/*
* security-core-clr.c: CoreCLR security
*
- * Author:
+ * Authors:
* Mark Probst <mark.probst@gmail.com>
+ * Sebastien Pouliot <sebastien@ximian.com>
*
- * (C) 2007 Novell, Inc
+ * Copyright 2007-2009 Novell, Inc (http://www.novell.com)
*/
#include <mono/metadata/class-internals.h>
#include <mono/metadata/security-manager.h>
#include <mono/metadata/assembly.h>
+#include <mono/metadata/appdomain.h>
+#include <mono/metadata/verify-internals.h>
+#include <mono/metadata/object.h>
+#include <mono/metadata/exception.h>
#include "security-core-clr.h"
return class;
}
-MonoSecurityCoreCLRLevel
+/*
+ * mono_security_core_clr_check_inheritance:
+ *
+ * Determine if the specified class can inherit from its parent using
+ * the CoreCLR inheritance rules.
+ *
+ * Base Type Allow Derived Type
+ * ------------ ------------------
+ * Transparent Transparent, SafeCritical, Critical
+ * SafeCritical SafeCritical, Critical
+ * Critical Critical
+ *
+ * Reference: http://msdn.microsoft.com/en-us/magazine/cc765416.aspx#id0190030
+ */
+void
+mono_security_core_clr_check_inheritance (MonoClass *class)
+{
+ MonoSecurityCoreCLRLevel class_level, parent_level;
+ MonoClass *parent = class->parent;
+
+ if (!parent)
+ return;
+
+ class_level = mono_security_core_clr_class_level (class);
+ parent_level = mono_security_core_clr_class_level (parent);
+
+ if (class_level < parent_level)
+ mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
+}
+
+/*
+ * mono_security_core_clr_check_override:
+ *
+ * Determine if the specified override can "legally" override the
+ * specified base method using the CoreCLR inheritance rules.
+ *
+ * Base (virtual/interface) Allowed override
+ * ------------------------ -------------------------
+ * Transparent Transparent, SafeCritical
+ * SafeCritical Transparent, SafeCritical
+ * Critical Critical
+ *
+ * Reference: http://msdn.microsoft.com/en-us/magazine/cc765416.aspx#id0190030
+ */
+void
+mono_security_core_clr_check_override (MonoClass *class, MonoMethod *override, MonoMethod *base)
+{
+ MonoSecurityCoreCLRLevel base_level = mono_security_core_clr_method_level (base, FALSE);
+ MonoSecurityCoreCLRLevel override_level = mono_security_core_clr_method_level (override, FALSE);
+ /* if the base method is decorated with [SecurityCritical] then the overrided method MUST be too */
+ if (base_level == MONO_SECURITY_CORE_CLR_CRITICAL) {
+ if (override_level != MONO_SECURITY_CORE_CLR_CRITICAL)
+ mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
+ } else {
+ /* base is [SecuritySafeCritical] or [SecurityTransparent], override MUST NOT be [SecurityCritical] */
+ if (override_level == MONO_SECURITY_CORE_CLR_CRITICAL)
+ mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
+ }
+}
+
+/*
+ * get_caller_no_reflection_related:
+ *
+ * Find the first managed caller that is either:
+ * (a) located outside the platform code assemblies; or
+ * (b) not related to reflection and delegates
+ *
+ * Returns TRUE to stop the stackwalk, FALSE to continue to the next frame.
