/* 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/. */

/*
 * p7verify -- A command to do a verification of a *detached* pkcs7 signature.
 */

#include "nspr.h"
#include "secutil.h"
#include "plgetopt.h"
#include "secpkcs7.h"
#include "cert.h"
#include "certdb.h"
#include "secoid.h"
#include "sechash.h" /* for HASH_GetHashObject() */
#include "nss.h"

#if defined(XP_UNIX)
#include <unistd.h>
#endif

#include <stdio.h>
#include <string.h>

#if (defined(XP_WIN) && !defined(WIN32)) || (defined(__sun) && !defined(SVR4))
extern int fread(char *, size_t, size_t, FILE *);
extern int fprintf(FILE *, char *, ...);
#endif

static HASH_HashType
AlgorithmToHashType(SECAlgorithmID *digestAlgorithms)
{

    SECOidTag tag;

    tag = SECOID_GetAlgorithmTag(digestAlgorithms);

    switch (tag) {
        case SEC_OID_MD2:
            return HASH_AlgMD2;
        case SEC_OID_MD5:
            return HASH_AlgMD5;
        case SEC_OID_SHA1:
            return HASH_AlgSHA1;
        default:
            fprintf(stderr, "should never get here\n");
            return HASH_AlgNULL;
    }
}

static int
DigestFile(unsigned char *digest, unsigned int *len, unsigned int maxLen,
           FILE *inFile, HASH_HashType hashType)
{
    int nb;
    unsigned char ibuf[4096];
    const SECHashObject *hashObj;
    void *hashcx;

    hashObj = HASH_GetHashObject(hashType);

    hashcx = (*hashObj->create)();
    if (hashcx == NULL)
        return -1;

    (*hashObj->begin)(hashcx);

    for (;;) {
        if (feof(inFile))
            break;
        nb = fread(ibuf, 1, sizeof(ibuf), inFile);
        if (nb != sizeof(ibuf)) {
            if (nb == 0) {
                if (ferror(inFile)) {
                    PORT_SetError(SEC_ERROR_IO);
                    (*hashObj->destroy)(hashcx, PR_TRUE);
                    return -1;
                }
                /* eof */
                break;
            }
        }
        (*hashObj->update)(hashcx, ibuf, nb);
    }

    (*hashObj->end)(hashcx, digest, len, maxLen);
    (*hashObj->destroy)(hashcx, PR_TRUE);

    return 0;
}

static void
Usage(char *progName)
{
    fprintf(stderr,
            "Usage:  %s -c content -s signature [-d dbdir] [-u certusage]\n",
            progName);
    fprintf(stderr, "%-20s content file that was signed\n",
            "-c content");
    fprintf(stderr, "%-20s file containing signature for that content\n",
            "-s signature");
    fprintf(stderr,
            "%-20s Key/Cert database directory (default is ~/.netscape)\n",
            "-d dbdir");
    fprintf(stderr, "%-20s Define the type of certificate usage (default is certUsageEmailSigner)\n",
            "-u certusage");
    fprintf(stderr, "%-25s  0 - certUsageSSLClient\n", " ");
    fprintf(stderr, "%-25s  1 - certUsageSSLServer\n", " ");
    fprintf(stderr, "%-25s  2 - certUsageSSLServerWithStepUp\n", " ");
    fprintf(stderr, "%-25s  3 - certUsageSSLCA\n", " ");
    fprintf(stderr, "%-25s  4 - certUsageEmailSigner\n", " ");
    fprintf(stderr, "%-25s  5 - certUsageEmailRecipient\n", " ");
    fprintf(stderr, "%-25s  6 - certUsageObjectSigner\n", " ");
    fprintf(stderr, "%-25s  7 - certUsageUserCertImport\n", " ");
    fprintf(stderr, "%-25s  8 - certUsageVerifyCA\n", " ");
    fprintf(stderr, "%-25s  9 - certUsageProtectedObjectSigner\n", " ");
    fprintf(stderr, "%-25s 10 - certUsageStatusResponder\n", " ");
    fprintf(stderr, "%-25s 11 - certUsageAnyCA\n", " ");
    fprintf(stderr, "%-25s 12 - certUsageIPsec\n", " ");

    exit(-1);
}

static int
HashDecodeAndVerify(FILE *out, FILE *content, PRFileDesc *signature,
                    SECCertUsage usage, char *progName)
{
    SECItem derdata;
    SEC_PKCS7ContentInfo *cinfo;
    SEC_PKCS7SignedData *signedData;
    HASH_HashType digestType;
    SECItem digest;
    unsigned char buffer[32];

