/* * security-core-clr.c: CoreCLR security * * Authors: * Mark Probst * Sebastien Pouliot * * Copyright 2007-2010 Novell, Inc (http://www.novell.com) */ #include #include #include #include #include #include #include #include #include #include "security-core-clr.h" gboolean mono_security_core_clr_test = FALSE; static MonoSecurityCoreCLROptions security_core_clr_options = MONO_SECURITY_CORE_CLR_OPTIONS_DEFAULT; /** * mono_security_core_clr_set_options: * @options: the new options for the coreclr system to use * * By default, the CoreCLRs security model forbids execution trough reflection of methods not visible from the calling code. * Even if the method being called is not in a platform assembly. For non moonlight CoreCLR users this restriction does not * make a lot of sense, since the author could have just changed the non platform assembly to allow the method to be called. * This function allows specific relaxations from the default behaviour to be set. * * Use MONO_SECURITY_CORE_CLR_OPTIONS_DEFAULT for the default coreclr coreclr behaviour as used in Moonlight. * * Use MONO_SECURITY_CORE_CLR_OPTIONS_RELAX_REFLECTION to allow transparent code to execute methods and access * fields that are not in platformcode, even if those methods and fields are private or otherwise not visible to the calling code. * * Use MONO_SECURITY_CORE_CLR_OPTIONS_RELAX_DELEGATE to allow delegates to be created that point at methods that are not in * platformcode even if those methods and fields are private or otherwise not visible to the calling code. * */ void mono_security_core_clr_set_options (MonoSecurityCoreCLROptions options) { security_core_clr_options = options; } /** * mono_security_core_clr_get_options: * * Retrieves the current options used by the coreclr system. */ MonoSecurityCoreCLROptions mono_security_core_clr_get_options () { return security_core_clr_options; } /* * 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_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; } /* * 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) { return image->core_clr_platform_code; } /* Note: The above functions are outside this guard so that the public API isn't affected. */ #ifndef DISABLE_SECURITY static MonoClass* security_critical_attribute (void) { static MonoClass *class = NULL; if (!class) { class = mono_class_from_name (mono_defaults.corlib, "System.Security", "SecurityCriticalAttribute"); } g_assert (class); return class; } static MonoClass* security_safe_critical_attribute (void) { static MonoClass *class = NULL; if (!class) { class = mono_class_from_name (mono_defaults.corlib, "System.Security", "SecuritySafeCriticalAttribute"); } g_assert (class); return class; } /* sometime we get a NULL (not found) caller (e.g. get_reflection_caller) */ static char* get_method_full_name (MonoMethod * method) { return method ? mono_method_full_name (method, TRUE) : g_strdup ("'no caller found'"); } /* * set_type_load_exception_type * * Set MONO_EXCEPTION_TYPE_LOAD on the specified 'class' and provide * a descriptive message for the exception. This message is also, * optionally, being logged (export MONO_LOG_MASK="security") for * debugging purposes. */ static void set_type_load_exception_type (const char *format, MonoClass *class) { char *type_name = mono_type_get_full_name (class); char *parent_name = mono_type_get_full_name (class->parent); char *message = g_strdup_printf (format, type_name, parent_name); g_free (parent_name); g_free (type_name); mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_SECURITY, message); mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, message); // note: do not free string given to mono_class_set_failure } /* * set_type_load_exception_methods * * Set MONO_EXCEPTION_TYPE_LOAD on the 'override' class and provide * a descriptive message for the exception. This message is also, * optionally, being logged (export MONO_LOG_MASK="security") for * debugging purposes. */ static void set_type_load_exception_methods (const char *format, MonoMethod *override, MonoMethod *base) { char *method_name = get_method_full_name (override); char *base_name = get_method_full_name (base); char *message = g_strdup_printf (format, method_name, base_name); g_free (base_name); g_free (method_name); mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_SECURITY, message); mono_class_set_failure (override->klass, MONO_EXCEPTION_TYPE_LOAD, message); // note: do not free string given to mono_class_set_failure } /* MonoClass is not fully initialized (inited is not yet == 1) when we * check the inheritance rules so we need to look for the default ctor * ourselve to avoid recursion (and aborting) */ static