Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1160 insertions, 0 deletions

diff --git a/onlineupdate/source/libmar/sign/mar_sign.c b/onlineupdate/source/libmar/sign/mar_sign.c
new file mode 100644
index 000000000..161cadc0d
--- /dev/null
+++ b/onlineupdate/source/libmar/sign/mar_sign.c
@@ -0,0 +1,1160 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef _WIN32
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <onlineupdate/mar_private.h>
+#include <onlineupdate/mar_cmdline.h>
+#include <onlineupdate/mar.h>
+#include "cryptox.h"
+#ifndef _WIN32
+#include <unistd.h>
+#endif
+
+#include "nss_secutil.h"
+#include "base64.h"
+
+/**
+ * Initializes the NSS context.
+ *
+ * @param NSSConfigDir The config dir containing the private key to use
+ * @return 0 on success
+ *         -1 on error
+*/
+int
+NSSInitCryptoContext(const char *NSSConfigDir)
+{
+  SECStatus status = NSS_Initialize(NSSConfigDir,
+                                    "", "", SECMOD_DB, NSS_INIT_READONLY);
+  if (SECSuccess != status) {
+    fprintf(stderr, "ERROR: Could not initialize NSS\n");
+    return -1;
+  }
+
+  return 0;
+}
+
+/**
+ * Obtains a signing context.
+ *
+ * @param  ctx A pointer to the signing context to fill
+ * @return 0 on success
+ *         -1 on error
+*/
+int
+NSSSignBegin(const char *certName,
+             SGNContext **ctx,
+             SECKEYPrivateKey **privKey,
+             CERTCertificate **cert,
+             uint32_t *signatureLength)
+{
+  secuPWData pwdata = { PW_NONE, 0 };
+  if (!certName || !ctx || !privKey || !cert || !signatureLength) {
+    fprintf(stderr, "ERROR: Invalid parameter passed to NSSSignBegin\n");
+    return -1;
+  }
+
+  /* Get the cert and embedded public key out of the database */
+  *cert = PK11_FindCertFromNickname(certName, &pwdata);
+  if (!*cert) {
+    fprintf(stderr, "ERROR: Could not find cert from nickname\n");
+    return -1;
+  }
+
+  /* Get the private key out of the database */
+  *privKey = PK11_FindKeyByAnyCert(*cert, &pwdata);
+  if (!*privKey) {
+    fprintf(stderr, "ERROR: Could not find private key\n");
+    return -1;
+  }
+
+  *signatureLength = PK11_SignatureLen(*privKey);
+
+  if (*signatureLength > BLOCKSIZE) {
+    fprintf(stderr,
+            "ERROR: Program must be compiled with a larger block size"
+            " to support signing with signatures this large: %u.\n",
+            *signatureLength);
+    return -1;
+  }
+
+  /* Check that the key length is large enough for our requirements */
+  if (*signatureLength < XP_MIN_SIGNATURE_LEN_IN_BYTES) {
+    fprintf(stderr, "ERROR: Key length must be >= %d bytes\n",
+            XP_MIN_SIGNATURE_LEN_IN_BYTES);
+    return -1;
+  }
+
+  *ctx = SGN_NewContext (SEC_OID_ISO_SHA1_WITH_RSA_SIGNATURE, *privKey);
+  if (!*ctx) {
+    fprintf(stderr, "ERROR: Could not create signature context\n");
+    return -1;
+  }
+
+  if (SGN_Begin(*ctx) != SECSuccess) {
+    fprintf(stderr, "ERROR: Could not begin signature\n");
+    return -1;
+  }
+
+  return 0;
+}
+
+/**
+ * Writes the passed buffer to the file fp and updates the signature contexts.
+ *
+ * @param  fpDest   The file pointer to write to.
+ * @param  buffer   The buffer to write.
+ * @param  size     The size of the buffer to write.
+ * @param  ctxs     Pointer to the first element in an array of signature
+ *                  contexts to update.
+ * @param  ctxCount The number of signature contexts pointed to by ctxs
+ * @param  err    The name of what is being written to in case of error.
+ * @return  0 on success
+ *         -2 on write error
+ *         -3 on signature update error
+*/
+int
+WriteAndUpdateSignatures(FILE *fpDest, void *buffer,
+                         uint32_t size, SGNContext **ctxs,
+                         uint32_t ctxCount,
+                         const char *err)
+{
+  uint32_t k;
+  if (!size) {
+    return 0;
+  }
+
+  if (fwrite(buffer, size, 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write %s\n", err);
+    return -2;
+  }
+
+  for (k = 0; k < ctxCount; ++k) {
+    if (SGN_Update(ctxs[k], buffer, size) != SECSuccess) {
+      fprintf(stderr, "ERROR: Could not update signature context for %s\n", err);
+      return -3;
+    }
+  }
+  return 0;
+}
+
+/**
+ * Adjusts each entry's content offset in the passed in index by the
+ * specified amount.
