[PATCH net 0/4] udp: a few fixes

[PATCH net 0/4] udp: a few fixes

[Paolo Abeni]

This series includes some UDP-related fixlet. All this stuff has been
pointed out by the sparse tool. The first two patches are just annotation
related, while the last 2 cover some very unlikely races.

Paolo Abeni (4):
  udpv6: add the required annotation to mib type
  fou6: fix proto error handler argument type
  udpv6: fix possible user after free in error handler
  udp: fix possible user after free in error handler

 net/ipv4/udp.c  |  6 ++++--
 net/ipv6/fou6.c |  2 +-
 net/ipv6/udp.c  | 12 +++++++-----
 3 files changed, 12 insertions(+), 8 deletions(-)

-- 
2.20.1

[PATCH net 1/4] udpv6: add the required annotation to mib type

[Paolo Abeni]

In commit 029a37434880 ("udp6: cleanup stats accounting in recvmsg()")
I forgot to add the percpu annotation for the mib pointer. Add it, and
make sparse happy.

Fixes: 029a37434880 ("udp6: cleanup stats accounting in recvmsg()")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/ipv6/udp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 2596ffdeebea..e6c52c27f354 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -288,8 +288,8 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	int peeked, peeking, off;
 	int err;
 	int is_udplite = IS_UDPLITE(sk);
+	struct udp_mib __percpu *mib;
 	bool checksum_valid = false;
-	struct udp_mib *mib;
 	int is_udp4;
 
 	if (flags & MSG_ERRQUEUE)
-- 
2.20.1

[PATCH net 2/4] fou6: fix proto error handler argument type

[Paolo Abeni]

Last argument of gue6_err_proto_handler() has a wrong type annotation,
fix it and make sparse happy again.

Fixes: b8a51b38e4d4 ("fou, fou6: ICMP error handlers for FoU and GUE")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
---
 net/ipv6/fou6.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c
index b858bd5280bf..867474abe269 100644
--- a/net/ipv6/fou6.c
+++ b/net/ipv6/fou6.c
@@ -72,7 +72,7 @@ static int gue6_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
 
 static int gue6_err_proto_handler(int proto, struct sk_buff *skb,
 				  struct inet6_skb_parm *opt,
-				  u8 type, u8 code, int offset, u32 info)
+				  u8 type, u8 code, int offset, __be32 info)
 {
 	const struct inet6_protocol *ipprot;
 
-- 
2.20.1

[PATCH net 3/4] udpv6: fix possible user after free in error handler

[Paolo Abeni]

Before derefencing the encap pointer, commit e7cc082455cb ("udp: Support
for error handlers of tunnels with arbitrary destination port") checks
for a NULL value, but the two fetch operation can race with removal.
Fix the above using a single access.
Also fix a couple of type annotations, to make sparse happy.

Fixes: e7cc082455cb ("udp: Support for error handlers of tunnels with arbitrary destination port")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
---
 net/ipv6/udp.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e6c52c27f354..b444483cdb2b 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -420,17 +420,19 @@ EXPORT_SYMBOL(udpv6_encap_enable);
  */
 static int __udp6_lib_err_encap_no_sk(struct sk_buff *skb,
 				      struct inet6_skb_parm *opt,
-				      u8 type, u8 code, int offset, u32 info)
+				      u8 type, u8 code, int offset, __be32 info)
 {
 	int i;
 
 	for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
 		int (*handler)(struct sk_buff *skb, struct inet6_skb_parm *opt,
-			       u8 type, u8 code, int offset, u32 info);
+			       u8 type, u8 code, int offset, __be32 info);
+		const struct ip6_tnl_encap_ops *encap;
 
-		if (!ip6tun_encaps[i])
+		encap = rcu_dereference(ip6tun_encaps[i]);
+		if (!encap)
 			continue;
-		handler = rcu_dereference(ip6tun_encaps[i]->err_handler);
+		handler = encap->err_handler;
 		if (handler && !handler(skb, opt, type, code, offset, info))
 			return 0;
 	}
-- 
2.20.1

[PATCH net 4/4] udp: fix possible user after free in error handler

[Paolo Abeni]

Similar to the previous commit, this addresses the same issue for
ipv4: use a single fetch operation and use the correct rcu
annotation.

Fixes: e7cc082455cb ("udp: Support for error handlers of tunnels with arbitrary destination port")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
---
 net/ipv4/udp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5c3cd5d84a6f..372fdc5381a9 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -562,10 +562,12 @@ static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info)
 
 	for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
 		int (*handler)(struct sk_buff *skb, u32 info);
+		const struct ip_tunnel_encap_ops *encap;
 
-		if (!iptun_encaps[i])
+		encap = rcu_dereference(iptun_encaps[i]);
+		if (!encap)
 			continue;
-		handler = rcu_dereference(iptun_encaps[i]->err_handler);
+		handler = encap->err_handler;
 		if (handler && !handler(skb, info))
 			return 0;
 	}
-- 
2.20.1

Re: [PATCH net 0/4] udp: a few fixes

[David Miller]

From: Paolo Abeni <pabeni@redhat.com>
Date: Thu, 21 Feb 2019 17:43:56 +0100

> This series includes some UDP-related fixlet. All this stuff has been
> pointed out by the sparse tool. The first two patches are just annotation
> related, while the last 2 cover some very unlikely races.

Series applied and queued up for -stable, thanks.