Signal control functions for TOMOYO Linux.
TOMOYO Linux checks sending signal by signal number and
the domain of target process. In order to check signal
permission, LSM expansion patch [TOMOYO 14/15] is needed.
Each permission can be automatically accumulated into
the policy of each domain using 'learning mode'.
Signed-off-by: Kentaro Takeda <[email protected]>
Signed-off-by: Tetsuo Handa <[email protected]>
---
security/tomoyo/signal.c | 229 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 229 insertions(+)
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/security/tomoyo/signal.c 2007-10-02 11:26:22.000000000 +0900
@@ -0,0 +1,229 @@
+/*
+ * security/tomoyo/signal.c
+ *
+ * Signal access contol functions for TOMOYO Linux.
+ */
+
+#include "tomoyo.h"
+#include "realpath.h"
+
+/************************* AUDIT FUNCTIONS *************************/
+
+static int tmy_audit_signal_log(const int signal,
+ const struct path_info *dest_domain,
+ const u8 is_granted,
+ const u8 is_enforce)
+{
+ char *buf;
+ int len;
+
+ if (is_granted) {
+ if (!tmy_audit_grant())
+ return 0;
+ } else {
+ if (!tmy_audit_reject())
+ return 0;
+ }
+
+ len = dest_domain->total_len;
+ buf = tmy_init_audit_log(&len);
+
+ if (!buf)
+ return -ENOMEM;
+
+ snprintf(buf + strlen(buf),
+ len - strlen(buf) - 1,
+ "%s%d %s",
+ TMY_ALLOW_SIGNAL, signal, dest_domain->name);
+
+ return tmy_write_audit_log(buf, is_granted, is_enforce);
+}
+
+/************************* SIGNAL ACL HANDLER *************************/
+
+static int tmy_add_signal_entry(const u16 sig, const char *dest_pattern,
+ struct domain_info *domain,
+ const struct condition_list *cond,
+ const u8 is_delete)
+{
+ struct acl_info *ptr;
+ const struct path_info *saved_dest_pattern;
+ int error = -ENOMEM;
+
+ if (!domain)
+ return -EINVAL;
+ if (!dest_pattern ||
+ !tmy_is_correct_domain(dest_pattern, __FUNCTION__))
+ return -EINVAL;
+
+ saved_dest_pattern = tmy_save_name(dest_pattern);
+ if (!saved_dest_pattern)
+ return -ENOMEM;
+
+ down(&domain_acl_lock);
+
+ if (is_delete)
+ goto remove;
+
+ ptr = domain->first_acl_ptr;
+ if (!ptr)
+ goto first_entry;
+
+ while (1) {
+ struct signal_acl *acl = (struct signal_acl *) ptr;
+
+ if (ptr->type == TMY_TYPE_SIGNAL_ACL && acl->sig == sig
+ && ptr->cond == cond
+ && !tmy_pathcmp(acl->domainname, saved_dest_pattern)) {
+ ptr->is_deleted = 0;
+ /* Found. Nothing to do. */
+ error = 0;
+ break;
+ }
+
+ if (ptr->next) {
+ ptr = ptr->next;
+ continue;
+ }
+
+first_entry: ;
+ /* Not found. Append it to the tail. */
+ acl = tmy_alloc_element(sizeof(*acl));
+ if (!acl)
+ break;
+
+ acl->head.type = TMY_TYPE_SIGNAL_ACL;
+ acl->head.cond = cond;
+ acl->sig = sig;
+ acl->domainname = saved_dest_pattern;
+ error = tmy_add_acl(ptr, domain, (struct acl_info *) acl);
+ break;
+ }
+ goto ok;
+remove: ;
+ error = -ENOENT;
+ for (ptr = domain->first_acl_ptr; ptr; ptr = ptr->next) {
+ struct signal_acl *acl = (struct signal_acl *) ptr;
+ if (ptr->type != TMY_TYPE_SIGNAL_ACL || ptr->cond != cond ||
+ ptr->is_deleted || acl->sig != sig ||
+ tmy_pathcmp(acl->domainname, saved_dest_pattern))
+ continue;
+ error = tmy_del_acl(ptr);
+ break;
+ }
+
+ok: ;
+ up(&domain_acl_lock);
+
+ return error;
+}
+
+/**
+ * tmy_signal_acl - check permission for kill(2)/tkill(2)/tgkill(2).