+ */
+static gboolean
+get_caller_no_reflection_related (MonoMethod *m, gint32 no, gint32 ilo, gboolean managed, gpointer data)
+{
+ MonoMethod **dest = data;
+ const char *ns;
+
+ /* skip unmanaged frames */
+ if (!managed)
+ return FALSE;
+
+ if (m->wrapper_type != MONO_WRAPPER_NONE)
+ return FALSE;
+
+ /* quick out (any namespace not starting with an 'S' */
+ ns = m->klass->name_space;
+ if (!ns || (*ns != 'S')) {
+ *dest = m;
+ return TRUE;
+ }
+
+ /* stop if the method is not part of platform code */
+ if (!mono_security_core_clr_is_platform_image (m->klass->image)) {
+ *dest = m;
+ return TRUE;
+ }
+
+ /* any number of calls inside System.Reflection are allowed */
+ if (strcmp (ns, "System.Reflection") == 0)
+ return FALSE;
+
+ /* any number of calls inside System.Reflection are allowed */
+ if (strcmp (ns, "System.Reflection.Emit") == 0)
+ return FALSE;
+
+ /* calls from System.Delegate are also possible and allowed */
+ if (strcmp (ns, "System") == 0) {
+ const char *kname = m->klass->name;
+ if ((*kname == 'A') && (strcmp (kname, "Activator") == 0))
+ return FALSE;
+
+ /* unlike most Invoke* cases InvokeMember is not inside System.Reflection[.Emit] but is SecuritySafeCritical */
+ if (((*kname == 'T') && (strcmp (kname, "Type") == 0)) ||
+ ((*kname == 'M') && (strcmp (kname, "MonoType")) == 0)) {
+
+ /* if calling InvokeMember then we can't stop the stackwalk here and need to look at the caller */
+ if (strcmp (m->name, "InvokeMember") == 0)
+ return FALSE;
+ }
+
+ /* the security check on the delegate is made at creation time, not at invoke time */
+ if (((*kname == 'D') && (strcmp (kname, "Delegate") == 0)) ||
+ ((*kname == 'M') && (strcmp (kname, "MulticastDelegate")) == 0)) {
+
+ /* if we're invoking then we can stop our stack walk */
+ if (strcmp (m->name, "DynamicInvoke") != 0)
+ return FALSE;
+ }
+ }
+
+ if (m == *dest) {
+ *dest = NULL;
+ return FALSE;
+ }
+
+ *dest = m;
+ return TRUE;
+}
+
+/*
+ * get_reflection_caller:
+ *
+ * Walk to the first managed method outside:
+ * - System.Reflection* namespaces
+ * - System.[MulticastDelegate]Delegate or Activator type
+ * - platform code
+ * and return a pointer to its MonoMethod.
+ *
+ * This is required since CoreCLR checks needs to be done on this "real" caller.
+ */
+static MonoMethod*
+get_reflection_caller (void)
+{
+ MonoMethod *m = NULL;
+ mono_stack_walk_no_il (get_caller_no_reflection_related, &m);
+ if (!m)
+ g_warning ("could not find a caller outside reflection");
+ return m;
+}
+
+/*
+ * check_field_access:
+ *
+ * Return TRUE if the caller method can access the specified field, FALSE otherwise.
+ */
+static gboolean
+check_field_access (MonoMethod *caller, MonoClassField *field)
+{
+ /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
+ if (caller) {
+ MonoClass *klass = (mono_field_get_flags (field) & FIELD_ATTRIBUTE_STATIC) ? NULL : mono_field_get_parent (field);
+ return mono_method_can_access_field_full (caller, field, klass);
+ }
+ return FALSE;
+}
+
+/*
+ * check_method_access:
+ *
+ * Return TRUE if the caller method can access the specified callee method, FALSE otherwise.
+ */
+static gboolean
+check_method_access (MonoMethod *caller, MonoMethod *callee)
+{
+ /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
+ if (caller) {
+ MonoClass *klass = (callee->flags & METHOD_ATTRIBUTE_STATIC) ? NULL : callee->klass;
+ return mono_method_can_access_method_full (caller, callee, klass);
+ }
+ return FALSE;
+}
+
+/*
+ * mono_security_core_clr_ensure_reflection_access_field:
+ *
+ * Ensure that the specified field can be used with reflection since
+ * Transparent code cannot access to Critical fields and can only use
+ * them if they are visible from it's point of view.
