diff options
| author | Kuniyuki Iwashima <kuniyu@google.com> | 2025-07-16 22:08:09 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-17 16:25:20 -0700 |
| commit | 0e5ac19c78654abbf43dc4ffdae290c8cb81c59c (patch) | |
| tree | 8903446233de02c2ee89f789d24cecdc3ec2ce5f | |
| parent | 3dfe0b57dcda070d9f1ed2bfb3a9bf0ec8632e08 (diff) | |
neighbour: Move neigh_find_table() to neigh_get().
neigh_valid_get_req() calls neigh_find_table() to fetch neigh_tables[].
neigh_find_table() uses rcu_dereference_rtnl(), but RTNL actually does
not protect it at all; neigh_table_clear() can be called without RTNL
and only waits for RCU readers by synchronize_rcu().
Fortunately, there is no bug because IPv4 is built-in, IPv6 cannot be
unloaded, and DECNET was removed.
To fetch neigh_tables[] by rcu_dereference() later, let's move
neigh_find_table() from neigh_valid_get_req() to neigh_get().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250716221221.442239-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/neighbour.c | 37 |
1 files changed, 20 insertions, 17 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 761593ea8c91..ffb8d80328ed 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -2911,10 +2911,9 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb) } static struct ndmsg *neigh_valid_get_req(const struct nlmsghdr *nlh, - struct neigh_table **tbl, void **dst, + struct nlattr **tb, struct netlink_ext_ack *extack) { - struct nlattr *tb[NDA_MAX + 1]; struct ndmsg *ndm; int err, i; @@ -2945,12 +2944,6 @@ static struct ndmsg *neigh_valid_get_req(const struct nlmsghdr *nlh, if (err < 0) return ERR_PTR(err); - *tbl = neigh_find_table(ndm->ndm_family); - if (!*tbl) { - NL_SET_ERR_MSG(extack, "Unsupported family in header for neighbor get request"); - return ERR_PTR(-EAFNOSUPPORT); - } - for (i = 0; i <= NDA_MAX; ++i) { switch (i) { case NDA_DST: @@ -2958,12 +2951,6 @@ static struct ndmsg *neigh_valid_get_req(const struct nlmsghdr *nlh, NL_SET_ERR_ATTR_MISS(extack, NULL, NDA_DST); return ERR_PTR(-EINVAL); } - - if (nla_len(tb[i]) != (int)(*tbl)->key_len) { - NL_SET_ERR_MSG(extack, "Invalid network address in neighbor get request"); - return ERR_PTR(-EINVAL); - } - *dst = nla_data(tb[i]); break; default: if (!tb[i]) @@ -3001,16 +2988,17 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh, { struct net *net = sock_net(in_skb->sk); u32 pid = NETLINK_CB(in_skb).portid; + struct nlattr *tb[NDA_MAX + 1]; struct net_device *dev = NULL; - struct neigh_table *tbl = NULL; u32 seq = nlh->nlmsg_seq; + struct neigh_table *tbl; struct neighbour *neigh; struct sk_buff *skb; struct ndmsg *ndm; - void *dst = NULL; + void *dst; int err; - ndm = neigh_valid_get_req(nlh, &tbl, &dst, extack); + ndm = neigh_valid_get_req(nlh, tb, extack); if (IS_ERR(ndm)) return PTR_ERR(ndm); @@ -3021,6 +3009,21 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh, if (!skb) return -ENOBUFS; + tbl = neigh_find_table(ndm->ndm_family); + if (!tbl) { + NL_SET_ERR_MSG(extack, "Unsupported family in header for neighbor get request"); + err = -EAFNOSUPPORT; + goto err_free_skb; + } + + if (nla_len(tb[NDA_DST]) != (int)tbl->key_len) { + NL_SET_ERR_MSG(extack, "Invalid network address in neighbor get request"); + err = -EINVAL; + goto err_free_skb; + } + + dst = nla_data(tb[NDA_DST]); + if (ndm->ndm_ifindex) { dev = __dev_get_by_index(net, ndm->ndm_ifindex); if (!dev) { |