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[alpine-aports] [PATCH edge] main/xen: security fixes for (XSA-248, XSA-249, XSA-250, XSA-251)

Daniel Sabogal <dsabogalcc@gmail.com>
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<20180120235842.27032-1-dsabogalcc@gmail.com>
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1516492722
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Patch: +308 -1
---
Rebased for edge. These fixes have already been applied to 3.7-stable.
---
 main/xen/APKBUILD     |  15 ++++-
 main/xen/xsa248.patch | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++
 main/xen/xsa249.patch |  42 +++++++++++++
 main/xen/xsa250.patch |  67 +++++++++++++++++++++
 main/xen/xsa251.patch |  21 +++++++
 5 files changed, 308 insertions(+), 1 deletion(-)
 create mode 100644 main/xen/xsa248.patch
 create mode 100644 main/xen/xsa249.patch
 create mode 100644 main/xen/xsa250.patch
 create mode 100644 main/xen/xsa251.patch

diff --git a/main/xen/APKBUILD b/main/xen/APKBUILD
index 64289fb261..b05d25d32d 100644
--- a/main/xen/APKBUILD
+++ b/main/xen/APKBUILD
@@ -3,7 +3,7 @@
# Maintainer: William Pitcock <nenolod@dereferenced.org>
pkgname=xen
pkgver=4.9.1
pkgrel=2
pkgrel=3
pkgdesc="Xen hypervisor"
url="http://www.xen.org/"
arch="x86_64 armhf aarch64"
@@ -103,6 +103,11 @@ options="!strip"
#     - XSA-247
#   4.9.1-r2:
#     - XSA-254 XPTI
#   4.9.1-r3:
#     - XSA-248
#     - XSA-249
#     - XSA-250
#     - XSA-251

case "$CARCH" in
x86*)
@@ -153,6 +158,10 @@ source="https://downloads.xenproject.org/release/$pkgname/$pkgver/$pkgname-$pkgv
	xsa246-4.9.patch
	xsa247-4.9-1.patch
	xsa247-4.9-2.patch
	xsa248.patch
	xsa249.patch
	xsa250.patch
	xsa251.patch

	0001-x86-entry-Remove-support-for-partial-cpu_user_regs-f.patch
	0002-x86-mm-Always-set-_PAGE_ACCESSED-on-L4e-updates.patch
@@ -420,6 +429,10 @@ c2bc9ffc8583aeae71cee9ddcc4418969768d4e3764d47307da54f93981c0109fb07d84b061b3a36
b00f42d2069f273e204698177d2c36950cee759a92dfe7833c812ddff4dedde2c4a842980927ec4fc46d1f54b49879bf3a3681c6faf30b72fb3ad6a7eba060b2  xsa246-4.9.patch
c5e064543048751fda86ce64587493518da87d219ff077abb83ac13d8381ceb29f1b6479fc0b761b8f7a04c8c70203791ac4a8cc79bbc6f4dcfa6661c4790c5e  xsa247-4.9-1.patch
71aefbe27cbd1d1d363b7d5826c69a238e4aad2958a1c6da330ae5daee791f54ce1d01fb79db84ed4248ab8b1593c9c28c3de5108f4d0953b04f7819af23a1d1  xsa247-4.9-2.patch
6415689190b8f4ead7a3482a2285485af4acd4f3565521736f8fe975c74c7c70b27608e0142a7165b4f735b547b688db99a6027697e77b3e1d15c09e14b4f0a6  xsa248.patch
05a2e954bab1877500eb5ed3a8c49edb27411ed3ec9dbfb2115b7804a3b03c6d45c9f08a7ed96ff2b586346f321142065a8c5a5d996468496b373637b6ee31b9  xsa249.patch
b3030f09ddb4f9e4a356519c7b74d393e8db085278a1e616788c81d19988699a6efdd8568277c25514f3298ca92e5a09e3cd08b0a308a4d2ddb55374a8445657  xsa250.patch
928153b48af2bd6b334058c5919880cfc7d665c63e0232932866941cbea6deb8d0d83f70dff0974d3df27fc84096beca51139a0b1c0585978f298256b3fd82eb  xsa251.patch
cda45e5a564e429a1299f07ea496b0e0614f6b2d71a5dcd24f5efdb571cc54d74d04c8e0766279fe2acb7d9bb9cf8505281d6c7ba2d6334009e14a10f83096ee  0001-x86-entry-Remove-support-for-partial-cpu_user_regs-f.patch
bce07e4094ae3036dafdf9fe3aeb1f566281484e1398184d774af9ad371066c0e8af232b8d1ab5d450923fb482e6dea6dfb921976b87b20ab56a3f2b4486d0d4  0002-x86-mm-Always-set-_PAGE_ACCESSED-on-L4e-updates.patch
ba09c54451fae35f3fc70e4f2a76791bc652ad373e87402ebc30c53f8e7db2368d52a9018cc28a5efcbcd77e85c9ae45d9580550f215a3f9bbf63bbd21ef938d  0003-x86-Meltdown-band-aid-against-malicious-64-bit-PV-gu.patch
diff --git a/main/xen/xsa248.patch b/main/xen/xsa248.patch
new file mode 100644
index 0000000000..966c16e043
--- /dev/null
+++ b/main/xen/xsa248.patch
@@ -0,0 +1,164 @@
From: Jan Beulich <jbeulich@suse.com>
Subject: x86/mm: don't wrongly set page ownership

