flask_op.c

xen虚拟机源代码安装包

    u32 sid;
    u32 len;
    int length;

    length = domain_has_security(current->domain, SECURITY__CHECK_CONTEXT);
    if ( length )
        goto out;

    if ( sscanf(buf, "%u", &sid) != 1 )
        goto out;

    length = security_sid_to_context(sid, &context, &len);
    if ( length < 0 )
        goto out;

    memset(buf, 0, count);
    memcpy(buf, context, len);
    length = len;

    xfree(context);

out:
    return length;
}

int flask_disable(void)
{
    static int flask_disabled = 0;

    if ( ss_initialized )
    {
        /* Not permitted after initial policy load. */
        return -EINVAL;
    }

    if ( flask_disabled )
    {
        /* Only do this once. */
        return -EINVAL;
    }

    printk("Flask:  Disabled at runtime.\n");

    flask_disabled = 1;

    /* Reset xsm_ops to the original module. */
    xsm_ops = original_ops;

    return 0;
}

static int flask_security_disable(char *buf, uint32_t count)
{
    int length;
    int new_value;

    length = -EINVAL;
    if ( sscanf(buf, "%d", &new_value) != 1 )
        goto out;

    if ( new_value )
    {
        length = flask_disable();
        if ( length < 0 )
            goto out;
    }

    length = count;

out:
    return length;
}

static int flask_security_setavc_threshold(char *buf, uint32_t count)
{
    int ret;
    int new_value;

    if ( sscanf(buf, "%u", &new_value) != 1 )
    {
        ret = -EINVAL;
        goto out;
    }

    if ( new_value != avc_cache_threshold )
    {
        ret = domain_has_security(current->domain, SECURITY__SETSECPARAM);
        if ( ret )
            goto out;
        avc_cache_threshold = new_value;
    }
    ret = count;

out:
    return ret;
}

static int flask_security_set_bool(char *buf, uint32_t count)
{
    int length = -EFAULT;
    int i, new_value;

    spin_lock(&sel_sem);

    length = domain_has_security(current->domain, SECURITY__SETBOOL);
    if ( length )
        goto out;

    length = -EINVAL;
    if ( sscanf(buf, "%d %d", &i, &new_value) != 2 )
        goto out;

    if ( new_value )
    {
        new_value = 1;
    }

    bool_pending_values[i] = new_value;
    length = count;

out:
    spin_unlock(&sel_sem);
    return length;
}

static int flask_security_commit_bools(char *buf, uint32_t count)
{
    int length = -EFAULT;
    int new_value;

    spin_lock(&sel_sem);

    length = domain_has_security(current->domain, SECURITY__SETBOOL);
    if ( length )
        goto out;

    length = -EINVAL;
    if ( sscanf(buf, "%d", &new_value) != 1 )
        goto out;

    if ( new_value )
        security_set_bools(bool_num, bool_pending_values);
    
    length = count;

out:
    spin_unlock(&sel_sem);
    return length;
}

static int flask_security_get_bool(char *buf, uint32_t count)
{
    int length;
    int i, cur_enforcing;
    
    spin_lock(&sel_sem);
    
    length = -EINVAL;
    if ( sscanf(buf, "%d", &i) != 1 )
        goto out;

    cur_enforcing = security_get_bool_value(i);
    if ( cur_enforcing < 0 )
    {
        length = cur_enforcing;
        goto out;
    }

    memset(buf, 0, count);
    length = snprintf(buf, count, "%d %d", cur_enforcing,
                bool_pending_values[i]);

out:
    spin_unlock(&sel_sem);
    return length;
}

static int flask_security_make_bools(void)
{
    int i, ret = 0;
    char **names = NULL;
    int num;
    int *values = NULL;
    
    xfree(bool_pending_values);
    
    ret = security_get_bools(&num, &names, &values);
    if ( ret != 0 )
        goto out;

    bool_num = num;
    bool_pending_values = values;

out:
    if ( names )
    {
        for ( i = 0; i < num; i++ )
            xfree(names[i]);
        xfree(names);
    }    
    return ret;
}

#ifdef FLASK_AVC_STATS

static int flask_security_avc_cachestats(char *buf, uint32_t count)
{
    char *page = NULL;
    int len = 0;
    int length = 0;
    long long idx = 0;
    int cpu;
    struct avc_cache_stats *st;

    page = (char *)xmalloc_bytes(PAGE_SIZE);
    if ( !page )
        return -ENOMEM;
    memset(page, 0, PAGE_SIZE);

    len = snprintf(page, PAGE_SIZE, "lookups hits misses allocations reclaims "
                                                                   "frees\n");
    if ( len > count ) {
        length = -EINVAL;
        goto out;
    }
    
    memcpy(buf, page, len);
    buf += len;
    length += len;
    count -= len;

    for ( cpu = idx; cpu < NR_CPUS; ++cpu )
    {
        if ( !cpu_possible(cpu) )
            continue;
        idx = cpu + 1;
        st = &per_cpu(avc_cache_stats, cpu);

