Fixed MTP to work with TWRP

security/selinux/ss/avtab.c

@@ -0,0 +1,620 @@
+/*
+ * Implementation of the access vector table type.
+ *
+ * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
+ */
+
+/* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
+ *
+ *	Added conditional policy language extensions
+ *
+ * Copyright (C) 2003 Tresys Technology, LLC
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License as published by
+ *	the Free Software Foundation, version 2.
+ *
+ * Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
+ *	Tuned number of hash slots for avtab to reduce memory usage
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include "avtab.h"
+#include "policydb.h"
+
+static struct kmem_cache *avtab_node_cachep;
+static struct kmem_cache *avtab_operation_cachep;
+
+static inline int avtab_hash(struct avtab_key *keyp, u16 mask)
+{
+	return ((keyp->target_class + (keyp->target_type << 2) +
+		 (keyp->source_type << 9)) & mask);
+}
+
+static struct avtab_node*
+avtab_insert_node(struct avtab *h, int hvalue,
+		  struct avtab_node *prev, struct avtab_node *cur,
+		  struct avtab_key *key, struct avtab_datum *datum)
+{
+	struct avtab_node *newnode;
+	struct avtab_operation *ops;
+	newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL);
+	if (newnode == NULL)
+		return NULL;
+	newnode->key = *key;
+
+	if (key->specified & AVTAB_OP) {
+		ops = kmem_cache_zalloc(avtab_operation_cachep, GFP_KERNEL);
+		if (ops == NULL) {
+			kmem_cache_free(avtab_node_cachep, newnode);
+			return NULL;
+		}
+		*ops = *(datum->u.ops);
+		newnode->datum.u.ops = ops;
+	} else {
+		newnode->datum.u.data = datum->u.data;
+	}
+
+	if (prev) {
+		newnode->next = prev->next;
+		prev->next = newnode;
+	} else {
+		newnode->next = h->htable[hvalue];
+		h->htable[hvalue] = newnode;
+	}
+
+	h->nel++;
+	return newnode;
+}
+
+static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_datum *datum)
+{
+	int hvalue;
+	struct avtab_node *prev, *cur, *newnode;
+	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+	if (!h || !h->htable)
+		return -EINVAL;
+
+	hvalue = avtab_hash(key, h->mask);
+	for (prev = NULL, cur = h->htable[hvalue];
+	     cur;
+	     prev = cur, cur = cur->next) {
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class == cur->key.target_class &&
+		    (specified & cur->key.specified)) {
+			if (specified & AVTAB_OPNUM)
+				break;
+			return -EEXIST;
+		}
+		if (key->source_type < cur->key.source_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type < cur->key.target_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class < cur->key.target_class)
+			break;
+	}
+
+	newnode = avtab_insert_node(h, hvalue, prev, cur, key, datum);
+	if (!newnode)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/* Unlike avtab_insert(), this function allow multiple insertions of the same
+ * key/specified mask into the table, as needed by the conditional avtab.
+ * It also returns a pointer to the node inserted.
+ */
+struct avtab_node *
+avtab_insert_nonunique(struct avtab *h, struct avtab_key *key, struct avtab_datum *datum)
+{
+	int hvalue;
+	struct avtab_node *prev, *cur;
+	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+	if (!h || !h->htable)
+		return NULL;
+	hvalue = avtab_hash(key, h->mask);
+	for (prev = NULL, cur = h->htable[hvalue];
+	     cur;
+	     prev = cur, cur = cur->next) {
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class == cur->key.target_class &&
+		    (specified & cur->key.specified))
+			break;
+		if (key->source_type < cur->key.source_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type < cur->key.target_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class < cur->key.target_class)
+			break;
+	}
+	return avtab_insert_node(h, hvalue, prev, cur, key, datum);
+}
+
+struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key)
+{
+	int hvalue;
+	struct avtab_node *cur;
