[Devel] [PATCH RHEL7 COMMIT] ms/netlink: have netlink per-protocol bind function return an error code.
Konstantin Khorenko
khorenko at virtuozzo.com
Wed Nov 30 03:46:48 PST 2016
The commit is pushed to "branch-rh7-3.10.0-327.36.1.vz7.20.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.36.1.vz7.20.7
------>
commit 2cfcca533778f35a2e9166602caf632c20e8d8a3
Author: Richard Guy Briggs <rgb at redhat.com>
Date: Wed Nov 30 15:46:48 2016 +0400
ms/netlink: have netlink per-protocol bind function return an error code.
Have the netlink per-protocol optional bind function return an int error code
rather than void to signal a failure.
This will enable netlink protocols to perform extra checks including
capabilities and permissions verifications when updating memberships in
multicast groups.
In netlink_bind() and netlink_setsockopt() the call to the per-protocol bind
function was moved above the multicast group update to prevent any access to
the multicast socket groups before checking with the per-protocol bind
function. This will enable the per-protocol bind function to be used to check
permissions which could be denied before making them available, and to avoid
the messy job of undoing the addition should the per-protocol bind function
fail.
The netfilter subsystem seems to be the only one currently using the
per-protocol bind function.
Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
This is done in the scope of
https://jira.sw.ru/browse/PSBM-54189
upstream commit: 4f520900522fd596e336c07e9aafd5b7a9564235
Signed-off-by: Igor Redko <redkoi at virtuozzo.com>
Acked-by: Andrei Vagin <avagin at openvz.org>
---
include/linux/netlink.h | 3 ++-
net/netfilter/nfnetlink.c | 3 ++-
net/netlink/af_netlink.c | 68 +++++++++++++++++++++++++++++++++--------------
net/netlink/af_netlink.h | 6 +++--
4 files changed, 56 insertions(+), 24 deletions(-)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 076b75c..ef68e5b 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -48,7 +48,8 @@ struct netlink_kernel_cfg {
unsigned int flags;
void (*input)(struct sk_buff *skb);
struct mutex *cb_mutex;
- void (*bind)(int group);
+ int (*bind)(int group);
+ void (*unbind)(int group);
bool (*compare)(struct net *net, struct sock *sk);
};
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 48cf7a1..81df6ce 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -399,7 +399,7 @@ static void nfnetlink_rcv(struct sk_buff *skb)
}
#ifdef CONFIG_MODULES
-static void nfnetlink_bind(int group)
+static int nfnetlink_bind(int group)
{
const struct nfnetlink_subsystem *ss;
int type = nfnl_group2type[group];
@@ -409,6 +409,7 @@ static void nfnetlink_bind(int group)
rcu_read_unlock();
if (!ss)
request_module("nfnetlink-subsys-%d", type);
+ return 0;
}
#endif
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 29a8d65..7a0f6fb 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1159,7 +1159,8 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
struct module *module = NULL;
struct mutex *cb_mutex;
struct netlink_sock *nlk;
- void (*bind)(int group);
+ int (*bind)(int group);
+ void (*unbind)(int group);
int err = 0;
sock->state = SS_UNCONNECTED;
@@ -1185,6 +1186,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
err = -EPROTONOSUPPORT;
cb_mutex = nl_table[protocol].cb_mutex;
bind = nl_table[protocol].bind;
+ unbind = nl_table[protocol].unbind;
netlink_unlock_table();
if (err < 0)
@@ -1201,6 +1203,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
nlk = nlk_sk(sock->sk);
nlk->module = module;
nlk->netlink_bind = bind;
+ nlk->netlink_unbind = unbind;
out:
return err;
@@ -1261,6 +1264,7 @@ static int netlink_release(struct socket *sock)
