[B.A.T.M.A.N.] [PATCH v2 1/2] batman-adv: Avoid nullptr derefence in batadv_v_neigh_is_sob

[B.A.T.M.A.N.] [PATCH v2 1/2] batman-adv: Avoid nullptr derefence in batadv_v_neigh_is_sob

[Sven Eckelmann]

batadv_neigh_ifinfo_get can return NULL when it cannot find (even when only
temporarily) anymore the neigh_ifinfo in the list neigh->ifinfo_list. This
has to be checked to avoid kernel Oopses when the ifinfo is dereferenced.

This a situation which isn't expected but is already handled by functions
like batadv_v_neigh_cmp. The same kind of warning is therefore used before
the function returns without dereferencing the pointers.

Fixes: b05bbab5e1fc ("batman-adv: B.A.T.M.A.N. V - implement neighbor comparison API calls")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
v2: Add patch to reduce the reference counter of these functions

 net/batman-adv/bat_v.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c
index 927d405..f271ae8 100644
--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -286,6 +286,9 @@ static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
 	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
 	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
 
+	if (WARN_ON(!ifinfo1 || !ifinfo2))
+		return false;
+
 	threshold = ifinfo1->bat_v.throughput / 4;
 	threshold = ifinfo1->bat_v.throughput - threshold;
 
-- 
2.8.1

[B.A.T.M.A.N.] [PATCH v2 2/2] batman-adv: Fix refcnt leak in batadv_v_*

[Sven Eckelmann]

The functions batadv_neigh_ifinfo_get increase the reference counter of the
batadv_neigh_ifinfo. These have to be reduced again when the reference is
not used anymore to correctly free the objects.

Fixes: b05bbab5e1fc ("batman-adv: B.A.T.M.A.N. V - implement neighbor comparison API calls")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
v2: Add patch to reduce the reference counter of these functions

 net/batman-adv/bat_v.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c
index f271ae8..b52d684 100644
--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -265,14 +265,23 @@ static int batadv_v_neigh_cmp(struct batadv_neigh_node *neigh1,
 			      struct batadv_hard_iface *if_outgoing2)
 {
 	struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;
+	int ret = 0;
 
 	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
+	if (WARN_ON(!ifinfo1))
+		goto err_ifinfo1;
+
 	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
+	if (WARN_ON(!ifinfo2))
+		goto err_ifinfo2;
 
-	if (WARN_ON(!ifinfo1 || !ifinfo2))
-		return 0;
+	ret = ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;
 
-	return ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;
+	batadv_neigh_ifinfo_put(ifinfo2);
+err_ifinfo2:
+	batadv_neigh_ifinfo_put(ifinfo1);
+err_ifinfo1:
+	return ret;
 }
 
 static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
@@ -282,17 +291,26 @@ static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
 {
 	struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;
 	u32 threshold;
+	bool ret = false;
 
 	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
-	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
+	if (WARN_ON(!ifinfo1))
+		goto err_ifinfo1;
 
-	if (WARN_ON(!ifinfo1 || !ifinfo2))
-		return false;
+	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
+	if (WARN_ON(!ifinfo2))
+		goto err_ifinfo2;
 
 	threshold = ifinfo1->bat_v.throughput / 4;
 	threshold = ifinfo1->bat_v.throughput - threshold;
 
-	return ifinfo2->bat_v.throughput > threshold;
+	ret = ifinfo2->bat_v.throughput > threshold;
+
+	batadv_neigh_ifinfo_put(ifinfo2);
+err_ifinfo2:
+	batadv_neigh_ifinfo_put(ifinfo1);
+err_ifinfo1:
+	return ret;
 }
 
 static struct batadv_algo_ops batadv_batman_v __read_mostly = {
-- 
2.8.1

Re: [B.A.T.M.A.N.] [PATCH v2 2/2] batman-adv: Fix refcnt leak in batadv_v_*

[Sven Eckelmann]

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Maybe it is better to rename the patch slightly.

    batman-adv: Fix refcnt leak in batadv_v_neigh_*

But I will not resent the patch for only this change when not explicitly asked 
for it.

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v2 2/2] batman-adv: Fix refcnt leak in batadv_v_*

[Marek Lindner]

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On Friday, May 06, 2016 11:43:39 Sven Eckelmann wrote:
> The functions batadv_neigh_ifinfo_get increase the reference counter of the
> batadv_neigh_ifinfo. These have to be reduced again when the reference is
> not used anymore to correctly free the objects.
> 
> Fixes: b05bbab5e1fc ("batman-adv: B.A.T.M.A.N. V - implement neighbor
> comparison API calls") Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> v2: Add patch to reduce the reference counter of these functions
> 
>  net/batman-adv/bat_v.c | 32 +++++++++++++++++++++++++-------
>  1 file changed, 25 insertions(+), 7 deletions(-)

Applied in revision 650d41d.

Thanks,
Marek

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Re: [B.A.T.M.A.N.] [PATCH v2 1/2] batman-adv: Avoid nullptr derefence in batadv_v_neigh_is_sob

[Marek Lindner]

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On Friday, May 06, 2016 11:43:38 Sven Eckelmann wrote:
> batadv_neigh_ifinfo_get can return NULL when it cannot find (even when only
> temporarily) anymore the neigh_ifinfo in the list neigh->ifinfo_list. This
> has to be checked to avoid kernel Oopses when the ifinfo is dereferenced.
> 
> This a situation which isn't expected but is already handled by functions
> like batadv_v_neigh_cmp. The same kind of warning is therefore used before
> the function returns without dereferencing the pointers.
> 
> Fixes: b05bbab5e1fc ("batman-adv: B.A.T.M.A.N. V - implement neighbor
> comparison API calls") Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> v2: Add patch to reduce the reference counter of these functions
> 
>  net/batman-adv/bat_v.c | 3 +++
>  1 file changed, 3 insertions(+)

Applied in revision 036aa7b.

Thanks,
Marek

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