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| author | David Ahern <dsahern@gmail.com> | 2019-04-16 17:31:43 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-04-17 23:19:07 -0700 |
| commit | b8fb1ab46169ac016a8552a6455bb0bfc401f8e2 (patch) | |
| tree | a7d8430a9044e9e3203915f401e68abfd6e30c31 /net | |
| parent | cea29a70727e7885b3fdf0d266a57818652a89c1 (diff) | |
| download | linux-b8fb1ab46169ac016a8552a6455bb0bfc401f8e2.tar.gz linux-b8fb1ab46169ac016a8552a6455bb0bfc401f8e2.tar.bz2 linux-b8fb1ab46169ac016a8552a6455bb0bfc401f8e2.zip | |
net ipv6: Prevent neighbor add if protocol is disabled on device
Disabling IPv6 on an interface removes existing entries but nothing prevents
new entries from being manually added. To that end, add a new neigh_table
operation, allow_add, that is called on RTM_NEWNEIGH to see if neighbor
entries are allowed on a given device. If IPv6 is disabled on the device,
allow_add returns false and passes a message back to the user via extack.
$ echo 1 > /proc/sys/net/ipv6/conf/eth1/disable_ipv6
$ ip -6 neigh add fe80::4c88:bff:fe21:2704 dev eth1 lladdr de:ad:be:ef:01:01
Error: IPv6 is disabled on this device.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/neighbour.c | 5 | ||||
| -rw-r--r-- | net/ipv6/ndisc.c | 17 |
2 files changed, 22 insertions, 0 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 30f6fd8f68e0..997cfa8f99ba 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1920,6 +1920,11 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, goto out; } + if (tbl->allow_add && !tbl->allow_add(dev, extack)) { + err = -EINVAL; + goto out; + } + neigh = neigh_lookup(tbl, dst, dev); if (neigh == NULL) { bool exempt_from_gc; diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 66c8b294e02b..4c8e2ea8bf19 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -77,6 +77,8 @@ static u32 ndisc_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd); static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey); +static bool ndisc_allow_add(const struct net_device *dev, + struct netlink_ext_ack *extack); static int ndisc_constructor(struct neighbour *neigh); static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb); static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb); @@ -117,6 +119,7 @@ struct neigh_table nd_tbl = { .pconstructor = pndisc_constructor, .pdestructor = pndisc_destructor, .proxy_redo = pndisc_redo, + .allow_add = ndisc_allow_add, .id = "ndisc_cache", .parms = { .tbl = &nd_tbl, @@ -392,6 +395,20 @@ static void pndisc_destructor(struct pneigh_entry *n) ipv6_dev_mc_dec(dev, &maddr); } +/* called with rtnl held */ +static bool ndisc_allow_add(const struct net_device *dev, + struct netlink_ext_ack *extack) +{ + struct inet6_dev *idev = __in6_dev_get(dev); + + if (!idev || idev->cnf.disable_ipv6) { + NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device"); + return false; + } + + return true; +} + static struct sk_buff *ndisc_alloc_skb(struct net_device *dev, int len) { |