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a0994dbe JY |
1 | /** @file\r |
2 | TCG MOR (Memory Overwrite Request) Lock Control support (DXE version).\r | |
3 | \r | |
4 | This module clears MemoryOverwriteRequestControlLock variable to indicate\r | |
5 | MOR lock control unsupported.\r | |
6 | \r | |
7 | Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>\r | |
98ee0c68 | 8 | Copyright (c) Microsoft Corporation.\r |
9d510e61 | 9 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
a0994dbe JY |
10 | \r |
11 | **/\r | |
12 | \r | |
13 | #include <PiDxe.h>\r | |
14 | #include <Guid/MemoryOverwriteControl.h>\r | |
15 | #include <IndustryStandard/MemoryOverwriteRequestControlLock.h>\r | |
16 | #include <Library/DebugLib.h>\r | |
17 | #include <Library/BaseLib.h>\r | |
18 | #include <Library/BaseMemoryLib.h>\r | |
19 | #include "Variable.h"\r | |
20 | \r | |
98ee0c68 BB |
21 | #include <Protocol/VariablePolicy.h>\r |
22 | #include <Library/VariablePolicyHelperLib.h>\r | |
a0994dbe JY |
23 | \r |
24 | /**\r | |
25 | This service is an MOR/MorLock checker handler for the SetVariable().\r | |
26 | \r | |
03877377 LE |
27 | @param[in] VariableName the name of the vendor's variable, as a\r |
28 | Null-Terminated Unicode String\r | |
29 | @param[in] VendorGuid Unify identifier for vendor.\r | |
30 | @param[in] Attributes Attributes bitmask to set for the variable.\r | |
31 | @param[in] DataSize The size in bytes of Data-Buffer.\r | |
32 | @param[in] Data Point to the content of the variable.\r | |
a0994dbe | 33 | \r |
03877377 LE |
34 | @retval EFI_SUCCESS The MOR/MorLock check pass, and Variable\r |
35 | driver can store the variable data.\r | |
36 | @retval EFI_INVALID_PARAMETER The MOR/MorLock data or data size or\r | |
37 | attributes is not allowed for MOR variable.\r | |
a0994dbe | 38 | @retval EFI_ACCESS_DENIED The MOR/MorLock is locked.\r |
03877377 LE |
39 | @retval EFI_ALREADY_STARTED The MorLock variable is handled inside this\r |
40 | function. Variable driver can just return\r | |
41 | EFI_SUCCESS.\r | |
a0994dbe JY |
42 | **/\r |
43 | EFI_STATUS\r | |
44 | SetVariableCheckHandlerMor (\r | |
45 | IN CHAR16 *VariableName,\r | |
46 | IN EFI_GUID *VendorGuid,\r | |
47 | IN UINT32 Attributes,\r | |
48 | IN UINTN DataSize,\r | |
49 | IN VOID *Data\r | |
50 | )\r | |
51 | {\r | |
52 | //\r | |
53 | // Just let it pass. No need provide protection for DXE version.\r | |
54 | //\r | |
55 | return EFI_SUCCESS;\r | |
56 | }\r | |
57 | \r | |
58 | /**\r | |
03877377 | 59 | Initialization for MOR Control Lock.\r |
a0994dbe | 60 | \r |
03877377 | 61 | @retval EFI_SUCCESS MorLock initialization success.\r |
a0994dbe JY |
62 | @return Others Some error occurs.\r |
63 | **/\r | |
64 | EFI_STATUS\r | |
65 | MorLockInit (\r | |
66 | VOID\r | |
67 | )\r | |
68 | {\r | |
69 | //\r | |
70 | // Always clear variable to report unsupported to OS.\r | |
71 | // The reason is that the DXE version is not proper to provide *protection*.\r | |
72 | // BIOS should use SMM version variable driver to provide such capability.\r | |
73 | //\r | |
74 | VariableServiceSetVariable (\r | |
75 | MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,\r | |
76 | &gEfiMemoryOverwriteRequestControlLockGuid,\r | |
