 			};
 
 			vxlan_ip_miss(dev, &ipa);

David Miller

maintainer

2014-08-22 04:27 UTC #5 lore raw

From: Gerhard Stenzel <[email protected]>
Date: Tue, 19 Aug 2014 22:36:43 +0200

Quoted 1 line

Trying again ...

This is not the correct way to resubmit a patch properly.

Do not ever submit a new copy of a patch as a reply to a discussion thread, quoting unrelated material, etc.

Instead, make a new, fresh, mailing list posting as if you were posting the patch for the first time. Except you add "[PATCH v2 net]" or similar to indicate this is a new submission of the patch.