On 6/6/23 15:46, Guillaume Nault wrote:
On Tue, Jun 06, 2023 at 08:24:54AM +0200, Mirsad Goran Todorovac wrote:
On 5/31/23 20:11, Guillaume Nault wrote:
I believe this condition should be relaxed to allow the case where
->sk_bound_dev_if is oif's master device (and maybe there are other
VRF cases to also consider).
I've tried something like this, but something makes the kernel stuck
here:
TEST: ping out, blocked by route - ns-B loopback IPv6 [ OK ]
TEST: ping out, device bind, blocked by route - ns-B loopback IPv6 [ OK ]
TEST: ping in, blocked by route - ns-A loopback IPv6 [ OK ]
TEST: ping out, unreachable route - ns-B loopback IPv6 [ OK ]
TEST: ping out, device bind, unreachable route - ns-B loopback IPv6 [ OK ]
#################################################################
With VRF
[hanged process and kernel won't shutdown]
The code is:
---
net/ipv6/ping.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index c4835dbdfcff..81293e902293 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -73,6 +73,9 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
struct rt6_info *rt;
struct pingfakehdr pfh;
struct ipcm6_cookie ipc6;
+ struct net *net = sock_net(sk);
+ struct net_device *dev = NULL;
+ struct net_device *mdev = NULL;
err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
sizeof(user_icmph));
@@ -111,10 +114,17 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
else if (!oif)
oif = np->ucast_oif;
+ if (oif) {
+ dev = dev_get_by_index(net, oif);
+ mdev = netdev_master_upper_dev_get(dev);
+ }
+
addr_type = ipv6_addr_type(daddr);
if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
(addr_type & IPV6_ADDR_MAPPED) ||
- (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
+ (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
+ !(mdev && sk->sk_bound_dev_if &&
+ mdev != dev_get_by_index(net, sk->sk_bound_dev_if))))
return -EINVAL;
ipcm6_init_sk(&ipc6, np);
I am obviously doing something very stupid.
The problem is that dev_get_by_index() holds a reference on 'dev' which
your code never releases. Also netdev_master_upper_dev_get() needs rtnl
protection. These should have generated some kernel oops.
You can try this instead:
-------- >8 --------
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index c4835dbdfcff..f804c11e2146 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -114,7 +114,8 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
addr_type = ipv6_addr_type(daddr);
if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
(addr_type & IPV6_ADDR_MAPPED) ||
- (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
+ (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
+ l3mdev_master_ifindex_by_index(sock_net(sk), oif) != sk->sk_bound_dev_if))
return -EINVAL;
ipcm6_init_sk(&ipc6, np);
Yes, I stupidly forgot that.
I came across a fixed version:
------
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index c4835dbdfcff..c1d81c49b775 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -73,6 +73,10 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
struct rt6_info *rt;
struct pingfakehdr pfh;
struct ipcm6_cookie ipc6;
+ struct net *net = sock_net(sk);
+ struct net_device *dev = NULL;
+ struct net_device *mdev = NULL;
+ struct net_device *bdev = NULL;
err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
sizeof(user_icmph));
@@ -111,10 +115,26 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
else if (!oif)
oif = np->ucast_oif;
+ if (oif) {
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(net, oif);
+ rcu_read_unlock();
+ rtnl_lock();
+ mdev = netdev_master_upper_dev_get(dev);
+ rtnl_unlock();
+ }
+
+ if (sk->sk_bound_dev_if) {
+ rcu_read_lock();
+ bdev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
+ rcu_read_unlock();
+ }
+
addr_type = ipv6_addr_type(daddr);
if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
(addr_type & IPV6_ADDR_MAPPED) ||
- (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
+ (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
+ !(mdev && sk->sk_bound_dev_if && bdev && mdev == bdev)))
return -EINVAL;
ipcm6_init_sk(&ipc6, np);
However, this works by the test (888 passed) but your two liner is obviously
better :-)
Best regards,
Mirsad
--
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
