ccs-patch/fs/tomoyo_signal.c

/*
 * fs/tomoyo_signal.c
 *
 * Implementation of the Domain-Based Mandatory Access Control.
 *
 * Copyright (C) 2005-2007  NTT DATA CORPORATION
 *
 * Version: 1.4.1-rc1   2007/05/20
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */
/***** TOMOYO Linux start. *****/

#include <linux/ccs_common.h>
#include <linux/tomoyo.h>
#include <linux/realpath.h>

/*************************  VARIABLES  *************************/

/* The initial domain. */
extern struct domain_info KERNEL_DOMAIN;

extern struct semaphore domain_acl_lock;

/*************************  AUDIT FUNCTIONS  *************************/

#ifdef CONFIG_TOMOYO_AUDIT
static int AuditSignalLog(const int signal, const struct path_info *dest_domain, const int is_granted)
{
        char *buf;
        int len;
        if (CanSaveAuditLog(is_granted) < 0) return -ENOMEM;
        len = dest_domain->total_len;
        if ((buf = InitAuditLog(&len)) == NULL) return -ENOMEM;
        snprintf(buf + strlen(buf), len - strlen(buf) - 1, KEYWORD_ALLOW_SIGNAL "%d %s\n", signal, dest_domain->name);
        return WriteAuditLog(buf, is_granted);
}
#else
static inline void AuditSignalLog(const int signal, const struct path_info *dest_domain, const int is_granted) {}
#endif

/*************************  SIGNAL ACL HANDLER  *************************/

static int AddSignalEntry(const int sig, const char *dest_pattern, struct domain_info *domain, const u8 is_add, const struct condition_list *condition)
{
        struct acl_info *ptr;
        const struct path_info *saved_dest_pattern;
        const u16 hash = sig;
        int error = -ENOMEM;
        if (!domain) return -EINVAL;
        if (!dest_pattern || !IsCorrectDomain(dest_pattern, __FUNCTION__)) return -EINVAL;
        if ((saved_dest_pattern = SaveName(dest_pattern)) == NULL) return -ENOMEM;
        down(&domain_acl_lock);
        if (is_add) {
                if ((ptr = domain->first_acl_ptr) == NULL) goto first_entry;
                while (1) {
                        struct signal_acl_record *new_ptr;
                        if (ptr->type == TYPE_SIGNAL_ACL && ptr->u.w == hash && ptr->cond == condition) {
                                if (!pathcmp(((struct signal_acl_record *) ptr)->domainname, saved_dest_pattern)) {
                                        ptr->is_deleted = 0;
                                        /* Found. Nothing to do. */
                                        error = 0;
                                        break;
                                }
                        }
                        if (ptr->next) {
                                ptr = ptr->next;
                                continue;
                        }
                first_entry: ;
                        if (is_add == 1 && TooManyDomainACL(domain)) break;
                        /* Not found. Append it to the tail. */
                        if ((new_ptr = alloc_element(sizeof(*new_ptr))) == NULL) break;
                        new_ptr->head.type = TYPE_SIGNAL_ACL;
                        new_ptr->head.u.w = hash;
                        new_ptr->head.cond = condition;
                        new_ptr->domainname = saved_dest_pattern;
                        error = AddDomainACL(ptr, domain, (struct acl_info *) new_ptr);
                        break;
                }
        } else {
                error = -ENOENT;
                for (ptr = domain->first_acl_ptr; ptr; ptr = ptr->next) {
                        if (ptr->type != TYPE_SIGNAL_ACL || ptr->is_deleted || ptr->u.w != hash || ptr->cond != condition) continue;
                        if (pathcmp(((struct signal_acl_record *) ptr)->domainname, saved_dest_pattern)) continue;
                        error = DelDomainACL(ptr);
                        break;
                }
        }
        up(&domain_acl_lock);
        return error;
}

int CheckSignalACL(const int sig, const int pid)
{
        struct domain_info *domain = current->domain_info;
        struct domain_info *dest = NULL;
        const char *dest_pattern;
        struct acl_info *ptr;
        const u16 hash = sig;
        const int is_enforce = CheckCCSEnforce(CCS_TOMOYO_MAC_FOR_SIGNAL);
        if (!CheckCCSFlags(CCS_TOMOYO_MAC_FOR_SIGNAL)) return 0;
        if (!sig) return 0;                               /* No check for NULL signal. */
        if (current->pid == pid) {
                AuditSignalLog(sig, domain->domainname, 1);
                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) dest = p->domain_info;
                read_unlock(&tasklist_lock);
                if (!dest) return 0; /* I can't find destinatioin. */
        }
        if (domain == dest) {
                AuditSignalLog(sig, dest->domainname, 1);
                return 0;
        }
        dest_pattern = dest->domainname->name;
        for (ptr = domain->first_acl_ptr; ptr; ptr = ptr->next) {
                if (ptr->type == TYPE_SIGNAL_ACL && ptr->is_deleted == 0 && ptr->u.w == hash && CheckCondition(ptr->cond, NULL) == 0) {
                        const int len = ((struct signal_acl_record *) ptr)->domainname->total_len;
                        if (strncmp(((struct signal_acl_record *) ptr)->domainname->name, dest_pattern, len) == 0 && (dest_pattern[len] == ' ' || dest_pattern[len] == '\0')) break;
                }
        }
        if (ptr) {
                AuditSignalLog(sig, dest->domainname, 1);
                return 0;
        }
        if (TomoyoVerboseMode()) {
                printk("TOMOYO-%s: Signal %d to %s denied for %s\n", GetMSG(is_enforce), sig, GetLastName(dest), GetLastName(domain));
        }
        AuditSignalLog(sig, dest->domainname, 0);
        if (is_enforce) return CheckSupervisor("%s\n" KEYWORD_ALLOW_SIGNAL "%d %s\n", domain->domainname->name, sig, dest_pattern);
        if (CheckCCSAccept(CCS_TOMOYO_MAC_FOR_SIGNAL)) AddSignalEntry(sig, dest_pattern, domain, 1, NULL);
        return 0;
}
EXPORT_SYMBOL(CheckSignalACL);

int AddSignalPolicy(char *data, struct domain_info *domain, const int is_delete)
{
        int sig;
        char *domainname = strchr(data, ' ');
        if (sscanf(data, "%d", &sig) == 1 && domainname && IsDomainDef(domainname + 1)) {
                const struct condition_list *condition = NULL;
                const char *cp = FindConditionPart(domainname + 1);
                if (cp && (condition = FindOrAssignNewCondition(cp)) == NULL) return -EINVAL;
                return AddSignalEntry(sig, domainname + 1, domain, is_delete ? 0 : -1, condition);
        }
        return -EINVAL;
}

/***** TOMOYO Linux end. *****/