PV domains can obtain mappings of any pages owned by the correct domain,
including ones that aren't actually assigned as "normal" RAM, but used
by Xen internally.  At the moment such "internal" pages marked as owned
by a guest include pages used to track logdirty bits, as well as p2m
pages and the "unpaged pagetable" for HVM guests. Since the PV memory
management and shadow code conflict in their use of struct page_info
fields, and since shadow code is being used for log-dirty handling for
PV domains, pages coming from the shadow pool must, for PV domains, not
have the domain set as their owner.

While the change could be done conditionally for just the PV case in
shadow code, do it unconditionally (and for consistency also for HAP),
just to be on the safe side.

There's one special case though for shadow code: The page table used for
running a HVM guest in unpaged mode is subject to get_page() (in
set_shadow_status()) and hence must have its owner set.

This is XSA-248.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
---
v2: Drop PGC_page_table related pieces.

--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -286,8 +286,7 @@ static struct page_info *hap_alloc_p2m_p
     {
         d->arch.paging.hap.total_pages--;
         d->arch.paging.hap.p2m_pages++;
-        page_set_owner(pg, d);
-        pg->count_info |= 1;
+        ASSERT(!page_get_owner(pg) && !(pg->count_info & PGC_count_mask));
     }
     else if ( !d->arch.paging.p2m_alloc_failed )
     {
@@ -302,21 +301,23 @@ static struct page_info *hap_alloc_p2m_p
 
 static void hap_free_p2m_page(struct domain *d, struct page_info *pg)
 {
+    struct domain *owner = page_get_owner(pg);
+
     /* This is called both from the p2m code (which never holds the 
      * paging lock) and the log-dirty code (which always does). */
     paging_lock_recursive(d);
 
-    ASSERT(page_get_owner(pg) == d);
-    /* Should have just the one ref we gave it in alloc_p2m_page() */
-    if ( (pg->count_info & PGC_count_mask) != 1 ) {
-        HAP_ERROR("Odd p2m page %p count c=%#lx t=%"PRtype_info"\n",
-                     pg, pg->count_info, pg->u.inuse.type_info);
+    /* Should still have no owner and count zero. */
+    if ( owner || (pg->count_info & PGC_count_mask) )
+    {
+        HAP_ERROR("d%d: Odd p2m page %"PRI_mfn" d=%d c=%lx t=%"PRtype_info"\n",
+                  d->domain_id, mfn_x(page_to_mfn(pg)),
+                  owner ? owner->domain_id : DOMID_INVALID,
+                  pg->count_info, pg->u.inuse.type_info);
         WARN();
+        pg->count_info &= ~PGC_count_mask;
+        page_set_owner(pg, NULL);
     }
-    pg->count_info &= ~PGC_count_mask;
-    /* Free should not decrement domain's total allocation, since
-     * these pages were allocated without an owner. */
-    page_set_owner(pg, NULL);
     d->arch.paging.hap.p2m_pages--;
     d->arch.paging.hap.total_pages++;
     hap_free(d, page_to_mfn(pg));
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -1503,32 +1503,29 @@ shadow_alloc_p2m_page(struct domain *d)
     pg = mfn_to_page(shadow_alloc(d, SH_type_p2m_table, 0));
     d->arch.paging.shadow.p2m_pages++;
     d->arch.paging.shadow.total_pages--;
+    ASSERT(!page_get_owner(pg) && !(pg->count_info & PGC_count_mask));
 
     paging_unlock(d);
 
