CryptoPkg: Add some comments for API usage clarification.

[mirror_edk2.git] / CryptoPkg / Library / BaseCryptLib / Pk / CryptAuthenticode.c

diff --git a/CryptoPkg/Library/BaseCryptLib/Pk/CryptAuthenticode.c b/CryptoPkg/Library/BaseCryptLib/Pk/CryptAuthenticode.c
index a1f8c58e746de62a8ba7db54ca3a034236ca0c4a..9e933558e65bb66f4b54ced5d9c139877fe4e6d9 100644 (file)
--- a/CryptoPkg/Library/BaseCryptLib/Pk/CryptAuthenticode.c
+++ b/CryptoPkg/Library/BaseCryptLib/Pk/CryptAuthenticode.c
@@ -1,7 +1,15 @@
 /** @file\r
   Authenticode Portable Executable Signature Verification over OpenSSL.\r
 \r
-Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>\r
+  Caution: This module requires additional review when modified.\r
+  This library will have external input - signature (e.g. PE/COFF Authenticode).\r
+  This external input must be validated carefully to avoid security issue like\r
+  buffer overflow, integer overflow.\r
+\r
+  AuthenticodeVerify() will get PE/COFF Authenticode and will do basic check for\r
+  data structure.\r
+\r
+Copyright (c) 2011 - 2015, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials\r
 are licensed and made available under the terms and conditions of the BSD License\r
 which accompanies this distribution.  The full text of the license may be found at\r
@@ -18,6 +26,12 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <openssl/x509.h>\r
 #include <openssl/pkcs7.h>\r
 \r
+//\r
+// OID ASN.1 Value for SPC_INDIRECT_DATA_OBJID\r
+//\r
+UINT8 mSpcIndirectOidValue[] = {\r
+  0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0x37, 0x02, 0x01, 0x04\r
+  };\r
 \r
 /**\r
   Verifies the validility of a PE/COFF Authenticode Signature as described in "Windows\r
@@ -26,6 +40,10 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
   If AuthData is NULL, then return FALSE.\r
   If ImageHash is NULL, then return FALSE.\r
 \r
+  Caution: This function may receive untrusted input.\r
+  PE/COFF Authenticode is external input, so this function will do basic check for\r
+  Authenticode data structure.\r
+\r
   @param[in]  AuthData     Pointer to the Authenticode Signature retrieved from signed\r
                            PE/COFF image to be verified.\r
   @param[in]  DataSize     Size of the Authenticode Signature in bytes.\r
@@ -54,10 +72,12 @@ AuthenticodeVerify (
 {\r
   BOOLEAN      Status;\r
   PKCS7        *Pkcs7;\r
+  CONST UINT8  *Temp;\r
   CONST UINT8  *OrigAuthData;\r
   UINT8        *SpcIndirectDataContent;\r
   UINT8        Asn1Byte;\r
   UINTN        ContentSize;\r
+  UINT8        *SpcIndirectDataOid;\r
 \r
   //\r
   // Check input parameters.\r
@@ -77,7 +97,8 @@ AuthenticodeVerify (
   //\r
   // Retrieve & Parse PKCS#7 Data (DER encoding) from Authenticode Signature\r
   //\r
-  Pkcs7 = d2i_PKCS7 (NULL, &AuthData, (int)DataSize);\r
+  Temp  = AuthData;\r
+  Pkcs7 = d2i_PKCS7 (NULL, &Temp, (int)DataSize);\r
   if (Pkcs7 == NULL) {\r
     goto _Exit;\r
   }\r
@@ -94,6 +115,19 @@ AuthenticodeVerify (
   //       some authenticode-specific structure. Use opaque ASN.1 string to retrieve\r
   //       PKCS#7 ContentInfo here.\r
   //\r
+  SpcIndirectDataOid = (UINT8 *)(Pkcs7->d.sign->contents->type->data);\r
+  if (CompareMem (\r
+        SpcIndirectDataOid,\r
+        mSpcIndirectOidValue,\r
+        sizeof (mSpcIndirectOidValue)\r
+        ) != 0) {\r
+    //\r
+    // Un-matched SPC_INDIRECT_DATA_OBJID.\r
+    //\r
+    goto _Exit;\r
+  }\r
+\r
+\r
   SpcIndirectDataContent = (UINT8 *)(Pkcs7->d.sign->contents->d.other->value.asn1_string->data);\r
 \r
   //\r
@@ -103,23 +137,35 @@ AuthenticodeVerify (
 \r
   if ((Asn1Byte & 0x80) == 0) {\r
     //\r
-    // Short Form of Length Encoding\r
+    // Short Form of Length Encoding (Length < 128)\r
     //\r
     ContentSize = (UINTN) (Asn1Byte & 0x7F);\r
     //\r
     // Skip the SEQUENCE Tag;\r
     //\r
     SpcIndirectDataContent += 2;\r
+\r
+  } else if ((Asn1Byte & 0x81) == 0x81) {\r
+    //\r
+    // Long Form of Length Encoding (128 <= Length < 255, Single Octet)\r
+    //\r
+    ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2));\r
+    //\r
+    // Skip the SEQUENCE Tag;\r
+    //\r
+    SpcIndirectDataContent += 3;\r
+\r
   } else if ((Asn1Byte & 0x82) == 0x82) {\r
     //\r
-    // Long Form of Length Encoding, only support two bytes.\r
+    // Long Form of Length Encoding (Length > 255, Two Octet)\r
     //\r
-    ContentSize  = (UINTN) (*(SpcIndirectDataContent + 2));\r
-    ContentSize = (ContentSize << 8) + (UINTN)(*(SpcIndirectDataContent + 3));\r
+    ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2));\r
+    ContentSize = (ContentSize << 8) + (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 3));\r
     //\r
     // Skip the SEQUENCE Tag;\r
     //\r
     SpcIndirectDataContent += 4;\r
+\r
   } else {\r
     goto _Exit;\r
   }\r