Merge tag 'lsm-pr-20250121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Improved handling of LSM "secctx" strings through lsm_context struct

   The LSM secctx string interface is from an older time when only one
   LSM was supported, migrate over to the lsm_context struct to better
   support the different LSMs we now have and make it easier to support
   new LSMs in the future.

   These changes explain the Rust, VFS, and networking changes in the
   diffstat.

 - Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are
   enabled

   Small tweak to be a bit smarter about when we build the LSM's common
   audit helpers.

 - Check for absurdly large policies from userspace in SafeSetID

   SafeSetID policies rules are fairly small, basically just "UID:UID",
   it easy to impose a limit of KMALLOC_MAX_SIZE on policy writes which
   helps quiet a number of syzbot related issues. While work is being
   done to address the syzbot issues through other mechanisms, this is a
   trivial and relatively safe fix that we can do now.

 - Various minor improvements and cleanups

   A collection of improvements to the kernel selftests, constification
   of some function parameters, removing redundant assignments, and
   local variable renames to improve readability.

* tag 'lsm-pr-20250121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lockdown: initialize local array before use to quiet static analysis
  safesetid: check size of policy writes
  net: corrections for security_secid_to_secctx returns
  lsm: rename variable to avoid shadowing
  lsm: constify function parameters
  security: remove redundant assignment to return variable
  lsm: Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are set
  selftests: refactor the lsm `flags_overset_lsm_set_self_attr` test
  binder: initialize lsm_context structure
  rust: replace lsm context+len with lsm_context
  lsm: secctx provider check on release
  lsm: lsm_context in security_dentry_init_security
  lsm: use lsm_context in security_inode_getsecctx
  lsm: replace context+len with lsm_context
  lsm: ensure the correct LSM context releaser

6 files changed, 57 insertions, 66 deletions

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index cf377377b52d..dadbf619b20f 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -128,20 +128,20 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 
 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
-	char *secdata;
-	u32 seclen, secid;
+	struct lsm_context ctx;
+	u32 secid;
 	int err;
 
 	err = security_socket_getpeersec_dgram(NULL, skb, &secid);
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(secid, &secdata, &seclen);
-	if (err)
+	err = security_secid_to_secctx(secid, &ctx);
+	if (err < 0)
 		return;
 
-	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
-	security_release_secctx(secdata, seclen);
+	put_cmsg(msg, SOL_IP, SCM_SECURITY, ctx.len, ctx.context);
+	security_release_secctx(&ctx);
 }
 
 static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 36168f8b6efa..7b74b24348fc 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -357,11 +357,11 @@ nla_put_failure:
 static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 {
 	struct nlattr *nest_secctx;
-	int len, ret;
-	char *secctx;
+	struct lsm_context ctx;
+	int ret;
 
-	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
-	if (ret)
+	ret = security_secid_to_secctx(ct->secmark, &ctx);
+	if (ret < 0)
 		return 0;
 
 	ret = -1;
@@ -369,13 +369,13 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	if (!nest_secctx)
 		goto nla_put_failure;
 
-	if (nla_put_string(skb, CTA_SECCTX_NAME, secctx))
+	if (nla_put_string(skb, CTA_SECCTX_NAME, ctx.context))
 		goto nla_put_failure;
 	nla_nest_end(skb, nest_secctx);
 
 	ret = 0;
 nla_put_failure:
-	security_release_secctx(secctx, len);
+	security_release_secctx(&ctx);
 	return ret;
 }
 #else
@@ -663,14 +663,14 @@ static inline size_t ctnetlink_acct_size(const struct nf_conn *ct)
 static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 {
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
-	int len, ret;
+	int ret;
 
-	ret = security_secid_to_secctx(ct->secmark, NULL, &len);
-	if (ret)
+	ret = security_secid_to_secctx(ct->secmark, NULL);
+	if (ret < 0)
 		return 0;
 
 	return nla_total_size(0) /* CTA_SECCTX */
-	       + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */
+	       + nla_total_size(sizeof(char) * ret); /* CTA_SECCTX_NAME */
 #else
 	return 0;
 #endif
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 7d4f0fa8b609..502cf10aab41 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -172,17 +172,16 @@ static void ct_seq_stop(struct seq_file *s, void *v)
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 {
+	struct lsm_context ctx;
 	int ret;
-	u32 len;
-	char *secctx;
 
-	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
-	if (ret)
+	ret = security_secid_to_secctx(ct->secmark, &ctx);
+	if (ret < 0)
 		return;
 
-	seq_printf(s, "secctx=%s ", secctx);
+	seq_printf(s, "secctx=%s ", ctx.context);
 
-	security_release_secctx(secctx, len);
+	security_release_secctx(&ctx);
 }
 #else
 static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index d2773ce9b585..5c913987901a 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -470,18 +470,18 @@ static int nfqnl_put_sk_classid(struct sk_buff *skb, struct sock *sk)
 	return 0;
 }
 
