hooks.c

xen虚拟机源代码安装包

 /*
 *  This file contains the Flask hook function implementations for Xen.
 *
 *  Author:  George Coker, <[e-mail]>
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License version 2,
 *      as published by the Free Software Foundation.
 */

#include <xen/init.h>
#include <xen/lib.h>
#include <xen/sched.h>
#include <xen/xmalloc.h>
#include <xsm/xsm.h>
#include <xen/spinlock.h>
#include <xen/cpumask.h>
#include <xen/errno.h>
#include <xen/guest_access.h>
#include <public/xen.h>
#include <public/physdev.h>
#include <public/platform.h>

#include <public/xsm/flask_op.h>

#include <avc.h>
#include <avc_ss.h>
#include <objsec.h>
#include <conditional.h>

struct xsm_operations *original_ops = NULL;

static int domain_has_perm(struct domain *dom1, struct domain *dom2, 
                                                        u16 class, u32 perms)
{
    struct domain_security_struct *dsec1, *dsec2;

    dsec1 = dom1->ssid;
    dsec2 = dom2->ssid;

    return avc_has_perm(dsec1->sid, dsec2->sid, class, perms, NULL);
}

static int domain_has_evtchn(struct domain *d, struct evtchn *chn, u32 perms)
{
    struct domain_security_struct *dsec;
    struct evtchn_security_struct *esec;

    dsec = d->ssid;
    esec = chn->ssid;

    return avc_has_perm(dsec->sid, esec->sid, SECCLASS_EVENT, perms, NULL);
}

static int domain_has_xen(struct domain *d, u32 perms)
{
    struct domain_security_struct *dsec;
    dsec = d->ssid;

    return avc_has_perm(dsec->sid, SECINITSID_XEN, SECCLASS_XEN, perms, NULL);
}

static int flask_domain_alloc_security(struct domain *d)
{
    struct domain_security_struct *dsec;

    dsec = xmalloc(struct domain_security_struct);

    if ( !dsec )
        return -ENOMEM;

    memset(dsec, 0, sizeof(struct domain_security_struct));

    dsec->d = d;

    if ( d->domain_id == IDLE_DOMAIN_ID )
    {
        dsec->sid = SECINITSID_XEN;
        dsec->create_sid = SECINITSID_DOM0;
    }
    else
    {
        dsec->sid = SECINITSID_UNLABELED;
        dsec->create_sid = SECSID_NULL;
    }

    d->ssid = dsec;

    return 0;
}

static void flask_domain_free_security(struct domain *d)
{
    struct domain_security_struct *dsec = d->ssid;

    if ( !dsec )
        return;

    d->ssid = NULL;
    xfree(dsec);
}

static int flask_evtchn_unbound(struct domain *d1, struct evtchn *chn, 
                                                                    domid_t id2)
{
    u32 newsid;
    int rc;
    domid_t id;
    struct domain *d2;
    struct domain_security_struct *dsec, *dsec1, *dsec2;
    struct evtchn_security_struct *esec;

    dsec = current->domain->ssid;
    dsec1 = d1->ssid;
    esec = chn->ssid;

    if ( id2 == DOMID_SELF )
        id = current->domain->domain_id;
    else
        id = id2;

    d2 = get_domain_by_id(id);
    if ( d2 == NULL )
        return -EPERM;

    dsec2 = d2->ssid;
    rc = security_transition_sid(dsec1->sid, dsec2->sid, SECCLASS_EVENT, 
                                                                    &newsid);
    if ( rc )
        goto out;

    rc = avc_has_perm(dsec->sid, newsid, SECCLASS_EVENT,
                                            EVENT__CREATE|EVENT__ALLOC, NULL);
    if ( rc )
        goto out;

    rc = avc_has_perm(newsid, dsec2->sid, SECCLASS_EVENT, EVENT__BIND, NULL);
    if ( rc )
        goto out;
    else
        esec->sid = newsid;

out:
    put_domain(d2);
    return rc;
}

static int flask_evtchn_interdomain(struct domain *d1, struct evtchn *chn1, 
                                        struct domain *d2, struct evtchn *chn2)
{
    u32 newsid1;
    u32 newsid2;
    int rc;
    struct domain_security_struct *dsec1, *dsec2;
    struct evtchn_security_struct *esec1, *esec2;

    dsec1 = d1->ssid;
    dsec2 = d2->ssid;

    esec1 = chn1->ssid;
    esec2 = chn2->ssid;

    rc = security_transition_sid(dsec1->sid, dsec2->sid, 
                                        SECCLASS_EVENT, &newsid1);
    if ( rc )
    {
        printk("%s: security_transition_sid failed, rc=%d (domain=%d)\n",
                                            __FUNCTION__, -rc, d2->domain_id);
        return rc;
    }

    rc = avc_has_perm(dsec1->sid, newsid1, SECCLASS_EVENT, EVENT__CREATE, NULL);
    if ( rc )
        return rc;

