diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 54cfbaeb3a4e..fa10ad8e9b17 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -25,6 +25,7 @@ #include #include #include +#include #include @@ -604,12 +605,88 @@ int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) EXPORT_SYMBOL_GPL(add_uevent_var); #if defined(CONFIG_NET) +static int uevent_net_broadcast(struct sock *usk, struct sk_buff *skb, + struct netlink_ext_ack *extack) +{ + /* u64 to chars: 2^64 - 1 = 21 chars */ + char buf[sizeof("SEQNUM=") + 21]; + struct sk_buff *skbc; + int ret; + + /* bump and prepare sequence number */ + ret = snprintf(buf, sizeof(buf), "SEQNUM=%llu", ++uevent_seqnum); + if (ret < 0 || (size_t)ret >= sizeof(buf)) + return -ENOMEM; + ret++; + + /* verify message does not overflow */ + if ((skb->len + ret) > UEVENT_BUFFER_SIZE) { + NL_SET_ERR_MSG(extack, "uevent message too big"); + return -EINVAL; + } + + /* copy skb and extend to accommodate sequence number */ + skbc = skb_copy_expand(skb, 0, ret, GFP_KERNEL); + if (!skbc) + return -ENOMEM; + + /* append sequence number */ + skb_put_data(skbc, buf, ret); + + /* remove msg header */ + skb_pull(skbc, NLMSG_HDRLEN); + + /* set portid 0 to inform userspace message comes from kernel */ + NETLINK_CB(skbc).portid = 0; + NETLINK_CB(skbc).dst_group = 1; + + ret = netlink_broadcast(usk, skbc, 0, 1, GFP_KERNEL); + /* ENOBUFS should be handled in userspace */ + if (ret == -ENOBUFS || ret == -ESRCH) + ret = 0; + + return ret; +} + +static int uevent_net_rcv_skb(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + struct net *net; + int ret; + + if (!nlmsg_data(nlh)) + return -EINVAL; + + /* + * Verify that we are allowed to send messages to the target + * network namespace. The caller must have CAP_SYS_ADMIN in the + * owning user namespace of the target network namespace. + */ + net = sock_net(NETLINK_CB(skb).sk); + if (!netlink_ns_capable(skb, net->user_ns, CAP_SYS_ADMIN)) { + NL_SET_ERR_MSG(extack, "missing CAP_SYS_ADMIN capability"); + return -EPERM; + } + + mutex_lock(&uevent_sock_mutex); + ret = uevent_net_broadcast(net->uevent_sock->sk, skb, extack); + mutex_unlock(&uevent_sock_mutex); + + return ret; +} + +static void uevent_net_rcv(struct sk_buff *skb) +{ + netlink_rcv_skb(skb, &uevent_net_rcv_skb); +} + static int uevent_net_init(struct net *net) { struct uevent_sock *ue_sk; struct netlink_kernel_cfg cfg = { .groups = 1, - .flags = NL_CFG_F_NONROOT_RECV, + .input = uevent_net_rcv, + .flags = NL_CFG_F_NONROOT_RECV }; ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);