+ *
+ * A FieldAccessException is thrown if the field is cannot be accessed.
+ */
+void
+mono_security_core_clr_ensure_reflection_access_field (MonoClassField *field)
+{
+ MonoMethod *caller = get_reflection_caller ();
+ /* CoreCLR restrictions applies to Transparent code/caller */
+ if (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)
+ return;
+
+ /* Transparent code cannot [get|set]value on Critical fields */
+ if (mono_security_core_clr_class_level (mono_field_get_parent (field)) == MONO_SECURITY_CORE_CLR_CRITICAL)
+ mono_raise_exception (mono_get_exception_field_access ());
+
+ /* also it cannot access a fields that is not visible from it's (caller) point of view */
+ if (!check_field_access (caller, field))
+ mono_raise_exception (mono_get_exception_field_access ());
+}
+
+/*
+ * mono_security_core_clr_ensure_reflection_access_method:
+ *
+ * Ensure that the specified method can be used with reflection since
+ * Transparent code cannot call Critical methods and can only call them
+ * if they are visible from it's point of view.
+ *
+ * A MethodAccessException is thrown if the field is cannot be accessed.
+ */
+void
+mono_security_core_clr_ensure_reflection_access_method (MonoMethod *method)
+{
+ MonoMethod *caller = get_reflection_caller ();
+ /* CoreCLR restrictions applies to Transparent code/caller */
+ if (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)
+ return;
+
+ /* Transparent code cannot invoke, even using reflection, Critical code */
+ if (mono_security_core_clr_method_level (method, TRUE) == MONO_SECURITY_CORE_CLR_CRITICAL)
+ mono_raise_exception (mono_get_exception_method_access ());
+
+ /* also it cannot invoke a method that is not visible from it's (caller) point of view */
+ if (!check_method_access (caller, method))
+ mono_raise_exception (mono_get_exception_method_access ());
+}
+
+/*
+ * can_avoid_corlib_reflection_delegate_optimization:
+ *
+ * Mono's mscorlib use delegates to optimize PropertyInfo and EventInfo
+ * reflection calls. This requires either a bunch of additional, and not
+ * really required, [SecuritySafeCritical] in the class libraries or
+ * (like this) a way to skip them. As a bonus we also avoid the stack
+ * walk to find the caller.
+ *
+ * Return TRUE if we can skip this "internal" delegate creation, FALSE
+ * otherwise.
+ */
+static gboolean
+can_avoid_corlib_reflection_delegate_optimization (MonoMethod *method)
+{
+ if (!mono_security_core_clr_is_platform_image (method->klass->image))
+ return FALSE;
+
+ if (strcmp (method->klass->name_space, "System.Reflection") != 0)
+ return FALSE;
+
+ if (strcmp (method->klass->name, "MonoProperty") == 0) {
+ if ((strcmp (method->name, "GetterAdapterFrame") == 0) || strcmp (method->name, "StaticGetterAdapterFrame") == 0)
+ return TRUE;
+ } else if (strcmp (method->klass->name, "EventInfo") == 0) {
+ if ((strcmp (method->name, "AddEventFrame") == 0) || strcmp (method->name, "StaticAddEventAdapterFrame") == 0)
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+/*
+ * mono_security_core_clr_ensure_delegate_creation:
+ *
+ * Return TRUE if a delegate can be created on the specified method.
+ * CoreCLR also affect the binding, so throwOnBindFailure must be
+ * FALSE to let this function return (FALSE) normally, otherwise (if
+ * throwOnBindFailure is TRUE) it will throw an ArgumentException.
+ *
+ * A MethodAccessException is thrown if the specified method is not
+ * visible from the caller point of view.
