Fixed MTP to work with TWRP

security/selinux/ss/context.h

@@ -0,0 +1,163 @@
+/*
+ * A security context is a set of security attributes
+ * associated with each subject and object controlled
+ * by the security policy.  Security contexts are
+  * externally represented as variable-length strings
+ * that can be interpreted by a user or application
+ * with an understanding of the security policy.
+ * Internally, the security server uses a simple
+ * structure.  This structure is private to the
+ * security server and can be changed without affecting
+ * clients of the security server.
+ *
+ * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
+ */
+#ifndef _SS_CONTEXT_H_
+#define _SS_CONTEXT_H_
+
+#include "ebitmap.h"
+#include "mls_types.h"
+#include "security.h"
+
+/*
+ * A security context consists of an authenticated user
+ * identity, a role, a type and a MLS range.
+ */
+struct context {
+	u32 user;
+	u32 role;
+	u32 type;
+	u32 len;        /* length of string in bytes */
+	struct mls_range range;
+	char *str;	/* string representation if context cannot be mapped. */
+};
+
+static inline void mls_context_init(struct context *c)
+{
+	memset(&c->range, 0, sizeof(c->range));
+}
+
+static inline int mls_context_cpy(struct context *dst, struct context *src)
+{
+	int rc;
+
+	dst->range.level[0].sens = src->range.level[0].sens;
+	rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
+	if (rc)
+		goto out;
+
+	dst->range.level[1].sens = src->range.level[1].sens;
+	rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat);
+	if (rc)
+		ebitmap_destroy(&dst->range.level[0].cat);
+out:
+	return rc;
+}
+
+/*
+ * Sets both levels in the MLS range of 'dst' to the low level of 'src'.
+ */
+static inline int mls_context_cpy_low(struct context *dst, struct context *src)
+{
+	int rc;
+
+	dst->range.level[0].sens = src->range.level[0].sens;
+	rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
+	if (rc)
+		goto out;
+
+	dst->range.level[1].sens = src->range.level[0].sens;
+	rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[0].cat);
+	if (rc)
+		ebitmap_destroy(&dst->range.level[0].cat);
+out:
+	return rc;
+}
+
+/*
+ * Sets both levels in the MLS range of 'dst' to the high level of 'src'.
+ */
+static inline int mls_context_cpy_high(struct context *dst, struct context *src)
+{
+	int rc;
+
+	dst->range.level[0].sens = src->range.level[1].sens;
+	rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[1].cat);
+	if (rc)
+		goto out;
+
+	dst->range.level[1].sens = src->range.level[1].sens;
+	rc = ebitmap_cpy(&dst->range.level[1].cat, &src->range.level[1].cat);
+	if (rc)
+		ebitmap_destroy(&dst->range.level[0].cat);
+out:
+	return rc;
+}
+
+static inline int mls_context_cmp(struct context *c1, struct context *c2)
+{
+	return ((c1->range.level[0].sens == c2->range.level[0].sens) &&
+		ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) &&
+		(c1->range.level[1].sens == c2->range.level[1].sens) &&
+		ebitmap_cmp(&c1->range.level[1].cat, &c2->range.level[1].cat));
+}
+
+static inline void mls_context_destroy(struct context *c)
+{
+	ebitmap_destroy(&c->range.level[0].cat);
+	ebitmap_destroy(&c->range.level[1].cat);
+	mls_context_init(c);
+}
+
+static inline void context_init(struct context *c)
+{
+	memset(c, 0, sizeof(*c));
+}
+
+static inline int context_cpy(struct context *dst, struct context *src)
+{
+	int rc;
+
+	dst->user = src->user;
+	dst->role = src->role;
+	dst->type = src->type;
+	if (src->str) {
+		dst->str = kstrdup(src->str, GFP_ATOMIC);
+		if (!dst->str)
+			return -ENOMEM;
+		dst->len = src->len;
+	} else {
+		dst->str = NULL;
+		dst->len = 0;
+	}
+	rc = mls_context_cpy(dst, src);
+	if (rc) {
+		kfree(dst->str);
+		return rc;
+	}
+	return 0;
+}
+
+static inline void context_destroy(struct context *c)
+{
+	c->user = c->role = c->type = 0;
+	kfree(c->str);
+	c->str = NULL;
+	c->len = 0;
+	mls_context_destroy(c);
+}
+
+static inline int context_cmp(struct context *c1, struct context *c2)
+{
+	if (c1->len && c2->len)
+		return (c1->len == c2->len && !strcmp(c1->str, c2->str));
+	if (c1->len || c2->len)
+		return 0;
+	return ((c1->user == c2->user) &&
+		(c1->role == c2->role) &&
+		(c1->type == c2->type) &&
+		mls_context_cmp(c1, c2));
+}
+
+#endif	/* _SS_CONTEXT_H_ */
+