+	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+	if (!h || !h->htable)
+		return NULL;
+
+	hvalue = avtab_hash(key, h->mask);
+	for (cur = h->htable[hvalue]; cur; cur = cur->next) {
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class == cur->key.target_class &&
+		    (specified & cur->key.specified))
+			return &cur->datum;
+
+		if (key->source_type < cur->key.source_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type < cur->key.target_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class < cur->key.target_class)
+			break;
+	}
+
+	return NULL;
+}
+
+/* This search function returns a node pointer, and can be used in
+ * conjunction with avtab_search_next_node()
+ */
+struct avtab_node*
+avtab_search_node(struct avtab *h, struct avtab_key *key)
+{
+	int hvalue;
+	struct avtab_node *cur;
+	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+
+	if (!h || !h->htable)
+		return NULL;
+
+	hvalue = avtab_hash(key, h->mask);
+	for (cur = h->htable[hvalue]; cur; cur = cur->next) {
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class == cur->key.target_class &&
+		    (specified & cur->key.specified))
+			return cur;
+
+		if (key->source_type < cur->key.source_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type < cur->key.target_type)
+			break;
+		if (key->source_type == cur->key.source_type &&
+		    key->target_type == cur->key.target_type &&
+		    key->target_class < cur->key.target_class)
+			break;
+	}
+	return NULL;
+}
+
+struct avtab_node*
+avtab_search_node_next(struct avtab_node *node, int specified)
+{
+	struct avtab_node *cur;
+
+	if (!node)
+		return NULL;
+
+	specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+	for (cur = node->next; cur; cur = cur->next) {
+		if (node->key.source_type == cur->key.source_type &&
+		    node->key.target_type == cur->key.target_type &&
+		    node->key.target_class == cur->key.target_class &&
+		    (specified & cur->key.specified))
+			return cur;
+
+		if (node->key.source_type < cur->key.source_type)
+			break;
+		if (node->key.source_type == cur->key.source_type &&
+		    node->key.target_type < cur->key.target_type)
+			break;
+		if (node->key.source_type == cur->key.source_type &&
+		    node->key.target_type == cur->key.target_type &&
+		    node->key.target_class < cur->key.target_class)
+			break;
+	}
+	return NULL;
+}
+
+void avtab_destroy(struct avtab *h)
+{
+	int i;
+	struct avtab_node *cur, *temp;
+
+	if (!h || !h->htable)
+		return;
+
+	for (i = 0; i < h->nslot; i++) {
+		cur = h->htable[i];
+		while (cur) {
+			temp = cur;
+			cur = cur->next;
+			if (temp->key.specified & AVTAB_OP)
+				kmem_cache_free(avtab_operation_cachep,
+							temp->datum.u.ops);
+			kmem_cache_free(avtab_node_cachep, temp);
+		}
+		h->htable[i] = NULL;
+	}
+	kfree(h->htable);
+	h->htable = NULL;
+	h->nslot = 0;
+	h->mask = 0;
+}
+
+int avtab_init(struct avtab *h)
+{
+	h->htable = NULL;
+	h->nel = 0;
+	return 0;
+}
+
+int avtab_alloc(struct avtab *h, u32 nrules)
+{
+	u16 mask = 0;
+	u32 shift = 0;
+	u32 work = nrules;
+	u32 nslot = 0;
+
+	if (nrules == 0)
+		goto avtab_alloc_out;
+
+	while (work) {
+		work  = work >> 1;
+		shift++;
+	}
+	if (shift > 2)
+		shift = shift - 2;
+	nslot = 1 << shift;
+	if (nslot > MAX_AVTAB_HASH_BUCKETS)
+		nslot = MAX_AVTAB_HASH_BUCKETS;
+	mask = nslot - 1;
+
+	h->htable = kcalloc(nslot, sizeof(*(h->htable)), GFP_KERNEL);
+	if (!h->htable)
+		return -ENOMEM;
+
+ avtab_alloc_out:
+	h->nel = 0;
+	h->nslot = nslot;
+	h->mask = mask;
+	printk(KERN_DEBUG "SELinux: %d avtab hash slots, %d rules.\n",
+	       h->nslot, nrules);
+	return 0;
+}
+
+void avtab_hash_eval(struct avtab *h, char *tag)
+{
+	int i, chain_len, slots_used, max_chain_len;
+	unsigned long long chain2_len_sum;
+	struct avtab_node *cur;
+
+	slots_used = 0;
+	max_chain_len = 0;
+	chain2_len_sum = 0;
+	for (i = 0; i < h->nslot; i++) {
+		cur = h->htable[i];