-    /* Unlike shadow pages, mark p2m pages as owned by the domain.
-     * Marking the domain as the owner would normally allow the guest to
-     * create mappings of these pages, but these p2m pages will never be
-     * in the domain's guest-physical address space, and so that is not
-     * believed to be a concern. */
-    page_set_owner(pg, d);
-    pg->count_info |= 1;
     return pg;
 }
 
 static void
 shadow_free_p2m_page(struct domain *d, struct page_info *pg)
 {
-    ASSERT(page_get_owner(pg) == d);
-    /* Should have just the one ref we gave it in alloc_p2m_page() */
-    if ( (pg->count_info & PGC_count_mask) != 1 )
+    struct domain *owner = page_get_owner(pg);
+
+    /* Should still have no owner and count zero. */
+    if ( owner || (pg->count_info & PGC_count_mask) )
     {
-        SHADOW_ERROR("Odd p2m page count c=%#lx t=%"PRtype_info"\n",
+        SHADOW_ERROR("d%d: Odd p2m page %"PRI_mfn" d=%d c=%lx t=%"PRtype_info"\n",
+                     d->domain_id, mfn_x(page_to_mfn(pg)),
+                     owner ? owner->domain_id : DOMID_INVALID,
                      pg->count_info, pg->u.inuse.type_info);
+        pg->count_info &= ~PGC_count_mask;
+        page_set_owner(pg, NULL);
     }
-    pg->count_info &= ~PGC_count_mask;
     pg->u.sh.type = SH_type_p2m_table; /* p2m code reuses type-info */
-    page_set_owner(pg, NULL);
 
     /* This is called both from the p2m code (which never holds the
      * paging lock) and the log-dirty code (which always does). */
@@ -3132,7 +3129,9 @@ int shadow_enable(struct domain *d, u32
         e = __map_domain_page(pg);
         write_32bit_pse_identmap(e);
         unmap_domain_page(e);
+        pg->count_info = 1;
         pg->u.inuse.type_info = PGT_l2_page_table | 1 | PGT_validated;
+        page_set_owner(pg, d);
     }
 
     paging_lock(d);
@@ -3170,7 +3169,11 @@ int shadow_enable(struct domain *d, u32
     if ( rv != 0 && !pagetable_is_null(p2m_get_pagetable(p2m)) )
         p2m_teardown(p2m);
     if ( rv != 0 && pg != NULL )
+    {
+        pg->count_info &= ~PGC_count_mask;
+        page_set_owner(pg, NULL);
         shadow_free_p2m_page(d, pg);
+    }
     domain_unpause(d);
     return rv;
 }
@@ -3279,7 +3282,22 @@ out:
 
     /* Must be called outside the lock */
     if ( unpaged_pagetable )
+    {
+        if ( page_get_owner(unpaged_pagetable) == d &&
+             (unpaged_pagetable->count_info & PGC_count_mask) == 1 )
+        {
+            unpaged_pagetable->count_info &= ~PGC_count_mask;
+            page_set_owner(unpaged_pagetable, NULL);
+        }
+        /* Complain here in cases where shadow_free_p2m_page() won't. */
+        else if ( !page_get_owner(unpaged_pagetable) &&
+                  !(unpaged_pagetable->count_info & PGC_count_mask) )
+            SHADOW_ERROR("d%d: Odd unpaged pt %"PRI_mfn" c=%lx t=%"PRtype_info"\n",
+                         d->domain_id, mfn_x(page_to_mfn(unpaged_pagetable)),
+                         unpaged_pagetable->count_info,
+                         unpaged_pagetable->u.inuse.type_info);
         shadow_free_p2m_page(d, unpaged_pagetable);
+    }
 }
 
 void shadow_final_teardown(struct domain *d)
diff --git a/main/xen/xsa249.patch b/main/xen/xsa249.patch
new file mode 100644
index 0000000000..ecfa4305e5
--- /dev/null
+++ b/main/xen/xsa249.patch
@@ -0,0 +1,42 @@
From: Jan Beulich <jbeulich@suse.com>
Subject: x86/shadow: fix refcount overflow check

Commit c385d27079 ("x86 shadow: for multi-page shadows, explicitly track
the first page") reduced the refcount width to 25, without adjusting the
overflow check. Eliminate the disconnect by using a manifest constant.

Interestingly, up to commit 047782fa01 ("Out-of-sync L1 shadows: OOS
snapshot") the refcount was 27 bits wide, yet the check was already
using 26.

This is XSA-249.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
---
v2: Simplify expression back to the style it was.