+ * @sig: signal number.
+ * @pid: pid of destination process.
+ *
+ * Returns zero if permission granted.
+ * Returns nonzero if permission denied.
+ */
+int tmy_signal_acl(const int sig, const int pid)
+{
+ struct domain_info *domain = TMY_SECURITY->domain;
+ struct domain_info *dest = NULL;
+ const char *dest_pattern;
+ struct acl_info *ptr;
+ const u16 hash = sig;
+ const u8 is_enforce = tmy_enforce(TMY_MAC_FOR_SIGNAL);
+
+ if (!tmy_flags(TMY_MAC_FOR_SIGNAL))
+ return 0;
+ if (!sig)
+ return 0; /* No check for NULL signal. */
+ if (current->pid == pid) {
+ tmy_audit_signal_log(sig, domain->domainname, 1, is_enforce);
+ return 0; /* No check for self. */
+ }
+
+ { /* Simplified checking. */
+ struct task_struct *p = NULL;
+ read_lock(&tasklist_lock);
+ if (pid > 0)
+ p = find_task_by_pid((pid_t) pid);
+ else if (pid == 0)
+ p = current;
+ else if (pid == -1)
+ dest = &KERNEL_DOMAIN;
+ else
+ p = find_task_by_pid((pid_t) -pid);
+ if (p)
+ /* "struct task_struct"->security is not NULL. */
+ dest = ((struct tmy_security *) p->security)->domain;
+ read_unlock(&tasklist_lock);
+ if (!dest)
+ return 0; /* I can't find destinatioin. */
+ }
+
+ if (domain == dest) {
+ tmy_audit_signal_log(sig, dest->domainname, 1, is_enforce);
+ return 0;
+ }
+
+ dest_pattern = dest->domainname->name;
+ for (ptr = domain->first_acl_ptr; ptr; ptr = ptr->next) {
+ struct signal_acl *acl = (struct signal_acl *) ptr;
+
+ if (ptr->type == TMY_TYPE_SIGNAL_ACL && ptr->is_deleted == 0
+ && acl->sig == hash &&
+ tmy_check_condition(ptr->cond, NULL) == 0) {
+ const int len = acl->domainname->total_len;
+
+ if (strncmp(acl->domainname->name,
+ dest_pattern, len) == 0
+ && (dest_pattern[len] == ' ' ||
+ dest_pattern[len] == '\0'))
+ break;
+
+ }
+ }
+
+ if (ptr) {
+ tmy_audit_signal_log(sig, dest->domainname, 1, is_enforce);
+ return 0;
+ }
+
+ tmy_audit_signal_log(sig, dest->domainname, 0, is_enforce);
+ if (is_enforce)
+ return tmy_supervisor("%s\n" TMY_ALLOW_SIGNAL "%d %s\n",
+ domain->domainname->name,
+ sig, dest_pattern);
+ if (tmy_accept(TMY_MAC_FOR_SIGNAL, domain))
+ tmy_add_signal_entry(sig, dest_pattern, domain, NULL, 0);
+
+ return 0;
+}
+
+/**
+ * tmy_add_signal_policy - add or delete signal policy.
+ * @data: a line to parse.
+ * @domain: pointer to "struct domain_info".
+ * @cond: pointer to "struct condition_list". May be NULL.
+ * @is_delete: is this delete request?
+ *
+ * Returns zero on success.
+ * Returns nonzero on failure.
+ */
+int tmy_add_signal_policy(char *data,
+ struct domain_info *domain,
+ const struct condition_list *cond,
+ const u8 is_delete)
+{
+ int sig;
+ char *domainname = strchr(data, ' ');
+
+ if (sscanf(data, "%d", &sig) == 1 && domainname &&
+ tmy_is_domain_def(domainname + 1))
+ return tmy_add_signal_entry(sig, domainname + 1, domain,
+ cond, is_delete);
+
+ return -EINVAL;
+}
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