+ *
+ * @param indexBuf     A buffer containing the MAR index
+ * @param indexLength  The length of the MAR index
+ * @param offsetAmount The amount to adjust each index entry by
+*/
+void
+AdjustIndexContentOffsets(char *indexBuf, uint32_t indexLength, uint32_t offsetAmount)
+{
+  char *indexBufLoc = indexBuf;
+
+  /* Consume the index and adjust each index by the specified amount */
+  while (indexBufLoc != (indexBuf + indexLength)) {
+    /* Adjust the offset */
+    uint32_t* offsetToContent = (uint32_t *)indexBufLoc;
+    *offsetToContent = ntohl(*offsetToContent);
+    *offsetToContent += offsetAmount;
+    *offsetToContent = htonl(*offsetToContent);
+    /* Skip past the offset, length, and flags */
+    indexBufLoc += 3 * sizeof(uint32_t);
+    indexBufLoc += strlen(indexBufLoc) + 1;
+  }
+}
+
+/**
+ * Reads from fpSrc, writes it to fpDest, and updates the signature contexts.
+ *
+ * @param  fpSrc    The file pointer to read from.
+ * @param  fpDest   The file pointer to write to.
+ * @param  buffer   The buffer to write.
+ * @param  size     The size of the buffer to write.
+ * @param  ctxs     Pointer to the first element in an array of signature
+ *                  contexts to update.
+ * @param  ctxCount The number of signature contexts pointed to by ctxs
+ * @param  err    The name of what is being written to in case of error.
+ * @return  0 on success
+ *         -1 on read error
+ *         -2 on write error
+ *         -3 on signature update error
+*/
+int
+ReadWriteAndUpdateSignatures(FILE *fpSrc, FILE *fpDest, void *buffer,
+                             uint32_t size, SGNContext **ctxs,
+                             uint32_t ctxCount,
+                             const char *err)
+{
+  if (!size) {
+    return 0;
+  }
+
+  if (fread(buffer, size, 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: Could not read %s\n", err);
+    return -1;
+  }
+
+  return WriteAndUpdateSignatures(fpDest, buffer, size, ctxs, ctxCount, err);
+}
+
+
+/**
+ * Reads from fpSrc, writes it to fpDest.
+ *
+ * @param  fpSrc  The file pointer to read from.
+ * @param  fpDest The file pointer to write to.
+ * @param  buffer The buffer to write.
+ * @param  size   The size of the buffer to write.
+ * @param  err    The name of what is being written to in case of error.
+ * @return  0 on success
+ *         -1 on read error
+ *         -2 on write error
+*/
+int
+ReadAndWrite(FILE *fpSrc, FILE *fpDest, void *buffer,
+             uint32_t size, const char *err)
+{
+  if (!size) {
+    return 0;
+  }
+
+  if (fread(buffer, size, 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: Could not read %s\n", err);
+    return -1;
+  }
+
+  if (fwrite(buffer, size, 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write %s\n", err);
+    return -2;
+  }
+
+  return 0;
+}
+
+/**
+ * Writes out a copy of the MAR at src but with the signature block stripped.
+ *
+ * @param  src  The path of the source MAR file
+ * @param  dest The path of the MAR file to write out that
+                has no signature block
+ * @return 0 on success
+ *         -1 on error
+*/
+int
+strip_signature_block(const char *src, const char * dest)
+{
+  uint32_t offsetToIndex, dstOffsetToIndex, indexLength,
+    numSignatures = 0, leftOver;
+  int32_t stripAmount = 0;
+  int64_t oldPos, sizeOfEntireMAR = 0, realSizeOfSrcMAR, numBytesToCopy,
+    numChunks, i;
+  FILE *fpSrc = NULL, *fpDest = NULL;
+  int rv = -1, hasSignatureBlock;
+  char buf[BLOCKSIZE];
+  char *indexBuf = NULL;
+
+  if (!src || !dest) {
+    fprintf(stderr, "ERROR: Invalid parameter passed in.\n");
+    return -1;
+  }
+
+  fpSrc = fopen(src, "rb");
+  if (!fpSrc) {
+    fprintf(stderr, "ERROR: could not open source file: %s\n", src);
+    goto failure;
+  }
+
+  fpDest = fopen(dest, "wb");
+  if (!fpDest) {
+    fprintf(stderr, "ERROR: could not create target file: %s\n", dest);
+    goto failure;
+  }
+
+  /* Determine if the source MAR file has the new fields for signing or not */
+  if (get_mar_file_info(src, &hasSignatureBlock, NULL, NULL, NULL, NULL)) {
+    fprintf(stderr, "ERROR: could not determine if MAR is old or new.\n");
+    goto failure;
+  }
+
+  /* MAR ID */
+  if (ReadAndWrite(fpSrc, fpDest, buf, MAR_ID_SIZE, "MAR ID")) {
+    goto failure;
+  }
+
+  /* Offset to index */
+  if (fread(&offsetToIndex, sizeof(offsetToIndex), 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: Could not read offset\n");
