The Tor Browser: modules/libmar/sign/mar_sign.c@b8a032363ba2 (annotated)

modules/libmar/sign/mar_sign.c@b8a032363ba2 (annotated)

modules/libmar/sign/mar_sign.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* 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 XP_WIN
 #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 "mar_private.h"
 #include "mar_cmdline.h"
 #include "mar.h"
 #include "cryptox.h"
 #ifndef XP_WIN
 #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 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)
 {
   uint32_t *offsetToContent;
   char *indexBufLoc = indexBuf;
   /* Consume the index and adjust each index by the specified amount */
   while (indexBufLoc != (indexBuf + indexLength)) {
     /* Adjust the offset */
     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, *indexBufLoc;
   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);
   indexBufLoc = indexBuf;
   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;
   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++) {
     /* 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,
 , 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, *indexBufLoc;
   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);
   indexBufLoc = indexBuf;
   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;
 }

The Tor Browser / annotate

modules/libmar/sign/mar_sign.c@b8a032363ba2 (annotated)

modules/libmar/sign/mar_sign.c