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From: "Jan Beulich" <JBeulich@suse.com>
To: xen-devel <xen-devel@lists.xenproject.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>
Subject: [PATCH 1/2] HVM: sanitize DOMCTL_gethvmcontext_partial handling
Date: Wed, 31 May 2017 01:24:52 -0600	[thread overview]
Message-ID: <592E8BE4020000780015DFD0@prv-mh.provo.novell.com> (raw)
In-Reply-To: <592E8AB8020000780015DFA8@prv-mh.provo.novell.com>

[-- Attachment #1: Type: text/plain, Size: 4465 bytes --]

Have the caller indicate its buffer size, provide a means to query the
needed size, don't ignore the upper halves of type code and instance,
and don't copy partial data.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -496,6 +496,7 @@ int xc_domain_hvm_getcontext_partial(xc_
     domctl.domain = (domid_t) domid;
     domctl.u.hvmcontext_partial.type = typecode;
     domctl.u.hvmcontext_partial.instance = instance;
+    domctl.u.hvmcontext_partial.bufsz = size;
     set_xen_guest_handle(domctl.u.hvmcontext_partial.buffer, ctxt_buf);
 
     ret = do_domctl(xch, &domctl);
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -590,8 +590,12 @@ long arch_do_domctl(
         domain_pause(d);
         ret = hvm_save_one(d, domctl->u.hvmcontext_partial.type,
                            domctl->u.hvmcontext_partial.instance,
-                           domctl->u.hvmcontext_partial.buffer);
+                           domctl->u.hvmcontext_partial.buffer,
+                           &domctl->u.hvmcontext_partial.bufsz);
         domain_unpause(d);
+
+        if ( !ret )
+            copyback = true;
         break;
 
     case XEN_DOMCTL_set_address_size:
--- a/xen/common/hvm/save.c
+++ b/xen/common/hvm/save.c
@@ -76,8 +76,8 @@ size_t hvm_save_size(struct domain *d)
 
 /* Extract a single instance of a save record, by marshalling all
  * records of that type and copying out the one we need. */
-int hvm_save_one(struct domain *d, uint16_t typecode, uint16_t instance, 
-                 XEN_GUEST_HANDLE_64(uint8) handle)
+int hvm_save_one(struct domain *d, unsigned int typecode, unsigned int instance,
+                 XEN_GUEST_HANDLE_64(uint8) handle, uint64_t *bufsz)
 {
     int rv = -ENOENT;
     size_t sz = 0;
@@ -117,16 +117,20 @@ int hvm_save_one(struct domain *d, uint1
             desc = (void *)(ctxt.data + off);
             /* Move past header */
             off += sizeof(*desc);
+            if ( ctxt.cur < desc->length ||
+                 off > ctxt.cur - desc->length )
+                break;
             if ( instance == desc->instance )
             {
-                uint32_t copy_length = desc->length;
-
-                if ( ctxt.cur < copy_length ||
-                     off > ctxt.cur - copy_length )
-                    copy_length = ctxt.cur - off;
                 rv = 0;
-                if ( copy_to_guest(handle, ctxt.data + off, copy_length) )
+                if ( guest_handle_is_null(handle) )
+                    *bufsz = desc->length;
+                else if ( *bufsz < desc->length )
+                    rv = -ENOBUFS;
+                else if ( copy_to_guest(handle, ctxt.data + off, desc->length) )
                     rv = -EFAULT;
+                else
+                    *bufsz = desc->length;
                 break;
             }
         }
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -37,7 +37,7 @@
 #include "hvm/save.h"
 #include "memory.h"
 
-#define XEN_DOMCTL_INTERFACE_VERSION 0x0000000d
+#define XEN_DOMCTL_INTERFACE_VERSION 0x0000000e
 
 /*
  * NB. xen_domctl.domain is an IN/OUT parameter for this operation.
@@ -747,6 +747,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_debug
 typedef struct xen_domctl_hvmcontext_partial {
     uint32_t type;                      /* IN: Type of record required */
     uint32_t instance;                  /* IN: Instance of that type */
+    uint64_aligned_t bufsz;             /* IN: size of buffer */
     XEN_GUEST_HANDLE_64(uint8) buffer;  /* OUT: buffer to write record into */
 } xen_domctl_hvmcontext_partial_t;
 DEFINE_XEN_GUEST_HANDLE(xen_domctl_hvmcontext_partial_t);
--- a/xen/include/xen/hvm/save.h
+++ b/xen/include/xen/hvm/save.h
@@ -132,8 +132,8 @@ __initcall(__hvm_register_##_x##_save_an
 /* Entry points for saving and restoring HVM domain state */
 size_t hvm_save_size(struct domain *d);
 int hvm_save(struct domain *d, hvm_domain_context_t *h);
-int hvm_save_one(struct domain *d,  uint16_t typecode, uint16_t instance, 
-                 XEN_GUEST_HANDLE_64(uint8) handle);
+int hvm_save_one(struct domain *d, unsigned int typecode, unsigned int instance,
+                 XEN_GUEST_HANDLE_64(uint8) handle, uint64_t *bufsz);
 int hvm_load(struct domain *d, hvm_domain_context_t *h);
 
 /* Arch-specific definitions. */



[-- Attachment #2: HVM-save-one-inputs.patch --]
[-- Type: text/plain, Size: 4516 bytes --]