+    goto failure;
+  }
+  offsetToIndex = ntohl(offsetToIndex);
+
+  /* Get the real size of the MAR */
+  oldPos = ftello(fpSrc);
+  if (fseeko(fpSrc, 0, SEEK_END)) {
+    fprintf(stderr, "ERROR: Could not seek to end of file.\n");
+    goto failure;
+  }
+  realSizeOfSrcMAR = ftello(fpSrc);
+  if (fseeko(fpSrc, oldPos, SEEK_SET)) {
+    fprintf(stderr, "ERROR: Could not seek back to current location.\n");
+    goto failure;
+  }
+
+  if (hasSignatureBlock) {
+    /* Get the MAR length and adjust its size */
+    if (fread(&sizeOfEntireMAR,
+              sizeof(sizeOfEntireMAR), 1, fpSrc) != 1) {
+      fprintf(stderr, "ERROR: Could read mar size\n");
+      goto failure;
+    }
+    sizeOfEntireMAR = NETWORK_TO_HOST64(sizeOfEntireMAR);
+    if (sizeOfEntireMAR != realSizeOfSrcMAR) {
+      fprintf(stderr, "ERROR: Source MAR is not of the right size\n");
+      goto failure;
+    }
+
+    /* Get the num signatures in the source file so we know what to strip */
+    if (fread(&numSignatures, sizeof(numSignatures), 1, fpSrc) != 1) {
+      fprintf(stderr, "ERROR: Could read num signatures\n");
+      goto failure;
+    }
+    numSignatures = ntohl(numSignatures);
+
+    for (i = 0; i < numSignatures; i++) {
+      uint32_t signatureLen;
+
+      /* Skip past the signature algorithm ID */
+      if (fseeko(fpSrc, sizeof(uint32_t), SEEK_CUR)) {
+        fprintf(stderr, "ERROR: Could not skip past signature algorithm ID\n");
+      }
+
+      /* Read in the length of the signature so we know how far to skip */
+      if (fread(&signatureLen, sizeof(uint32_t), 1, fpSrc) != 1) {
+        fprintf(stderr, "ERROR: Could not read signatures length.\n");
+        return CryptoX_Error;
+      }
+      signatureLen = ntohl(signatureLen);
+
+      /* Skip past the signature */
+      if (fseeko(fpSrc, signatureLen, SEEK_CUR)) {
+        fprintf(stderr, "ERROR: Could not skip past signature algorithm ID\n");
+      }
+
+      stripAmount += sizeof(uint32_t) + sizeof(uint32_t) + signatureLen;
+    }
+
+  } else {
+    sizeOfEntireMAR = realSizeOfSrcMAR;
+    numSignatures = 0;
+  }
+
+  if (((int64_t)offsetToIndex) > sizeOfEntireMAR) {
+    fprintf(stderr, "ERROR: Offset to index is larger than the file size.\n");
+    goto failure;
+  }
+
+  dstOffsetToIndex = offsetToIndex;
+  if (!hasSignatureBlock) {
+    dstOffsetToIndex += sizeof(sizeOfEntireMAR) + sizeof(numSignatures);
+  }
+  dstOffsetToIndex -= stripAmount;
+
+  /* Write out the index offset */
+  dstOffsetToIndex = htonl(dstOffsetToIndex);
+  if (fwrite(&dstOffsetToIndex, sizeof(dstOffsetToIndex), 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write offset to index\n");
+    goto failure;
+  }
+  dstOffsetToIndex = ntohl(dstOffsetToIndex);
+
+  /* Write out the new MAR file size */
+  if (!hasSignatureBlock) {
+    sizeOfEntireMAR += sizeof(sizeOfEntireMAR) + sizeof(numSignatures);
+  }
+  sizeOfEntireMAR -= stripAmount;
+
+  /* Write out the MAR size */
+  sizeOfEntireMAR = HOST_TO_NETWORK64(sizeOfEntireMAR);
+  if (fwrite(&sizeOfEntireMAR, sizeof(sizeOfEntireMAR), 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write size of MAR\n");
+    goto failure;
+  }
+  sizeOfEntireMAR = NETWORK_TO_HOST64(sizeOfEntireMAR);
+
+  /* Write out the number of signatures, which is 0 */
+  numSignatures = 0;
+  if (fwrite(&numSignatures, sizeof(numSignatures), 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write out num signatures\n");
+    goto failure;
+  }
+
+  /* Write out the rest of the MAR excluding the index header and index
+     offsetToIndex unfortunately has to remain 32-bit because for backwards
+     compatibility with the old MAR file format. */
+  if (ftello(fpSrc) > ((int64_t)offsetToIndex)) {
+    fprintf(stderr, "ERROR: Index offset is too small.\n");
+    goto failure;
+  }
+  numBytesToCopy = ((int64_t)offsetToIndex) - ftello(fpSrc);
+  numChunks = numBytesToCopy / BLOCKSIZE;
+  leftOver = numBytesToCopy % BLOCKSIZE;
+
+  /* Read each file and write it to the MAR file */
+  for (i = 0; i < numChunks; ++i) {
+    if (ReadAndWrite(fpSrc, fpDest, buf, BLOCKSIZE, "content block")) {
+      goto failure;
+    }
+  }
+
+  /* Write out the left over */
+  if (ReadAndWrite(fpSrc, fpDest, buf,
+                   leftOver, "left over content block")) {
+    goto failure;
+  }
+
+  /* Length of the index */
+  if (ReadAndWrite(fpSrc, fpDest, &indexLength,
+                   sizeof(indexLength), "index length")) {
