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authorNikolay Aleksandrov <nikolay@cumulusnetworks.com>2020-02-20 16:42:13 +0200
committerDavid S. Miller <davem@davemloft.net>2020-02-20 16:02:08 -0800
commit3a20773beeeeadec41477a5ba872175b778ff752 (patch)
treee6bf9989b00065892e06d785ceb4e198cdcbd914
parent971617c3b761c876d686a2188220a33898c90e99 (diff)
net: netlink: cap max groups which will be considered in netlink_bind()
Since nl_groups is a u32 we can't bind more groups via ->bind (netlink_bind) call, but netlink has supported more groups via setsockopt() for a long time and thus nlk->ngroups could be over 32. Recently I added support for per-vlan notifications and increased the groups to 33 for NETLINK_ROUTE which exposed an old bug in the netlink_bind() code causing out-of-bounds access on archs where unsigned long is 32 bits via test_bit() on a local variable. Fix this by capping the maximum groups in netlink_bind() to BITS_PER_TYPE(u32), effectively capping them at 32 which is the minimum of allocated groups and the maximum groups which can be bound via netlink_bind(). CC: Christophe Leroy <christophe.leroy@c-s.fr> CC: Richard Guy Briggs <rgb@redhat.com> Fixes: 4f520900522f ("netlink: have netlink per-protocol bind function return an error code.") Reported-by: Erhard F. <erhard_f@mailbox.org> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/netlink/af_netlink.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 4e31721e7293..edf3e285e242 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1014,7 +1014,8 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
if (nlk->netlink_bind && groups) {
int group;
- for (group = 0; group < nlk->ngroups; group++) {
+ /* nl_groups is a u32, so cap the maximum groups we can bind */
+ for (group = 0; group < BITS_PER_TYPE(u32); group++) {
if (!test_bit(group, &groups))
continue;
err = nlk->netlink_bind(net, group + 1);
@@ -1033,7 +1034,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
netlink_insert(sk, nladdr->nl_pid) :
netlink_autobind(sock);
if (err) {
- netlink_undo_bind(nlk->ngroups, groups, sk);
+ netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
goto unlock;
}
}