On Mon, 2011-03-21 at 14:57 -0400, Stephen Smalley wrote:
> This is an attempt to properly fix the hypervisor crash previously
> described in
> http://marc.info/?l=xen-devel&m=128396289707362&w=2
>
> In looking into this issue, I think the proper fix is to move the
> xsm_mmu_* and xsm_update_va_mapping hook calls later in the callers,
> after more validation has been performed and the page_info struct is
> readily available, and pass the page_info to the hooks. This patch moves
> the xsm_mmu_normal_update, xsm_mmu_machphys_update and
> xsm_update_va_mapping hook calls accordingly, and updates their
> interfaces and hook function implementations. This appears to resolve
> the crashes for me. However, as I am not overly familiar with this area
> of code, I'd appreciate any feedback or suggestions for improvement.
>
> Signed-off-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
Zero replies after two postings. Should I retry, abort, or fail?
Seriously though - if there is something wrong with this patch, then let
me know, and if not, can it get applied sometime?
> ---
>
> xen/arch/x86/mm.c | 29 ++++++++++++++++++-----------
> xen/include/xsm/xsm.h | 28 +++++++++++++++-------------
> xen/xsm/dummy.c | 11 ++++++-----
> xen/xsm/flask/hooks.c | 41 ++++++++---------------------------------
> 4 files changed, 47 insertions(+), 62 deletions(-)
>
> diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -3448,9 +3448,6 @@
> {
> p2m_type_t p2mt;
>
> - rc = xsm_mmu_normal_update(d, pg_owner, req.val);
> - if ( rc )
> - break;
> rc = -EINVAL;
>
> req.ptr -= cmd;
> @@ -3478,6 +3475,13 @@
> (unsigned long)(req.ptr & ~PAGE_MASK));
> page = mfn_to_page(mfn);
>
> + rc = xsm_mmu_normal_update(d, req.val, page);
> + if ( rc ) {
> + unmap_domain_page_with_cache(va, &mapcache);
> + put_page(page);
> + break;
> + }
> +
> if ( page_lock(page) )
> {
> switch ( page->u.inuse.type_info & PGT_type_mask )
> @@ -3640,10 +3644,6 @@
> mfn = req.ptr >> PAGE_SHIFT;
> gpfn = req.val;
>
> - rc = xsm_mmu_machphys_update(d, mfn);
> - if ( rc )
> - break;
> -
> if ( unlikely(!get_page_from_pagenr(mfn, pg_owner)) )
> {
> MEM_LOG("Could not get page for mach->phys update");
> @@ -3658,6 +3658,10 @@
> break;
> }
>
> + rc = xsm_mmu_machphys_update(d, mfn_to_page(mfn));
> + if ( rc )
> + break;
> +
> set_gpfn_from_mfn(mfn, gpfn);
>
> paging_mark_dirty(pg_owner, mfn);
> @@ -4272,10 +4276,6 @@
>
> perfc_incr(calls_to_update_va);
>
> - rc = xsm_update_va_mapping(d, pg_owner, val);
> - if ( rc )
> - return rc;
> -
> rc = -EINVAL;
> pl1e = guest_map_l1e(v, va, &gl1mfn);
> if ( unlikely(!pl1e || !get_page_from_pagenr(gl1mfn, d)) )
> @@ -4295,6 +4295,13 @@
> goto out;
> }
>
> + rc = xsm_update_va_mapping(d, val, gl1pg);
> + if ( rc ) {
> + page_unlock(gl1pg);
> + put_page(gl1pg);
> + goto out;
> + }
> +
> rc = mod_l1_entry(pl1e, val, gl1mfn, 0, v, pg_owner);
>
> page_unlock(gl1pg);
> diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
> --- a/xen/include/xsm/xsm.h
> +++ b/xen/include/xsm/xsm.h
> @@ -136,11 +136,12 @@
> int (*getidletime) (void);
> int (*machine_memory_map) (void);
> int (*domain_memory_map) (struct domain *d);
> - int (*mmu_normal_update) (struct domain *d, struct domain *f,
> - intpte_t
> fpte);
> - int (*mmu_machphys_update) (struct domain *d, unsigned long mfn);
> - int (*update_va_mapping) (struct domain *d, struct domain *f,
> - l1_pgentry_t
> pte);
> + int (*mmu_normal_update) (struct domain *d,
> + intpte_t fpte, struct page_info *page);
> + int (*mmu_machphys_update) (struct domain *d, struct page_info *page);
> + int (*update_va_mapping) (struct domain *d,
> + l1_pgentry_t pte,
> + struct page_info *page);
> int (*add_to_physmap) (struct domain *d1, struct domain *d2);
> int (*sendtrigger) (struct domain *d);
> int (*test_assign_device) (uint32_t machine_bdf);
> @@ -567,21 +568,22 @@
> return xsm_call(domain_memory_map(d));
> }
>