+ */
+gboolean
+mono_security_core_clr_ensure_delegate_creation (MonoMethod *method, gboolean throwOnBindFailure)
+{
+ MonoMethod *caller;
+
+ /* note: mscorlib creates delegates to avoid reflection (optimization), we ignore those cases */
+ if (can_avoid_corlib_reflection_delegate_optimization (method))
+ return TRUE;
+
+ caller = get_reflection_caller ();
+ /* if the "real" caller is not Transparent then it do can anything */
+ if (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)
+ return TRUE;
+
+ /* otherwise it (as a Transparent caller) cannot create a delegate on a Critical method... */
+ if (mono_security_core_clr_method_level (method, TRUE) == MONO_SECURITY_CORE_CLR_CRITICAL) {
+ /* but this throws only if 'throwOnBindFailure' is TRUE */
+ if (!throwOnBindFailure)
+ return FALSE;
+
+ mono_raise_exception (mono_get_exception_argument ("method", "Transparent code cannot call Critical code"));
+ }
+
+ /* also it cannot create the delegate on a method that is not visible from it's (caller) point of view */
+ if (!check_method_access (caller, method))
+ mono_raise_exception (mono_get_exception_method_access ());
+
+ return TRUE;
+}
+
+/*
+ * mono_security_core_clr_ensure_dynamic_method_resolved_object:
+ *
+ * Called from mono_reflection_create_dynamic_method (reflection.c) to add some extra checks required for CoreCLR.
+ * Dynamic methods needs to check to see if the objects being used (e.g. methods, fields) comes from platform code
+ * and do an accessibility check in this case. Otherwise (i.e. user/application code) can be used without this extra
+ * accessbility check.
+ */
+MonoException*
+mono_security_core_clr_ensure_dynamic_method_resolved_object (gpointer ref, MonoClass *handle_class)
+{
+ /* XXX find/create test cases for other handle_class XXX */
+ if (handle_class == mono_defaults.fieldhandle_class) {
+ MonoClassField *field = (MonoClassField*) ref;
+ MonoClass *klass = mono_field_get_parent (field);
+ /* fields coming from platform code have extra protection (accessibility check) */
+ if (mono_security_core_clr_is_platform_image (klass->image)) {
+ MonoMethod *caller = get_reflection_caller ();
+ /* XXX Critical code probably can do this / need some test cases (safer off otherwise) XXX */
+ if (!check_field_access (caller, field))
+ return mono_get_exception_field_access ();
+ }
+ } else if (handle_class == mono_defaults.methodhandle_class) {
+ MonoMethod *method = (MonoMethod*) ref;
+ /* methods coming from platform code have extra protection (accessibility check) */
+ if (mono_security_core_clr_is_platform_image (method->klass->image)) {
+ MonoMethod *caller = get_reflection_caller ();
+ /* XXX Critical code probably can do this / need some test cases (safer off otherwise) XXX */
+ if (!check_method_access (caller, method))
+ return mono_get_exception_method_access ();
+ }
+ }
+ return NULL;
+}
+
+/*
+ * mono_security_core_clr_can_access_internals
+ *
+ * Check if we allow [InternalsVisibleTo] to work between two images.
+ */
+gboolean
+mono_security_core_clr_can_access_internals (MonoImage *accessing, MonoImage* accessed)
+{
+ /* are we trying to access internals of a platform assembly ? if not this is acceptable */
+ if (!mono_security_core_clr_is_platform_image (accessed))
+ return TRUE;
+
+ /* we can't let everyone with the right name and public key token access the internals of platform code.
+ * (Silverlight can rely on the strongname signature of the assemblies, but Mono does not verify them)
+ * However platform code is fully trusted so it can access the internals of other platform code assemblies */
+ if (mono_security_core_clr_is_platform_image (accessing))
+ return TRUE;
+
+ /* catch-22: System.Xml needs access to mscorlib's internals (e.g. ArrayList) but is not considered platform code.
+ * Promoting it to platform code would create another issue since (both Mono/Moonlight or MS version of)
+ * System.Xml.Linq.dll (an SDK, not platform, assembly) needs access to System.Xml.dll internals (either ).
