From ab9f2115081ab7ba63b77a759e0f3eb5d6463d7f Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Thu, 24 May 2018 13:27:47 -0700 Subject: apparmor: Allow filtering based on secmark policy Add support for dropping or accepting packets based on their secmark tags. Signed-off-by: Matthew Garrett Signed-off-by: John Johansen --- security/apparmor/lsm.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++- security/apparmor/net.c | 66 ++++++++++++++++++++++++++++ 2 files changed, 177 insertions(+), 1 deletion(-) (limited to 'security') diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index f09fea0b4db7..2c842f24821b 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -23,6 +23,8 @@ #include #include #include +#include +#include #include #include "include/apparmor.h" @@ -1030,7 +1032,13 @@ static int apparmor_socket_shutdown(struct socket *sock, int how) */ static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) { - return 0; + struct aa_sk_ctx *ctx = SK_CTX(sk); + + if (!skb->secmark) + return 0; + + return apparmor_secmark_check(ctx->label, OP_RECVMSG, AA_MAY_RECEIVE, + skb->secmark, sk); } @@ -1126,6 +1134,18 @@ static void apparmor_sock_graft(struct sock *sk, struct socket *parent) ctx->label = aa_get_current_label(); } +static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb, + struct request_sock *req) +{ + struct aa_sk_ctx *ctx = SK_CTX(sk); + + if (!skb->secmark) + return 0; + + return apparmor_secmark_check(ctx->label, OP_CONNECT, AA_MAY_CONNECT, + skb->secmark, sk); +} + static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check), LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme), @@ -1183,6 +1203,7 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(socket_getpeersec_dgram, apparmor_socket_getpeersec_dgram), LSM_HOOK_INIT(sock_graft, apparmor_sock_graft), + LSM_HOOK_INIT(inet_conn_request, apparmor_inet_conn_request), LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank), LSM_HOOK_INIT(cred_free, apparmor_cred_free), @@ -1538,6 +1559,95 @@ static inline int apparmor_init_sysctl(void) } #endif /* CONFIG_SYSCTL */ +static unsigned int apparmor_ip_postroute(void *priv, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct aa_sk_ctx *ctx; + struct sock *sk; + + if (!skb->secmark) + return NF_ACCEPT; + + sk = skb_to_full_sk(skb); + if (sk == NULL) + return NF_ACCEPT; + + ctx = SK_CTX(sk); + if (!apparmor_secmark_check(ctx->label, OP_SENDMSG, AA_MAY_SEND, + skb->secmark, sk)) + return NF_ACCEPT; + + return NF_DROP_ERR(-ECONNREFUSED); + +} + +static unsigned int apparmor_ipv4_postroute(void *priv, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ + return apparmor_ip_postroute(priv, skb, state); +} + +static unsigned int apparmor_ipv6_postroute(void *priv, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ + return apparmor_ip_postroute(priv, skb, state); +} + +static const struct nf_hook_ops apparmor_nf_ops[] = { + { + .hook = apparmor_ipv4_postroute, + .pf = NFPROTO_IPV4, + .hooknum = NF_INET_POST_ROUTING, + .priority = NF_IP_PRI_SELINUX_FIRST, + }, +#if IS_ENABLED(CONFIG_IPV6) + { + .hook = apparmor_ipv6_postroute, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_POST_ROUTING, + .priority = NF_IP6_PRI_SELINUX_FIRST, + }, +#endif +}; + +static int __net_init apparmor_nf_register(struct net *net) +{ + int ret; + + ret = nf_register_net_hooks(net, apparmor_nf_ops, + ARRAY_SIZE(apparmor_nf_ops)); + return ret; +} + +static void __net_exit apparmor_nf_unregister(struct net *net) +{ + nf_unregister_net_hooks(net, apparmor_nf_ops, + ARRAY_SIZE(apparmor_nf_ops)); +} + +static struct pernet_operations apparmor_net_ops = { + .init = apparmor_nf_register, + .exit = apparmor_nf_unregister, +}; + +static int __init apparmor_nf_ip_init(void) +{ + int err; + + if (!apparmor_enabled) + return 0; + + err = register_pernet_subsys(&apparmor_net_ops); + if (err) + panic("Apparmor: register_pernet_subsys: error %d\n", err); + + return 0; +} +__initcall(apparmor_nf_ip_init); + static int __init apparmor_init(void) { int error; diff --git a/security/apparmor/net.c b/security/apparmor/net.c index d5d72dd1ca1f..f9a678ce994f 100644 --- a/security/apparmor/net.c +++ b/security/apparmor/net.c @@ -18,6 +18,7 @@ #include "include/label.h" #include "include/net.h" #include "include/policy.h" +#include "include/secid.h" #include "net_names.h" @@ -188,3 +189,68 @@ int aa_sock_file_perm(struct aa_label *label, const char *op, u32 request, return aa_label_sk_perm(label, op, request, sock->sk); } + +static int apparmor_secmark_init(struct aa_secmark *secmark) +{ + struct aa_label *label; + + if (secmark->label[0] == '*') { + secmark->secid = AA_SECID_WILDCARD; + return 0; + } + + label = aa_label_strn_parse(&root_ns->unconfined->label, + secmark->label, strlen(secmark->label), + GFP_ATOMIC, false, false); + + if (IS_ERR(label)) + return PTR_ERR(label); + + secmark->secid = label->secid; + + return 0; +} + +static int aa_secmark_perm(struct aa_profile *profile, u32 request, u32 secid, + struct common_audit_data *sa, struct sock *sk) +{ + int i, ret; + struct aa_perms perms = { }; + + if (profile->secmark_count == 0) + return 0; + + for (i = 0; i < profile->secmark_count; i++) { + if (!profile->secmark[i].secid) { + ret = apparmor_secmark_init(&profile->secmark[i]); + if (ret) + return ret; + } + + if (profile->secmark[i].secid == secid || + profile->secmark[i].secid == AA_SECID_WILDCARD) { + if (profile->secmark[i].deny) + perms.deny = ALL_PERMS_MASK; + else + perms.allow = ALL_PERMS_MASK; + + if (profile->secmark[i].audit) + perms.audit = ALL_PERMS_MASK; + } + } + + aa_apply_modes_to_perms(profile, &perms); + + return aa_check_perms(profile, &perms, request, sa, audit_net_cb); +} + +int apparmor_secmark_check(struct aa_label *label, char *op, u32 request, + u32 secid, struct sock *sk) +{ + struct aa_profile *profile; + DEFINE_AUDIT_SK(sa, op, sk); + + return fn_for_each_confined(label, profile, + aa_secmark_perm(profile, request, secid, + &sa, sk)); +} -- cgit v1.2.3