[PATCH v20 17/23] LSM: security_secid_to_secctx in netlink netfilter

Change netlink netfilter interfaces to use lsmcontext pointers, and remove scaffolding. Reviewed-by: Kees Cook <keescook(a)chromium.org&gt; Reviewed-by: John Johansen <john.johansen(a)canonical.com&gt; Acked-by: Stephen Smalley <sds(a)tycho.nsa.gov&gt; Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com&gt; cc: netdev(a)vger.kernel.org --- net/netfilter/nfnetlink_queue.c | 31 ++++++++++++------------------- 1 file changed, 12 insertions(+), 19 deletions(-) diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index d3f8e808c5d3..c830401f7792 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -301,12 +301,10 @@ static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk) return -1; } -static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata) +static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context) { - u32 seclen = 0; #if IS_ENABLED(CONFIG_NETWORK_SECMARK) struct lsmblob blob; - struct lsmcontext context = { }; if (!skb || !sk_fullsock(skb->sk)) return 0; @@ -318,14 +316,14 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata) * blob. security_secid_to_secctx() will know which security * module to use to create the secctx. */ lsmblob_init(&blob, skb->secmark); - security_secid_to_secctx(&blob, &context); - *secdata = context.context; + security_secid_to_secctx(&blob, context); } read_unlock_bh(&skb->sk->sk_callback_lock); - seclen = context.len; + return context->len; +#else + return 0; #endif - return seclen; } static u32 nfqnl_get_bridge_size(struct nf_queue_entry *entry) @@ -401,8 +399,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, enum ip_conntrack_info ctinfo; struct nfnl_ct_hook *nfnl_ct; bool csum_verify; - struct lsmcontext scaff; /* scaffolding */ - char *secdata = NULL; + struct lsmcontext context = { }; u32 seclen = 0; size = nlmsg_total_size(sizeof(struct nfgenmsg)) @@ -469,7 +466,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, } if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) { - seclen = nfqnl_get_sk_secctx(entskb, &secdata); + seclen = nfqnl_get_sk_secctx(entskb, &context); if (seclen) size += nla_total_size(seclen); } @@ -604,7 +601,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, nfqnl_put_sk_uidgid(skb, entskb->sk) < 0) goto nla_put_failure; - if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata)) + if (seclen && nla_put(skb, NFQA_SECCTX, context.len, context.context)) goto nla_put_failure; if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0) @@ -632,10 +629,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, } nlh->nlmsg_len = skb->len; - if (seclen) { - lsmcontext_init(&scaff, secdata, seclen, 0); - security_release_secctx(&scaff); - } + if (seclen) + security_release_secctx(&context); return skb; nla_put_failure: @@ -643,10 +638,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, kfree_skb(skb); net_err_ratelimited("nf_queue: error creating packet message\n"); nlmsg_failure: - if (seclen) { - lsmcontext_init(&scaff, secdata, seclen, 0); - security_release_secctx(&scaff); - } + if (seclen) + security_release_secctx(&context); return NULL; } -- 2.24.1