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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>
This commit is contained in:
Johannes Berg 2013-11-21 18:17:04 +01:00 committed by David S. Miller
parent e40526cb20
commit 220815a966
2 changed files with 3 additions and 6 deletions
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5
include/net/genetlink.h
View File

@ -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);
}

4
net/netlink/genetlink.c
View File

@ -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);