Stephen Smalley | f074036 | 2012-01-04 12:30:47 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Class and permission mappings. |
| 3 | */ |
| 4 | |
| 5 | #include <errno.h> |
| 6 | #include <stdio.h> |
| 7 | #include <stdlib.h> |
| 8 | #include <stdarg.h> |
| 9 | #include <assert.h> |
| 10 | #include <selinux/selinux.h> |
| 11 | #include <selinux/avc.h> |
| 12 | #include "mapping.h" |
| 13 | |
| 14 | /* |
| 15 | * Class and permission mappings |
| 16 | */ |
| 17 | |
| 18 | struct selinux_mapping { |
| 19 | security_class_t value; /* real, kernel value */ |
| 20 | unsigned num_perms; |
| 21 | access_vector_t perms[sizeof(access_vector_t) * 8]; |
| 22 | }; |
| 23 | |
| 24 | static struct selinux_mapping *current_mapping = NULL; |
| 25 | static security_class_t current_mapping_size = 0; |
| 26 | |
| 27 | /* |
| 28 | * Mapping setting function |
| 29 | */ |
| 30 | |
| 31 | int |
| 32 | selinux_set_mapping(struct security_class_mapping *map) |
| 33 | { |
| 34 | size_t size = sizeof(struct selinux_mapping); |
| 35 | security_class_t i, j; |
| 36 | unsigned k; |
| 37 | |
| 38 | free(current_mapping); |
| 39 | current_mapping = NULL; |
| 40 | current_mapping_size = 0; |
| 41 | |
| 42 | if (avc_reset() < 0) |
| 43 | goto err; |
| 44 | |
| 45 | /* Find number of classes in the input mapping */ |
| 46 | if (!map) { |
| 47 | errno = EINVAL; |
| 48 | goto err; |
| 49 | } |
| 50 | i = 0; |
| 51 | while (map[i].name) |
| 52 | i++; |
| 53 | |
| 54 | /* Allocate space for the class records, plus one for class zero */ |
| 55 | current_mapping = (struct selinux_mapping *)calloc(++i, size); |
| 56 | if (!current_mapping) |
| 57 | goto err; |
| 58 | |
| 59 | /* Store the raw class and permission values */ |
| 60 | j = 0; |
| 61 | while (map[j].name) { |
| 62 | struct security_class_mapping *p_in = map + (j++); |
| 63 | struct selinux_mapping *p_out = current_mapping + j; |
| 64 | |
| 65 | p_out->value = string_to_security_class(p_in->name); |
| 66 | if (!p_out->value) |
| 67 | goto err2; |
| 68 | |
| 69 | k = 0; |
| 70 | while (p_in->perms && p_in->perms[k]) { |
| 71 | /* An empty permission string skips ahead */ |
| 72 | if (!*p_in->perms[k]) { |
| 73 | k++; |
| 74 | continue; |
| 75 | } |
| 76 | p_out->perms[k] = string_to_av_perm(p_out->value, |
| 77 | p_in->perms[k]); |
| 78 | if (!p_out->perms[k]) |
| 79 | goto err2; |
| 80 | k++; |
| 81 | } |
| 82 | p_out->num_perms = k; |
| 83 | } |
| 84 | |
| 85 | /* Set the mapping size here so the above lookups are "raw" */ |
| 86 | current_mapping_size = i; |
| 87 | return 0; |
| 88 | err2: |
| 89 | free(current_mapping); |
| 90 | current_mapping = NULL; |
| 91 | current_mapping_size = 0; |
| 92 | err: |
| 93 | return -1; |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | * Get real, kernel values from mapped values |
| 98 | */ |
| 99 | |
| 100 | security_class_t |
| 101 | unmap_class(security_class_t tclass) |
| 102 | { |
| 103 | if (tclass < current_mapping_size) |
| 104 | return current_mapping[tclass].value; |
| 105 | |
| 106 | assert(current_mapping_size == 0); |
| 107 | return tclass; |
| 108 | } |
| 109 | |
| 110 | access_vector_t |
| 111 | unmap_perm(security_class_t tclass, access_vector_t tperm) |
| 112 | { |
| 113 | if (tclass < current_mapping_size) { |
| 114 | unsigned i; |
| 115 | access_vector_t kperm = 0; |
| 116 | |
| 117 | for (i=0; i<current_mapping[tclass].num_perms; i++) |
| 118 | if (tperm & (1<<i)) { |
| 119 | assert(current_mapping[tclass].perms[i]); |
| 120 | kperm |= current_mapping[tclass].perms[i]; |
| 121 | tperm &= ~(1<<i); |
| 122 | } |
| 123 | assert(tperm == 0); |
| 124 | return kperm; |
| 125 | } |
| 126 | |
| 127 | assert(current_mapping_size == 0); |
| 128 | return tperm; |
| 129 | } |
| 130 | |
| 131 | /* |
| 132 | * Get mapped values from real, kernel values |
| 133 | */ |
| 134 | |
| 135 | security_class_t |
| 136 | map_class(security_class_t kclass) |
| 137 | { |
| 138 | security_class_t i; |
| 139 | |
| 140 | for (i=0; i<current_mapping_size; i++) |
| 141 | if (current_mapping[i].value == kclass) |
| 142 | return i; |
| 143 | |
| 144 | assert(current_mapping_size == 0); |
| 145 | return kclass; |
| 146 | } |
| 147 | |
| 148 | access_vector_t |
| 149 | map_perm(security_class_t tclass, access_vector_t kperm) |
| 150 | { |
| 151 | if (tclass < current_mapping_size) { |
| 152 | unsigned i; |
| 153 | access_vector_t tperm = 0; |
| 154 | |
| 155 | for (i=0; i<current_mapping[tclass].num_perms; i++) |
| 156 | if (kperm & current_mapping[tclass].perms[i]) { |
| 157 | tperm |= 1<<i; |
| 158 | kperm &= ~current_mapping[tclass].perms[i]; |
| 159 | } |
| 160 | assert(kperm == 0); |
| 161 | return tperm; |
| 162 | } |
| 163 | |
| 164 | assert(current_mapping_size == 0); |
| 165 | return kperm; |
| 166 | } |
| 167 | |
| 168 | void |
| 169 | map_decision(security_class_t tclass, struct av_decision *avd) |
| 170 | { |
| 171 | if (tclass < current_mapping_size) { |
| 172 | unsigned i; |
| 173 | access_vector_t result; |
| 174 | |
| 175 | for (i=0, result=0; i<current_mapping[tclass].num_perms; i++) |
| 176 | if (avd->allowed & current_mapping[tclass].perms[i]) |
| 177 | result |= 1<<i; |
| 178 | avd->allowed = result; |
| 179 | |
| 180 | for (i=0, result=0; i<current_mapping[tclass].num_perms; i++) |
| 181 | if (avd->decided & current_mapping[tclass].perms[i]) |
| 182 | result |= 1<<i; |
| 183 | avd->decided = result; |
| 184 | |
| 185 | for (i=0, result=0; i<current_mapping[tclass].num_perms; i++) |
| 186 | if (avd->auditallow & current_mapping[tclass].perms[i]) |
| 187 | result |= 1<<i; |
| 188 | avd->auditallow = result; |
| 189 | |
| 190 | for (i=0, result=0; i<current_mapping[tclass].num_perms; i++) |
| 191 | if (avd->auditdeny & current_mapping[tclass].perms[i]) |
| 192 | result |= 1<<i; |
| 193 | avd->auditdeny = result; |
| 194 | } |
| 195 | } |