From 220815a9665f7deca98a09ecca655044f94cfa44 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Thu, 21 Nov 2013 18:17:04 +0100
Subject: [PATCH] genetlink: fix genlmsg_multicast() bug
Unfortunately, I introduced a tremendously stupid bug into
genlmsg_multicast() when doing all those multicast group
changes: it adjusts the group number, but then passes it
to genlmsg_multicast_netns() which does that again.
Somehow, my tests failed to catch this, so add a warning
into genlmsg_multicast_netns() and remove the offending
group ID adjustment.
Also add a warning to the similar code in other functions
so people who misuse them are more loudly warned.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/genetlink.h | 5 +----
net/netlink/genetlink.c | 4 ++--
2 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index ace4abf118d7d..771af09e90eb8 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -265,7 +265,7 @@ static inline int genlmsg_multicast_netns(struct genl_family *family,
struct net *net, struct sk_buff *skb,
u32 portid, unsigned int group, gfp_t flags)
{
- if (group >= family->n_mcgrps)
+ if (WARN_ON_ONCE(group >= family->n_mcgrps))
return -EINVAL;
group = family->mcgrp_offset + group;
return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
@@ -283,9 +283,6 @@ static inline int genlmsg_multicast(struct genl_family *family,
struct sk_buff *skb, u32 portid,
unsigned int group, gfp_t flags)
{
- if (group >= family->n_mcgrps)
- return -EINVAL;
- group = family->mcgrp_offset + group;
return genlmsg_multicast_netns(family, &init_net, skb,
portid, group, flags);
}
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 7dbc4f732c75a..4518a57aa5feb 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1045,7 +1045,7 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
u32 portid, unsigned int group, gfp_t flags)
{
- if (group >= family->n_mcgrps)
+ if (WARN_ON_ONCE(group >= family->n_mcgrps))
return -EINVAL;
group = family->mcgrp_offset + group;
return genlmsg_mcast(skb, portid, group, flags);
@@ -1062,7 +1062,7 @@ void genl_notify(struct genl_family *family,
if (nlh)
report = nlmsg_report(nlh);
- if (group >= family->n_mcgrps)
+ if (WARN_ON_ONCE(group >= family->n_mcgrps))
return;
group = family->mcgrp_offset + group;
nlmsg_notify(sk, skb, portid, group, report, flags);
--
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