From 5187cd055b6e81fc6526109456f8b20623148d5f Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 23 Apr 2014 14:25:48 -0700 Subject: netlink: Rename netlink_capable netlink_allowed netlink_capable is a static internal function in af_netlink.c and we have better uses for the name netlink_capable. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'net/netlink') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 894cda0..7f931fe 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1360,7 +1360,7 @@ retry: return err; } -static inline int netlink_capable(const struct socket *sock, unsigned int flag) +static inline int netlink_allowed(const struct socket *sock, unsigned int flag) { return (nl_table[sock->sk->sk_protocol].flags & flag) || ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN); @@ -1428,7 +1428,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, /* Only superuser is allowed to listen multicasts */ if (nladdr->nl_groups) { - if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV)) + if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) return -EPERM; err = netlink_realloc_groups(sk); if (err) @@ -1490,7 +1490,7 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, return -EINVAL; if ((nladdr->nl_groups || nladdr->nl_pid) && - !netlink_capable(sock, NL_CFG_F_NONROOT_SEND)) + !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) return -EPERM; if (!nlk->portid) @@ -2096,7 +2096,7 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, break; case NETLINK_ADD_MEMBERSHIP: case NETLINK_DROP_MEMBERSHIP: { - if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV)) + if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) return -EPERM; err = netlink_realloc_groups(sk); if (err) @@ -2247,7 +2247,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, dst_group = ffs(addr->nl_groups); err = -EPERM; if ((dst_group || dst_portid) && - !netlink_capable(sock, NL_CFG_F_NONROOT_SEND)) + !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) goto out; } else { dst_portid = nlk->dst_portid; -- cgit v1.1 From aa4cf9452f469f16cea8c96283b641b4576d4a7b Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 23 Apr 2014 14:28:03 -0700 Subject: net: Add variants of capable for use on netlink messages netlink_net_capable - The common case use, for operations that are safe on a network namespace netlink_capable - For operations that are only known to be safe for the global root netlink_ns_capable - The general case of capable used to handle special cases __netlink_ns_capable - Same as netlink_ns_capable except taking a netlink_skb_parms instead of the skbuff of a netlink message. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) (limited to 'net/netlink') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 7f931fe..81dca96 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1360,6 +1360,71 @@ retry: return err; } +/** + * __netlink_ns_capable - General netlink message capability test + * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace. + * @user_ns: The user namespace of the capability to use + * @cap: The capability to use + * + * Test to see if the opener of the socket we received the message + * from had when the netlink socket was created and the sender of the + * message has has the capability @cap in the user namespace @user_ns. + */ +bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, + struct user_namespace *user_ns, int cap) +{ + return sk_ns_capable(nsp->sk, user_ns, cap); +} +EXPORT_SYMBOL(__netlink_ns_capable); + +/** + * netlink_ns_capable - General netlink message capability test + * @skb: socket buffer holding a netlink command from userspace + * @user_ns: The user namespace of the capability to use + * @cap: The capability to use + * + * Test to see if the opener of the socket we received the message + * from had when the netlink socket was created and the sender of the + * message has has the capability @cap in the user namespace @user_ns. + */ +bool netlink_ns_capable(const struct sk_buff *skb, + struct user_namespace *user_ns, int cap) +{ + return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap); +} +EXPORT_SYMBOL(netlink_ns_capable); + +/** + * netlink_capable - Netlink global message capability test + * @skb: socket buffer holding a netlink command from userspace + * @cap: The capability to use + * + * Test to see if the opener of the socket we received the message + * from had when the netlink socket was created and the sender of the + * message has has the capability @cap in all user namespaces. + */ +bool netlink_capable(const struct sk_buff *skb, int cap) +{ + return netlink_ns_capable(skb, &init_user_ns, cap); +} +EXPORT_SYMBOL(netlink_capable); + +/** + * netlink_net_capable - Netlink network namespace message capability test + * @skb: socket buffer holding a netlink command from userspace + * @cap: The capability to use + * + * Test to see if the opener of the socket we received the message + * from had when the netlink socket was created and the sender of the + * message has has the capability @cap over the network namespace of + * the socket we received the message from. + */ +bool netlink_net_capable(const struct sk_buff *skb, int cap) +{ + return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap); +} +EXPORT_SYMBOL(netlink_net_capable); + static inline int netlink_allowed(const struct socket *sock, unsigned int flag) { return (nl_table[sock->sk->sk_protocol].flags & flag) || -- cgit v1.1 From 90f62cf30a78721641e08737bda787552428061e Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 23 Apr 2014 14:29:27 -0700 Subject: net: Use netlink_ns_capable to verify the permisions of netlink messages It is possible by passing a netlink socket to a more privileged executable and then to fool that executable into writing to the socket data that happens to be valid netlink message to do something that privileged executable did not intend to do. To keep this from happening replace bare capable and ns_capable calls with netlink_capable, netlink_net_calls and netlink_ns_capable calls. Which act the same as the previous calls except they verify that the opener of the socket had the desired permissions as well. Reported-by: Andy Lutomirski Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- net/netlink/genetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/netlink') diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index b1dcdb9..a3ba3ca 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -561,7 +561,7 @@ static int genl_family_rcv_msg(struct genl_family *family, return -EOPNOTSUPP; if ((ops->flags & GENL_ADMIN_PERM) && - !capable(CAP_NET_ADMIN)) + !netlink_capable(skb, CAP_NET_ADMIN)) return -EPERM; if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { -- cgit v1.1