From 9fb6012d26b2d4335a3a3d19ec73a8a1c5a09de6 Mon Sep 17 00:00:00 2001 From: Pablo Neira Date: Mon, 29 Jul 2013 12:30:04 +0200 Subject: UPSTREAM: genetlink: fix usage of NLM_F_EXCL or NLM_F_REPLACE Currently, it is not possible to use neither NLM_F_EXCL nor NLM_F_REPLACE from genetlink. This is due to this checking in genl_family_rcv_msg: if (nlh->nlmsg_flags & NLM_F_DUMP) NLM_F_DUMP is NLM_F_MATCH|NLM_F_ROOT. Thus, if NLM_F_EXCL or NLM_F_REPLACE flag is set, genetlink believes that you're requesting a dump and it calls the .dumpit callback. The solution that I propose is to refine this checking to make it stricter: if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) And given the combination NLM_F_REPLACE and NLM_F_EXCL does not make sense to me, it removes the ambiguity. There was a patch that tried to fix this some time ago (0ab03c2 netlink: test for all flags of the NLM_F_DUMP composite) but it tried to resolve this ambiguity in *all* existing netlink subsystems, not only genetlink. That patch was reverted since it broke iproute2, which is using NLM_F_ROOT to request the dump of the routing cache. Signed-off-by: Pablo Neira Ayuso Signed-off-by: David S. Miller (cherry picked from commit e1ee3673a83cc02b6b5e43c9e647d8dd5e1c4e26) Change-Id: I1e7dfdfb1accfd22a171eb9a9a993e5b191dd27f --- net/netlink/genetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/netlink') diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index ade434b8a..c7408dd8f 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -595,7 +595,7 @@ static int genl_family_rcv_msg(struct genl_family *family, !netlink_capable(skb, CAP_NET_ADMIN)) return -EPERM; - if (nlh->nlmsg_flags & NLM_F_DUMP) { + if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { int rc; if (ops->dumpit == NULL) -- cgit v1.2.3