+    goto failure;
+  }
+  indexLength = ntohl(indexLength);
+
+  /* Consume the index and adjust each index by the difference */
+  indexBuf = malloc(indexLength);
+  if (fread(indexBuf, indexLength, 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: Could not read index\n");
+    goto failure;
+  }
+
+  /* Adjust each entry in the index */
+  if (hasSignatureBlock) {
+    AdjustIndexContentOffsets(indexBuf, indexLength, -stripAmount);
+  } else {
+    AdjustIndexContentOffsets(indexBuf, indexLength,
+                              sizeof(sizeOfEntireMAR) +
+                              sizeof(numSignatures) -
+                              stripAmount);
+  }
+
+  if (fwrite(indexBuf, indexLength, 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write index\n");
+    goto failure;
+  }
+
+  rv = 0;
+failure:
+  if (fpSrc) {
+    fclose(fpSrc);
+  }
+
+  if (fpDest) {
+    fclose(fpDest);
+  }
+
+  if (rv) {
+    remove(dest);
+  }
+
+  if (indexBuf) {
+    free(indexBuf);
+  }
+
+  if (rv) {
+    remove(dest);
+  }
+  return rv;
+}
+
+/**
+ * Extracts a signature from a MAR file, base64 encodes it, and writes it out
+ *
+ * @param  src       The path of the source MAR file
+ * @param  sigIndex  The index of the signature to extract
+ * @param  dest      The path of file to write the signature to
+ * @return 0 on success
+ *         -1 on error
+*/
+int
+extract_signature(const char *src, uint32_t sigIndex, const char * dest)
+{
+  FILE *fpSrc = NULL, *fpDest = NULL;
+  uint32_t i;
+  uint32_t signatureCount;
+  uint32_t signatureLen = 0;
+  uint8_t *extractedSignature = NULL;
+  char *base64Encoded = NULL;
+  int rv = -1;
+  if (!src || !dest) {
+    fprintf(stderr, "ERROR: Invalid parameter passed in.\n");
+    goto failure;
+  }
+
+  fpSrc = fopen(src, "rb");
+  if (!fpSrc) {
+    fprintf(stderr, "ERROR: could not open source file: %s\n", src);
+    goto failure;
+  }
+
+  fpDest = fopen(dest, "wb");
+  if (!fpDest) {
+    fprintf(stderr, "ERROR: could not create target file: %s\n", dest);
+    goto failure;
+  }
+
+  /* Skip to the start of the signature block */
+  if (fseeko(fpSrc, SIGNATURE_BLOCK_OFFSET, SEEK_SET)) {
+    fprintf(stderr, "ERROR: could not seek to signature block\n");
+    goto failure;
+  }
+
+  /* Get the number of signatures */
+  if (fread(&signatureCount, sizeof(signatureCount), 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: could not read signature count\n");
+    goto failure;
+  }
+  signatureCount = ntohl(signatureCount);
+  if (sigIndex >= signatureCount) {
+    fprintf(stderr, "ERROR: Signature index was out of range\n");
+    goto failure;
+  }
+
+  /* Skip to the correct signature */
+  for (i = 0; i <= sigIndex; i++) {
+    /* Avoid leaking while skipping signatures */
+    free(extractedSignature);
+
+    /* skip past the signature algorithm ID */
+    if (fseeko(fpSrc, sizeof(uint32_t), SEEK_CUR)) {
+      fprintf(stderr, "ERROR: Could not seek past sig algorithm ID.\n");
+      goto failure;
+    }
+
+    /* Get the signature length */
+    if (fread(&signatureLen, sizeof(signatureLen), 1, fpSrc) != 1) {
+      fprintf(stderr, "ERROR: could not read signature length\n");
+      goto failure;
+    }
+    signatureLen = ntohl(signatureLen);
+
+    /* Get the signature */
+    extractedSignature = malloc(signatureLen);
+    if (fread(extractedSignature, signatureLen, 1, fpSrc) != 1) {
+      fprintf(stderr, "ERROR: could not read signature\n");
+      goto failure;
+    }
+  }
+
+  base64Encoded = BTOA_DataToAscii(extractedSignature, signatureLen);
+  if (!base64Encoded) {
+    fprintf(stderr, "ERROR: could not obtain base64 encoded data\n");
+    goto failure;
+  }
+
+  if (fwrite(base64Encoded, strlen(base64Encoded), 1, fpDest) != 1) {
+    fprintf(stderr, "ERROR: Could not write base64 encoded string\n");
+    goto failure;
+  }
+
+  rv = 0;
+failure:
+  if (base64Encoded) {
+    PORT_Free(base64Encoded);
+  }
+
+  if (extractedSignature) {
+    free(extractedSignature);
+  }
+
+  if (fpSrc) {
+    fclose(fpSrc);
+  }
+
+  if (fpDest) {
+    fclose(fpDest);
+  }
+
+  if (rv) {
+    remove(dest);
+  }
+
+  return rv;
+}
+
+/**
+ * Imports a base64 encoded signature into a MAR file
+ *
+ * @param  src           The path of the source MAR file
+ * @param  sigIndex      The index of the signature to import
+ * @param  base64SigFile A file which contains the signature to import
