cregit-Linux how code gets into the kernel

Release 4.11 security/selinux/ss/avtab.c

/*
 * 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_xperms_cachep;

/* Based on MurmurHash3, written by Austin Appleby and placed in the
 * public domain.
 */

static inline int avtab_hash(struct avtab_key *keyp, u32 mask) { static const u32 c1 = 0xcc9e2d51; static const u32 c2 = 0x1b873593; static const u32 r1 = 15; static const u32 r2 = 13; static const u32 m = 5; static const u32 n = 0xe6546b64; u32 hash = 0; #define mix(input) { \ u32 v = input; \ v *= c1; \ v = (v << r1) | (v >> (32 - r1)); \ v *= c2; \ hash ^= v; \ hash = (hash << r2) | (hash >> (32 - r2)); \ hash = hash * m + n; \ } mix(keyp->target_class); mix(keyp->target_type); mix(keyp->source_type); #undef mix hash ^= hash >> 16; hash *= 0x85ebca6b; hash ^= hash >> 13; hash *= 0xc2b2ae35; hash ^= hash >> 16; return hash & mask; }

Contributors

PersonTokensPropCommitsCommitProp
John Brooks9879.03%150.00%
Yuichi Nakamura2620.97%150.00%
Total124100.00%2100.00%


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_extended_perms *xperms; newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL); if (newnode == NULL) return NULL; newnode->key = *key; if (key->specified & AVTAB_XPERMS) { xperms = kmem_cache_zalloc(avtab_xperms_cachep, GFP_KERNEL); if (xperms == NULL) { kmem_cache_free(avtab_node_cachep, newnode); return NULL; } *xperms = *(datum->u.xperms); newnode->datum.u.xperms = xperms; } else { newnode->datum.u.data = datum->u.data; } if (prev) { newnode->next = prev->next; prev->next = newnode; } else { newnode->next = flex_array_get_ptr(h->htable, hvalue); if (flex_array_put_ptr(h->htable, hvalue, newnode, GFP_KERNEL|__GFP_ZERO)) { kmem_cache_free(avtab_node_cachep, newnode); return NULL; } } h->nel++; return newnode; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton11552.27%116.67%
Jeff Vander Stoep7534.09%116.67%
Stephen D. Smalley2712.27%116.67%
Christoph Lameter10.45%116.67%
James Morris10.45%116.67%
Robert P. J. Day10.45%116.67%
Total220100.00%6100.00%


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 = flex_array_get_ptr(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)) { /* extended perms may not be unique */ if (specified & AVTAB_XPERMS) 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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton21984.56%228.57%
Stephen D. Smalley207.72%342.86%
Jeff Vander Stoep103.86%114.29%
Yuichi Nakamura103.86%114.29%
Total259100.00%7100.00%

/* 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 = flex_array_get_ptr(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); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton20086.96%233.33%
Stephen D. Smalley198.26%233.33%
Yuichi Nakamura104.35%116.67%
Vesa-Matti J Kari10.43%116.67%
Total230100.00%6100.00%


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 = flex_array_get_ptr(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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton17785.92%125.00%
Stephen D. Smalley199.22%250.00%
Yuichi Nakamura104.85%125.00%
Total206100.00%4100.00%

/* 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 = flex_array_get_ptr(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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton17485.71%240.00%
Stephen D. Smalley199.36%240.00%
Yuichi Nakamura104.93%120.00%
Total203100.00%5100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton18094.74%266.67%
Stephen D. Smalley105.26%133.33%
Total190100.00%3100.00%


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 = flex_array_get_ptr(h->htable, i); while (cur) { temp = cur; cur = cur->next; if (temp->key.specified & AVTAB_XPERMS) kmem_cache_free(avtab_xperms_cachep, temp->datum.u.xperms); kmem_cache_free(avtab_node_cachep, temp); } } flex_array_free(h->htable); h->htable = NULL; h->nslot = 0; h->mask = 0; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton8564.89%233.33%
Jeff Vander Stoep2317.56%116.67%
Yuichi Nakamura1511.45%116.67%
Stephen D. Smalley53.82%116.67%
James Morris32.29%116.67%
Total131100.00%6100.00%


int avtab_init(struct avtab *h) { h->htable = NULL; h->nel = 0; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Yuichi Nakamura1664.00%150.00%
Andrew Morton936.00%150.00%
Total25100.00%2100.00%


int avtab_alloc(struct avtab *h, u32 nrules) { u32 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 = flex_array_alloc(sizeof(struct avtab_node *), nslot, GFP_KERNEL | __GFP_ZERO); 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; }

Contributors

PersonTokensPropCommitsCommitProp
Yuichi Nakamura10868.79%116.67%
Andrew Morton3824.20%116.67%
Stephen D. Smalley74.46%116.67%
Eric Paris21.27%116.67%
James Morris10.64%116.67%
John Brooks10.64%116.67%
Total157100.00%6100.00%