HVM: sanitize DOMCTL_gethvmcontext_partial handling

Have the caller indicate its buffer size, provide a means to query the
needed size, don't ignore the upper halves of type code and instance,
and don't copy partial data.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -496,6 +496,7 @@ int xc_domain_hvm_getcontext_partial(xc_
     domctl.domain = (domid_t) domid;
     domctl.u.hvmcontext_partial.type = typecode;
     domctl.u.hvmcontext_partial.instance = instance;
+    domctl.u.hvmcontext_partial.bufsz = size;
     set_xen_guest_handle(domctl.u.hvmcontext_partial.buffer, ctxt_buf);
 
     ret = do_domctl(xch, &domctl);
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -590,8 +590,12 @@ long arch_do_domctl(
         domain_pause(d);
         ret = hvm_save_one(d, domctl->u.hvmcontext_partial.type,
                            domctl->u.hvmcontext_partial.instance,
-                           domctl->u.hvmcontext_partial.buffer);
+                           domctl->u.hvmcontext_partial.buffer,
+                           &domctl->u.hvmcontext_partial.bufsz);
         domain_unpause(d);
+
+        if ( !ret )
+            copyback = true;
         break;
 
     case XEN_DOMCTL_set_address_size:
--- a/xen/common/hvm/save.c
+++ b/xen/common/hvm/save.c
@@ -76,8 +76,8 @@ size_t hvm_save_size(struct domain *d)
 
 /* Extract a single instance of a save record, by marshalling all
  * records of that type and copying out the one we need. */
-int hvm_save_one(struct domain *d, uint16_t typecode, uint16_t instance, 
-                 XEN_GUEST_HANDLE_64(uint8) handle)
+int hvm_save_one(struct domain *d, unsigned int typecode, unsigned int instance,
+                 XEN_GUEST_HANDLE_64(uint8) handle, uint64_t *bufsz)
 {
     int rv = -ENOENT;
     size_t sz = 0;
@@ -117,16 +117,20 @@ int hvm_save_one(struct domain *d, uint1
             desc = (void *)(ctxt.data + off);
             /* Move past header */
             off += sizeof(*desc);
+            if ( ctxt.cur < desc->length ||
+                 off > ctxt.cur - desc->length )
+                break;
             if ( instance == desc->instance )
             {
-                uint32_t copy_length = desc->length;
-
-                if ( ctxt.cur < copy_length ||
-                     off > ctxt.cur - copy_length )
-                    copy_length = ctxt.cur - off;
                 rv = 0;
-                if ( copy_to_guest(handle, ctxt.data + off, copy_length) )
+                if ( guest_handle_is_null(handle) )
+                    *bufsz = desc->length;
+                else if ( *bufsz < desc->length )
+                    rv = -ENOBUFS;
+                else if ( copy_to_guest(handle, ctxt.data + off, desc->length) )
                     rv = -EFAULT;
+                else
+                    *bufsz = desc->length;
                 break;
             }
         }
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -37,7 +37,7 @@
 #include "hvm/save.h"
 #include "memory.h"
 
-#define XEN_DOMCTL_INTERFACE_VERSION 0x0000000d
+#define XEN_DOMCTL_INTERFACE_VERSION 0x0000000e
 
 /*
  * NB. xen_domctl.domain is an IN/OUT parameter for this operation.
@@ -747,6 +747,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_debug
 typedef struct xen_domctl_hvmcontext_partial {
     uint32_t type;                      /* IN: Type of record required */
     uint32_t instance;                  /* IN: Instance of that type */
+    uint64_aligned_t bufsz;             /* IN: size of buffer */
     XEN_GUEST_HANDLE_64(uint8) buffer;  /* OUT: buffer to write record into */
 } xen_domctl_hvmcontext_partial_t;
 DEFINE_XEN_GUEST_HANDLE(xen_domctl_hvmcontext_partial_t);
--- a/xen/include/xen/hvm/save.h
+++ b/xen/include/xen/hvm/save.h
@@ -132,8 +132,8 @@ __initcall(__hvm_register_##_x##_save_an
 /* Entry points for saving and restoring HVM domain state */
 size_t hvm_save_size(struct domain *d);
 int hvm_save(struct domain *d, hvm_domain_context_t *h);
-int hvm_save_one(struct domain *d,  uint16_t typecode, uint16_t instance, 
-                 XEN_GUEST_HANDLE_64(uint8) handle);
+int hvm_save_one(struct domain *d, unsigned int typecode, unsigned int instance,
+                 XEN_GUEST_HANDLE_64(uint8) handle, uint64_t *bufsz);
 int hvm_load(struct domain *d, hvm_domain_context_t *h);
 
 /* Arch-specific definitions. */

[-- Attachment #3: Type: text/plain, Size: 127 bytes --]

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  reply	other threads:[~2017-05-31  7:24 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-31  7:19 [PATCH 0/2] hvm/save: cleanup Jan Beulich
2017-05-31  7:24 ` Jan Beulich [this message]
2017-05-31 12:11   ` [PATCH 1/2] HVM: sanitize DOMCTL_gethvmcontext_partial handling Wei Liu
2017-05-31  7:25 ` [PATCH 2/2] HVM: clean up hvm_save_one() Jan Beulich
2017-06-06 17:52   ` Wei Liu
2017-06-07 10:07     ` Jan Beulich
2017-06-07 10:29       ` Wei Liu
2017-06-07 10:39         ` Jan Beulich
2017-06-06 15:49 ` Ping: [PATCH 0/2] hvm/save: cleanup Jan Beulich

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