704b71d7 LE |
77 | 0, // Attributes\r |
78 | 0, // DataSize\r | |
79 | NULL // Data\r | |
a0994dbe JY |
80 | );\r |
81 | \r | |
704b71d7 LE |
82 | //\r |
83 | // The MOR variable can effectively improve platform security only when the\r | |
84 | // MorLock variable protects the MOR variable. In turn MorLock cannot be made\r | |
85 | // secure without SMM support in the platform firmware (see above).\r | |
86 | //\r | |
87 | // Thus, delete the MOR variable, should it exist for any reason (some OSes\r | |
88 | // are known to create MOR unintentionally, in an attempt to set it), then\r | |
89 | // also lock the MOR variable, in order to prevent other modules from\r | |
90 | // creating it.\r | |
91 | //\r | |
92 | VariableServiceSetVariable (\r | |
93 | MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,\r | |
94 | &gEfiMemoryOverwriteControlDataGuid,\r | |
95 | 0, // Attributes\r | |
96 | 0, // DataSize\r | |
97 | NULL // Data\r | |
98 | );\r | |
704b71d7 | 99 | \r |
a0994dbe JY |
100 | return EFI_SUCCESS;\r |
101 | }\r | |
f1304280 LE |
102 | \r |
103 | /**\r | |
104 | Delayed initialization for MOR Control Lock at EndOfDxe.\r | |
105 | \r | |
106 | This function performs any operations queued by MorLockInit().\r | |
107 | **/\r | |
108 | VOID\r | |
109 | MorLockInitAtEndOfDxe (\r | |
110 | VOID\r | |
111 | )\r | |
112 | {\r | |
98ee0c68 BB |
113 | EFI_STATUS Status;\r |
114 | EDKII_VARIABLE_POLICY_PROTOCOL *VariablePolicy;\r | |
115 | \r | |
116 | // First, we obviously need to locate the VariablePolicy protocol.\r | |
117 | Status = gBS->LocateProtocol( &gEdkiiVariablePolicyProtocolGuid, NULL, (VOID**)&VariablePolicy );\r | |
118 | if (EFI_ERROR( Status )) {\r | |
119 | DEBUG(( DEBUG_ERROR, "%a - Could not locate VariablePolicy protocol! %r\n", __FUNCTION__, Status ));\r | |
120 | return;\r | |
121 | }\r | |
122 | \r | |
123 | // If we're successful, go ahead and set the policies to protect the target variables.\r | |
124 | Status = RegisterBasicVariablePolicy( VariablePolicy,\r | |
125 | &gEfiMemoryOverwriteRequestControlLockGuid,\r | |
126 | MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,\r | |
127 | VARIABLE_POLICY_NO_MIN_SIZE,\r | |
128 | VARIABLE_POLICY_NO_MAX_SIZE,\r | |
129 | VARIABLE_POLICY_NO_MUST_ATTR,\r | |
130 | VARIABLE_POLICY_NO_CANT_ATTR,\r | |
131 | VARIABLE_POLICY_TYPE_LOCK_NOW );\r | |
132 | if (EFI_ERROR( Status )) {\r | |
133 | DEBUG(( DEBUG_ERROR, "%a - Could not lock variable %s! %r\n", __FUNCTION__, MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME, Status ));\r | |
134 | }\r | |
135 | Status = RegisterBasicVariablePolicy( VariablePolicy,\r | |
136 | &gEfiMemoryOverwriteControlDataGuid,\r | |
137 | MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,\r | |
138 | VARIABLE_POLICY_NO_MIN_SIZE,\r | |
139 | VARIABLE_POLICY_NO_MAX_SIZE,\r | |
140 | VARIABLE_POLICY_NO_MUST_ATTR,\r | |
141 | VARIABLE_POLICY_NO_CANT_ATTR,\r | |
142 | VARIABLE_POLICY_TYPE_LOCK_NOW );\r | |
143 | if (EFI_ERROR( Status )) {\r | |
144 | DEBUG(( DEBUG_ERROR, "%a - Could not lock variable %s! %r\n", __FUNCTION__, MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME, Status ));\r | |
145 | }\r | |
146 | \r | |
147 | return;\r | |
f1304280 | 148 | }\r |