system/xen: XSA 226-228 and 230 update.

Signed-off-by: Mario Preksavec <mario@slackware.hr>

5 files changed, 422 insertions, 1 deletions

diff --git a/system/xen/xen.SlackBuild b/system/xen/xen.SlackBuild
index 54e278aad4..78a7548e1c 100644
--- a/system/xen/xen.SlackBuild
+++ b/system/xen/xen.SlackBuild
@@ -24,7 +24,7 @@
 
 PRGNAM=xen
 VERSION=${VERSION:-4.9.0}
-BUILD=${BUILD:-1}
+BUILD=${BUILD:-2}
 TAG=${TAG:-_SBo}
 
 SEABIOS=${SEABIOS:-1.10.0}
diff --git a/system/xen/xsa/xsa226.patch b/system/xen/xsa/xsa226.patch
new file mode 100644
index 0000000000..48fae12172
--- /dev/null
+++ b/system/xen/xsa/xsa226.patch
@@ -0,0 +1,133 @@
+From: Andrew Cooper <andrew.cooper3@citrix.com>
+Subject: grant_table: Default to v1, and disallow transitive grants
+
+The reference counting and locking discipline for transitive grants is broken.
+Their use is therefore declared out of security support.
+
+This is XSA-226.
+
+Transitive grants are expected to be unconditionally available with grant
+table v2.  Hiding transitive grants alone is an ABI breakage for the guest.
+Modern versions of Linux and the Windows PV drivers use grant table v1, but
+older versions did use v2.
+
+In principle, disabling gnttab v2 entirely is the safer way to cause guests to
+avoid using transitive grants. However, some older guests which defaulted to
+using gnttab v2 don't tolerate falling back from v2 to v1 over migrate.
+
+This patch introduces a new command line option to control grant table
+behaviour.  One suboption allows a choice of the maximum grant table version
+Xen will allow the guest to use, and defaults to v2.  A different suboption
+independently controls whether transitive grants can be used.
+
+The default case is:
+
+    gnttab=max_ver:2
+
+To disable gnttab v2 entirely, use:
+
+    gnttab=max_ver:1
+
+To allow gnttab v2 and transitive grants, use:
+
+    gnttab=max_ver:2,transitive
+
+Reported-by: Jan Beulich <jbeulich@suse.com>
+Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
+diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
+index 4002eab..af079b4 100644
+--- a/docs/misc/xen-command-line.markdown
++++ b/docs/misc/xen-command-line.markdown
+@@ -868,6 +868,22 @@ Controls EPT related features.
+ 
+ Specify which console gdbstub should use. See **console**.
+ 
++### gnttab
++> `= List of [ max_ver:<integer>, transitive ]`
++
++> Default: `gnttab=max_ver:2,no-transitive`
++
++Control various aspects of the grant table behaviour available to guests.
++
++* `max_ver` Select the maximum grant table version to offer to guests.  Valid
++version are 1 and 2.
++* `transitive` Permit or disallow the use of transitive grants.  Note that the
++use of grant table v2 without transitive grants is an ABI breakage from the
++guests point of view.
++
++*Warning:*
++Due to XSA-226, the use of transitive grants is outside of security support.
++
+ ### gnttab\_max\_frames
+ > `= <integer>`
+ 
+diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
+index ae34547..87131f8 100644
+--- a/xen/common/grant_table.c
++++ b/xen/common/grant_table.c
+@@ -50,6 +50,42 @@ integer_param("gnttab_max_nr_frames", max_nr_grant_frames);
+ unsigned int __read_mostly max_grant_frames;
+ integer_param("gnttab_max_frames", max_grant_frames);
+ 
++static unsigned int __read_mostly opt_gnttab_max_version = 2;
++static bool __read_mostly opt_transitive_grants;
++
++static void __init parse_gnttab(char *s)
++{
++    char *ss;
++
++    do {
++        ss = strchr(s, ',');
++        if ( ss )
++            *ss = '\0';
++
++        if ( !strncmp(s, "max_ver:", 8) )
++        {
++            long ver = simple_strtol(s + 8, NULL, 10);
++
++            if ( ver >= 1 && ver <= 2 )
++                opt_gnttab_max_version = ver;
++        }
++        else
++        {
++            bool val = !!strncmp(s, "no-", 3);
++
++            if ( !val )
++                s += 3;
++
++            if ( !strcmp(s, "transitive") )
++                opt_transitive_grants = val;
++        }
++
++        s = ss + 1;
++    } while ( ss );
++}
++
++custom_param("gnttab", parse_gnttab);
++
+ /* The maximum number of grant mappings is defined as a multiplier of the
+  * maximum number of grant table entries. This defines the multiplier used.
