lsm: replace context+len with lsm_context

cschaufler · pcmoore · commit 2d470c778120 · 2024-12-04T14:42:31.000-05:00
Replace the (secctx,seclen) pointer pair with a single
lsm_context pointer to allow return of the LSM identifier
along with the context and context length. This allows
security_release_secctx() to know how to release the
context. Callers have been modified to use or save the
returned data from the new structure.

security_secid_to_secctx() and security_lsmproc_to_secctx()
will now return the length value on success instead of 0.

Cc: netdev@vger.kernel.org
Cc: audit@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
Cc: Todd Kjos &lt;tkjos@google.com&gt;
Signed-off-by: Casey Schaufler &lt;casey@schaufler-ca.com&gt;
[PM: subject tweak, kdoc fix, signedness fix from Dan Carpenter]
Signed-off-by: Paul Moore &lt;paul@paul-moore.com&gt;
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
@@ -3296,9 +3296,8 @@ static void binder_transaction(struct binder_proc *proc,
 		size_t added_size;
 
 		security_cred_getsecid(proc->cred, &secid);
-		ret = security_secid_to_secctx(secid, &lsmctx.context,
-					       &lsmctx.len);
-		if (ret) {
+		ret = security_secid_to_secctx(secid, &lsmctx);
+		if (ret < 0) {
 			binder_txn_error("%d:%d failed to get security context\n",
 				thread->pid, proc->pid);
 			return_error = BR_FAILED_REPLY;
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
@@ -295,10 +295,9 @@ LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, const char *name,
 	 char **value)
 LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size)
 LSM_HOOK(int, 0, ismaclabel, const char *name)
-LSM_HOOK(int, -EOPNOTSUPP, secid_to_secctx, u32 secid, char **secdata,
-	 u32 *seclen)
+LSM_HOOK(int, -EOPNOTSUPP, secid_to_secctx, u32 secid, struct lsm_context *cp)
 LSM_HOOK(int, -EOPNOTSUPP, lsmprop_to_secctx, struct lsm_prop *prop,
-	 char **secdata, u32 *seclen)
+	 struct lsm_context *cp)
 LSM_HOOK(int, 0, secctx_to_secid, const char *secdata, u32 seclen, u32 *secid)
 LSM_HOOK(void, LSM_RET_VOID, release_secctx, struct lsm_context *cp)
 LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode)
diff --git a/include/linux/security.h b/include/linux/security.h
@@ -584,8 +584,8 @@ int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
 int security_setprocattr(int lsmid, const char *name, void *value, size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
-int security_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, u32 *seclen);
+int security_secid_to_secctx(u32 secid, struct lsm_context *cp);
+int security_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp);
 int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
 void security_release_secctx(struct lsm_context *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
@@ -1557,14 +1557,13 @@ static inline int security_ismaclabel(const char *name)
 	return 0;
 }
 
-static inline int security_secid_to_secctx(u32 secid, char **secdata,
-					   u32 *seclen)
+static inline int security_secid_to_secctx(u32 secid, struct lsm_context *cp)
 {
 	return -EOPNOTSUPP;
 }
 
 static inline int security_lsmprop_to_secctx(struct lsm_prop *prop,
-					     char **secdata, u32 *seclen)
+					     struct lsm_context *cp)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
@@ -109,10 +109,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(scm->secid, &ctx.context,
-					       &ctx.len);
+		err = security_secid_to_secctx(scm->secid, &ctx);
 
-		if (!err) {
+		if (err >= 0) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, ctx.len,
 				 ctx.context);
 			security_release_secctx(&ctx);
diff --git a/kernel/audit.c b/kernel/audit.c
@@ -1473,9 +1473,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 	case AUDIT_SIGNAL_INFO:
 		if (lsmprop_is_set(&audit_sig_lsm)) {
 			err = security_lsmprop_to_secctx(&audit_sig_lsm,
-							 &lsmctx.context,
-							 &lsmctx.len);
-			if (err)
+							 &lsmctx);
+			if (err < 0)
 				return err;
 		}
 		sig_data = kmalloc(struct_size(sig_data, ctx, lsmctx.len),
@@ -2188,8 +2187,8 @@ int audit_log_task_context(struct audit_buffer *ab)
 	if (!lsmprop_is_set(&prop))
 		return 0;
 