    rc = security_transition_sid(dsec2->sid, dsec1->sid, 
                                        SECCLASS_EVENT, &newsid2);
    if ( rc )
    {
        printk("%s: security_transition_sid failed, rc=%d (domain=%d)\n",
                                            __FUNCTION__, -rc, d1->domain_id);
        return rc;
    }

    rc = avc_has_perm(dsec2->sid, newsid2, SECCLASS_EVENT, EVENT__CREATE, NULL);
    if ( rc )
        return rc;

    rc = avc_has_perm(newsid1, dsec2->sid, SECCLASS_EVENT, EVENT__BIND, NULL);
    if ( rc )
        return rc;

    rc = avc_has_perm(newsid2, dsec1->sid, SECCLASS_EVENT, EVENT__BIND, NULL);
    if ( rc )
        return rc;    

    esec1->sid = newsid1;
    esec2->sid = newsid2;

    return rc;
}

static void flask_evtchn_close_post(struct evtchn *chn)
{
    struct evtchn_security_struct *esec;
    esec = chn->ssid;

    esec->sid = SECINITSID_UNLABELED;
}

static int flask_evtchn_send(struct domain *d, struct evtchn *chn)
{
    return domain_has_evtchn(d, chn, EVENT__SEND);
}

static int flask_evtchn_status(struct domain *d, struct evtchn *chn)
{
    return domain_has_evtchn(d, chn, EVENT__STATUS);
}

static int flask_evtchn_reset(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_EVENT, EVENT__RESET);
}

static int flask_alloc_security_evtchn(struct evtchn *chn)
{
    struct evtchn_security_struct *esec;

    esec = xmalloc(struct evtchn_security_struct);

    if ( !esec )
        return -ENOMEM;

    memset(esec, 0, sizeof(struct evtchn_security_struct));

    esec->chn = chn;
    esec->sid = SECINITSID_UNLABELED;

    chn->ssid = esec;

    return 0;    
}

static void flask_free_security_evtchn(struct evtchn *chn)
{
    struct evtchn_security_struct *esec;

    if ( !chn )
        return;

    esec = chn->ssid;

    if ( !esec )
        return;

    chn->ssid = NULL;
    xfree(esec);
}

static int flask_grant_mapref(struct domain *d1, struct domain *d2, 
                                                                uint32_t flags)
{
    u32 perms = GRANT__MAP_READ;

    if ( flags & GTF_writing )
        perms |= GRANT__MAP_WRITE;

    return domain_has_perm(d1, d2, SECCLASS_GRANT, perms);
}

static int flask_grant_unmapref(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_GRANT, GRANT__UNMAP);
}

static int flask_grant_setup(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_GRANT, GRANT__SETUP);
}

static int flask_grant_transfer(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_GRANT, GRANT__TRANSFER);
}

static int flask_grant_copy(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_GRANT, GRANT__COPY);
}

static int flask_grant_query_size(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_GRANT, GRANT__QUERY);
}

static int get_page_sid(struct page_info *page, u32 *sid)
{
    int rc = 0;
    struct domain *d;
    struct domain_security_struct *dsec;
    unsigned long mfn;

    d = page_get_owner(page);

    if ( d == NULL )
    {
        mfn = page_to_mfn(page);
        rc = security_iomem_sid(mfn, sid);
        return rc;
    }

    switch ( d->domain_id )
    {
        case DOMID_IO:
            /*A tracked IO page?*/
            *sid = SECINITSID_DOMIO;
        break;

        case DOMID_XEN:
            /*A page from Xen's private heap?*/
            *sid = SECINITSID_DOMXEN;
        break;

        default:
            /*Pages are implicitly labeled by domain ownership!*/
            dsec = d->ssid;
            *sid = dsec->sid;
        break;
    }

    return rc;
}

static int get_mfn_sid(unsigned long mfn, u32 *sid)
{
    int rc = 0;
    struct page_info *page;

    if ( mfn_valid(mfn) )
    {
        /*mfn is valid if this is a page that Xen is tracking!*/
        page = mfn_to_page(mfn);        
        rc = get_page_sid(page, sid);
    }
    else
    {
        /*Possibly an untracked IO page?*/
        rc = security_iomem_sid(mfn, sid);
    }

    return rc;    
}

static int flask_translate_gpfn_list(struct domain *d, unsigned long mfn)
{
    int rc = 0;
    u32 sid;
    struct domain_security_struct *dsec;
    dsec = d->ssid;

    rc = get_mfn_sid(mfn, &sid);
    if ( rc )
        return rc;

    return avc_has_perm(dsec->sid, sid, SECCLASS_MMU, MMU__TRANSLATEGP, NULL);
}

static int flask_memory_adjust_reservation(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_MMU, MMU__ADJUST);
}

static int flask_memory_stat_reservation(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_MMU, MMU__STAT);
}

static int flask_memory_pin_page(struct domain *d, struct page_info *page)
{
    int rc = 0;
    u32 sid;
    struct domain_security_struct *dsec;
    dsec = d->ssid;

    rc = get_page_sid(page, &sid);
    if ( rc )
        return rc;

