From: Kristian Evensen kristian.evensen@gmail.com
[ Upstream commit f8e608982022fad035160870f5b06086d3cba54d ]
Commit 59c08c69c278 ("netfilter: ctnetlink: Support L3 protocol-filter on flush") introduced a user-space regression when flushing connection track entries. Before this commit, the nfgen_family field was not used by the kernel and all entries were removed. Since this commit, nfgen_family is used to filter out entries that should not be removed. One example a broken tool is conntrack. conntrack always sets nfgen_family to AF_INET, so after 59c08c69c278 only IPv4 entries were removed with the -F parameter.
Pablo Neira Ayuso suggested using nfgenmsg->version to resolve the regression, and this commit implements his suggestion. nfgenmsg->version is so far set to zero, so it is well-suited to be used as a flag for selecting old or new flush behavior. If version is 0, nfgen_family is ignored and all entries are used. If user-space sets the version to one (or any other value than 0), then the new behavior is used. As version only can have two valid values, I chose not to add a new NFNETLINK_VERSION-constant.
Fixes: 59c08c69c278 ("netfilter: ctnetlink: Support L3 protocol-filter on flush") Reported-by: Nicolas Dichtel nicolas.dichtel@6wind.com Suggested-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Kristian Evensen kristian.evensen@gmail.com Tested-by: Nicolas Dichtel nicolas.dichtel@6wind.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_conntrack_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index d7f61b0547c65..d2715b4d2e72e 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1254,7 +1254,7 @@ static int ctnetlink_del_conntrack(struct net *net, struct sock *ctnl, struct nf_conntrack_tuple tuple; struct nf_conn *ct; struct nfgenmsg *nfmsg = nlmsg_data(nlh); - u_int8_t u3 = nfmsg->nfgen_family; + u_int8_t u3 = nfmsg->version ? nfmsg->nfgen_family : AF_UNSPEC; struct nf_conntrack_zone zone; int err;