Patchwork [net-next] ipv6: check return value of ipv6_get_lladdr

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Submitter Hannes Frederic Sowa
Date June 23, 2013, 7:56 p.m.
Message ID <20130623195648.GC13836@order.stressinduktion.org>
Download mbox | patch
Permalink /patch/253593/
State Superseded
Delegated to: David Miller
Headers show

Comments

Hannes Frederic Sowa - June 23, 2013, 7:56 p.m.
We should check the return value of ipv6_get_lladdr in inet6_set_iftoken.

A possible situation, which could leave ll_addr unassigned is, when
the user removed her link-local address but a global scoped address was
already set. In this case the interface would still be IF_READY and not
dead. In that case the RS source address is some value from the stack.

Cc: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
Maybe -net, or even stable?

 net/ipv6/addrconf.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)
Hannes Frederic Sowa - June 23, 2013, 10:30 p.m.
On Sun, Jun 23, 2013 at 09:56:48PM +0200, Hannes Frederic Sowa wrote:
> We should check the return value of ipv6_get_lladdr in inet6_set_iftoken.
> 
> A possible situation, which could leave ll_addr unassigned is, when
> the user removed her link-local address but a global scoped address was
> already set. In this case the interface would still be IF_READY and not
> dead. In that case the RS source address is some value from the stack.
> 
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> ---
> Maybe -net, or even stable?

Actually, stable is nonsense because tokenized ipv6 addresses first
appeared in v3.10-rc1 in mainline.

Greetings,

  Hannes

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Daniel Borkmann - June 24, 2013, 7:19 a.m.
On 06/23/2013 09:56 PM, Hannes Frederic Sowa wrote:
> We should check the return value of ipv6_get_lladdr in inet6_set_iftoken.
>
> A possible situation, which could leave ll_addr unassigned is, when
> the user removed her link-local address but a global scoped address was
> already set. In this case the interface would still be IF_READY and not
> dead. In that case the RS source address is some value from the stack.
>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

Acked-by: Daniel Borkmann <dborkman@redhat.com>
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Flavio Leitner - June 24, 2013, 6:22 p.m.
On Sun, Jun 23, 2013 at 09:56:48PM +0200, Hannes Frederic Sowa wrote:
> We should check the return value of ipv6_get_lladdr in inet6_set_iftoken.
> 
> A possible situation, which could leave ll_addr unassigned is, when
> the user removed her link-local address but a global scoped address was
> already set. In this case the interface would still be IF_READY and not
> dead. In that case the RS source address is some value from the stack.
> 
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> ---

Reviewed-by: Flavio Leitner <fbl@redhat.com>

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Patch

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 8044912..9392c6e 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4317,6 +4317,7 @@  static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token)
 	struct inet6_ifaddr *ifp;
 	struct net_device *dev = idev->dev;
 	bool update_rs = false;
+	struct in6_addr ll_addr;
 
 	if (token == NULL)
 		return -EINVAL;
@@ -4336,11 +4337,9 @@  static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token)
 
 	write_unlock_bh(&idev->lock);
 
-	if (!idev->dead && (idev->if_flags & IF_READY)) {
-		struct in6_addr ll_addr;
-
-		ipv6_get_lladdr(dev, &ll_addr, IFA_F_TENTATIVE |
-				IFA_F_OPTIMISTIC);
+	if (!idev->dead && (idev->if_flags & IF_READY) &&
+	    !ipv6_get_lladdr(dev, &ll_addr, IFA_F_TENTATIVE |
+					    IFA_F_OPTIMISTIC)) {
 
 		/* If we're not ready, then normal ifup will take care
 		 * of this. Otherwise, we need to request our rs here.