apparmor: Parse secmark policy

Add support for parsing secmark policy provided by userspace, and
store that in the overall policy.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/include/net.h

@@ -83,6 +83,13 @@ struct aa_sk_ctx {
 	__e;					\
 })
 
+struct aa_secmark {
+	u8 audit;
+	u8 deny;
+	u32 secid;
+	char *label;
+};
+
 extern struct aa_sfs_entry aa_sfs_entry_network[];
 
 void audit_net_cb(struct audit_buffer *ab, void *va);
@@ -103,4 +110,7 @@ int aa_sk_perm(const char *op, u32 request, struct sock *sk);
 int aa_sock_file_perm(struct aa_label *label, const char *op, u32 request,
 		      struct socket *sock);
 
+int apparmor_secmark_check(struct aa_label *label, char *op, u32 request,
+			   u32 secid, struct sock *sk);
+
 #endif /* __AA_NET_H */

security/apparmor/include/policy.h

@@ -155,6 +155,9 @@ struct aa_profile {
 
 	struct aa_rlimit rlimits;
 
+	int secmark_count;
+	struct aa_secmark *secmark;
+
 	struct aa_loaddata *rawdata;
 	unsigned char *hash;
 	char *dirname;

security/apparmor/policy.c

@@ -231,6 +231,9 @@ void aa_free_profile(struct aa_profile *profile)
 	for (i = 0; i < profile->xattr_count; i++)
 		kzfree(profile->xattrs[i]);
 	kzfree(profile->xattrs);
+	for (i=0; i < profile->secmark_count; i++)
+		kzfree(profile->secmark[i].label);
+	kzfree(profile->secmark);
 	kzfree(profile->dirname);
 	aa_put_dfa(profile->xmatch);
 	aa_put_dfa(profile->policy.dfa);

security/apparmor/policy_unpack.c

@@ -292,6 +292,19 @@ static bool unpack_nameX(struct aa_ext *e, enum aa_code code, const char *name)
 	return 0;
 }
 
+static bool unpack_u8(struct aa_ext *e, u8 *data, const char *name)
+{
+	if (unpack_nameX(e, AA_U8, name)) {
+		if (!inbounds(e, sizeof(u8)))
+			return 0;
+		if (data)
+			*data = get_unaligned((u8 *)e->pos);
+		e->pos += sizeof(u8);
+		return 1;
+	}
+	return 0;
+}
+
 static bool unpack_u32(struct aa_ext *e, u32 *data, const char *name)
 {
 	if (unpack_nameX(e, AA_U32, name)) {
@@ -529,6 +542,49 @@ static bool unpack_xattrs(struct aa_ext *e, struct aa_profile *profile)
 	return 0;
 }
 
+static bool unpack_secmark(struct aa_ext *e, struct aa_profile *profile)
+{
+	void *pos = e->pos;
+	int i, size;
+
+	if (unpack_nameX(e, AA_STRUCT, "secmark")) {
+		size = unpack_array(e, NULL);
+
+		profile->secmark = kcalloc(size, sizeof(struct aa_secmark),
+					   GFP_KERNEL);
+		if (!profile->secmark)
+			goto fail;
+
+		profile->secmark_count = size;
+
+		for (i = 0; i < size; i++) {
+			if (!unpack_u8(e, &profile->secmark[i].audit, NULL))
+				goto fail;
+			if (!unpack_u8(e, &profile->secmark[i].deny, NULL))
+				goto fail;
+			if (!unpack_strdup(e, &profile->secmark[i].label, NULL))
+				goto fail;
+		}
+		if (!unpack_nameX(e, AA_ARRAYEND, NULL))
+			goto fail;
+		if (!unpack_nameX(e, AA_STRUCTEND, NULL))
+			goto fail;
+	}
+
+	return 1;
+
+fail:
+	if (profile->secmark) {
+		for (i = 0; i < size; i++)
+			kfree(profile->secmark[i].label);
+		kfree(profile->secmark);
+		profile->secmark_count = 0;
+	}
+
+	e->pos = pos;
+	return 0;
+}
+
 static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)
 {
 	void *pos = e->pos;
@@ -727,6 +783,11 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
 		goto fail;
 	}
 
+	if (!unpack_secmark(e, profile)) {
+		info = "failed to unpack profile secmark rules";
+		goto fail;
+	}
+
 	if (unpack_nameX(e, AA_STRUCT, "policydb")) {
 		/* generic policy dfa - optional and may be NULL */
 		info = "failed to unpack policydb";