diff options
Diffstat (limited to 'tools/sepolicy-analyze/neverallow.c')
-rw-r--r-- | tools/sepolicy-analyze/neverallow.c | 515 |
1 files changed, 515 insertions, 0 deletions
diff --git a/tools/sepolicy-analyze/neverallow.c b/tools/sepolicy-analyze/neverallow.c new file mode 100644 index 0000000..1da88c0 --- /dev/null +++ b/tools/sepolicy-analyze/neverallow.c @@ -0,0 +1,515 @@ +#include <ctype.h> +#include <fcntl.h> +#include <getopt.h> +#include <stdbool.h> +#include <stdio.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +#include "neverallow.h" + +static int debug; +static int warn; + +void neverallow_usage() { + fprintf(stderr, "\tneverallow [-w|--warn] [-d|--debug] [-n|--neverallows <neverallow-rules>] | [-f|--file <neverallow-file>]\n"); +} + +static int read_typeset(policydb_t *policydb, char **ptr, char *end, + type_set_t *typeset, uint32_t *flags) +{ + const char *keyword = "self"; + size_t keyword_size = strlen(keyword), len; + char *p = *ptr; + unsigned openparens = 0; + char *start, *id; + type_datum_t *type; + struct ebitmap_node *n; + unsigned int bit; + bool negate = false; + int rc; + + do { + while (p < end && isspace(*p)) + p++; + + if (p == end) + goto err; + + if (*p == '~') { + if (debug) + printf(" ~"); + typeset->flags = TYPE_COMP; + p++; + while (p < end && isspace(*p)) + p++; + if (p == end) + goto err; + } + + if (*p == '{') { + if (debug && !openparens) + printf(" {"); + openparens++; + p++; + continue; + } + + if (*p == '}') { + if (debug && openparens == 1) + printf(" }"); + if (openparens == 0) + goto err; + openparens--; + p++; + continue; + } + + if (*p == '*') { + if (debug) + printf(" *"); + typeset->flags = TYPE_STAR; + p++; + continue; + } + + if (*p == '-') { + if (debug) + printf(" -"); + negate = true; + p++; + continue; + } + + if (*p == '#') { + while (p < end && *p != '\n') + p++; + continue; + } + + start = p; + while (p < end && !isspace(*p) && *p != ':' && *p != ';' && *p != '{' && *p != '}' && *p != '#') + p++; + + if (p == start) + goto err; + + len = p - start; + if (len == keyword_size && !strncmp(start, keyword, keyword_size)) { + if (debug) + printf(" self"); + *flags |= RULE_SELF; + continue; + } + + id = calloc(1, len + 1); + if (!id) + goto err; + memcpy(id, start, len); + if (debug) + printf(" %s", id); + type = hashtab_search(policydb->p_types.table, id); + if (!type) { + if (warn) + fprintf(stderr, "Warning! Type or attribute %s used in neverallow undefined in policy being checked.\n", id); + negate = false; + continue; + } + free(id); + + if (type->flavor == TYPE_ATTRIB) { + if (negate) + rc = ebitmap_union(&typeset->negset, &policydb->attr_type_map[type->s.value - 1]); + else + rc = ebitmap_union(&typeset->types, &policydb->attr_type_map[type->s.value - 1]); + } else if (negate) { + rc = ebitmap_set_bit(&typeset->negset, type->s.value - 1, 1); + } else { + rc = ebitmap_set_bit(&typeset->types, type->s.value - 1, 1); + } + + negate = false; + + if (rc) + goto err; + + } while (p < end && openparens); + + if (p == end) + goto err; + + if (typeset->flags & TYPE_STAR) { + for (bit = 0; bit < policydb->p_types.nprim; bit++) { + if (ebitmap_get_bit(&typeset->negset, bit)) + continue; + if (policydb->type_val_to_struct[bit] && + policydb->type_val_to_struct[bit]->flavor == TYPE_ATTRIB) + continue; + if (ebitmap_set_bit(&typeset->types, bit, 1)) + goto err; + } + } + + ebitmap_for_each_bit(&typeset->negset, n, bit) { + if (!ebitmap_node_get_bit(n, bit)) + continue; + if (ebitmap_set_bit(&typeset->types, bit, 0)) + goto err; + } + + if (typeset->flags & TYPE_COMP) { + for (bit = 0; bit < policydb->p_types.nprim; bit++) { + if (policydb->type_val_to_struct[bit] && + policydb->type_val_to_struct[bit]->flavor == TYPE_ATTRIB) + continue; + if (ebitmap_get_bit(&typeset->types, bit)) + ebitmap_set_bit(&typeset->types, bit, 0); + else { + if (ebitmap_set_bit(&typeset->types, bit, 1)) + goto err; + } + } + } + + if (warn && ebitmap_length(&typeset->types) == 0 && !