kfree_rcu(old, rcu);
nl_table[sk->sk_protocol].module = NULL;
nl_table[sk->sk_protocol].bind = NULL;
+ nl_table[sk->sk_protocol].unbind = NULL;
nl_table[sk->sk_protocol].flags = 0;
nl_table[sk->sk_protocol].registered = 0;
}
@@ -1431,6 +1435,19 @@ static int netlink_realloc_groups(struct sock *sk)
return err;
}
+static void netlink_unbind(int group, long unsigned int groups,
+ struct netlink_sock *nlk)
+{
+ int undo;
+
+ if (!nlk->netlink_unbind)
+ return;
+
+ for (undo = 0; undo < group; undo++)
+ if (test_bit(group, &groups))
+ nlk->netlink_unbind(undo);
+}
+
static int netlink_bind(struct socket *sock, struct sockaddr *addr,
int addr_len)
{
@@ -1439,6 +1456,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
int err;
+ long unsigned int groups = nladdr->nl_groups;
if (addr_len < sizeof(struct sockaddr_nl))
return -EINVAL;
@@ -1447,7 +1465,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
return -EINVAL;
/* Only superuser is allowed to listen multicasts */
- if (nladdr->nl_groups) {
+ if (groups) {
if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
return -EPERM;
err = netlink_realloc_groups(sk);
@@ -1455,37 +1473,45 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
return err;
}
- if (nlk->portid) {
+ if (nlk->portid)
if (nladdr->nl_pid != nlk->portid)
return -EINVAL;
- } else {
+
+ if (nlk->netlink_bind && groups) {
+ int group;
+
+ for (group = 0; group < nlk->ngroups; group++) {
+ if (!test_bit(group, &groups))
+ continue;
+ err = nlk->netlink_bind(group);
+ if (!err)
+ continue;
+ netlink_unbind(group, groups, nlk);
+ return err;
+ }
+ }
+
+ if (!nlk->portid) {
err = nladdr->nl_pid ?
netlink_insert(sk, net, nladdr->nl_pid) :
netlink_autobind(sock);
- if (err)
+ if (err) {
+ netlink_unbind(nlk->ngroups - 1, groups, nlk);
return err;
+ }
}
- if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
+ if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
return 0;
netlink_table_grab();
netlink_update_subscriptions(sk, nlk->subscriptions +
- hweight32(nladdr->nl_groups) -
+ hweight32(groups) -
hweight32(nlk->groups[0]));
- nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
+ nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
netlink_update_listeners(sk);
netlink_table_ungrab();
- if (nlk->netlink_bind && nlk->groups[0]) {
- int i;
-
- for (i=0; i<nlk->ngroups; i++) {
- if (test_bit(i, nlk->groups))
- nlk->netlink_bind(i);
- }
- }
-
return 0;
}
@@ -2162,14 +2188,16 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
return err;
if (!val || val - 1 >= nlk->ngroups)
return -EINVAL;
+ if (nlk->netlink_bind) {
+ err = nlk->netlink_bind(val);
+ if (err)
+ return err;
+ }
netlink_table_grab();
netlink_update_socket_mc(nlk, val,
optname == NETLINK_ADD_MEMBERSHIP);
netlink_table_ungrab();
- if (nlk->netlink_bind)
- nlk->netlink_bind(val);
-
err = 0;
break;
}
diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h
index f95dc85..af0c6f2 100644
--- a/net/netlink/af_netlink.h
+++ b/net/netlink/af_netlink.h
@@ -48,7 +48,8 @@ struct netlink_sock {
struct mutex *cb_mutex;
struct mutex cb_def_mutex;
void (*netlink_rcv)(struct sk_buff *skb);
- void (*netlink_bind)(int group);
+ int (*netlink_bind)(int group);
+ void (*netlink_unbind)(int group);
struct module *module;
#ifdef CONFIG_NETLINK_MMAP
struct mutex pg_vec_lock;
@@ -74,7 +75,8 @@ struct netlink_table {
unsigned int groups;
struct mutex *cb_mutex;
struct module *module;
- void (*bind)(int group);
+ int (*bind)(int group);
+ void (*unbind)(int group);
bool (*compare)(struct net *net, struct sock *sock);
int registered;
};
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