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head/emulators/xen-kernel47/files/xsa212.patch
Property | Old Value | New Value |
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fbsd:nokeywords | null | yes \ No newline at end of property |
svn:eol-style | null | native \ No newline at end of property |
svn:mime-type | null | text/plain \ No newline at end of property |
memory: properly check guest memory ranges in XENMEM_exchange handling | |||||
The use of guest_handle_okay() here (as introduced by the XSA-29 fix) | |||||
is insufficient here, guest_handle_subrange_okay() needs to be used | |||||
instead. | |||||
Note that the uses are okay in | |||||
- XENMEM_add_to_physmap_batch handling due to the size field being only | |||||
16 bits wide, | |||||
- livepatch_list() due to the limit of 1024 enforced on the | |||||
number-of-entries input (leaving aside the fact that this can be | |||||
called by a privileged domain only anyway), | |||||
- compat mode handling due to counts there being limited to 32 bits, | |||||
- everywhere else due to guest arrays being accessed sequentially from | |||||
index zero. | |||||
This is XSA-212. | |||||
Reported-by: Jann Horn <jannh@google.com> | |||||
Signed-off-by: Jan Beulich <jbeulich@suse.com> | |||||
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> | |||||
--- a/xen/common/memory.c | |||||
+++ b/xen/common/memory.c | |||||
@@ -436,8 +436,8 @@ static long memory_exchange(XEN_GUEST_HA | |||||
goto fail_early; | |||||
} | |||||
- if ( !guest_handle_okay(exch.in.extent_start, exch.in.nr_extents) || | |||||
- !guest_handle_okay(exch.out.extent_start, exch.out.nr_extents) ) | |||||
+ if ( !guest_handle_subrange_okay(exch.in.extent_start, exch.nr_exchanged, | |||||
+ exch.in.nr_extents - 1) ) | |||||
{ | |||||
rc = -EFAULT; | |||||
goto fail_early; | |||||
@@ -447,11 +447,27 @@ static long memory_exchange(XEN_GUEST_HA | |||||
{ | |||||
in_chunk_order = exch.out.extent_order - exch.in.extent_order; | |||||
out_chunk_order = 0; | |||||
+ | |||||
+ if ( !guest_handle_subrange_okay(exch.out.extent_start, | |||||
+ exch.nr_exchanged >> in_chunk_order, | |||||
+ exch.out.nr_extents - 1) ) | |||||
+ { | |||||
+ rc = -EFAULT; | |||||
+ goto fail_early; | |||||
+ } | |||||
} | |||||
else | |||||
{ | |||||
in_chunk_order = 0; | |||||
out_chunk_order = exch.in.extent_order - exch.out.extent_order; | |||||
+ | |||||
+ if ( !guest_handle_subrange_okay(exch.out.extent_start, | |||||
+ exch.nr_exchanged << out_chunk_order, | |||||
+ exch.out.nr_extents - 1) ) | |||||
+ { | |||||
+ rc = -EFAULT; | |||||
+ goto fail_early; | |||||
+ } | |||||
} | |||||
d = rcu_lock_domain_by_any_id(exch.in.domid); | |||||
--- a/xen/include/asm-x86/x86_64/uaccess.h | |||||
+++ b/xen/include/asm-x86/x86_64/uaccess.h | |||||
@@ -29,8 +29,9 @@ extern void *xlat_malloc(unsigned long * | |||||
/* | |||||
* Valid if in +ve half of 48-bit address space, or above Xen-reserved area. | |||||
* This is also valid for range checks (addr, addr+size). As long as the | |||||
- * start address is outside the Xen-reserved area then we will access a | |||||
- * non-canonical address (and thus fault) before ever reaching VIRT_START. | |||||
+ * start address is outside the Xen-reserved area, sequential accesses | |||||
+ * (starting at addr) will hit a non-canonical address (and thus fault) | |||||
+ * before ever reaching VIRT_START. | |||||
*/ | |||||
#define __addr_ok(addr) \ | |||||
(((unsigned long)(addr) < (1UL<<47)) || \ | |||||
@@ -40,7 +41,8 @@ extern void *xlat_malloc(unsigned long * | |||||
(__addr_ok(addr) || is_compat_arg_xlat_range(addr, size)) | |||||
#define array_access_ok(addr, count, size) \ | |||||
- (access_ok(addr, (count)*(size))) | |||||
+ (likely(((count) ?: 0UL) < (~0UL / (size))) && \ | |||||
+ access_ok(addr, (count) * (size))) | |||||
#define __compat_addr_ok(d, addr) \ | |||||
((unsigned long)(addr) < HYPERVISOR_COMPAT_VIRT_START(d)) |