+ * The solution is to trust, even transparent code, in the plugin directory to access platform code internals */
+ return (strcmp (accessed->assembly->basedir, accessing->assembly->basedir) == 0);
+}
+
+/*
+ * mono_security_core_clr_level_from_cinfo:
+ *
+ * Return the MonoSecurityCoreCLRLevel that match the attribute located
+ * in the specified custom attributes. If no attribute is present it
+ * defaults to MONO_SECURITY_CORE_CLR_TRANSPARENT, which is the default
+ * level for all code under the CoreCLR.
+ */
+static MonoSecurityCoreCLRLevel
mono_security_core_clr_level_from_cinfo (MonoCustomAttrInfo *cinfo, MonoImage *image)
{
int level = MONO_SECURITY_CORE_CLR_TRANSPARENT;
- if (!mono_security_core_clr_test && !mono_security_core_clr_is_platform_image (image))
- return level;
-
if (cinfo && mono_custom_attrs_has_attr (cinfo, security_safe_critical_attribute ()))
level = MONO_SECURITY_CORE_CLR_SAFE_CRITICAL;
if (cinfo && mono_custom_attrs_has_attr (cinfo, security_critical_attribute ()))
return level;
}
-MonoSecurityCoreCLRLevel
-mono_security_core_clr_class_level (MonoClass *class)
+/*
+ * mono_security_core_clr_class_level_no_platform_check:
+ *
+ * Return the MonoSecurityCoreCLRLevel for the specified class, without
+ * checking for platform code. This help us avoid multiple redundant
+ * checks, e.g.
+ * - a check for the method and one for the class;
+ * - a check for the class and outer class(es) ...
+ */
+static MonoSecurityCoreCLRLevel
+mono_security_core_clr_class_level_no_platform_check (MonoClass *class)
{
+ MonoSecurityCoreCLRLevel level = MONO_SECURITY_CORE_CLR_TRANSPARENT;
MonoCustomAttrInfo *cinfo = mono_custom_attrs_from_class (class);
- MonoSecurityCoreCLRLevel lvl = mono_security_core_clr_level_from_cinfo (cinfo, class->image);
-
- if (cinfo)
+ if (cinfo) {
+ level = mono_security_core_clr_level_from_cinfo (cinfo, class->image);
mono_custom_attrs_free (cinfo);
+ }
+
+ if (level == MONO_SECURITY_CORE_CLR_TRANSPARENT && class->nested_in)
+ level = mono_security_core_clr_class_level_no_platform_check (class->nested_in);
- if (lvl == MONO_SECURITY_CORE_CLR_TRANSPARENT && class->nested_in)
- return mono_security_core_clr_class_level (class->nested_in);
- else
- return lvl;
+ return level;
}
+/*
+ * mono_security_core_clr_class_level:
+ *
+ * Return the MonoSecurityCoreCLRLevel for the specified class.
+ */
+MonoSecurityCoreCLRLevel
+mono_security_core_clr_class_level (MonoClass *class)
+{
+ /* non-platform code is always Transparent - whatever the attributes says */
+ if (!mono_security_core_clr_test && !mono_security_core_clr_is_platform_image (class->image))
+ return MONO_SECURITY_CORE_CLR_TRANSPARENT;
+
+ return mono_security_core_clr_class_level_no_platform_check (class);
+}
+
+/*
+ * mono_security_core_clr_method_level:
+ *
+ * Return the MonoSecurityCoreCLRLevel for the specified method.
+ * If with_class_level is TRUE then the type (class) will also be
+ * checked, otherwise this will only report the information about
+ * the method itself.