        len = snprintf(page, PAGE_SIZE, "%u %u %u %u %u %u\n", st->lookups,
                                       st->hits, st->misses, st->allocations,
                                                       st->reclaims, st->frees);
        if ( len > count ) {
            length = -EINVAL;
            goto out;
        }
        memcpy(buf, page, len);
        buf += len;
        length += len;
        count -= len;
    }

out:
    xfree(page);    
    return length;
}

#endif

static int flask_security_load(char *buf, uint32_t count)
{
    int ret;
    int length;

    spin_lock(&sel_sem);

    length = domain_has_security(current->domain, SECURITY__LOAD_POLICY);
    if ( length )
        goto out;

    length = security_load_policy(buf, count);
    if ( length )
        goto out;

    ret = flask_security_make_bools();
    if ( ret )
        length = ret;
    else
        length = count;

out:
    spin_unlock(&sel_sem);
    return length;
}

long do_flask_op(XEN_GUEST_HANDLE(xsm_op_t) u_flask_op)
{
    flask_op_t curop, *op = &curop;
    int rc = 0;
    int length = 0;
    char *arg = NULL;

    if ( copy_from_guest(op, u_flask_op, 1) )
        return -EFAULT;

    if ( op->cmd > FLASK_LAST)
        return -EINVAL;

    if ( op->size > MAX_POLICY_SIZE )
        return -EINVAL;

    if ( (op->buf == NULL && op->size != 0) || 
                                    (op->buf != NULL && op->size == 0) )
        return -EINVAL;

    arg = xmalloc_bytes(op->size + 1);
    if ( !arg )
        return -ENOMEM;

    memset(arg, 0, op->size + 1);

    if ( (FLASK_COPY_IN&(1UL<<op->cmd)) && op->buf != NULL && 
           copy_from_guest(arg, guest_handle_from_ptr(op->buf, char), op->size) )
    {
        rc = -EFAULT;
        goto out;
    }

    switch ( op->cmd )
    {

    case FLASK_LOAD:
    {
        length = flask_security_load(arg, op->size);
    }
    break;
    
    case FLASK_GETENFORCE:
    {
        length = snprintf(arg, op->size, "%d", flask_enforcing);
    }
    break;    

    case FLASK_SETENFORCE:
    {
        length = flask_security_setenforce(arg, op->size);
    }
    break;    

    case FLASK_CONTEXT_TO_SID:
    {
        length = flask_security_context(arg, op->size);
    }
    break;    

    case FLASK_SID_TO_CONTEXT:
    {
        length = flask_security_sid(arg, op->size);
    }
    break; 

    case FLASK_ACCESS:
    {
        length = flask_security_access(arg, op->size);
    }
    break;    

    case FLASK_CREATE:
    {
        length = flask_security_create(arg, op->size);
    }
    break;    

    case FLASK_RELABEL:
    {
        length = flask_security_relabel(arg, op->size);
    }
    break;

    case FLASK_USER:
    {
        length = flask_security_user(arg, op->size);
    }
    break;    

    case FLASK_POLICYVERS:
    {
        length = snprintf(arg, op->size, "%d", POLICYDB_VERSION_MAX);
    }
    break;    

    case FLASK_GETBOOL:
    {
        length = flask_security_get_bool(arg, op->size);
    }
    break;

    case FLASK_SETBOOL:
    {
        length = flask_security_set_bool(arg, op->size);
    }
    break;

    case FLASK_COMMITBOOLS:
    {
        length = flask_security_commit_bools(arg, op->size);
    }
    break;

    case FLASK_MLS:
    {
        length = snprintf(arg, op->size, "%d", flask_mls_enabled);
    }
    break;    

    case FLASK_DISABLE:
    {
        length = flask_security_disable(arg, op->size);
    }
    break;    

    case FLASK_GETAVC_THRESHOLD:
    {
        length = snprintf(arg, op->size, "%d", avc_cache_threshold);
    }
    break;

    case FLASK_SETAVC_THRESHOLD:
    {
        length = flask_security_setavc_threshold(arg, op->size);
    }
    break;

    case FLASK_AVC_HASHSTATS:
    {
        length = avc_get_hash_stats(arg, op->size);
    }
    break;

#ifdef FLASK_AVC_STATS    
    case FLASK_AVC_CACHESTATS:
    {
        length = flask_security_avc_cachestats(arg, op->size);
    }
    break;
#endif

    case FLASK_MEMBER:
    {
        length = flask_security_member(arg, op->size);
    }
    break;    

    default:
        length = -ENOSYS;
        break;

    }

    if ( length < 0 )
    {
        rc = length;
        goto out;
    }
    
    if ( (FLASK_COPY_OUT&(1UL<<op->cmd)) && op->buf != NULL && 
             copy_to_guest(guest_handle_from_ptr(op->buf, char), arg, op->size) )
    {
        rc = -EFAULT;
        goto out;
    }

    op->size = length;
    if ( copy_to_guest(u_flask_op, op, 1) )
        rc = -EFAULT;

out:
    xfree(arg);
    return rc;
}