X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=FmpDevicePkg%2FFmpDxe%2FDetectTestKey.c;fp=FmpDevicePkg%2FFmpDxe%2FDetectTestKey.c;h=0a6e37ededae7360268ffd60264987cb5667ad46;hp=0000000000000000000000000000000000000000;hb=b0bacc003a6890d1881ea269d785d42928a7f340;hpb=403d4bcdec33630b37b4830eb4a521b906870ede

diff --git a/FmpDevicePkg/FmpDxe/DetectTestKey.c b/FmpDevicePkg/FmpDxe/DetectTestKey.c
new file mode 100644
index 0000000000..0a6e37eded
--- /dev/null
+++ b/FmpDevicePkg/FmpDxe/DetectTestKey.c
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+/**  @file
+  Detects if PcdFmpDevicePkcs7CertBufferXdr contains a test key.
+
+  Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+  1. Redistributions of source code must retain the above copyright notice,
+  this list of conditions and the following disclaimer.
+  2. Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+  OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+**/
+
+#include <PiDxe.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/PcdLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/BaseCryptLib.h>
+
+/**
+  Check to see if any of the keys in PcdFmpDevicePkcs7CertBufferXdr matches
+  the test key.  PcdFmpDeviceTestKeySha256Digest contains the SHA256 hash of
+  the test key.  For each key in PcdFmpDevicePkcs7CertBufferXdr, compute the
+  SHA256 hash and compare it to PcdFmpDeviceTestKeySha256Digest.  If the
+  SHA256 hash matches or there is then error computing the SHA256 hash, then
+  set PcdTestKeyUsed to TRUE.  Skip this check if PcdTestKeyUsed is already
+  TRUE or PcdFmpDeviceTestKeySha256Digest is not exactly SHA256_DIGEST_SIZE
+  bytes.
+**/
+VOID
+DetectTestKey (
+  VOID
+  )
+{
+  BOOLEAN  TestKeyUsed;
+  UINTN    PublicKeyDataLength;
+  UINT8    *PublicKeyDataXdr;
+  UINT8    *PublicKeyDataXdrEnd;
+  VOID     *HashContext;
+  UINT8    Digest[SHA256_DIGEST_SIZE];
+
+  //
+  // If PcdFmpDeviceTestKeySha256Digest is not exacty SHA256_DIGEST_SIZE bytes,
+  // then skip the test key detection.
+  //
+  if (PcdGetSize (PcdFmpDeviceTestKeySha256Digest) != SHA256_DIGEST_SIZE) {
+    return;
+  }
+
+  //
+  // If PcdTestKeyUsed is already TRUE, then skip test key detection
+  //
+  TestKeyUsed = PcdGetBool (PcdTestKeyUsed);
+  if (TestKeyUsed) {
+    return;
+  }
+
+  //
+  // If PcdFmpDevicePkcs7CertBufferXdr is invalid, then skip test key detection
+  //
+  PublicKeyDataXdr    = PcdGetPtr (PcdFmpDevicePkcs7CertBufferXdr);
+  PublicKeyDataXdrEnd = PublicKeyDataXdr + PcdGetSize (PcdFmpDevicePkcs7CertBufferXdr);
+  if (PublicKeyDataXdr == NULL || PublicKeyDataXdr == PublicKeyDataXdrEnd) {
+    return;
+  }
+
+  //
+  // Allocate hash context buffer required for SHA 256
+  //
+  HashContext = AllocatePool (Sha256GetContextSize ());
+  if (HashContext == NULL) {
+    TestKeyUsed = TRUE;
+  }
+
+  //
+  // Loop through all keys in PcdFmpDevicePkcs7CertBufferXdr
+  //
+  while (!TestKeyUsed && PublicKeyDataXdr < PublicKeyDataXdrEnd) {
+    if (PublicKeyDataXdr + sizeof (UINT32) > PublicKeyDataXdrEnd) {
+      //
+      // Key data extends beyond end of PCD
+      //
+      break;
+    }
+    //
+    // Read key length stored in big endian format
+    //
+    PublicKeyDataLength = SwapBytes32 (*(UINT32 *)(PublicKeyDataXdr));
+    //
+    // Point to the start of the key data
+    //
+    PublicKeyDataXdr += sizeof (UINT32);
+    if (PublicKeyDataXdr + PublicKeyDataLength > PublicKeyDataXdrEnd) {
+      //
+      // Key data extends beyond end of PCD
+      //
+      break;
+    }
+
+    //
+    // Hash public key from PcdFmpDevicePkcs7CertBufferXdr using SHA256.
+    // If error occurs computing SHA256, then assume test key is in use.
+    //
+    ZeroMem (Digest, SHA256_DIGEST_SIZE);
+    if (!Sha256Init (HashContext)) {
+      TestKeyUsed = TRUE;
+      break;
+    }
+    if (!Sha256Update (HashContext, PublicKeyDataXdr, PublicKeyDataLength)) {
+      TestKeyUsed = TRUE;
+      break;
+    }
+    if (!Sha256Final (HashContext, Digest)) {
+      TestKeyUsed = TRUE;
+      break;
+    }
+
+    //
+    // Check if SHA256 hash of public key matches SHA256 hash of test key
+    //
+    if (CompareMem (Digest, PcdGetPtr (PcdFmpDeviceTestKeySha256Digest), SHA256_DIGEST_SIZE) == 0) {
+      TestKeyUsed = TRUE;
+      break;
+    }
+
+    //
+    // Point to start of next key
+    //
+    PublicKeyDataXdr += PublicKeyDataLength;
+    PublicKeyDataXdr = (UINT8 *)ALIGN_POINTER (PublicKeyDataXdr, sizeof (UINT32));
+  }
+
+  //
+  // Free hash context buffer required for SHA 256
+  //
+  if (HashContext != NULL) {
+    FreePool (HashContext);
+    HashContext = NULL;
+  }
+
+  //
+  // If test key detected or an error occured checking for the test key, then
+  // set PcdTestKeyUsed to TRUE.
+  //
+  if (TestKeyUsed) {
+    DEBUG ((DEBUG_INFO, "FmpDxe: Test key detected in PcdFmpDevicePkcs7CertBufferXdr.\n"));
+    PcdSetBoolS (PcdTestKeyUsed, TRUE);
+  } else {
+    DEBUG ((DEBUG_INFO, "FmpDxe: No test key detected in PcdFmpDevicePkcs7CertBufferXdr.\n"));
+  }
+}