--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -529,7 +529,7 @@ static inline int sh_get_ref(struct doma
     x = sp->u.sh.count;
     nx = x + 1;
 
-    if ( unlikely(nx >= 1U<<26) )
+    if ( unlikely(nx >= (1U << PAGE_SH_REFCOUNT_WIDTH)) )
     {
         SHADOW_PRINTK("shadow ref overflow, gmfn=%lx smfn=%lx\n",
                        __backpointer(sp), mfn_x(smfn));
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -82,7 +82,8 @@ struct page_info
             unsigned long type:5;   /* What kind of shadow is this? */
             unsigned long pinned:1; /* Is the shadow pinned? */
             unsigned long head:1;   /* Is this the first page of the shadow? */
-            unsigned long count:25; /* Reference count */
+#define PAGE_SH_REFCOUNT_WIDTH 25
+            unsigned long count:PAGE_SH_REFCOUNT_WIDTH; /* Reference count */
         } sh;
 
         /* Page is on a free list: ((count_info & PGC_count_mask) == 0). */
diff --git a/main/xen/xsa250.patch b/main/xen/xsa250.patch
new file mode 100644
index 0000000000..26aeb33fed
--- /dev/null
+++ b/main/xen/xsa250.patch
@@ -0,0 +1,67 @@
From: Jan Beulich <jbeulich@suse.com>
Subject: x86/shadow: fix ref-counting error handling

The old-Linux handling in shadow_set_l4e() mistakenly ORed together the
results of sh_get_ref() and sh_pin(). As the latter failing is not a
correctness problem, simply ignore its return value.

In sh_set_toplevel_shadow() a failing sh_get_ref() must not be
accompanied by installing the entry, despite the domain being crashed.

This is XSA-250.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>

--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -923,7 +923,7 @@ static int shadow_set_l4e(struct domain
                           shadow_l4e_t new_sl4e,
                           mfn_t sl4mfn)
 {
-    int flags = 0, ok;
+    int flags = 0;
     shadow_l4e_t old_sl4e;
     paddr_t paddr;
     ASSERT(sl4e != NULL);
@@ -938,15 +938,16 @@ static int shadow_set_l4e(struct domain
     {
         /* About to install a new reference */
         mfn_t sl3mfn = shadow_l4e_get_mfn(new_sl4e);
-        ok = sh_get_ref(d, sl3mfn, paddr);
-        /* Are we pinning l3 shadows to handle wierd linux behaviour? */
-        if ( sh_type_is_pinnable(d, SH_type_l3_64_shadow) )
-            ok |= sh_pin(d, sl3mfn);
-        if ( !ok )
+
+        if ( !sh_get_ref(d, sl3mfn, paddr) )
         {
             domain_crash(d);
             return SHADOW_SET_ERROR;
         }
+
+        /* Are we pinning l3 shadows to handle weird Linux behaviour? */
+        if ( sh_type_is_pinnable(d, SH_type_l3_64_shadow) )
+            sh_pin(d, sl3mfn);
     }
 
     /* Write the new entry */
@@ -3965,14 +3966,15 @@ sh_set_toplevel_shadow(struct vcpu *v,
 
     /* Take a ref to this page: it will be released in sh_detach_old_tables()
      * or the next call to set_toplevel_shadow() */
-    if ( !sh_get_ref(d, smfn, 0) )
+    if ( sh_get_ref(d, smfn, 0) )
+        new_entry = pagetable_from_mfn(smfn);
+    else
     {
         SHADOW_ERROR("can't install %#lx as toplevel shadow\n", mfn_x(smfn));
         domain_crash(d);
+        new_entry = pagetable_null();
     }
 
-    new_entry = pagetable_from_mfn(smfn);
-
  install_new_entry:
     /* Done.  Install it */
     SHADOW_PRINTK("%u/%u [%u] gmfn %#"PRI_mfn" smfn %#"PRI_mfn"\n",
diff --git a/main/xen/xsa251.patch b/main/xen/xsa251.patch
new file mode 100644
index 0000000000..582ef622eb
--- /dev/null
+++ b/main/xen/xsa251.patch
@@ -0,0 +1,21 @@
From: Jan Beulich <jbeulich@suse.com>
Subject: x86/paging: don't unconditionally BUG() on finding SHARED_M2P_ENTRY

PV guests can fully control the values written into the P2M.

This is XSA-251.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -274,7 +274,7 @@ void paging_mark_pfn_dirty(struct domain
         return;
 
     /* Shared MFNs should NEVER be marked dirty */
-    BUG_ON(SHARED_M2P(pfn_x(pfn)));
+    BUG_ON(paging_mode_translate(d) && SHARED_M2P(pfn_x(pfn)));
 
     /*
      * Values with the MSB set denote MFNs that aren't really part of the
-- 
2.15.0



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