+		if (cur) {
+			slots_used++;
+			chain_len = 0;
+			while (cur) {
+				chain_len++;
+				cur = cur->next;
+			}
+
+			if (chain_len > max_chain_len)
+				max_chain_len = chain_len;
+			chain2_len_sum += chain_len * chain_len;
+		}
+	}
+
+	printk(KERN_DEBUG "SELinux: %s:  %d entries and %d/%d buckets used, "
+	       "longest chain length %d sum of chain length^2 %llu\n",
+	       tag, h->nel, slots_used, h->nslot, max_chain_len,
+	       chain2_len_sum);
+}
+
+static uint16_t spec_order[] = {
+	AVTAB_ALLOWED,
+	AVTAB_AUDITDENY,
+	AVTAB_AUDITALLOW,
+	AVTAB_TRANSITION,
+	AVTAB_CHANGE,
+	AVTAB_MEMBER,
+	AVTAB_OPNUM_ALLOWED,
+	AVTAB_OPNUM_AUDITALLOW,
+	AVTAB_OPNUM_DONTAUDIT,
+	AVTAB_OPTYPE_ALLOWED,
+	AVTAB_OPTYPE_AUDITALLOW,
+	AVTAB_OPTYPE_DONTAUDIT
+};
+
+int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
+		    int (*insertf)(struct avtab *a, struct avtab_key *k,
+				   struct avtab_datum *d, void *p),
+		    void *p)
+{
+	__le16 buf16[4];
+	u16 enabled;
+	u32 items, items2, val, vers = pol->policyvers;
+	struct avtab_key key;
+	struct avtab_datum datum;
+	struct avtab_operation ops;
+	__le32 buf32[ARRAY_SIZE(ops.op.perms)];
+	int i, rc;
+	unsigned set;
+
+	memset(&key, 0, sizeof(struct avtab_key));
+	memset(&datum, 0, sizeof(struct avtab_datum));
+
+	if (vers < POLICYDB_VERSION_AVTAB) {
+		rc = next_entry(buf32, fp, sizeof(u32));
+		if (rc) {
+			printk(KERN_ERR "SELinux: avtab: truncated entry\n");
+			return rc;
+		}
+		items2 = le32_to_cpu(buf32[0]);
+		if (items2 > ARRAY_SIZE(buf32)) {
+			printk(KERN_ERR "SELinux: avtab: entry overflow\n");
+			return -EINVAL;
+
+		}
+		rc = next_entry(buf32, fp, sizeof(u32)*items2);
+		if (rc) {
+			printk(KERN_ERR "SELinux: avtab: truncated entry\n");
+			return rc;
+		}
+		items = 0;
+
+		val = le32_to_cpu(buf32[items++]);
+		key.source_type = (u16)val;
+		if (key.source_type != val) {
+			printk(KERN_ERR "SELinux: avtab: truncated source type\n");
+			return -EINVAL;
+		}
+		val = le32_to_cpu(buf32[items++]);
+		key.target_type = (u16)val;
+		if (key.target_type != val) {
+			printk(KERN_ERR "SELinux: avtab: truncated target type\n");
+			return -EINVAL;
+		}
+		val = le32_to_cpu(buf32[items++]);
+		key.target_class = (u16)val;
+		if (key.target_class != val) {
+			printk(KERN_ERR "SELinux: avtab: truncated target class\n");
+			return -EINVAL;
+		}
+
+		val = le32_to_cpu(buf32[items++]);
+		enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0;
+
+		if (!(val & (AVTAB_AV | AVTAB_TYPE))) {
+			printk(KERN_ERR "SELinux: avtab: null entry\n");
+			return -EINVAL;
+		}
+		if ((val & AVTAB_AV) &&
+		    (val & AVTAB_TYPE)) {
+			printk(KERN_ERR "SELinux: avtab: entry has both access vectors and types\n");
+			return -EINVAL;
+		}
+		if (val & AVTAB_OP) {
+			printk(KERN_ERR "SELinux: avtab: entry has operations\n");
+			return -EINVAL;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
+			if (val & spec_order[i]) {
+				key.specified = spec_order[i] | enabled;
+				datum.u.data = le32_to_cpu(buf32[items++]);
+				rc = insertf(a, &key, &datum, p);
+				if (rc)
+					return rc;
+			}
+		}
+
+		if (items != items2) {
+			printk(KERN_ERR "SELinux: avtab: entry only had %d items, expected %d\n", items2, items);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	rc = next_entry(buf16, fp, sizeof(u16)*4);
+	if (rc) {
+		printk(KERN_ERR "SELinux: avtab: truncated entry\n");
+		return rc;
+	}
+	items = 0;
+	key.source_type = le16_to_cpu(buf16[items++]);
+	key.target_type = le16_to_cpu(buf16[items++]);
+	key.target_class = le16_to_cpu(buf16[items++]);
+	key.specified = le16_to_cpu(buf16[items++]);
+
+	if (!policydb_type_isvalid(pol, key.source_type) ||
+	    !policydb_type_isvalid(pol, key.target_type) ||
+	    !policydb_class_isvalid(pol, key.target_class)) {
+		printk(KERN_ERR "SELinux: avtab: invalid type or class\n");
+		return -EINVAL;
+	}
+
+	set = 0;
