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-rw-r--r--system/xen/xen.SlackBuild2
-rw-r--r--system/xen/xsa/xsa226.patch133
-rw-r--r--system/xen/xsa/xsa227.patch52
-rw-r--r--system/xen/xsa/xsa228.patch198
-rw-r--r--system/xen/xsa/xsa230.patch38
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 )
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-23 18:17:31 +0000