-	error = security_lsmprop_to_secctx(&prop, &ctx.context, &ctx.len);
-	if (error) {
+	error = security_lsmprop_to_secctx(&prop, &ctx);
+	if (error < 0) {
 		if (error != -EINVAL)
 			goto error_path;
 		return 0;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
@@ -1109,7 +1109,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmprop_is_set(prop)) {
-		if (security_lsmprop_to_secctx(prop, &ctx.context, &ctx.len)) {
+		if (security_lsmprop_to_secctx(prop, &ctx) < 0) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1370,7 +1370,6 @@ static void audit_log_time(struct audit_context *context, struct audit_buffer **
 
 static void show_special(struct audit_context *context, int *call_panic)
 {
-	struct lsm_context lsmcxt;
 	struct audit_buffer *ab;
 	int i;
 
@@ -1393,16 +1392,14 @@ static void show_special(struct audit_context *context, int *call_panic)
 				 from_kgid(&init_user_ns, context->ipc.gid),
 				 context->ipc.mode);
 		if (lsmprop_is_set(&context->ipc.oprop)) {
-			char *ctx = NULL;
-			u32 len;
+			struct lsm_context lsmctx;
 
 			if (security_lsmprop_to_secctx(&context->ipc.oprop,
-						       &ctx, &len)) {
+						       &lsmctx) < 0) {
 				*call_panic = 1;
 			} else {
-				audit_log_format(ab, " obj=%s", ctx);
-				lsmcontext_init(&lsmcxt, ctx, len, 0);
-				security_release_secctx(&lsmcxt);
+				audit_log_format(ab, " obj=%s", lsmctx.context);
+				security_release_secctx(&lsmctx);
 			}
 		}
 		if (context->ipc.has_perm) {
@@ -1563,8 +1560,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 	if (lsmprop_is_set(&n->oprop)) {
 		struct lsm_context ctx;
 
-		if (security_lsmprop_to_secctx(&n->oprop, &ctx.context,
-					       &ctx.len)) {
+		if (security_lsmprop_to_secctx(&n->oprop, &ctx) < 0) {
 			if (call_panic)
 				*call_panic = 2;
 		} else {
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
@@ -136,8 +136,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(secid, &ctx.context, &ctx.len);
-	if (err)
+	err = security_secid_to_secctx(secid, &ctx);
+	if (err < 0)
 		return;
 
 	put_cmsg(msg, SOL_IP, SCM_SECURITY, ctx.len, ctx.context);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
@@ -360,8 +360,8 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	struct lsm_context ctx;
 	int ret;
 
-	ret = security_secid_to_secctx(ct->secmark, &ctx.context, &ctx.len);
-	if (ret)
+	ret = security_secid_to_secctx(ct->secmark, &ctx);
+	if (ret < 0)
 		return 0;
 
 	ret = -1;
@@ -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
@@ -175,8 +175,8 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	struct lsm_context ctx;
 	int ret;
 
-	ret = security_secid_to_secctx(ct->secmark, &ctx.context, &ctx.len);
-	if (ret)
+	ret = security_secid_to_secctx(ct->secmark, &ctx);
+	if (ret < 0)
 		return;
 
 	seq_printf(s, "secctx=%s ", ctx.context);
diff --git 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 u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsm_context *ctx)
 {
 	u32 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 +567,7 @@ 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;
-	struct lsm_context scaff; /* scaffolding */
-	char *secdata = NULL;
+	struct lsm_context ctx;
 	u32 seclen = 0;
 	ktime_t tstamp;
 
@@ -643,8 +642,8 @@ 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)
+		seclen = nfqnl_get_sk_secctx(entskb, &ctx);
+		if (seclen >= 0)
 			size += nla_total_size(seclen);
 	}
 
@@ -783,7 +782,7 @@ 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 && 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)
@@ -811,21 +810,17 @@ 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 >= 0)
+		security_release_secctx(&ctx);
 	return skb;
 
 nla_put_failure:
 	skb_tx_error(entskb);
 	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 >= 0)
+		security_release_secctx(&ctx);
 	return NULL;
 }
 
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
@@ -437,9 +437,7 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(secid,
-					     &ctx.context,
-					     &ctx.len) == 0) {
+		if (security_secid_to_secctx(secid, &ctx) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", ctx.context);
 			security_release_secctx(&ctx);
 		}
@@ -492,8 +490,7 @@ 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,
-					     &ctx.context, &ctx.len) == 0) {
+		    security_secid_to_secctx(entry->secid, &ctx) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", ctx.context);
 			security_release_secctx(&ctx);
 		}
@@ -551,8 +548,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
-					     &ctx.context, &ctx.len) == 0) {
+		    security_secid_to_secctx(entry->secid, &ctx) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", ctx.context);
 			security_release_secctx(&ctx);
 		}
@@ -1123,8 +1119,8 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		secid = addr6->secid;
 	}
 