(*flags)) + fprintf(stderr, "Warning! Empty type set\n"); + + *ptr = p; + return 0; +err: + return -1; +} + +static int read_classperms(policydb_t *policydb, char **ptr, char *end, + class_perm_node_t **perms) +{ + char *p = *ptr; + unsigned openparens = 0; + char *id, *start; + class_datum_t *cls = NULL; + perm_datum_t *perm = NULL; + class_perm_node_t *classperms = NULL, *node = NULL; + bool complement = false; + + while (p < end && isspace(*p)) + p++; + + if (p == end || *p != ':') + goto err; + p++; + + if (debug) + printf(" :"); + + do { + while (p < end && isspace(*p)) + p++; + + if (p == end) + goto err; + + if (*p == '{') { + if (debug && !openparens) + printf(" {"); + openparens++; + p++; + continue; + } + + if (*p == '}') { + if (debug && openparens == 1) + printf(" }"); + if (openparens == 0) + goto err; + openparens--; + p++; + continue; + } + + if (*p == '#') { + while (p < end && *p != '\n') + p++; + continue; + } + + start = p; + while (p < end && !isspace(*p) && *p != '{' && *p != '}' && *p != ';' && *p != '#') + p++; + + if (p == start) + goto err; + + id = calloc(1, p - start + 1); + if (!id) + goto err; + memcpy(id, start, p - start); + if (debug) + printf(" %s", id); + cls = hashtab_search(policydb->p_classes.table, id); + if (!cls) { + if (warn) + fprintf(stderr, "Warning! Class %s used in neverallow undefined in policy being checked.\n", id); + continue; + } + + node = calloc(1, sizeof *node); + if (!node) + goto err; + node->class = cls->s.value; + node->next = classperms; + classperms = node; + free(id); + } while (p < end && openparens); + + if (p == end) + goto err; + + if (warn && !classperms) + fprintf(stderr, "Warning! Empty class set\n"); + + do { + while (p < end && isspace(*p)) + p++; + + if (p == end) + goto err; + + if (*p == '~') { + if (debug) + printf(" ~"); + complement = true; + p++; + while (p < end && isspace(*p)) + p++; + if (p == end) + goto err; + } + + if (*p == '{') { + if (debug && !openparens) + printf(" {"); + openparens++; + p++; + continue; + } + + if (*p == '}') { + if (debug && openparens == 1) + printf(" }"); + if (openparens == 0) + goto err; + openparens--; + p++; + continue; + } + + if (*p == '#') { + while (p < end && *p != '\n') + p++; + continue; + } + + start = p; + while (p < end && !isspace(*p) && *p != '{' && *p != '}' && *p != ';' && *p != '#') + p++; + + if (p == start) + goto err; + + id = calloc(1, p - start + 1); + if (!id) + goto err; + memcpy(id, start, p - start); + if (debug) + printf(" %s", id); + + if (!strcmp(id, "*")) { + for (node = classperms; node; node = node->next) + node->data = ~0; + continue; + } + + for (node = classperms; node; node = node->next) { + cls = policydb->class_val_to_struct[node->class-1]; + perm = hashtab_search(cls->permissions.table, id); + if (cls->comdatum && !perm) + perm = hashtab_search(cls->comdatum->permissions.table, id); + if (!perm) { + if (warn) + fprintf(stderr, "Warning! Permission %s used in neverallow undefined in class %s in policy being checked.