Re: [PATCH v22 16/23] 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 Cc: netfilter-devel(a)vger.kernel.org

--- net/netfilter/nfnetlink_queue.c | 37 +++++++++++++-------------------- 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 84be5a49a157..0d8b83d84422 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -301,15 +301,13 @@ 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 void 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; + return; read_lock_bh(&skb->sk->sk_callback_lock); @@ -318,14 +316,12 @@ 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; #endif - return seclen; + return; } static u32 nfqnl_get_bridge_size(struct nf_queue_entry *entry) @@ -398,12 +394,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, struct net_device *indev; struct net_device *outdev; struct nf_conn *ct = NULL; + struct lsmcontext context = { }; enum ip_conntrack_info ctinfo; struct nfnl_ct_hook *nfnl_ct; bool csum_verify; - struct lsmcontext scaff; /* scaffolding */ - char *secdata = NULL; - u32 seclen = 0; size = nlmsg_total_size(sizeof(struct nfgenmsg)) + nla_total_size(sizeof(struct nfqnl_msg_packet_hdr)) @@ -469,9 +463,9 @@ 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); - if (seclen) - size += nla_total_size(seclen); + nfqnl_get_sk_secctx(entskb, &context); + if (context.len) + size += nla_total_size(context.len); } skb = alloc_skb(size, GFP_ATOMIC); @@ -604,7 +598,8 @@ 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 (context.len && + 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 +627,8 @@ 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 (context.len) + security_release_secctx(&context); return skb; nla_put_failure: @@ -643,10 +636,8 @@ 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 (context.len) + security_release_secctx(&context); return NULL; } -- 2.24.1