TOMOYO: Allow using UID/GID etc. of current thread as conditions.
This patch adds support for permission checks using current thread's UID/GID
etc. in addition to pathnames.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/tomoyo/condition.c b/security/tomoyo/condition.c
new file mode 100644
index 0000000..0692df3
--- /dev/null
+++ b/security/tomoyo/condition.c
@@ -0,0 +1,349 @@
+/*
+ * security/tomoyo/condition.c
+ *
+ * Copyright (C) 2005-2011 NTT DATA CORPORATION
+ */
+
+#include "common.h"
+#include <linux/slab.h>
+
+/* List of "struct tomoyo_condition". */
+LIST_HEAD(tomoyo_condition_list);
+
+/**
+ * tomoyo_same_condition - Check for duplicated "struct tomoyo_condition" entry.
+ *
+ * @a: Pointer to "struct tomoyo_condition".
+ * @b: Pointer to "struct tomoyo_condition".
+ *
+ * Returns true if @a == @b, false otherwise.
+ */
+static inline bool tomoyo_same_condition(const struct tomoyo_condition *a,
+ const struct tomoyo_condition *b)
+{
+ return a->size == b->size && a->condc == b->condc &&
+ a->numbers_count == b->numbers_count &&
+ !memcmp(a + 1, b + 1, a->size - sizeof(*a));
+}
+
+/**
+ * tomoyo_condition_type - Get condition type.
+ *
+ * @word: Keyword string.
+ *
+ * Returns one of values in "enum tomoyo_conditions_index" on success,
+ * TOMOYO_MAX_CONDITION_KEYWORD otherwise.
+ */
+static u8 tomoyo_condition_type(const char *word)
+{
+ u8 i;
+ for (i = 0; i < TOMOYO_MAX_CONDITION_KEYWORD; i++) {
+ if (!strcmp(word, tomoyo_condition_keyword[i]))
+ break;
+ }
+ return i;
+}
+
+/* Define this to enable debug mode. */
+/* #define DEBUG_CONDITION */
+
+#ifdef DEBUG_CONDITION
+#define dprintk printk
+#else
+#define dprintk(...) do { } while (0)
+#endif
+
+/**
+ * tomoyo_commit_condition - Commit "struct tomoyo_condition".
+ *
+ * @entry: Pointer to "struct tomoyo_condition".
+ *
+ * Returns pointer to "struct tomoyo_condition" on success, NULL otherwise.
+ *
+ * This function merges duplicated entries. This function returns NULL if
+ * @entry is not duplicated but memory quota for policy has exceeded.
+ */
+static struct tomoyo_condition *tomoyo_commit_condition
+(struct tomoyo_condition *entry)
+{
+ struct tomoyo_condition *ptr;
+ bool found = false;
+ if (mutex_lock_interruptible(&tomoyo_policy_lock)) {
+ dprintk(KERN_WARNING "%u: %s failed\n", __LINE__, __func__);
+ ptr = NULL;
+ found = true;
+ goto out;
+ }
+ list_for_each_entry_rcu(ptr, &tomoyo_condition_list, head.list) {
+ if (!tomoyo_same_condition(ptr, entry))
+ continue;
+ /* Same entry found. Share this entry. */
+ atomic_inc(&ptr->head.users);
+ found = true;
+ break;
+ }
+ if (!found) {
+ if (tomoyo_memory_ok(entry)) {
+ atomic_set(&entry->head.users, 1);
+ list_add_rcu(&entry->head.list,
+ &tomoyo_condition_list);
+ } else {
+ found = true;
+ ptr = NULL;
+ }
+ }
+ mutex_unlock(&tomoyo_policy_lock);
+out:
+ if (found) {
+ tomoyo_del_condition(&entry->head.list);
+ kfree(entry);
+ entry = ptr;
+ }
+ return entry;
+}
+
+/**
+ * tomoyo_get_condition - Parse condition part.
+ *
+ * @param: Pointer to "struct tomoyo_acl_param".
+ *
+ * Returns pointer to "struct tomoyo_condition" on success, NULL otherwise.