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 = flex_array_get_ptr(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); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton11078.57%228.57%
Yuichi Nakamura2316.43%114.29%
Stephen D. Smalley42.86%114.29%
Eric Paris32.14%342.86%
Total140100.00%7100.00%

static uint16_t spec_order[] = { AVTAB_ALLOWED, AVTAB_AUDITDENY, AVTAB_AUDITALLOW, AVTAB_TRANSITION, AVTAB_CHANGE, AVTAB_MEMBER, AVTAB_XPERMS_ALLOWED, AVTAB_XPERMS_AUDITALLOW, AVTAB_XPERMS_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_extended_perms xperms; __le32 buf32[ARRAY_SIZE(xperms.perms.p)]; 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_XPERMS) { printk(KERN_ERR "SELinux: avtab: entry has extended permissions\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_XPERMS_IOCTL) && (key.specified & AVTAB_XPERMS)) { printk(KERN_ERR "SELinux: avtab: policy version %u does not " "support extended permissions rules and one " "was specified\n", vers); return -EINVAL; } else if (key.specified & AVTAB_XPERMS) { memset(&xperms, 0, sizeof(struct avtab_extended_perms)); rc = next_entry(&xperms.specified, fp, sizeof(u8)); if (rc) { printk(KERN_ERR "SELinux: avtab: truncated entry\n"); return rc; } rc = next_entry(&xperms.driver, fp, sizeof(u8)); if (rc) { printk(KERN_ERR "SELinux: avtab: truncated entry\n"); return rc; } rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p)); if (rc) { printk(KERN_ERR "SELinux: avtab: truncated entry\n"); return rc; } for (i = 0; i < ARRAY_SIZE(xperms.perms.p); i++) xperms.perms.p[i] = le32_to_cpu(buf32[i]); datum.u.xperms = &xperms; } else { 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); } 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); }

Contributors

PersonTokensPropCommitsCommitProp
Stephen D. Smalley49748.07%327.27%
Jeff Vander Stoep24924.08%19.09%
Andrew Morton24423.60%218.18%
James Morris141.35%19.09%
Dan Carpenter141.35%19.09%
Eric Paris111.06%19.09%
Alexey Dobriyan40.39%19.09%
Tobias Klauser10.10%19.09%
Total1034100.00%11100.00%


static int avtab_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *p) { return avtab_insert(a, k, d); }

Contributors

PersonTokensPropCommitsCommitProp
Stephen D. Smalley3291.43%150.00%
Andrew Morton38.57%150.00%
Total35100.00%2100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton14775.00%225.00%
Stephen D. Smalley2814.29%337.50%
Yuichi Nakamura168.16%112.50%
James Morris42.04%112.50%
Alexey Dobriyan10.51%112.50%
Total196100.00%8100.00%


int avtab_write_item(struct policydb *p, struct avtab_node *cur, void *fp) { __le16 buf16[4]; __le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)]; 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_XPERMS) { rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp); if (rc) return rc; rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp); if (rc) return rc; for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++) buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]); rc = put_entry(buf32, sizeof(u32), ARRAY_SIZE(cur->datum.u.xperms->perms.p), 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; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Vander Stoep17753.80%150.00%
Eric Paris15246.20%150.00%
Total329100.00%2100.00%


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 = flex_array_get_ptr(a->htable, i); cur; cur = cur->next) { rc = avtab_write_item(p, cur, fp); if (rc) return rc; } } return rc; }

Contributors

PersonTokensPropCommitsCommitProp
Eric Paris13197.04%150.00%
Stephen D. Smalley42.96%150.00%
Total135100.00%2100.00%


void avtab_cache_init(void) { avtab_node_cachep = kmem_cache_create("avtab_node", sizeof(struct avtab_node), 0, SLAB_PANIC, NULL); avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms", sizeof(struct avtab_extended_perms), 0, SLAB_PANIC, NULL); }

Contributors

PersonTokensPropCommitsCommitProp
James Morris2657.78%150.00%
Jeff Vander Stoep1942.22%150.00%
Total45100.00%2100.00%


void avtab_cache_destroy(void) { kmem_cache_destroy(avtab_node_cachep); kmem_cache_destroy(avtab_xperms_cachep); }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Mahoney1270.59%150.00%
Jeff Vander Stoep529.41%150.00%
Total17100.00%2100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton171946.05%414.29%
Stephen D. Smalley71019.02%517.86%
Jeff Vander Stoep57015.27%13.57%
Eric Paris3008.04%621.43%
Yuichi Nakamura2446.54%13.57%
John Brooks1002.68%13.57%
James Morris531.42%27.14%
Dan Carpenter140.38%13.57%
Jeff Mahoney120.32%13.57%
Alexey Dobriyan50.13%13.57%
Christoph Lameter30.08%27.14%
Tobias Klauser10.03%13.57%
Robert P. J. Day10.03%13.57%
Vesa-Matti J Kari10.03%13.57%
Total3733100.00%28100.00%
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