    if (SECU_ReadDERFromFile(&derdata, signature, PR_FALSE,
                             PR_FALSE) != SECSuccess) {
        SECU_PrintError(progName, "error reading signature file");
        return -1;
    }

    cinfo = SEC_PKCS7DecodeItem(&derdata, NULL, NULL, NULL, NULL,
                                NULL, NULL, NULL);
    if (cinfo == NULL)
        return -1;

    if (!SEC_PKCS7ContentIsSigned(cinfo)) {
        fprintf(out, "Signature file is pkcs7 data, but not signed.\n");
        return -1;
    }

    signedData = cinfo->content.signedData;

    /* assume that there is only one digest algorithm for now */
    digestType = AlgorithmToHashType(signedData->digestAlgorithms[0]);
    if (digestType == HASH_AlgNULL) {
        fprintf(out, "Invalid hash algorithmID\n");
        return -1;
    }

    digest.data = buffer;
    if (DigestFile(digest.data, &digest.len, 32, content, digestType)) {
        SECU_PrintError(progName, "problem computing message digest");
        return -1;
    }

    fprintf(out, "Signature is ");
    if (SEC_PKCS7VerifyDetachedSignature(cinfo, usage, &digest, digestType,
                                         PR_FALSE))
        fprintf(out, "valid.\n");
    else
        fprintf(out, "invalid (Reason: %s).\n",
                SECU_Strerror(PORT_GetError()));

    SECITEM_FreeItem(&derdata, PR_FALSE);
    SEC_PKCS7DestroyContentInfo(cinfo);
    return 0;
}

int
main(int argc, char **argv)
{
    char *progName;
    FILE *contentFile, *outFile;
    PRFileDesc *signatureFile;
    SECCertUsage certUsage = certUsageEmailSigner;
    PLOptState *optstate;
    PLOptStatus status;
    SECStatus rv;

    progName = strrchr(argv[0], '/');
    progName = progName ? progName + 1 : argv[0];

    contentFile = NULL;
    signatureFile = NULL;
    outFile = NULL;

    /*
     * Parse command line arguments
     */
    optstate = PL_CreateOptState(argc, argv, "c:d:o:s:u:");
    while ((status = PL_GetNextOpt(optstate)) == PL_OPT_OK) {
        switch (optstate->option) {
            case '?':
                Usage(progName);
                break;

            case 'c':
                contentFile = fopen(optstate->value, "r");
                if (!contentFile) {
                    fprintf(stderr, "%s: unable to open \"%s\" for reading\n",
                            progName, optstate->value);
                    return -1;
                }
                break;

            case 'd':
                SECU_ConfigDirectory(optstate->value);
                break;

            case 'o':
                outFile = fopen(optstate->value, "w");
                if (!outFile) {
                    fprintf(stderr, "%s: unable to open \"%s\" for writing\n",
                            progName, optstate->value);
                    return -1;
                }
                break;

            case 's':
                signatureFile = PR_Open(optstate->value, PR_RDONLY, 0);
                if (!signatureFile) {
                    fprintf(stderr, "%s: unable to open \"%s\" for reading\n",
                            progName, optstate->value);
                    return -1;
                }
                break;

            case 'u': {
                int usageType;

                usageType = atoi(strdup(optstate->value));
                if (usageType < certUsageSSLClient || usageType > certUsageAnyCA)
                    return -1;
                certUsage = (SECCertUsage)usageType;
                break;
            }
        }
    }
    PL_DestroyOptState(optstate);

    if (!contentFile)
        Usage(progName);
    if (!signatureFile)
        Usage(progName);
    if (!outFile)
        outFile = stdout;

    /* Call the NSS initialization routines */
    PR_Init(PR_SYSTEM_THREAD, PR_PRIORITY_NORMAL, 1);
    rv = NSS_Init(SECU_ConfigDirectory(NULL));
    if (rv != SECSuccess) {
        SECU_PrintPRandOSError(progName);
        return -1;
    }

    if (HashDecodeAndVerify(outFile, contentFile, signatureFile,
                            certUsage, progName)) {
        SECU_PrintError(progName, "problem decoding/verifying signature");
        return -1;
    }

    fclose(contentFile);
    PR_Close(signatureFile);
    if (outFile && outFile != stdout) {
        fclose(outFile);
    }

    if (NSS_Shutdown() != SECSuccess) {
        exit(1);
    }

    return 0;
}