+	for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
+		if (key.specified & spec_order[i])
+			set++;
+	}
+	if (!set || set > 1) {
+		printk(KERN_ERR "SELinux:  avtab:  more than one specifier\n");
+		return -EINVAL;
+	}
+
+	if ((vers < POLICYDB_VERSION_IOCTL_OPERATIONS)
+			|| !(key.specified & AVTAB_OP)) {
+		rc = next_entry(buf32, fp, sizeof(u32));
+		if (rc) {
+			printk(KERN_ERR "SELinux: avtab: truncated entry\n");
+			return rc;
+		}
+		datum.u.data = le32_to_cpu(*buf32);
+	} else {
+		memset(&ops, 0, sizeof(struct avtab_operation));
+		rc = next_entry(&ops.type, fp, sizeof(u8));
+		if (rc) {
+			printk(KERN_ERR "SELinux: avtab: truncated entry\n");
+			return rc;
+		}
+		rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(ops.op.perms));
+		if (rc) {
+			printk(KERN_ERR "SELinux: avtab: truncated entry\n");
+			return rc;
+		}
+		for (i = 0; i < ARRAY_SIZE(ops.op.perms); i++)
+			ops.op.perms[i] = le32_to_cpu(buf32[i]);
+		datum.u.ops = &ops;
+	}
+	if ((key.specified & AVTAB_TYPE) &&
+	    !policydb_type_isvalid(pol, datum.u.data)) {
+		printk(KERN_ERR "SELinux: avtab: invalid type\n");
+		return -EINVAL;
+	}
+	return insertf(a, &key, &datum, p);
+}
+
+static int avtab_insertf(struct avtab *a, struct avtab_key *k,
+			 struct avtab_datum *d, void *p)
+{
+	return avtab_insert(a, k, d);
+}
+
+int avtab_read(struct avtab *a, void *fp, struct policydb *pol)
+{
+	int rc;
+	__le32 buf[1];
+	u32 nel, i;
+
+
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc < 0) {
+		printk(KERN_ERR "SELinux: avtab: truncated table\n");
+		goto bad;
+	}
+	nel = le32_to_cpu(buf[0]);
+	if (!nel) {
+		printk(KERN_ERR "SELinux: avtab: table is empty\n");
+		rc = -EINVAL;
+		goto bad;
+	}
+
+	rc = avtab_alloc(a, nel);
+	if (rc)
+		goto bad;
+
+	for (i = 0; i < nel; i++) {
+		rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL);
+		if (rc) {
+			if (rc == -ENOMEM)
+				printk(KERN_ERR "SELinux: avtab: out of memory\n");
+			else if (rc == -EEXIST)
+				printk(KERN_ERR "SELinux: avtab: duplicate entry\n");
+
+			goto bad;
+		}
+	}
+
+	rc = 0;
+out:
+	return rc;
+
+bad:
+	avtab_destroy(a);
+	goto out;
+}
+
+int avtab_write_item(struct policydb *p, struct avtab_node *cur, void *fp)
+{
+	__le16 buf16[4];
+	__le32 buf32[ARRAY_SIZE(cur->datum.u.ops->op.perms)];
+	int rc;
+	unsigned int i;
+
+	buf16[0] = cpu_to_le16(cur->key.source_type);
+	buf16[1] = cpu_to_le16(cur->key.target_type);
+	buf16[2] = cpu_to_le16(cur->key.target_class);
+	buf16[3] = cpu_to_le16(cur->key.specified);
+	rc = put_entry(buf16, sizeof(u16), 4, fp);
+	if (rc)
+		return rc;
+
+	if (cur->key.specified & AVTAB_OP) {
+		rc = put_entry(&cur->datum.u.ops->type, sizeof(u8), 1, fp);
+		if (rc)
+			return rc;
+		for (i = 0; i < ARRAY_SIZE(cur->datum.u.ops->op.perms); i++)
+			buf32[i] = cpu_to_le32(cur->datum.u.ops->op.perms[i]);
+		rc = put_entry(buf32, sizeof(u32),
+				ARRAY_SIZE(cur->datum.u.ops->op.perms), fp);
+	} else {
+		buf32[0] = cpu_to_le32(cur->datum.u.data);
+		rc = put_entry(buf32, sizeof(u32), 1, fp);
+	}
+	if (rc)
+		return rc;
+	return 0;
+}
+
+int avtab_write(struct policydb *p, struct avtab *a, void *fp)
+{
+	unsigned int i;
+	int rc = 0;
+	struct avtab_node *cur;
+	__le32 buf[1];
+
+	buf[0] = cpu_to_le32(a->nel);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < a->nslot; i++) {
+		for (cur = a->htable[i]; cur; cur = cur->next) {
+			rc = avtab_write_item(p, cur, fp);
+			if (rc)
+				return rc;
+		}
+	}
+
+	return rc;
+}
+void avtab_cache_init(void)
+{
+	avtab_node_cachep = kmem_cache_create("avtab_node",
+					      sizeof(struct avtab_node),
+					      0, SLAB_PANIC, NULL);
+	avtab_operation_cachep = kmem_cache_create("avtab_operation",
+					      sizeof(struct avtab_operation),
+					      0, SLAB_PANIC, NULL);
+}
+
+void avtab_cache_destroy(void)
+{
+	kmem_cache_destroy(avtab_node_cachep);
+	kmem_cache_destroy(avtab_operation_cachep);
+}