diff options
Diffstat (limited to 'security/selinux/ss/avtab.c')
| -rw-r--r-- | security/selinux/ss/avtab.c | 556 |
1 files changed, 556 insertions, 0 deletions
diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c new file mode 100644 index 00000000..a3dd9faa --- /dev/null +++ b/security/selinux/ss/avtab.c @@ -0,0 +1,556 @@ +/* + * 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 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; + newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL); + if (newnode == NULL) + return NULL; + newnode->key = *key; + newnode->datum = *datum; + 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)) + 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; + 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 +}; + +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; + __le32 buf32[7]; + u32 items, items2, val, vers = pol->policyvers; + struct avtab_key key; + struct avtab_datum datum; + 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; + } + + for (i = 0; i < ARRAY_SIZE(spec_order); i++) { + if (val & spec_order[i]) { + key.specified = spec_order[i] | enabled; + datum.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; + } + + rc = next_entry(buf32, fp, sizeof(u32)); + if (rc) { + printk(KERN_ERR "SELinux: avtab: truncated entry\n"); + return rc; + } + datum.data = le32_to_cpu(*buf32); + if ((key.specified & AVTAB_TYPE) && + !policydb_type_isvalid(pol, datum.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[1]; + int rc; + + 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; + buf32[0] = cpu_to_le32(cur->datum.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); +} + +void avtab_cache_destroy(void) +{ + kmem_cache_destroy(avtab_node_cachep); +} |