+ * @param  dest          The path of the destination MAR file with replaced signature
+ * @return 0 on success
+ *         -1 on error
+*/
+int
+import_signature(const char *src, uint32_t sigIndex,
+                 const char *base64SigFile, const char *dest)
+{
+  int rv = -1;
+  FILE *fpSrc = NULL;
+  FILE *fpDest = NULL;
+  FILE *fpSigFile = NULL;
+  uint32_t i;
+  uint32_t signatureCount, signatureLen, signatureAlgorithmID,
+           numChunks, leftOver;
+  char buf[BLOCKSIZE];
+  uint64_t sizeOfSrcMAR, sizeOfBase64EncodedFile;
+  char *passedInSignatureB64 = NULL;
+  uint8_t *passedInSignatureRaw = NULL;
+  uint8_t *extractedMARSignature = NULL;
+  unsigned int passedInSignatureLenRaw;
+
+  if (!src || !dest) {
+    fprintf(stderr, "ERROR: Invalid parameter passed in.\n");
+    goto failure;
+  }
+
+  fpSrc = fopen(src, "rb");
+  if (!fpSrc) {
+    fprintf(stderr, "ERROR: could not open source file: %s\n", src);
+    goto failure;
+  }
+
+  fpDest = fopen(dest, "wb");
+  if (!fpDest) {
+    fprintf(stderr, "ERROR: could not open dest file: %s\n", dest);
+    goto failure;
+  }
+
+  fpSigFile = fopen(base64SigFile , "rb");
+  if (!fpSigFile) {
+    fprintf(stderr, "ERROR: could not open sig file: %s\n", base64SigFile);
+    goto failure;
+  }
+
+  /* Get the src file size */
+  if (fseeko(fpSrc, 0, SEEK_END)) {
+    fprintf(stderr, "ERROR: Could not seek to end of src file.\n");
+    goto failure;
+  }
+  sizeOfSrcMAR = ftello(fpSrc);
+  if (fseeko(fpSrc, 0, SEEK_SET)) {
+    fprintf(stderr, "ERROR: Could not seek to start of src file.\n");
+    goto failure;
+  }
+
+  /* Get the sig file size */
+  if (fseeko(fpSigFile, 0, SEEK_END)) {
+    fprintf(stderr, "ERROR: Could not seek to end of sig file.\n");
+    goto failure;
+  }
+  sizeOfBase64EncodedFile= ftello(fpSigFile);
+  if (fseeko(fpSigFile, 0, SEEK_SET)) {
+    fprintf(stderr, "ERROR: Could not seek to start of sig file.\n");
+    goto failure;
+  }
+
+  /* Read in the base64 encoded signature to import */
+  passedInSignatureB64 = malloc(sizeOfBase64EncodedFile + 1);
+  passedInSignatureB64[sizeOfBase64EncodedFile] = '\0';
+  if (fread(passedInSignatureB64, sizeOfBase64EncodedFile, 1, fpSigFile) != 1) {
+    fprintf(stderr, "ERROR: Could read b64 sig file.\n");
+    goto failure;
+  }
+
+  /* Decode the base64 encoded data */
+  passedInSignatureRaw = ATOB_AsciiToData(passedInSignatureB64, &passedInSignatureLenRaw);
+  if (!passedInSignatureRaw) {
+    fprintf(stderr, "ERROR: could not obtain base64 decoded data\n");
+    goto failure;
+  }
+
+  /* Read everything up until the signature block offset and write it out */
+  if (ReadAndWrite(fpSrc, fpDest, buf,
+                   SIGNATURE_BLOCK_OFFSET, "signature block offset")) {
+    goto failure;
+  }
+
+  /* Get the number of signatures */
+  if (ReadAndWrite(fpSrc, fpDest, &signatureCount,
+                   sizeof(signatureCount), "signature count")) {
+    goto failure;
+  }
+  signatureCount = ntohl(signatureCount);
+  if (signatureCount > MAX_SIGNATURES) {
+    fprintf(stderr, "ERROR: Signature count was out of range\n");
+    goto failure;
+  }
+
+  if (sigIndex >= signatureCount) {
+    fprintf(stderr, "ERROR: Signature index was out of range\n");
+    goto failure;
+  }
+
+  /* Read and write the whole signature block, but if we reach the
+     signature offset, then we should replace it with the specified
+     base64 decoded signature */
+  for (i = 0; i < signatureCount; i++) {
+    /* Read/Write the signature algorithm ID */
+    if (ReadAndWrite(fpSrc, fpDest,
+                     &signatureAlgorithmID,
+                     sizeof(signatureAlgorithmID), "sig algorithm ID")) {
+      goto failure;
+    }
+
+    /* Read/Write the signature length */
+    if (ReadAndWrite(fpSrc, fpDest,
+                     &signatureLen, sizeof(signatureLen), "sig length")) {
+      goto failure;
+    }
+    signatureLen = ntohl(signatureLen);
+
+    /* Get the signature */
+    if (extractedMARSignature) {
+      free(extractedMARSignature);
+    }
+    extractedMARSignature = malloc(signatureLen);
+
+    if (sigIndex == i) {
+      if (passedInSignatureLenRaw != signatureLen) {
+        fprintf(stderr, "ERROR: Signature length must be the same\n");
+        goto failure;
+      }
+
+      if (fread(extractedMARSignature, signatureLen, 1, fpSrc) != 1) {
+        fprintf(stderr, "ERROR: Could not read signature\n");
+        goto failure;
+      }