+  * Pretty arbitrary. [POLICY]
+@@ -2191,6 +2227,10 @@ __acquire_grant_for_copy(
+         }
+         else if ( (shah->flags & GTF_type_mask) == GTF_transitive )
+         {
++            if ( !opt_transitive_grants )
++                PIN_FAIL(unlock_out_clear, GNTST_general_error,
++                         "transitive grant disallowed by policy\n");
++
+             if ( !allow_transitive )
+                 PIN_FAIL(unlock_out_clear, GNTST_general_error,
+                          "transitive grant when transitivity not allowed\n");
+@@ -3159,7 +3199,10 @@ do_grant_table_op(
+     }
+     case GNTTABOP_set_version:
+     {
+-        rc = gnttab_set_version(guest_handle_cast(uop, gnttab_set_version_t));
++        if ( opt_gnttab_max_version == 1 )
++            rc = -ENOSYS; /* Behave as before set_version was introduced. */
++        else
++            rc = gnttab_set_version(guest_handle_cast(uop, gnttab_set_version_t));
+         break;
+     }
+     case GNTTABOP_get_status_frames:
diff --git a/system/xen/xsa/xsa227.patch b/system/xen/xsa/xsa227.patch
new file mode 100644
index 0000000000..86aa41e2d4
--- /dev/null
+++ b/system/xen/xsa/xsa227.patch
@@ -0,0 +1,52 @@
+From fa7268b94f8a0a7792ee12d5b8e23a60e52a3a84 Mon Sep 17 00:00:00 2001
+From: Andrew Cooper <andrew.cooper3@citrix.com>
+Date: Tue, 20 Jun 2017 19:18:54 +0100
+Subject: [PATCH] x86/grant: Disallow misaligned PTEs
+
+Pagetable entries must be aligned to function correctly.  Disallow attempts
+from the guest to have a grant PTE created at a misaligned address, which
+would result in corruption of the L1 table with largely-guest-controlled
+values.
+
+This is XSA-227
+
+Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Reviewed-by: Jan Beulich <jbeulich@suse.com>
+---
+ xen/arch/x86/mm.c | 13 +++++++++++++
+ 1 file changed, 13 insertions(+)
+
+diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
+index 97b3b4b..00f517a 100644
+--- a/xen/arch/x86/mm.c
++++ b/xen/arch/x86/mm.c
+@@ -3763,6 +3763,9 @@ static int create_grant_pte_mapping(
+     l1_pgentry_t ol1e;
+     struct domain *d = v->domain;
+ 
++    if ( !IS_ALIGNED(pte_addr, sizeof(nl1e)) )
++        return GNTST_general_error;
++
+     adjust_guest_l1e(nl1e, d);
+ 
+     gmfn = pte_addr >> PAGE_SHIFT;
+@@ -3819,6 +3822,16 @@ static int destroy_grant_pte_mapping(
+     struct page_info *page;
+     l1_pgentry_t ol1e;
+ 
++    /*
++     * addr comes from Xen's active_entry tracking so isn't guest controlled,
++     * but it had still better be PTE-aligned.
++     */
++    if ( !IS_ALIGNED(addr, sizeof(ol1e)) )
++    {
++        ASSERT_UNREACHABLE();
++        return GNTST_general_error;
++    }
++
+     gmfn = addr >> PAGE_SHIFT;
+     page = get_page_from_gfn(d, gmfn, NULL, P2M_ALLOC);
+ 
+-- 
+2.1.4
+
diff --git a/system/xen/xsa/xsa228.patch b/system/xen/xsa/xsa228.patch
new file mode 100644
index 0000000000..65add3a588
--- /dev/null
+++ b/system/xen/xsa/xsa228.patch
@@ -0,0 +1,198 @@
+From 9a52c78eb4ff7836bf7ac9ecd918b289cead1f3f Mon Sep 17 00:00:00 2001
+From: Jan Beulich <jbeulich@suse.com>
+Date: Mon, 31 Jul 2017 15:17:56 +0100
+Subject: [PATCH] gnttab: split maptrack lock to make it fulfill its purpose
+ again
+
+The way the lock is currently being used in get_maptrack_handle(), it
+protects only the maptrack limit: The function acts on current's list
+only, so races on list accesses are impossible even without the lock.
+
+Otoh list access races are possible between __get_maptrack_handle() and
+put_maptrack_handle(), due to the invocation of the former for other
+than current from steal_maptrack_handle(). Introduce a per-vCPU lock
+for list accesses to become race free again. This lock will be
+uncontended except when it becomes necessary to take the steal path,
+i.e. in the common case there should be no meaningful performance
+impact.