MonoMethod* get_default_ctor (MonoClass *klass) { int i; mono_class_setup_methods (klass); if (!klass->methods) return NULL; for (i = 0; i < klass->method.count; ++i) { MonoMethodSignature *sig; MonoMethod *method = klass->methods [i]; if (!method) continue; if ((method->flags & METHOD_ATTRIBUTE_SPECIAL_NAME) == 0) continue; if ((method->name[0] != '.') || strcmp (".ctor", method->name)) continue; sig = mono_method_signature (method); if (sig && (sig->param_count == 0)) return method; } return NULL; } /* * 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 * * Furthermore a class MUST have a default constructor if its base * class has a non-transparent, public or protected, default constructor. * The same inheritance rule applies to both default constructors. * * Reference: message from a SecurityException in SL4RC * Reference: fxcop CA2132 rule */ 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) { set_type_load_exception_type ( "Inheritance failure for type %s. Parent class %s is more restricted.", class); } else { MonoMethod *parent_ctor = get_default_ctor (parent); if (parent_ctor && ((parent_ctor->flags & METHOD_ATTRIBUTE_PUBLIC) != 0)) { class_level = mono_security_core_clr_method_level (get_default_ctor (class), FALSE); parent_level = mono_security_core_clr_method_level (parent_ctor, FALSE); if (class_level < parent_level) { set_type_load_exception_type ( "Inheritance failure for type %s. Default constructor security mismatch with %s.", class); } } } } /* * 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) { set_type_load_exception_methods ( "Override failure for %s over %s. Override MUST be [SecurityCritical].", override, base); } } else { /* base is [SecuritySafeCritical] or [SecurityTransparent], override MUST NOT be [SecurityCritical] */ if (override_level == MONO_SECURITY_CORE_CLR_CRITICAL) { set_type_load_exception_methods ( "Override failure for %s over %s. Override must NOT be [SecurityCritical].", override, base); } } } /* * 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.[Multicast]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 (G_UNLIKELY (!m)) { mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_SECURITY, "No caller outside reflection was found"); } return m; } typedef struct { int depth; MonoMethod *caller; } ElevatedTrustCookie; /* * get_caller_of_elevated_trust_code * * Stack walk to find who is calling code requiring Elevated Trust. * If a critical method is found then the caller is platform code * and has elevated trust, otherwise (transparent) a check needs to * be done (on the managed side) to determine if the application is * running with elevated permissions. */ static gboolean get_caller_of_elevated_trust_code (MonoMethod *m, gint32 no, gint32 ilo, gboolean managed, gpointer data) { ElevatedTrustCookie *cookie = data; /* skip unmanaged frames and wrappers */ if (!managed || (m->wrapper_type != MONO_WRAPPER_NONE)) return FALSE; /* end stack walk if we find ourselves outside platform code (we won't find critical code anymore) */ if (!mono_security_core_clr_is_platform_image (m->klass->image)) { cookie->caller = m; return TRUE; } switch (cookie->depth) { /* while depth == 0 look for SecurityManager::[Check|Ensure]ElevatedPermissions */ case 0: if (strcmp (m->klass->name_space, "System.Security")) return FALSE; if (strcmp (m->klass->name, "SecurityManager")) return FALSE; if ((strcmp (m->name, "EnsureElevatedPermissions")) && strcmp (m->name, "CheckElevatedPermissions")) return FALSE; cookie->depth = 1; break; /* while depth == 1 look for the caller to SecurityManager::[Check|Ensure]ElevatedPermissions */ case 1: /* this frame is [SecuritySafeCritical] because it calls [SecurityCritical] [Check|Ensure]ElevatedPermissions */ /* the next frame will contain the caller(s) we want to check */ cookie->depth = 2; break; /* while depth >= 2 look for [safe]critical caller, end stack walk if we find it */ default: cookie->depth++; /* if the caller is transparent then we continue the stack walk */ if (mono_security_core_clr_method_level (m, TRUE) == MONO_SECURITY_CORE_CLR_TRANSPARENT) break; /* Security[Safe]Critical code is always allowed to call elevated-trust code */ cookie->caller = m; return TRUE; } return FALSE; } /* * mono_security_core_clr_require_elevated_permissions: * * Return TRUE if the caller of the current method (the code who * called SecurityManager.get_RequiresElevatedPermissions) needs * elevated trust to perform an action. * * A stack walk is done to find the callers. If one of the callers * is either [SecurityCritical] or [SecuritySafeCritical] then the * action is needed for platform code (i.e. no restriction). * Otherwise (transparent) the