Joshua Brindle | 13cd4c8 | 2008-08-19 15:30:36 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Implementation of the userspace SID hashtable. |
| 3 | * |
| 4 | * Author : Eamon Walsh, <ewalsh@epoch.ncsc.mil> |
| 5 | */ |
| 6 | #include <errno.h> |
| 7 | #include <stdio.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <stdint.h> |
| 10 | #include <string.h> |
| 11 | #include "selinux_internal.h" |
| 12 | #include <selinux/avc.h> |
| 13 | #include "avc_sidtab.h" |
| 14 | #include "avc_internal.h" |
| 15 | |
| 16 | static inline unsigned sidtab_hash(security_context_t key) |
| 17 | { |
| 18 | char *p, *keyp; |
| 19 | unsigned int size; |
| 20 | unsigned int val; |
| 21 | |
| 22 | val = 0; |
| 23 | keyp = (char *)key; |
| 24 | size = strlen(keyp); |
| 25 | for (p = keyp; (unsigned int)(p - keyp) < size; p++) |
| 26 | val = |
| 27 | (val << 4 | (val >> (8 * sizeof(unsigned int) - 4))) ^ (*p); |
| 28 | return val & (SIDTAB_SIZE - 1); |
| 29 | } |
| 30 | |
| 31 | int sidtab_init(struct sidtab *s) |
| 32 | { |
| 33 | int i, rc = 0; |
| 34 | |
| 35 | s->htable = (struct sidtab_node **)avc_malloc |
| 36 | (sizeof(struct sidtab_node *) * SIDTAB_SIZE); |
| 37 | |
| 38 | if (!s->htable) { |
| 39 | rc = -1; |
| 40 | goto out; |
| 41 | } |
| 42 | for (i = 0; i < SIDTAB_SIZE; i++) |
| 43 | s->htable[i] = NULL; |
| 44 | s->nel = 0; |
| 45 | out: |
| 46 | return rc; |
| 47 | } |
| 48 | |
KaiGai Kohei | 6a17cfa | 2010-06-14 15:21:51 -0400 | [diff] [blame] | 49 | int sidtab_insert(struct sidtab *s, const security_context_t ctx) |
Joshua Brindle | 13cd4c8 | 2008-08-19 15:30:36 -0400 | [diff] [blame] | 50 | { |
| 51 | int hvalue, rc = 0; |
| 52 | struct sidtab_node *newnode; |
| 53 | security_context_t newctx; |
| 54 | |
| 55 | newnode = (struct sidtab_node *)avc_malloc(sizeof(*newnode)); |
| 56 | if (!newnode) { |
| 57 | rc = -1; |
| 58 | goto out; |
| 59 | } |
| 60 | newctx = (security_context_t) strdup(ctx); |
| 61 | if (!newctx) { |
| 62 | rc = -1; |
| 63 | avc_free(newnode); |
| 64 | goto out; |
| 65 | } |
| 66 | |
| 67 | hvalue = sidtab_hash(newctx); |
| 68 | newnode->next = s->htable[hvalue]; |
| 69 | newnode->sid_s.ctx = newctx; |
Eamon Walsh | 58866dd | 2009-09-02 17:41:22 -0400 | [diff] [blame] | 70 | newnode->sid_s.refcnt = 1; /* unused */ |
Joshua Brindle | 13cd4c8 | 2008-08-19 15:30:36 -0400 | [diff] [blame] | 71 | s->htable[hvalue] = newnode; |
| 72 | s->nel++; |
| 73 | out: |
| 74 | return rc; |
| 75 | } |
| 76 | |
Joshua Brindle | 13cd4c8 | 2008-08-19 15:30:36 -0400 | [diff] [blame] | 77 | int |
| 78 | sidtab_context_to_sid(struct sidtab *s, |
KaiGai Kohei | 6a17cfa | 2010-06-14 15:21:51 -0400 | [diff] [blame] | 79 | const security_context_t ctx, security_id_t * sid) |
Joshua Brindle | 13cd4c8 | 2008-08-19 15:30:36 -0400 | [diff] [blame] | 80 | { |
| 81 | int hvalue, rc = 0; |
| 82 | struct sidtab_node *cur; |
| 83 | |
| 84 | *sid = NULL; |
| 85 | hvalue = sidtab_hash(ctx); |
| 86 | |
| 87 | loop: |
| 88 | cur = s->htable[hvalue]; |
| 89 | while (cur != NULL && strcmp(cur->sid_s.ctx, ctx)) |
| 90 | cur = cur->next; |
| 91 | |
| 92 | if (cur == NULL) { /* need to make a new entry */ |
| 93 | rc = sidtab_insert(s, ctx); |
| 94 | if (rc) |
| 95 | goto out; |
| 96 | goto loop; /* find the newly inserted node */ |
| 97 | } |
| 98 | |
| 99 | *sid = &cur->sid_s; |
| 100 | out: |
| 101 | return rc; |
| 102 | } |
| 103 | |
| 104 | void sidtab_sid_stats(struct sidtab *h, char *buf, int buflen) |
| 105 | { |
| 106 | int i, chain_len, slots_used, max_chain_len; |
| 107 | struct sidtab_node *cur; |
| 108 | |
| 109 | slots_used = 0; |
| 110 | max_chain_len = 0; |
| 111 | for (i = 0; i < SIDTAB_SIZE; i++) { |
| 112 | cur = h->htable[i]; |
| 113 | if (cur) { |
| 114 | slots_used++; |
| 115 | chain_len = 0; |
| 116 | while (cur) { |
| 117 | chain_len++; |
| 118 | cur = cur->next; |
| 119 | } |
| 120 | |
| 121 | if (chain_len > max_chain_len) |
| 122 | max_chain_len = chain_len; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | snprintf(buf, buflen, |
| 127 | "%s: %d SID entries and %d/%d buckets used, longest " |
| 128 | "chain length %d\n", avc_prefix, h->nel, slots_used, |
| 129 | SIDTAB_SIZE, max_chain_len); |
| 130 | } |
| 131 | |
| 132 | void sidtab_destroy(struct sidtab *s) |
| 133 | { |
| 134 | int i; |
| 135 | struct sidtab_node *cur, *temp; |
| 136 | |
| 137 | if (!s) |
| 138 | return; |
| 139 | |
| 140 | for (i = 0; i < SIDTAB_SIZE; i++) { |
| 141 | cur = s->htable[i]; |
| 142 | while (cur != NULL) { |
| 143 | temp = cur; |
| 144 | cur = cur->next; |
| 145 | freecon(temp->sid_s.ctx); |
| 146 | avc_free(temp); |
| 147 | } |
| 148 | s->htable[i] = NULL; |
| 149 | } |
| 150 | avc_free(s->htable); |
| 151 | s->htable = NULL; |
| 152 | } |