+ */
MonoSecurityCoreCLRLevel
mono_security_core_clr_method_level (MonoMethod *method, gboolean with_class_level)
{
- MonoCustomAttrInfo *cinfo = mono_custom_attrs_from_method (method);
- MonoSecurityCoreCLRLevel level = mono_security_core_clr_level_from_cinfo (cinfo, method->klass->image);
+ MonoCustomAttrInfo *cinfo;
+ MonoSecurityCoreCLRLevel level = MONO_SECURITY_CORE_CLR_TRANSPARENT;
- if (with_class_level && level == MONO_SECURITY_CORE_CLR_TRANSPARENT)
- level = mono_security_core_clr_class_level (method->klass);
+ /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
+ if (!method)
+ return level;
+
+ /* non-platform code is always Transparent - whatever the attributes says */
+ if (!mono_security_core_clr_test && !mono_security_core_clr_is_platform_image (method->klass->image))
+ return level;
- if (cinfo)
+ cinfo = mono_custom_attrs_from_method (method);
+ if (cinfo) {
+ level = mono_security_core_clr_level_from_cinfo (cinfo, method->klass->image);
mono_custom_attrs_free (cinfo);
+ }
+
+ if (with_class_level && level == MONO_SECURITY_CORE_CLR_TRANSPARENT)
+ level = mono_security_core_clr_class_level (method->klass);
return level;
}
+/*
+ * mono_security_core_clr_is_platform_image:
+ *
+ * Return the (cached) boolean value indicating if this image represent platform code
+ */
gboolean
mono_security_core_clr_is_platform_image (MonoImage *image)
{
- const char *prefix = mono_assembly_getrootdir ();
- int prefix_len = strlen (prefix);
- static const char subprefix[] = "/mono/2.1/";
- int subprefix_len = strlen (subprefix);
+ return image->core_clr_platform_code;
+}
- if (!image->name)
- return FALSE;
- if (strncmp (prefix, image->name, prefix_len) != 0)
- return FALSE;
- if (strncmp (subprefix, image->name + prefix_len, subprefix_len) != 0)
- return FALSE;
- if (strchr (image->name + prefix_len + subprefix_len, '/'))
- return FALSE;
- return TRUE;
+/*
+ * default_platform_check:
+ *
+ * Default platform check. Always TRUE for current corlib (minimum
+ * trust-able subset) otherwise return FALSE. Any real CoreCLR host
+ * should provide its own callback to define platform code (i.e.
+ * this default is meant for test only).
+ */
+static gboolean
+default_platform_check (const char *image_name)
+{
+ if (mono_defaults.corlib) {
+ return (strcmp (mono_defaults.corlib->name, image_name) == 0);
+ } else {
+ /* this can get called even before we load corlib (e.g. the EXE itself) */
+ const char *corlib = "mscorlib.dll";
+ int ilen = strlen (image_name);
+ int clen = strlen (corlib);
+ return ((ilen >= clen) && (strcmp ("mscorlib.dll", image_name + ilen - clen) == 0));
+ }
}
+
+static MonoCoreClrPlatformCB platform_callback = default_platform_check;
+
+/*
+ * mono_security_core_clr_determine_platform_image:
+ *
+ * Call the supplied callback (from mono_security_set_core_clr_platform_callback)
+ * to determine if this image represents platform code.
+ */
+gboolean
+mono_security_core_clr_determine_platform_image (MonoImage *image)
+{
+ return platform_callback (image->name);
+}
+
+/*
+ * mono_security_enable_core_clr:
+ *
+ * Enable the verifier and the CoreCLR security model
+ */
+void
+mono_security_enable_core_clr ()
+{
+ mono_verifier_set_mode (MONO_VERIFIER_MODE_VERIFIABLE);
+ mono_security_set_mode (MONO_SECURITY_MODE_CORE_CLR);
+}
+
+/*
+ * mono_security_set_core_clr_platform_callback:
+ *
+ * Set the callback function that will be used to determine if an image
+ * is part, or not, of the platform code.
+ */
+void
+mono_security_set_core_clr_platform_callback (MonoCoreClrPlatformCB callback)
+{
+ platform_callback = callback;
+}
+
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