    return avc_has_perm(dsec->sid, sid, SECCLASS_MMU, MMU__PINPAGE, NULL);
}

/* Used to defer flushing of memory structures. */
struct percpu_mm_info {
#define DOP_FLUSH_TLB      (1<<0) /* Flush the local TLB.                    */
#define DOP_FLUSH_ALL_TLBS (1<<1) /* Flush TLBs of all VCPUs of current dom. */
#define DOP_RELOAD_LDT     (1<<2) /* Reload the LDT shadow mapping.          */
    unsigned int   deferred_ops;
    /* If non-NULL, specifies a foreign subject domain for some operations. */
    struct domain *foreign;
};
static DEFINE_PER_CPU(struct percpu_mm_info, percpu_mm_info);

/*
 * Returns the current foreign domain; defaults to the currently-executing
 * domain if a foreign override hasn't been specified.
 */
#define FOREIGNDOM (this_cpu(percpu_mm_info).foreign ?: current->domain)

static int flask_console_io(struct domain *d, int cmd)
{
    u32 perm;

    switch ( cmd )
    {
        case CONSOLEIO_read:
            perm = XEN__READCONSOLE;
        break;
        case CONSOLEIO_write:
            perm = XEN__WRITECONSOLE;
        break;
        default:
            return -EPERM;
    }

    return domain_has_xen(d, perm);
}

static int flask_profile(struct domain *d, int op)
{
    u32 perm;

    switch ( op )
    {
        case XENOPROF_init:
        case XENOPROF_enable_virq:
        case XENOPROF_disable_virq:
        case XENOPROF_get_buffer:
            perm = XEN__NONPRIVPROFILE;
        break;
        case XENOPROF_reset_active_list:
        case XENOPROF_reset_passive_list:
        case XENOPROF_set_active:
        case XENOPROF_set_passive:
        case XENOPROF_reserve_counters:
        case XENOPROF_counter:
        case XENOPROF_setup_events:
        case XENOPROF_start:
        case XENOPROF_stop:
        case XENOPROF_release_counters:
        case XENOPROF_shutdown:
            perm = XEN__PRIVPROFILE;
        break;
        default:
            return -EPERM;
    }

    return domain_has_xen(d, perm);
}

static int flask_kexec(void)
{
    return domain_has_xen(current->domain, XEN__KEXEC);
}

static int flask_schedop_shutdown(struct domain *d1, struct domain *d2)
{
    return domain_has_perm(d1, d2, SECCLASS_DOMAIN, DOMAIN__SHUTDOWN);
}

static void flask_security_domaininfo(struct domain *d, 
                                        struct xen_domctl_getdomaininfo *info)
{
    struct domain_security_struct *dsec;

    dsec = d->ssid;
    info->ssidref = dsec->sid;
}

static int flask_setvcpucontext(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, 
                                                        DOMAIN__SETVCPUCONTEXT);
}

static int flask_pausedomain(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, DOMAIN__PAUSE);
}

static int flask_unpausedomain(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, DOMAIN__UNPAUSE);
}

static int flask_resumedomain(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, DOMAIN__RESUME);
}

static int flask_domain_create(struct domain *d, u32 ssidref)
{
    int rc;
    struct domain_security_struct *dsec1;
    struct domain_security_struct *dsec2;

    dsec1 = current->domain->ssid;

    if ( dsec1->create_sid == SECSID_NULL )
        dsec1->create_sid = ssidref;

    rc = avc_has_perm(dsec1->sid, dsec1->create_sid, SECCLASS_DOMAIN, 
                                                        DOMAIN__CREATE, NULL);
    if ( rc )
    {
        dsec1->create_sid = SECSID_NULL;
        return rc;
    }

    dsec2 = d->ssid;
    dsec2->sid = dsec1->create_sid;

    dsec1->create_sid = SECSID_NULL;
    dsec2->create_sid = SECSID_NULL;

    return rc;
}

static int flask_max_vcpus(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, 
                                                            DOMAIN__MAX_VCPUS);
}

static int flask_destroydomain(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, 
                                                            DOMAIN__DESTROY);
}

static int flask_vcpuaffinity(int cmd, struct domain *d)
{
    u32 perm;

    switch ( cmd )
    {
        case XEN_DOMCTL_setvcpuaffinity:
            perm = DOMAIN__SETVCPUAFFINITY;
        break;
        case XEN_DOMCTL_getvcpuaffinity:
            perm = DOMAIN__GETVCPUAFFINITY;
        break;
        default:
            return -EPERM;
    }

    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, perm );
}

static int flask_scheduler(struct domain *d)
{
    int rc = 0;

    rc = domain_has_xen(current->domain, XEN__SCHEDULER);
    if ( rc )
        return rc;

    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN, 
                                                            DOMAIN__SCHEDULER);
}

static int flask_getdomaininfo(struct domain *d)
{
    return domain_has_perm(current->domain, d, SECCLASS_DOMAIN,
                                                        DOMAIN__GETDOMAININFO);