+
+      if (fwrite(passedInSignatureRaw, passedInSignatureLenRaw,
+                 1, fpDest) != 1) {
+        fprintf(stderr, "ERROR: Could not write signature\n");
+        goto failure;
+      }
+    } else {
+      if (ReadAndWrite(fpSrc, fpDest,
+                       extractedMARSignature, signatureLen, "signature")) {
+        goto failure;
+      }
+    }
+  }
+
+  /* We replaced the signature so let's just skip past the rest o the
+     file. */
+  numChunks = (sizeOfSrcMAR - ftello(fpSrc)) / BLOCKSIZE;
+  leftOver = (sizeOfSrcMAR - ftello(fpSrc)) % BLOCKSIZE;
+
+  /* Read each file and write it to the MAR file */
+  for (i = 0; i < numChunks; ++i) {
+    if (ReadAndWrite(fpSrc, fpDest, buf, BLOCKSIZE, "content block")) {
+      goto failure;
+    }
+  }
+
+  if (ReadAndWrite(fpSrc, fpDest, buf, leftOver, "left over content block")) {
+    goto failure;
+  }
+
+  rv = 0;
+
+failure:
+
+  if (fpSrc) {
+    fclose(fpSrc);
+  }
+
+  if (fpDest) {
+    fclose(fpDest);
+  }
+
+  if (fpSigFile) {
+    fclose(fpSigFile);
+  }
+
+  if (rv) {
+    remove(dest);
+  }
+
+  if (extractedMARSignature) {
+    free(extractedMARSignature);
+  }
+
+  if (passedInSignatureB64) {
+    free(passedInSignatureB64);
+  }
+
+  if (passedInSignatureRaw) {
+    PORT_Free(passedInSignatureRaw);
+  }
+
+  return rv;
+}
+
+/**
+ * Writes out a copy of the MAR at src but with embedded signatures.
+ * The passed in MAR file must not already be signed or an error will
+ * be returned.
+ *
+ * @param  NSSConfigDir  The NSS directory containing the private key for signing
+ * @param  certNames     The nicknames of the certificate to use for signing
+ * @param  certCount     The number of certificate names contained in certNames.
+ *                       One signature will be produced for each certificate.
+ * @param  src           The path of the source MAR file to sign
+ * @param  dest          The path of the MAR file to write out that is signed
+ * @return 0 on success
+ *         -1 on error
+*/
+int
+mar_repackage_and_sign(const char *NSSConfigDir,
+                       const char * const *certNames,
+                       uint32_t certCount,
+                       const char *src,
+                       const char *dest)
+{
+  uint32_t offsetToIndex, dstOffsetToIndex, indexLength,
+    numSignatures = 0, leftOver,
+    signatureAlgorithmID, signatureSectionLength = 0;
+  uint32_t signatureLengths[MAX_SIGNATURES];
+  int64_t oldPos, sizeOfEntireMAR = 0, realSizeOfSrcMAR,
+    signaturePlaceholderOffset, numBytesToCopy,
+    numChunks, i;
+  FILE *fpSrc = NULL, *fpDest = NULL;
+  int rv = -1, hasSignatureBlock;
+  SGNContext *ctxs[MAX_SIGNATURES];
+  SECItem secItems[MAX_SIGNATURES];
+  char buf[BLOCKSIZE];
+  SECKEYPrivateKey *privKeys[MAX_SIGNATURES];
+  CERTCertificate *certs[MAX_SIGNATURES];
+  char *indexBuf = NULL;
+  uint32_t k;
+
+  memset(signatureLengths, 0, sizeof(signatureLengths));
+  memset(ctxs, 0, sizeof(ctxs));
+  memset(secItems, 0, sizeof(secItems));
+  memset(privKeys, 0, sizeof(privKeys));
+  memset(certs, 0, sizeof(certs));
+
+  if (!NSSConfigDir || !certNames || certCount == 0 || !src || !dest) {
+    fprintf(stderr, "ERROR: Invalid parameter passed in.\n");
+    return -1;
+  }
+
+  if (NSSInitCryptoContext(NSSConfigDir)) {
+    fprintf(stderr, "ERROR: Could not init config dir: %s\n", NSSConfigDir);
+    goto failure;
+  }
+
+  PK11_SetPasswordFunc(SECU_GetModulePassword);
+
+  fpSrc = fopen(src, "rb");
+  if (!fpSrc) {
+    fprintf(stderr, "ERROR: could not open source file: %s\n", src);
+    goto failure;
+  }
+
+  fpDest = fopen(dest, "wb");
+  if (!fpDest) {
+    fprintf(stderr, "ERROR: could not create target file: %s\n", dest);
+    goto failure;
+  }
+
+  /* Determine if the source MAR file has the new fields for signing or not */
+  if (get_mar_file_info(src, &hasSignatureBlock, NULL, NULL, NULL, NULL)) {
+    fprintf(stderr, "ERROR: could not determine if MAR is old or new.\n");
+    goto failure;
+  }
+
+  for (k = 0; k < certCount; k++) {
+    if (NSSSignBegin(certNames[k], &ctxs[k], &privKeys[k],
+                     &certs[k], &signatureLengths[k])) {
+      fprintf(stderr, "ERROR: NSSSignBegin failed\n");
+      goto failure;
+    }
+  }
+
+  /* MAR ID */
+  if (ReadWriteAndUpdateSignatures(fpSrc, fpDest,
+                                   buf, MAR_ID_SIZE,
+                                   ctxs, certCount, "MAR ID")) {