-static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
+static int nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsm_context *ctx)
 {
-	u32 seclen = 0;
+	int seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
+
 	if (!skb || !sk_fullsock(skb->sk))
 		return 0;
 
 	read_lock_bh(&skb->sk->sk_callback_lock);
 
 	if (skb->secmark)
-		security_secid_to_secctx(skb->secmark, secdata, &seclen);
-
+		seclen = security_secid_to_secctx(skb->secmark, ctx);
 	read_unlock_bh(&skb->sk->sk_callback_lock);
 #endif
 	return seclen;
@@ -567,8 +567,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	enum ip_conntrack_info ctinfo = 0;
 	const struct nfnl_ct_hook *nfnl_ct;
 	bool csum_verify;
-	char *secdata = NULL;
-	u32 seclen = 0;
+	struct lsm_context ctx;
+	int seclen = 0;
 	ktime_t tstamp;
 
 	size = nlmsg_total_size(sizeof(struct nfgenmsg))
@@ -642,7 +642,9 @@ 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);
+		seclen = nfqnl_get_sk_secctx(entskb, &ctx);
+		if (seclen < 0)
+			return NULL;
 		if (seclen)
 			size += nla_total_size(seclen);
 	}
@@ -782,7 +784,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	if (nfqnl_put_sk_classid(skb, entskb->sk) < 0)
 		goto nla_put_failure;
 
-	if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata))
+	if (seclen > 0 && nla_put(skb, NFQA_SECCTX, ctx.len, ctx.context))
 		goto nla_put_failure;
 
 	if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)
@@ -810,8 +812,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	nlh->nlmsg_len = skb->len;
-	if (seclen)
-		security_release_secctx(secdata, seclen);
+	if (seclen >= 0)
+		security_release_secctx(&ctx);
 	return skb;
 
 nla_put_failure:
@@ -819,8 +821,8 @@ nla_put_failure:
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 nlmsg_failure:
-	if (seclen)
-		security_release_secctx(secdata, seclen);
+	if (seclen >= 0)
+		security_release_secctx(&ctx);
 	return NULL;
 }
 
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 1bc2d0890a9f..dfda9ea61971 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -374,8 +374,7 @@ int netlbl_unlhsh_add(struct net *net,
 	struct net_device *dev;
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
-	char *secctx = NULL;
-	u32 secctx_len;
+	struct lsm_context ctx;
 
 	if (addr_len != sizeof(struct in_addr) &&
 	    addr_len != sizeof(struct in6_addr))
@@ -438,11 +437,9 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(secid,
-					     &secctx,
-					     &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+		if (security_secid_to_secctx(secid, &ctx) >= 0) {
+			audit_log_format(audit_buf, " sec_obj=%s", ctx.context);
+			security_release_secctx(&ctx);
 		}
 		audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -473,8 +470,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct netlbl_unlhsh_addr4 *entry;
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
-	char *secctx;
-	u32 secctx_len;
+	struct lsm_context ctx;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
@@ -494,10 +490,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 					  addr->s_addr, mask->s_addr);
 		dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
-					     &secctx, &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+		    security_secid_to_secctx(entry->secid, &ctx) >= 0) {
+			audit_log_format(audit_buf, " sec_obj=%s", ctx.context);
+			security_release_secctx(&ctx);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -534,8 +529,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct netlbl_unlhsh_addr6 *entry;
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
-	char *secctx;
-	u32 secctx_len;
+	struct lsm_context ctx;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
@@ -554,10 +548,9 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
-					     &secctx, &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+		    security_secid_to_secctx(entry->secid, &ctx) >= 0) {
+			audit_log_format(audit_buf, " sec_obj=%s", ctx.context);
+			security_release_secctx(&ctx);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -1069,10 +1062,9 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	int ret_val = -ENOMEM;
 	struct netlbl_unlhsh_walk_arg *cb_arg = arg;
 	struct net_device *dev;
+	struct lsm_context ctx;
 	void *data;
 	u32 secid;
-	char *secctx;
-	u32 secctx_len;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
 			   cb_arg->seq, &netlbl_unlabel_gnl_family,
@@ -1127,14 +1119,14 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		secid = addr6->secid;
 	}
 
-	ret_val = security_secid_to_secctx(secid, &secctx, &secctx_len);
-	if (ret_val != 0)
+	ret_val = security_secid_to_secctx(secid, &ctx);
+	if (ret_val < 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
 			  NLBL_UNLABEL_A_SECCTX,
-			  secctx_len,
-			  secctx);
-	security_release_secctx(secctx, secctx_len);
+			  ctx.len,
+			  ctx.context);
+	security_release_secctx(&ctx);
 	if (ret_val != 0)
 		goto list_cb_failure;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 81635a13987b..0d04d23aafe7 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,8 +84,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
-	char *secctx;
-	u32 secctx_len;
+	struct lsm_context ctx;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
@@ -99,10 +98,9 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 audit_info->sessionid);
 
 	if (lsmprop_is_set(&audit_info->prop) &&
-	    security_lsmprop_to_secctx(&audit_info->prop, &secctx,
-				       &secctx_len) == 0) {
-		audit_log_format(audit_buf, " subj=%s", secctx);
-		security_release_secctx(secctx, secctx_len);
+	    security_lsmprop_to_secctx(&audit_info->prop, &ctx) > 0) {
+		audit_log_format(audit_buf, " subj=%s", ctx.context);
+		security_release_secctx(&ctx);
 	}
 
 	return audit_buf;