\n", id, policydb->p_class_val_to_name[node->class-1]); + continue; + } + node->data |= 1U << (perm->s.value - 1); + } + free(id); + } while (p < end && openparens); + + if (p == end) + goto err; + + if (complement) { + for (node = classperms; node; node = node->next) + node->data = ~node->data; + } + + if (warn) { + for (node = classperms; node; node = node->next) + if (!node->data) + fprintf(stderr, "Warning! Empty permission set\n"); + } + + *perms = classperms; + *ptr = p; + return 0; +err: + return -1; +} + +static int check_neverallows(policydb_t *policydb, char *text, char *end) +{ + const char *keyword = "neverallow"; + size_t keyword_size = strlen(keyword), len; + struct avrule *neverallows = NULL, *avrule; + char *p, *start; + + p = text; + while (p < end) { + while (p < end && isspace(*p)) + p++; + + if (*p == '#') { + while (p < end && *p != '\n') + p++; + continue; + } + + start = p; + while (p < end && !isspace(*p)) + p++; + + len = p - start; + if (len != keyword_size || strncmp(start, keyword, keyword_size)) + continue; + + if (debug) + printf("neverallow"); + + avrule = calloc(1, sizeof *avrule); + if (!avrule) + goto err; + + avrule->specified = AVRULE_NEVERALLOW; + + if (read_typeset(policydb, &p, end, &avrule->stypes, &avrule->flags)) + goto err; + + if (read_typeset(policydb, &p, end, &avrule->ttypes, &avrule->flags)) + goto err; + + if (read_classperms(policydb, &p, end, &avrule->perms)) + goto err; + + while (p < end && *p != ';') + p++; + + if (p == end || *p != ';') + goto err; + + if (debug) + printf(";\n"); + + avrule->next = neverallows; + neverallows = avrule; + } + + if (!neverallows) + goto err; + + return check_assertions(NULL, policydb, neverallows); +err: + if (errno == ENOMEM) { + fprintf(stderr, "Out of memory while parsing neverallow rules\n"); + } else + fprintf(stderr, "Error while parsing neverallow rules\n"); + return -1; +} + +static int check_neverallows_file(policydb_t *policydb, const char *filename) +{ + int fd; + struct stat sb; + char *text, *end; + + fd = open(filename, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "Could not open %s: %s\n", filename, strerror(errno)); + return -1; + } + if (fstat(fd, &sb) < 0) { + fprintf(stderr, "Can't stat '%s': %s\n", filename, strerror(errno)); + close(fd); + return -1; + } + text = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + end = text + sb.st_size; + if (text == MAP_FAILED) { + fprintf(stderr, "Can't mmap '%s': %s\n", filename, strerror(errno)); + close(fd); + return -1; + } + close(fd); + return check_neverallows(policydb, text, end); +} + +static int check_neverallows_string(policydb_t *policydb, char *string, size_t len) +{ + char *text, *end; + text = string; + end = text + len; + return check_neverallows(policydb, text, end); +} + +int neverallow_func (int argc, char **argv, policydb_t *policydb) { + char *rules = 0, *file = 0; + char ch; + + struct option neverallow_options[] = { + {"debug", no_argument, NULL, 'd'}, + {"file_input", required_argument, NULL, 'f'}, + {"neverallow", required_argument, NULL, 'n'}, + {"warn", no_argument, NULL, 'w'}, + {NULL, 0, NULL, 0} + }; + + while ((ch = getopt_long(argc, argv, "df:n:w", neverallow_options, NULL)) != -1) { + switch (ch) { + case 'd': + debug = 1; + break; + case 'f': + file = optarg; + break; + case 'n': + rules = optarg; + break; + case 'w': + warn = 1; + break; + default: + USAGE_ERROR = true; + return -1; + } + } + + if (!(rules || file) || (rules && file)){ + USAGE_ERROR = true; + return -1; + } + if (file) { + return check_neverallows_file(policydb, file); + } else { + return check_neverallows_string(policydb, rules, strlen(rules)); + } +} |