+    goto failure;
+  }
+
+  /* Offset to index */
+  if (fread(&offsetToIndex, sizeof(offsetToIndex), 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: Could not read offset\n");
+    goto failure;
+  }
+  offsetToIndex = ntohl(offsetToIndex);
+
+  /* Get the real size of the MAR */
+  oldPos = ftello(fpSrc);
+  if (fseeko(fpSrc, 0, SEEK_END)) {
+    fprintf(stderr, "ERROR: Could not seek to end of file.\n");
+    goto failure;
+  }
+  realSizeOfSrcMAR = ftello(fpSrc);
+  if (fseeko(fpSrc, oldPos, SEEK_SET)) {
+    fprintf(stderr, "ERROR: Could not seek back to current location.\n");
+    goto failure;
+  }
+
+  if (hasSignatureBlock) {
+    /* Get the MAR length and adjust its size */
+    if (fread(&sizeOfEntireMAR,
+              sizeof(sizeOfEntireMAR), 1, fpSrc) != 1) {
+      fprintf(stderr, "ERROR: Could read mar size\n");
+      goto failure;
+    }
+    sizeOfEntireMAR = NETWORK_TO_HOST64(sizeOfEntireMAR);
+    if (sizeOfEntireMAR != realSizeOfSrcMAR) {
+      fprintf(stderr, "ERROR: Source MAR is not of the right size\n");
+      goto failure;
+    }
+
+    /* Get the num signatures in the source file */
+    if (fread(&numSignatures, sizeof(numSignatures), 1, fpSrc) != 1) {
+      fprintf(stderr, "ERROR: Could read num signatures\n");
+      goto failure;
+    }
+    numSignatures = ntohl(numSignatures);
+
+    /* We do not support resigning, if you have multiple signatures,
+       you must add them all at the same time. */
+    if (numSignatures) {
+      fprintf(stderr, "ERROR: MAR is already signed\n");
+      goto failure;
+    }
+  } else {
+    sizeOfEntireMAR = realSizeOfSrcMAR;
+  }
+
+  if (((int64_t)offsetToIndex) > sizeOfEntireMAR) {
+    fprintf(stderr, "ERROR: Offset to index is larger than the file size.\n");
+    goto failure;
+  }
+
+  /* Calculate the total signature block length */
+  for (k = 0; k < certCount; k++) {
+    signatureSectionLength += sizeof(signatureAlgorithmID) +
+                              sizeof(signatureLengths[k]) +
+                              signatureLengths[k];
+  }
+  dstOffsetToIndex = offsetToIndex;
+  if (!hasSignatureBlock) {
+    dstOffsetToIndex += sizeof(sizeOfEntireMAR) + sizeof(numSignatures);
+  }
+  dstOffsetToIndex += signatureSectionLength;
+
+  /* Write out the index offset */
+  dstOffsetToIndex = htonl(dstOffsetToIndex);
+  if (WriteAndUpdateSignatures(fpDest, &dstOffsetToIndex,
+                               sizeof(dstOffsetToIndex), ctxs, certCount,
+                               "index offset")) {
+    goto failure;
+  }
+  dstOffsetToIndex = ntohl(dstOffsetToIndex);
+
+  /* Write out the new MAR file size */
+  sizeOfEntireMAR += signatureSectionLength;
+  if (!hasSignatureBlock) {
+    sizeOfEntireMAR += sizeof(sizeOfEntireMAR) + sizeof(numSignatures);
+  }
+
+  /* Write out the MAR size */
+  sizeOfEntireMAR = HOST_TO_NETWORK64(sizeOfEntireMAR);
+  if (WriteAndUpdateSignatures(fpDest, &sizeOfEntireMAR,
+                               sizeof(sizeOfEntireMAR), ctxs, certCount,
+                               "size of MAR")) {
+    goto failure;
+  }
+  sizeOfEntireMAR = NETWORK_TO_HOST64(sizeOfEntireMAR);
+
+  /* Write out the number of signatures */
+  numSignatures = certCount;
+  numSignatures = htonl(numSignatures);
+  if (WriteAndUpdateSignatures(fpDest, &numSignatures,
+                               sizeof(numSignatures), ctxs, certCount,
+                               "num signatures")) {
+    goto failure;
+  }
+  numSignatures = ntohl(numSignatures);
+
+  signaturePlaceholderOffset = ftello(fpDest);
+
+  for (k = 0; k < certCount; k++) {
+    /* Write out the signature algorithm ID, Only an ID of 1 is supported */
+    signatureAlgorithmID = htonl(1);
+    if (WriteAndUpdateSignatures(fpDest, &signatureAlgorithmID,
+                                 sizeof(signatureAlgorithmID),
+                                 ctxs, certCount, "num signatures")) {
+      goto failure;
+    }
+    signatureAlgorithmID = ntohl(signatureAlgorithmID);
+
+    /* Write out the signature length */
+    signatureLengths[k] = htonl(signatureLengths[k]);
+    if (WriteAndUpdateSignatures(fpDest, &signatureLengths[k],
+                                 sizeof(signatureLengths[k]),
+                                 ctxs, certCount, "signature length")) {
+      goto failure;
+    }
+    signatureLengths[k] = ntohl(signatureLengths[k]);
+
+    /* Write out a placeholder for the signature, we'll come back to this later
