diff options
| author | Nikolay Aleksandrov <nikolay@cumulusnetworks.com> | 2020-02-20 16:42:13 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-20 16:02:08 -0800 |
| commit | 3a20773beeeeadec41477a5ba872175b778ff752 (patch) | |
| tree | e6bf9989b00065892e06d785ceb4e198cdcbd914 | |
| parent | 971617c3b761c876d686a2188220a33898c90e99 (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.c | 5 |
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; } } |