+ */
+struct tomoyo_condition *tomoyo_get_condition(struct tomoyo_acl_param *param)
+{
+ struct tomoyo_condition *entry = NULL;
+ struct tomoyo_condition_element *condp = NULL;
+ struct tomoyo_number_union *numbers_p = NULL;
+ struct tomoyo_condition e = { };
+ char * const start_of_string = param->data;
+ char * const end_of_string = start_of_string + strlen(start_of_string);
+ char *pos;
+rerun:
+ pos = start_of_string;
+ while (1) {
+ u8 left = -1;
+ u8 right = -1;
+ char *left_word = pos;
+ char *cp;
+ char *right_word;
+ bool is_not;
+ if (!*left_word)
+ break;
+ /*
+ * Since left-hand condition does not allow use of "path_group"
+ * or "number_group" and environment variable's names do not
+ * accept '=', it is guaranteed that the original line consists
+ * of one or more repetition of $left$operator$right blocks
+ * where "$left is free from '=' and ' '" and "$operator is
+ * either '=' or '!='" and "$right is free from ' '".
+ * Therefore, we can reconstruct the original line at the end
+ * of dry run even if we overwrite $operator with '\0'.
+ */
+ cp = strchr(pos, ' ');
+ if (cp) {
+ *cp = '\0'; /* Will restore later. */
+ pos = cp + 1;
+ } else {
+ pos = "";
+ }
+ right_word = strchr(left_word, '=');
+ if (!right_word || right_word == left_word)
+ goto out;
+ is_not = *(right_word - 1) == '!';
+ if (is_not)
+ *(right_word++ - 1) = '\0'; /* Will restore later. */
+ else if (*(right_word + 1) != '=')
+ *right_word++ = '\0'; /* Will restore later. */
+ else
+ goto out;
+ dprintk(KERN_WARNING "%u: <%s>%s=<%s>\n", __LINE__, left_word,
+ is_not ? "!" : "", right_word);
+ left = tomoyo_condition_type(left_word);
+ dprintk(KERN_WARNING "%u: <%s> left=%u\n", __LINE__, left_word,
+ left);
+ if (left == TOMOYO_MAX_CONDITION_KEYWORD) {
+ if (!numbers_p) {
+ e.numbers_count++;
+ } else {
+ e.numbers_count--;
+ left = TOMOYO_NUMBER_UNION;
+ param->data = left_word;
+ if (*left_word == '@' ||
+ !tomoyo_parse_number_union(param,
+ numbers_p++))
+ goto out;
+ }
+ }
+ if (!condp)
+ e.condc++;
+ else
+ e.condc--;
+ right = tomoyo_condition_type(right_word);
+ if (right == TOMOYO_MAX_CONDITION_KEYWORD) {
+ if (!numbers_p) {
+ e.numbers_count++;
+ } else {
+ e.numbers_count--;
+ right = TOMOYO_NUMBER_UNION;
+ param->data = right_word;
+ if (!tomoyo_parse_number_union(param,
+ numbers_p++))
+ goto out;
+ }
+ }
+ if (!condp) {
+ dprintk(KERN_WARNING "%u: dry_run left=%u right=%u "
+ "match=%u\n", __LINE__, left, right, !is_not);
+ continue;
+ }
+ condp->left = left;
+ condp->right = right;
+ condp->equals = !is_not;
+ dprintk(KERN_WARNING "%u: left=%u right=%u match=%u\n",
+ __LINE__, condp->left, condp->right,
+ condp->equals);
+ condp++;
+ }
+ dprintk(KERN_INFO "%u: cond=%u numbers=%u\n",
+ __LINE__, e.condc, e.numbers_count);
+ if (entry) {
+ BUG_ON(e.numbers_count | e.condc);
+ return tomoyo_commit_condition(entry);
+ }
+ e.size = sizeof(*entry)
+ + e.condc * sizeof(struct tomoyo_condition_element)
+ + e.numbers_count * sizeof(struct tomoyo_number_union);
+ entry = kzalloc(e.size, GFP_NOFS);
+ if (!entry)
+ return NULL;
+ *entry = e;
+ condp = (struct tomoyo_condition_element *) (entry + 1);
+ numbers_p = (struct tomoyo_number_union *) (condp + e.condc);
+ {
+ bool flag = false;
+ for (pos = start_of_string; pos < end_of_string; pos++) {
+ if (*pos)
+ continue;
+ if (flag) /* Restore " ". */
+ *pos = ' ';
+ else if (*(pos + 1) == '=') /* Restore "!=". */
+ *pos = '!';
+ else /* Restore "=". */
+ *pos = '=';
+ flag = !flag;
+ }
+ }
+ goto rerun;
+out:
+ dprintk(KERN_WARNING "%u: %s failed\n", __LINE__, __func__);
+ if (entry) {
+ tomoyo_del_condition(&entry->head.list);
+ kfree(entry);
+ }
+ return NULL;
+}
+
+/**
+ * tomoyo_condition - Check condition part.
