[PATCH net v2] net: ipv6: fix return value of ip6_skb_dst_mtu

[PATCH net v2] net: ipv6: fix return value of ip6_skb_dst_mtu

[Vadim Fedorenko]

Commit 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE") introduced
ip6_skb_dst_mtu with return value of signed int which is inconsistent
with actually returned values. Also 2 users of this function actually
assign its value to unsigned int variable and only __xfrm6_output
assigns result of this function to signed variable but actually uses
as unsigned in further comparisons and calls. Change this function
to return unsigned int value.

Fixes: 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE")
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
---
 v2: rebase on top current net

 Actually I'm not sure why it could not be applied last time
---
 include/net/ip6_route.h | 2 +-
 net/ipv6/xfrm6_output.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index f14149df5a65..625a38ccb5d9 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -263,7 +263,7 @@ static inline bool ipv6_anycast_destination(const struct dst_entry *dst,
 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 		 int (*output)(struct net *, struct sock *, struct sk_buff *));
 
-static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
+static inline unsigned int ip6_skb_dst_mtu(struct sk_buff *skb)
 {
 	int mtu;
 
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 57fa27c1cdf9..d0d280077721 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -49,7 +49,7 @@ static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct xfrm_state *x = dst->xfrm;
-	int mtu;
+	unsigned int mtu;
 	bool toobig;
 
 #ifdef CONFIG_NETFILTER
-- 
2.18.4

Re: [PATCH net v2] net: ipv6: fix return value of ip6_skb_dst_mtu

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Fri,  2 Jul 2021 02:47:00 +0300 you wrote:
> Commit 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE") introduced
> ip6_skb_dst_mtu with return value of signed int which is inconsistent
> with actually returned values. Also 2 users of this function actually
> assign its value to unsigned int variable and only __xfrm6_output
> assigns result of this function to signed variable but actually uses
> as unsigned in further comparisons and calls. Change this function
> to return unsigned int value.
> 
> [...]

Here is the summary with links:
  - [net,v2] net: ipv6: fix return value of ip6_skb_dst_mtu
    https://git.kernel.org/netdev/net/c/40fc3054b458

You are awesome, thank you!
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