+
+When in get_maptrack_handle adds a stolen entry to a fresh, empty,
+freelist, we think that there is probably no concurrency.  However,
+this is not a fast path and adding the locking there makes the code
+clearly correct.
+
+Also, while we are here: the stolen maptrack_entry's tail pointer was
+not properly set.  Set it.
+
+This is XSA-228.
+
+Reported-by: Ian Jackson <ian.jackson@eu.citrix.com>
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
+---
+ docs/misc/grant-tables.txt    |  7 ++++++-
+ xen/common/grant_table.c      | 30 ++++++++++++++++++++++++------
+ xen/include/xen/grant_table.h |  2 +-
+ xen/include/xen/sched.h       |  1 +
+ 4 files changed, 32 insertions(+), 8 deletions(-)
+
+diff --git a/docs/misc/grant-tables.txt b/docs/misc/grant-tables.txt
+index 417ce2d..64da5cf 100644
+--- a/docs/misc/grant-tables.txt
++++ b/docs/misc/grant-tables.txt
+@@ -87,7 +87,8 @@ is complete.
+                                inconsistent grant table state such as current
+                                version, partially initialized active table pages,
+                                etc.
+-  grant_table->maptrack_lock : spinlock used to protect the maptrack free list
++  grant_table->maptrack_lock : spinlock used to protect the maptrack limit
++  v->maptrack_freelist_lock  : spinlock used to protect the maptrack free list
+   active_grant_entry->lock   : spinlock used to serialize modifications to
+                                active entries
+ 
+@@ -102,6 +103,10 @@ is complete.
+  The maptrack free list is protected by its own spinlock. The maptrack
+  lock may be locked while holding the grant table lock.
+ 
++ The maptrack_freelist_lock is an innermost lock.  It may be locked
++ while holding other locks, but no other locks may be acquired within
++ it.
++
+  Active entries are obtained by calling active_entry_acquire(gt, ref).
+  This function returns a pointer to the active entry after locking its
+  spinlock. The caller must hold the grant table read lock before
+diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
+index ae34547..ee33bd8 100644
+--- a/xen/common/grant_table.c
++++ b/xen/common/grant_table.c
+@@ -304,11 +304,16 @@ __get_maptrack_handle(
+ {
+     unsigned int head, next, prev_head;
+ 
++    spin_lock(&v->maptrack_freelist_lock);
++
+     do {
+         /* No maptrack pages allocated for this VCPU yet? */
+         head = read_atomic(&v->maptrack_head);
+         if ( unlikely(head == MAPTRACK_TAIL) )
++        {
++            spin_unlock(&v->maptrack_freelist_lock);
+             return -1;
++        }
+ 
+         /*
+          * Always keep one entry in the free list to make it easier to
+@@ -316,12 +321,17 @@ __get_maptrack_handle(
+          */
+         next = read_atomic(&maptrack_entry(t, head).ref);
+         if ( unlikely(next == MAPTRACK_TAIL) )
++        {
++            spin_unlock(&v->maptrack_freelist_lock);
+             return -1;
++        }
+ 
+         prev_head = head;
+         head = cmpxchg(&v->maptrack_head, prev_head, next);
+     } while ( head != prev_head );
+ 
++    spin_unlock(&v->maptrack_freelist_lock);
++
+     return head;
+ }
+ 
+@@ -380,6 +390,8 @@ put_maptrack_handle(
+     /* 2. Add entry to the tail of the list on the original VCPU. */
+     v = currd->vcpu[maptrack_entry(t, handle).vcpu];
+ 
++    spin_lock(&v->maptrack_freelist_lock);
++
+     cur_tail = read_atomic(&v->maptrack_tail);
+     do {
+         prev_tail = cur_tail;
+@@ -388,6 +400,8 @@ put_maptrack_handle(
+ 
+     /* 3. Update the old tail entry to point to the new entry. */
+     write_atomic(&maptrack_entry(t, prev_tail).ref, handle);
++
++    spin_unlock(&v->maptrack_freelist_lock);
+ }
+ 
+ static inline int
+@@ -411,10 +425,6 @@ get_maptrack_handle(
+      */
+     if ( nr_maptrack_frames(lgt) >= max_maptrack_frames )
+     {
+-        /*
+-         * Can drop the lock since no other VCPU can be adding a new
+-         * frame once they've run out.