-	ret_val = security_secid_to_secctx(secid, &ctx.context, &ctx.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,
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
@@ -98,8 +98,7 @@ 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, &ctx.context,
-				       &ctx.len) == 0) {
+	    security_lsmprop_to_secctx(&audit_info->prop, &ctx) > 0) {
 		audit_log_format(audit_buf, " subj=%s", ctx.context);
 		security_release_secctx(&ctx);
 	}
diff --git a/security/apparmor/include/secid.h b/security/apparmor/include/secid.h
@@ -25,9 +25,8 @@ struct aa_label;
 extern int apparmor_display_secid_mode;
 
 struct aa_label *aa_secid_to_label(u32 secid);
-int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
-int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata,
-			       u32 *seclen);
+int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp);
+int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp);
 int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
 void apparmor_release_secctx(struct lsm_context *cp);
 
diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c
@@ -47,50 +47,50 @@ struct aa_label *aa_secid_to_label(u32 secid)
 	return xa_load(&aa_secids, secid);
 }
 
-static int apparmor_label_to_secctx(struct aa_label *label, char **secdata,
-				    u32 *seclen)
+static int apparmor_label_to_secctx(struct aa_label *label,
+				    struct lsm_context *cp)
 {
 	/* TODO: cache secctx and ref count so we don't have to recreate */
 	int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT;
 	int len;
 
-	AA_BUG(!seclen);
-
 	if (!label)
 		return -EINVAL;
 
 	if (apparmor_display_secid_mode)
 		flags |= FLAG_SHOW_MODE;
 
-	if (secdata)
-		len = aa_label_asxprint(secdata, root_ns, label,
+	if (cp)
+		len = aa_label_asxprint(&cp->context, root_ns, label,
 					flags, GFP_ATOMIC);
 	else
 		len = aa_label_snxprint(NULL, 0, root_ns, label, flags);
 
 	if (len < 0)
 		return -ENOMEM;
 
-	*seclen = len;
+	if (cp) {
+		cp->len = len;
+		cp->id = LSM_ID_APPARMOR;
+	}
 
-	return 0;
+	return len;
 }
 
-int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp)
 {
 	struct aa_label *label = aa_secid_to_label(secid);
 
-	return apparmor_label_to_secctx(label, secdata, seclen);
+	return apparmor_label_to_secctx(label, cp);
 }
 
-int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata,
-			       u32 *seclen)
+int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp)
 {
 	struct aa_label *label;
 
 	label = prop->apparmor.label;
 
-	return apparmor_label_to_secctx(label, secdata, seclen);
+	return apparmor_label_to_secctx(label, cp);
 }
 
 int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
diff --git a/security/security.c b/security/security.c
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c

Original file line number	Diff line number	Diff line change
`@@ -584,8 +584,8 @@ int security_getprocattr(struct task_struct p, int lsmid, const char name,`
`584`	`584`	`int security_setprocattr(int lsmid, const char name, void value, size_t size);`
`585`	`585`	`int security_netlink_send(struct sock sk, struct sk_buff skb);`
`586`	`586`	`int security_ismaclabel(const char *name);`
`587`		`-int security_secid_to_secctx(u32 secid, char *secdata, u32 seclen);`
`588`		`-int security_lsmprop_to_secctx(struct lsm_prop prop, char secdata, u32 seclen);`
	`587`	`+int security_secid_to_secctx(u32 secid, struct lsm_context *cp);`
	`588`	`+int security_lsmprop_to_secctx(struct lsm_prop prop, struct lsm_context cp);`
`589`	`589`	`int security_secctx_to_secid(const char secdata, u32 seclen, u32 secid);`
`590`	`590`	`void security_release_secctx(struct lsm_context *cp);`
`591`	`591`	`void security_inode_invalidate_secctx(struct inode *inode);`
`@@ -1557,14 +1557,13 @@ static inline int security_ismaclabel(const char *name)`
`1557`	`1557`	`return 0;`
`1558`	`1558`	`}`
`1559`	`1559`
`1560`		`-static inline int security_secid_to_secctx(u32 secid, char **secdata,`
`1561`		`- u32 *seclen)`
	`1560`	`+static inline int security_secid_to_secctx(u32 secid, struct lsm_context *cp)`
`1562`	`1561`	`{`
`1563`	`1562`	`return -EOPNOTSUPP;`
`1564`	`1563`	`}`
`1565`	`1564`
`1566`	`1565`	`static inline int security_lsmprop_to_secctx(struct lsm_prop *prop,`
`1567`		`- char *secdata, u32 seclen)`
	`1566`	`+ struct lsm_context *cp)`
`1568`	`1567`	`{`
`1569`	`1568`	`return -EOPNOTSUPP;`
`1570`	`1569`	`}`