> -static inline int xsm_mmu_normal_update (struct domain *d, struct domain *f,
> - intpte_t
> fpte)
> +static inline int xsm_mmu_normal_update (struct domain *d,
> + intpte_t fpte, struct page_info *page)
> {
> - return xsm_call(mmu_normal_update(d, f, fpte));
> + return xsm_call(mmu_normal_update(d, fpte, page));
> }
>
> -static inline int xsm_mmu_machphys_update (struct domain *d, unsigned long
> mfn)
> +static inline int xsm_mmu_machphys_update (struct domain *d, struct
> page_info *page)
> {
> - return xsm_call(mmu_machphys_update(d, mfn));
> + return xsm_call(mmu_machphys_update(d, page));
> }
>
> -static inline int xsm_update_va_mapping(struct domain *d, struct domain *f,
> - l1_pgentry_t pte)
> +static inline int xsm_update_va_mapping(struct domain *d,
> + l1_pgentry_t pte,
> + struct page_info *page)
> {
> - return xsm_call(update_va_mapping(d, f, pte));
> + return xsm_call(update_va_mapping(d, pte, page));
> }
>
> static inline int xsm_add_to_physmap(struct domain *d1, struct domain *d2)
> diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
> --- a/xen/xsm/dummy.c
> +++ b/xen/xsm/dummy.c
> @@ -405,19 +405,20 @@
> return 0;
> }
>
> -static int dummy_mmu_normal_update (struct domain *d, struct domain *f,
> - intpte_t
> fpte)
> +static int dummy_mmu_normal_update (struct domain *d,
> + intpte_t fpte, struct page_info *page)
> {
> return 0;
> }
>
> -static int dummy_mmu_machphys_update (struct domain *d, unsigned long mfn)
> +static int dummy_mmu_machphys_update (struct domain *d, struct page_info
> *page)
> {
> return 0;
> }
>
> -static int dummy_update_va_mapping (struct domain *d, struct domain *f,
> - l1_pgentry_t pte)
> +static int dummy_update_va_mapping (struct domain *d,
> + l1_pgentry_t pte,
> + struct page_info *page)
> {
> return 0;
> }
> diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
> --- a/xen/xsm/flask/hooks.c
> +++ b/xen/xsm/flask/hooks.c
> @@ -347,26 +347,6 @@
> 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_memory_adjust_reservation(struct domain *d1, struct domain
> *d2)
> {
> return domain_has_perm(d1, d2, SECCLASS_MMU, MMU__ADJUST);
> @@ -1006,12 +986,11 @@
> return domain_has_perm(current->domain, d, SECCLASS_MMU, MMU__MEMORYMAP);
> }
>
> -static int flask_mmu_normal_update(struct domain *d, struct domain *f,
> - intpte_t fpte)
> +static int flask_mmu_normal_update(struct domain *d,
> + intpte_t fpte, struct page_info *page)
> {
> int rc = 0;
> u32 map_perms = MMU__MAP_READ;
> - unsigned long fmfn;
> struct domain_security_struct *dsec;
> u32 fsid;
>
> @@ -1020,42 +999,38 @@
> if ( l1e_get_flags(l1e_from_intpte(fpte)) & _PAGE_RW )
> map_perms |= MMU__MAP_WRITE;
>
> - fmfn = gmfn_to_mfn(f, l1e_get_pfn(l1e_from_intpte(fpte)));
> -
> - rc = get_mfn_sid(fmfn, &fsid);
> + rc = get_page_sid(page, &fsid);
> if ( rc )
> return rc;
>
> return avc_has_perm(dsec->sid, fsid, SECCLASS_MMU, map_perms, NULL);
> }
>
> -static int flask_mmu_machphys_update(struct domain *d, unsigned long mfn)
> +static int flask_mmu_machphys_update(struct domain *d, struct page_info
> *page)
> {
> int rc = 0;
> u32 psid;
> struct domain_security_struct *dsec;
> dsec = d->ssid;
>
> - rc = get_mfn_sid(mfn, &psid);
> + rc = get_page_sid(page, &psid);
> if ( rc )
> return rc;
>
> return avc_has_perm(dsec->sid, psid, SECCLASS_MMU, MMU__UPDATEMP, NULL);
> }
>
> -static int flask_update_va_mapping(struct domain *d, struct domain *f,
> - l1_pgentry_t pte)
> +static int flask_update_va_mapping(struct domain *d,
> + l1_pgentry_t pte, struct page_info *page)
> {
> int rc = 0;
> u32 psid;
> u32 map_perms = MMU__MAP_READ;
> - unsigned long mfn;
> struct domain_security_struct *dsec;
>
> dsec = d->ssid;
>
> - mfn = gmfn_to_mfn(f, l1e_get_pfn(pte));
> - rc = get_mfn_sid(mfn, &psid);
> + rc = get_page_sid(page, &psid);
> if ( rc )
> return rc;
>
>
--
Stephen Smalley
National Security Agency
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