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1 | /** @file\r |
2 | Functions related to managing the UEFI variable runtime cache. This file should only include functions\r | |
3 | used by the SMM UEFI variable driver.\r | |
4 | \r | |
5 | Caution: This module requires additional review when modified.\r | |
6 | This driver will have external input - variable data. They may be input in SMM mode.\r | |
7 | This external input must be validated carefully to avoid security issue like\r | |
8 | buffer overflow, integer overflow.\r | |
9 | \r | |
10 | Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>\r | |
11 | SPDX-License-Identifier: BSD-2-Clause-Patent\r | |
12 | \r | |
13 | **/\r | |
14 | \r | |
15 | #include "VariableParsing.h"\r | |
16 | #include "VariableRuntimeCache.h"\r | |
17 | \r | |
18 | extern VARIABLE_MODULE_GLOBAL *mVariableModuleGlobal;\r | |
19 | extern VARIABLE_STORE_HEADER *mNvVariableCache;\r | |
20 | \r | |
21 | /**\r | |
22 | Copies any pending updates to runtime variable caches.\r | |
23 | \r | |
24 | @retval EFI_UNSUPPORTED The volatile store to be updated is not initialized properly.\r | |
25 | @retval EFI_SUCCESS The volatile store was updated successfully.\r | |
26 | \r | |
27 | **/\r | |
28 | EFI_STATUS\r | |
29 | FlushPendingRuntimeVariableCacheUpdates (\r | |
30 | VOID\r | |
31 | )\r | |
32 | {\r | |
33 | VARIABLE_RUNTIME_CACHE_CONTEXT *VariableRuntimeCacheContext;\r | |
34 | \r | |
35 | VariableRuntimeCacheContext = &mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext;\r | |
36 | \r | |
37 | if (VariableRuntimeCacheContext->VariableRuntimeNvCache.Store == NULL ||\r | |
38 | VariableRuntimeCacheContext->VariableRuntimeVolatileCache.Store == NULL ||\r | |
39 | VariableRuntimeCacheContext->PendingUpdate == NULL) {\r | |
40 | return EFI_UNSUPPORTED;\r | |
41 | }\r | |
42 | \r | |
43 | if (*(VariableRuntimeCacheContext->PendingUpdate)) {\r | |
44 | if (VariableRuntimeCacheContext->VariableRuntimeHobCache.Store != NULL &&\r | |
45 | mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0) {\r | |
46 | CopyMem (\r | |
47 | (VOID *) (\r | |
48 | ((UINT8 *) (UINTN) VariableRuntimeCacheContext->VariableRuntimeHobCache.Store) +\r | |
49 | VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateOffset\r | |
50 | ),\r | |
51 | (VOID *) (\r | |
52 | ((UINT8 *) (UINTN) mVariableModuleGlobal->VariableGlobal.HobVariableBase) +\r | |
53 | VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateOffset\r | |
54 | ),\r | |
55 | VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateLength\r | |
56 | );\r | |
57 | VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateLength = 0;\r | |
58 | VariableRuntimeCacheContext->VariableRuntimeHobCache.PendingUpdateOffset = 0;\r | |
59 | }\r | |
60 | \r | |
61 | CopyMem (\r | |
62 | (VOID *) (\r | |
63 | ((UINT8 *) (UINTN) VariableRuntimeCacheContext->VariableRuntimeNvCache.Store) +\r | |
64 | VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateOffset\r | |
65 | ),\r | |
66 | (VOID *) (\r | |
67 | ((UINT8 *) (UINTN) mNvVariableCache) +\r | |
68 | VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateOffset\r | |
69 | ),\r | |
70 | VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateLength\r | |
71 | );\r | |
72 | VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateLength = 0;\r | |
73 | VariableRuntimeCacheContext->VariableRuntimeNvCache.PendingUpdateOffset = 0;\r | |
74 | \r | |
75 | CopyMem (\r | |
76 | (VOID *) (\r | |
77 | ((UINT8 *) (UINTN) VariableRuntimeCacheContext->VariableRuntimeVolatileCache.Store) +\r | |
78 | VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateOffset\r | |
79 | ),\r | |
80 | (VOID *) (\r | |