+ *
+ * @r: Pointer to "struct tomoyo_request_info".
+ * @cond: Pointer to "struct tomoyo_condition". Maybe NULL.
+ *
+ * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+bool tomoyo_condition(struct tomoyo_request_info *r,
+ const struct tomoyo_condition *cond)
+{
+ u32 i;
+ unsigned long min_v[2] = { 0, 0 };
+ unsigned long max_v[2] = { 0, 0 };
+ const struct tomoyo_condition_element *condp;
+ const struct tomoyo_number_union *numbers_p;
+ u16 condc;
+ if (!cond)
+ return true;
+ condc = cond->condc;
+ condp = (struct tomoyo_condition_element *) (cond + 1);
+ numbers_p = (const struct tomoyo_number_union *) (condp + condc);
+ for (i = 0; i < condc; i++) {
+ const bool match = condp->equals;
+ const u8 left = condp->left;
+ const u8 right = condp->right;
+ u8 j;
+ condp++;
+ /* Check numeric or bit-op expressions. */
+ for (j = 0; j < 2; j++) {
+ const u8 index = j ? right : left;
+ unsigned long value = 0;
+ switch (index) {
+ case TOMOYO_TASK_UID:
+ value = current_uid();
+ break;
+ case TOMOYO_TASK_EUID:
+ value = current_euid();
+ break;
+ case TOMOYO_TASK_SUID:
+ value = current_suid();
+ break;
+ case TOMOYO_TASK_FSUID:
+ value = current_fsuid();
+ break;
+ case TOMOYO_TASK_GID:
+ value = current_gid();
+ break;
+ case TOMOYO_TASK_EGID:
+ value = current_egid();
+ break;
+ case TOMOYO_TASK_SGID:
+ value = current_sgid();
+ break;
+ case TOMOYO_TASK_FSGID:
+ value = current_fsgid();
+ break;
+ case TOMOYO_TASK_PID:
+ value = tomoyo_sys_getpid();
+ break;
+ case TOMOYO_TASK_PPID:
+ value = tomoyo_sys_getppid();
+ break;
+ case TOMOYO_NUMBER_UNION:
+ /* Fetch values later. */
+ break;
+ default:
+ break;
+ }
+ max_v[j] = value;
+ min_v[j] = value;
+ }
+ if (left == TOMOYO_NUMBER_UNION) {
+ /* Fetch values now. */
+ const struct tomoyo_number_union *ptr = numbers_p++;
+ min_v[0] = ptr->values[0];
+ max_v[0] = ptr->values[1];
+ }
+ if (right == TOMOYO_NUMBER_UNION) {
+ /* Fetch values now. */
+ const struct tomoyo_number_union *ptr = numbers_p++;
+ if (ptr->group) {
+ if (tomoyo_number_matches_group(min_v[0],
+ max_v[0],
+ ptr->group)
+ == match)
+ continue;
+ } else {
+ if ((min_v[0] <= ptr->values[1] &&
+ max_v[0] >= ptr->values[0]) == match)
+ continue;
+ }
+ goto out;
+ }
+ /* Normal value range comparison. */
+ if ((min_v[0] <= max_v[1] && max_v[0] >= min_v[1]) == match)
+ continue;
+out:
+ return false;
+ }
+ return true;
+}