+      *** THIS IS NOT SIGNED because it is a placeholder that will be replaced
+          below, plus it is going to be the signature itself. *** */
+    memset(buf, 0, sizeof(buf));
+    if (fwrite(buf, signatureLengths[k], 1, fpDest) != 1) {
+      fprintf(stderr, "ERROR: Could not write signature length\n");
+      goto failure;
+    }
+  }
+
+  /* Write out the rest of the MAR excluding the index header and index
+     offsetToIndex unfortunately has to remain 32-bit because for backwards
+     compatibility with the old MAR file format. */
+  if (ftello(fpSrc) > ((int64_t)offsetToIndex)) {
+    fprintf(stderr, "ERROR: Index offset is too small.\n");
+    goto failure;
+  }
+  numBytesToCopy = ((int64_t)offsetToIndex) - ftello(fpSrc);
+  numChunks = numBytesToCopy / BLOCKSIZE;
+  leftOver = numBytesToCopy % BLOCKSIZE;
+
+  /* Read each file and write it to the MAR file */
+  for (i = 0; i < numChunks; ++i) {
+    if (ReadWriteAndUpdateSignatures(fpSrc, fpDest, buf,
+                                     BLOCKSIZE, ctxs, certCount,
+                                     "content block")) {
+      goto failure;
+    }
+  }
+
+  /* Write out the left over */
+  if (ReadWriteAndUpdateSignatures(fpSrc, fpDest, buf,
+                                   leftOver, ctxs, certCount,
+                                   "left over content block")) {
+    goto failure;
+  }
+
+  /* Length of the index */
+  if (ReadWriteAndUpdateSignatures(fpSrc, fpDest, &indexLength,
+                                   sizeof(indexLength), ctxs, certCount,
+                                   "index length")) {
+    goto failure;
+  }
+  indexLength = ntohl(indexLength);
+
+  /* Consume the index and adjust each index by signatureSectionLength */
+  indexBuf = malloc(indexLength);
+  if (fread(indexBuf, indexLength, 1, fpSrc) != 1) {
+    fprintf(stderr, "ERROR: Could not read index\n");
+    goto failure;
+  }
+
+  /* Adjust each entry in the index */
+  if (hasSignatureBlock) {
+    AdjustIndexContentOffsets(indexBuf, indexLength, signatureSectionLength);
+  } else {
+    AdjustIndexContentOffsets(indexBuf, indexLength,
+                              sizeof(sizeOfEntireMAR) +
+                              sizeof(numSignatures) +
+                              signatureSectionLength);
+  }
+
+  if (WriteAndUpdateSignatures(fpDest, indexBuf,
+                               indexLength, ctxs, certCount, "index")) {
+    goto failure;
+  }
+
+  /* Ensure that we don't sign a file that is too large to be accepted by
+     the verification function. */
+  if (ftello(fpDest) > MAX_SIZE_OF_MAR_FILE) {
+    goto failure;
+  }
+
+  for (k = 0; k < certCount; k++) {
+    /* Get the signature */
+    if (SGN_End(ctxs[k], &secItems[k]) != SECSuccess) {
+      fprintf(stderr, "ERROR: Could not end signature context\n");
+      goto failure;
+    }
+    if (signatureLengths[k] != secItems[k].len) {
+      fprintf(stderr, "ERROR: Signature is not the expected length\n");
+      goto failure;
+    }
+  }
+
+  /* Get back to the location of the signature placeholder */
+  if (fseeko(fpDest, signaturePlaceholderOffset, SEEK_SET)) {
+    fprintf(stderr, "ERROR: Could not seek to signature offset\n");
+    goto failure;
+  }
+
+  for (k = 0; k < certCount; k++) {
+    /* Skip to the position of the next signature */
+    if (fseeko(fpDest, sizeof(signatureAlgorithmID) +
+               sizeof(signatureLengths[k]), SEEK_CUR)) {
+      fprintf(stderr, "ERROR: Could not seek to signature offset\n");
+      goto failure;
+    }
+
+    /* Write out the calculated signature.
+      *** THIS IS NOT SIGNED because it is the signature itself. *** */
+    if (fwrite(secItems[k].data, secItems[k].len, 1, fpDest) != 1) {
+      fprintf(stderr, "ERROR: Could not write signature\n");
+      goto failure;
+    }
+  }
+
+  rv = 0;
+failure:
+  if (fpSrc) {
+    fclose(fpSrc);
+  }
+
+  if (fpDest) {
+    fclose(fpDest);
+  }
+
+  if (rv) {
+    remove(dest);
+  }
+
+  if (indexBuf) {
+    free(indexBuf);
+  }
+
+  /* Cleanup */
+  for (k = 0; k < certCount; k++) {
+    if (ctxs[k]) {
+      SGN_DestroyContext(ctxs[k], PR_TRUE);
+    }
+
+    if (certs[k]) {
+      CERT_DestroyCertificate(certs[k]);
+    }
+
+    if (privKeys[k]) {
+      SECKEY_DestroyPrivateKey(privKeys[k]);
+    }
+
+    SECITEM_FreeItem(&secItems[k], PR_FALSE);
+  }
+
+  if (rv) {
+    remove(dest);
+  }
+
+  return rv;
+}