81 | ((UINT8 *) (UINTN) mVariableModuleGlobal->VariableGlobal.VolatileVariableBase) +\r | |
82 | VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateOffset\r | |
83 | ),\r | |
84 | VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateLength\r | |
85 | );\r | |
86 | VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateLength = 0;\r | |
87 | VariableRuntimeCacheContext->VariableRuntimeVolatileCache.PendingUpdateOffset = 0;\r | |
88 | *(VariableRuntimeCacheContext->PendingUpdate) = FALSE;\r | |
89 | }\r | |
90 | \r | |
91 | return EFI_SUCCESS;\r | |
92 | }\r | |
93 | \r | |
94 | /**\r | |
95 | Synchronizes the runtime variable caches with all pending updates outside runtime.\r | |
96 | \r | |
97 | Ensures all conditions are met to maintain coherency for runtime cache updates. This function will attempt\r | |
98 | to write the given update (and any other pending updates) if the ReadLock is available. Otherwise, the\r | |
99 | update is added as a pending update for the given variable store and it will be flushed to the runtime cache\r | |
100 | at the next opportunity the ReadLock is available.\r | |
101 | \r | |
102 | @param[in] VariableRuntimeCache Variable runtime cache structure for the runtime cache being synchronized.\r | |
103 | @param[in] Offset Offset in bytes to apply the update.\r | |
104 | @param[in] Length Length of data in bytes of the update.\r | |
105 | \r | |
106 | @retval EFI_SUCCESS The update was added as a pending update successfully. If the variable runtime\r | |
107 | cache ReadLock was available, the runtime cache was updated successfully.\r | |
108 | @retval EFI_UNSUPPORTED The volatile store to be updated is not initialized properly.\r | |
109 | \r | |
110 | **/\r | |
111 | EFI_STATUS\r | |
112 | SynchronizeRuntimeVariableCache (\r | |
113 | IN VARIABLE_RUNTIME_CACHE *VariableRuntimeCache,\r | |
114 | IN UINTN Offset,\r | |
115 | IN UINTN Length\r | |
116 | )\r | |
117 | {\r | |
118 | if (VariableRuntimeCache == NULL) {\r | |
119 | return EFI_INVALID_PARAMETER;\r | |
120 | } else if (VariableRuntimeCache->Store == NULL) {\r | |
121 | // The runtime cache may not be active or allocated yet.\r | |
122 | // In either case, return EFI_SUCCESS instead of EFI_NOT_AVAILABLE_YET.\r | |
123 | return EFI_SUCCESS;\r | |
124 | }\r | |
125 | \r | |
126 | if (mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.PendingUpdate == NULL ||\r | |
127 | mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.ReadLock == NULL) {\r | |
128 | return EFI_UNSUPPORTED;\r | |
129 | }\r | |
130 | \r | |
131 | if (*(mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) &&\r | |
132 | VariableRuntimeCache->PendingUpdateLength > 0) {\r | |
133 | VariableRuntimeCache->PendingUpdateLength =\r | |
134 | (UINT32) (\r | |
135 | MAX (\r | |
136 | (UINTN) (VariableRuntimeCache->PendingUpdateOffset + VariableRuntimeCache->PendingUpdateLength),\r | |
137 | Offset + Length\r | |
138 | ) - MIN ((UINTN) VariableRuntimeCache->PendingUpdateOffset, Offset)\r | |
139 | );\r | |
140 | VariableRuntimeCache->PendingUpdateOffset =\r | |
141 | (UINT32) MIN ((UINTN) VariableRuntimeCache->PendingUpdateOffset, Offset);\r | |
142 | } else {\r | |
143 | VariableRuntimeCache->PendingUpdateLength = (UINT32) Length;\r | |
144 | VariableRuntimeCache->PendingUpdateOffset = (UINT32) Offset;\r | |
145 | }\r | |
146 | *(mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) = TRUE;\r | |
147 | \r | |
148 | if (*(mVariableModuleGlobal->VariableGlobal.VariableRuntimeCacheContext.ReadLock) == FALSE) {\r | |
149 | return FlushPendingRuntimeVariableCacheUpdates ();\r | |
150 | }\r | |
151 | \r | |
152 | return EFI_SUCCESS;\r | |
153 | }\r |