requested action needs elevated trust */ gboolean mono_security_core_clr_require_elevated_permissions (void) { ElevatedTrustCookie cookie; cookie.depth = 0; cookie.caller = NULL; mono_stack_walk_no_il (get_caller_of_elevated_trust_code, &cookie); /* return TRUE if the stack walk did not reach far enough or did not find callers */ if (!cookie.caller || cookie.depth < 3) return TRUE; /* return TRUE if the caller is transparent, i.e. if elevated trust is required to continue executing the method */ return (mono_security_core_clr_method_level (cookie.caller, TRUE) == MONO_SECURITY_CORE_CLR_TRANSPARENT); } /* * 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) { MonoError error; MonoClass *klass; /* this check can occur before the field's type is resolved (and that can fail) */ mono_field_get_type_checked (field, &error); if (!mono_error_ok (&error)) { mono_error_cleanup (&error); return FALSE; } 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; } /* * get_argument_exception * * Helper function to create an MonoException (ArgumentException in * managed-land) and provide a descriptive message for it. This * message is also, optionally, being logged (export * MONO_LOG_MASK="security") for debugging purposes. */ static MonoException* get_argument_exception (const char *format, MonoMethod *caller, MonoMethod *callee) { MonoException *ex; char *caller_name = get_method_full_name (caller); char *callee_name = get_method_full_name (callee); char *message = g_strdup_printf (format, caller_name, callee_name); g_free (callee_name); g_free (caller_name); mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_SECURITY, message); ex = mono_get_exception_argument ("method", message); g_free (message); return ex; } /* * get_field_access_exception * * Helper function to create an MonoException (FieldAccessException * in managed-land) and provide a descriptive message for it. This * message is also, optionally, being logged (export * MONO_LOG_MASK="security") for debugging purposes. */ static MonoException* get_field_access_exception (const char *format, MonoMethod *caller, MonoClassField *field) { MonoException *ex; char *caller_name = get_method_full_name (caller); char *field_name = mono_field_full_name (field); char *message = g_strdup_printf (format, caller_name, field_name); g_free (field_name); g_free (caller_name); mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_SECURITY, message); ex = mono_get_exception_field_access_msg (message); g_free (message); return ex; } /* * get_method_access_exception * * Helper function to create an MonoException (MethodAccessException * in managed-land) and provide a descriptive message for it. This * message is also, optionally, being logged (export * MONO_LOG_MASK="security") for debugging purposes. */ static MonoException* get_method_access_exception (const char *format, MonoMethod *caller, MonoMethod *callee) { MonoException *ex; char *caller_name = get_method_full_name (caller); char *callee_name = get_method_full_name (callee); char *message = g_strdup_printf (format, caller_name, callee_name); g_free (callee_name); g_free (caller_name); mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_SECURITY, message); ex = mono_get_exception_method_access_msg (message); g_free (message); return ex; } /* * 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; if (mono_security_core_clr_get_options () & MONO_SECURITY_CORE_CLR_OPTIONS_RELAX_REFLECTION) { if (!mono_security_core_clr_is_platform_image (mono_field_get_parent(field)->image)) 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 (get_field_access_exception ( "Transparent method %s cannot get or set Critical field %s.", caller, field)); } /* 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 (get_field_access_exception ( "Transparent method %s cannot get or set private/internal field %s.", caller, field)); } } /* * 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; if (mono_security_core_clr_get_options () & MONO_SECURITY_CORE_CLR_OPTIONS_RELAX_REFLECTION) { if (!mono_security_core_clr_is_platform_image (method->klass->image)) 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 (get_method_access_exception ( "Transparent method %s cannot invoke Critical method %s.", caller, method)); } /* 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 (get_method_access_exception ( "Transparent method %s cannot invoke private/internal method %s.", caller, method)); } } /* * 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 (get_argument_exception ( "Transparent method %s cannot create a delegate on Critical method %s.", caller, method)); } if (mono_security_core_clr_get_options () & MONO_SECURITY_CORE_CLR_OPTIONS_RELAX_DELEGATE) { if (!mono_security_core_clr_is_platform_image (method->klass->image)) return TRUE; } /* 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 (get_method_access_exception ( "Transparent method %s cannot create a delegate on private/internal method %s.", caller, method)); } 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 get_field_access_exception ( "Dynamic method %s cannot create access private/internal field %s.", caller, field); } } } 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 get_method_access_exception ( "Dynamic method %s cannot create access private/internal method %s.", caller, method); } } } 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 */ if (!accessed->assembly->basedir || !accessing->assembly->basedir) return FALSE; return (strcmp (accessed->assembly->basedir, accessing->assembly->basedir) == 0); } /* * mono_security_core_clr_is_field_access_allowed * * Return a MonoException (FieldccessException in managed-land) if * the access from "caller" to "field" is not valid under CoreCLR - * i.e. a [SecurityTransparent] method calling a [SecurityCritical] * field. */ MonoException* mono_security_core_clr_is_field_access_allowed (MonoMethod *caller, MonoClassField *field) { /* there's no restriction to access Transparent or SafeCritical fields, so we only check calls to Critical methods */ if (mono_security_core_clr_class_level (mono_field_get_parent (field)) != MONO_SECURITY_CORE_CLR_CRITICAL) return NULL; /* caller is Critical! only SafeCritical and Critical callers can access the field, so we throw if caller is Transparent */ if (!caller || (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)) return NULL; return get_field_access_exception ( "Transparent method %s cannot call use Critical field %s.", caller, field); } /* * mono_security_core_clr_is_call_allowed * * Return a MonoException (MethodAccessException in managed-land) if * the call from "caller" to "callee" is not valid under CoreCLR - * i.e. a [SecurityTransparent] method calling a [SecurityCritical] * method. */ MonoException* mono_security_core_clr_is_call_allowed (MonoMethod *caller, MonoMethod *callee) { /* there's no restriction to call Transparent or SafeCritical code, so we only check calls to Critical methods */ if (mono_security_core_clr_method_level (callee, TRUE) != MONO_SECURITY_CORE_CLR_CRITICAL) return NULL; /* callee is Critical! only SafeCritical and Critical callers can call it, so we throw if the caller is Transparent */ if (!caller || (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)) return NULL; return get_method_access_exception ( "Transparent method %s cannot call Critical method %s.", caller, callee); } /* * 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 (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 ())) level = MONO_SECURITY_CORE_CLR_CRITICAL; return level; } /* * 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); 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); 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; MonoSecurityCoreCLRLevel level = MONO_SECURITY_CORE_CLR_TRANSPARENT; /* 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; 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_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); } #else void mono_security_core_clr_check_inheritance (MonoClass *class) { } void mono_security_core_clr_check_override (MonoClass *class, MonoMethod *override, MonoMethod *base) { } gboolean mono_security_core_clr_require_elevated_permissions (void) { return FALSE; } void mono_security_core_clr_ensure_reflection_access_field (MonoClassField *field) { } void mono_security_core_clr_ensure_reflection_access_method (MonoMethod *method) { } gboolean mono_security_core_clr_ensure_delegate_creation (MonoMethod *method, gboolean throwOnBindFailure) { return TRUE; } MonoException* mono_security_core_clr_ensure_dynamic_method_resolved_object (gpointer ref, MonoClass *handle_class) { return NULL; } gboolean mono_security_core_clr_can_access_internals (MonoImage *accessing, MonoImage* accessed) { return TRUE; } MonoException* mono_security_core_clr_is_field_access_allowed (MonoMethod *caller, MonoClassField *field) { return NULL; } MonoException* mono_security_core_clr_is_call_allowed (MonoMethod *caller, MonoMethod *callee) { return NULL; } MonoSecurityCoreCLRLevel mono_security_core_clr_class_level (MonoClass *class) { return MONO_SECURITY_CORE_CLR_TRANSPARENT; } MonoSecurityCoreCLRLevel mono_security_core_clr_method_level (MonoMethod *method, gboolean with_class_level) { return MONO_SECURITY_CORE_CLR_TRANSPARENT; } void mono_security_enable_core_clr () { } #endif /* DISABLE_SECURITY */