+-         */
+         spin_unlock(&lgt->maptrack_lock);
+ 
+         /*
+@@ -426,8 +436,12 @@ get_maptrack_handle(
+             handle = steal_maptrack_handle(lgt, curr);
+             if ( handle == -1 )
+                 return -1;
++            spin_lock(&curr->maptrack_freelist_lock);
++            maptrack_entry(lgt, handle).ref = MAPTRACK_TAIL;
+             curr->maptrack_tail = handle;
+-            write_atomic(&curr->maptrack_head, handle);
++            if ( curr->maptrack_head == MAPTRACK_TAIL )
++                write_atomic(&curr->maptrack_head, handle);
++            spin_unlock(&curr->maptrack_freelist_lock);
+         }
+         return steal_maptrack_handle(lgt, curr);
+     }
+@@ -460,12 +474,15 @@ get_maptrack_handle(
+     smp_wmb();
+     lgt->maptrack_limit += MAPTRACK_PER_PAGE;
+ 
++    spin_unlock(&lgt->maptrack_lock);
++    spin_lock(&curr->maptrack_freelist_lock);
++
+     do {
+         new_mt[i - 1].ref = read_atomic(&curr->maptrack_head);
+         head = cmpxchg(&curr->maptrack_head, new_mt[i - 1].ref, handle + 1);
+     } while ( head != new_mt[i - 1].ref );
+ 
+-    spin_unlock(&lgt->maptrack_lock);
++    spin_unlock(&curr->maptrack_freelist_lock);
+ 
+     return handle;
+ }
+@@ -3475,6 +3492,7 @@ grant_table_destroy(
+ 
+ void grant_table_init_vcpu(struct vcpu *v)
+ {
++    spin_lock_init(&v->maptrack_freelist_lock);
+     v->maptrack_head = MAPTRACK_TAIL;
+     v->maptrack_tail = MAPTRACK_TAIL;
+ }
+diff --git a/xen/include/xen/grant_table.h b/xen/include/xen/grant_table.h
+index 4e77899..100f2b3 100644
+--- a/xen/include/xen/grant_table.h
++++ b/xen/include/xen/grant_table.h
+@@ -78,7 +78,7 @@ struct grant_table {
+     /* Mapping tracking table per vcpu. */
+     struct grant_mapping **maptrack;
+     unsigned int          maptrack_limit;
+-    /* Lock protecting the maptrack page list, head, and limit */
++    /* Lock protecting the maptrack limit */
+     spinlock_t            maptrack_lock;
+     /* The defined versions are 1 and 2.  Set to 0 if we don't know
+        what version to use yet. */
+diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
+index 6673b27..8690f29 100644
+--- a/xen/include/xen/sched.h
++++ b/xen/include/xen/sched.h
+@@ -230,6 +230,7 @@ struct vcpu
+     int              controller_pause_count;
+ 
+     /* Grant table map tracking. */
++    spinlock_t       maptrack_freelist_lock;
+     unsigned int     maptrack_head;
+     unsigned int     maptrack_tail;
+ 
+-- 
+2.1.4
+
diff --git a/system/xen/xsa/xsa230.patch b/system/xen/xsa/xsa230.patch
new file mode 100644
index 0000000000..c3b50c8aaa
--- /dev/null
+++ b/system/xen/xsa/xsa230.patch
@@ -0,0 +1,38 @@
+From: Jan Beulich <jbeulich@suse.com>
+Subject: gnttab: correct pin status fixup for copy
+
+Regardless of copy operations only setting GNTPIN_hst*, GNTPIN_dev*
+also need to be taken into account when deciding whether to clear
+_GTF_{read,writ}ing. At least for consistency with code elsewhere the
+read part better doesn't use any mask at all.
+
+This is XSA-230.
+
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
+diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
+index ae34547..9c9d33c 100644
+--- a/xen/common/grant_table.c
++++ b/xen/common/grant_table.c
+@@ -2107,10 +2107,10 @@ __release_grant_for_copy(
+ static void __fixup_status_for_copy_pin(const struct active_grant_entry *act,
+                                    uint16_t *status)
+ {
+-    if ( !(act->pin & GNTPIN_hstw_mask) )
++    if ( !(act->pin & (GNTPIN_hstw_mask | GNTPIN_devw_mask)) )
+         gnttab_clear_flag(_GTF_writing, status);
+ 
+-    if ( !(act->pin & GNTPIN_hstr_mask) )
++    if ( !act->pin )
+         gnttab_clear_flag(_GTF_reading, status);
+ }
+ 
+@@ -2318,7 +2318,7 @@ __acquire_grant_for_copy(
+  
+  unlock_out_clear:
+     if ( !(readonly) &&
+-         !(act->pin & GNTPIN_hstw_mask) )
++         !(act->pin & (GNTPIN_hstw_mask | GNTPIN_devw_mask)) )
+         gnttab_clear_flag(_GTF_writing, status);
+ 
+     if ( !act->pin )