path: root/contrib/libs/openssl/apps/smime.c

/* 
 * Copyright 1999-2018 The OpenSSL Project Authors. All Rights Reserved. 
 * 
 * Licensed under the OpenSSL license (the "License").  You may not use 
 * this file except in compliance with the License.  You can obtain a copy 
 * in the file LICENSE in the source distribution or at 
 * https://www.openssl.org/source/license.html 
 */ 
 
/* S/MIME utility function */ 
 
#include <stdio.h> 
#include <string.h> 
#include "apps.h" 
#include "progs.h" 
#include <openssl/crypto.h> 
#include <openssl/pem.h> 
#include <openssl/err.h> 
#include <openssl/x509_vfy.h> 
#include <openssl/x509v3.h> 
 
static int save_certs(char *signerfile, STACK_OF(X509) *signers); 
static int smime_cb(int ok, X509_STORE_CTX *ctx); 
 
#define SMIME_OP        0x10 
#define SMIME_IP        0x20 
#define SMIME_SIGNERS   0x40 
#define SMIME_ENCRYPT   (1 | SMIME_OP) 
#define SMIME_DECRYPT   (2 | SMIME_IP) 
#define SMIME_SIGN      (3 | SMIME_OP | SMIME_SIGNERS) 
#define SMIME_VERIFY    (4 | SMIME_IP) 
#define SMIME_PK7OUT    (5 | SMIME_IP | SMIME_OP) 
#define SMIME_RESIGN    (6 | SMIME_IP | SMIME_OP | SMIME_SIGNERS) 
 
typedef enum OPTION_choice { 
    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP, 
    OPT_ENCRYPT, OPT_DECRYPT, OPT_SIGN, OPT_RESIGN, OPT_VERIFY, 
    OPT_PK7OUT, OPT_TEXT, OPT_NOINTERN, OPT_NOVERIFY, OPT_NOCHAIN, 
    OPT_NOCERTS, OPT_NOATTR, OPT_NODETACH, OPT_NOSMIMECAP, 
    OPT_BINARY, OPT_NOSIGS, OPT_STREAM, OPT_INDEF, OPT_NOINDEF, 
    OPT_CRLFEOL, OPT_ENGINE, OPT_PASSIN, 
    OPT_TO, OPT_FROM, OPT_SUBJECT, OPT_SIGNER, OPT_RECIP, OPT_MD, 
    OPT_CIPHER, OPT_INKEY, OPT_KEYFORM, OPT_CERTFILE, OPT_CAFILE, 
    OPT_R_ENUM, 
    OPT_V_ENUM, 
    OPT_CAPATH, OPT_NOCAFILE, OPT_NOCAPATH, OPT_IN, OPT_INFORM, OPT_OUT, 
    OPT_OUTFORM, OPT_CONTENT 
} OPTION_CHOICE; 
 
const OPTIONS smime_options[] = { 
    {OPT_HELP_STR, 1, '-', "Usage: %s [options] cert.pem...\n"}, 
    {OPT_HELP_STR, 1, '-', 
        "  cert.pem... recipient certs for encryption\n"}, 
    {OPT_HELP_STR, 1, '-', "Valid options are:\n"}, 
    {"help", OPT_HELP, '-', "Display this summary"}, 
    {"encrypt", OPT_ENCRYPT, '-', "Encrypt message"}, 
    {"decrypt", OPT_DECRYPT, '-', "Decrypt encrypted message"}, 
    {"sign", OPT_SIGN, '-', "Sign message"}, 
    {"verify", OPT_VERIFY, '-', "Verify signed message"}, 
    {"pk7out", OPT_PK7OUT, '-', "Output PKCS#7 structure"}, 
    {"nointern", OPT_NOINTERN, '-', 
     "Don't search certificates in message for signer"}, 
    {"nosigs", OPT_NOSIGS, '-', "Don't verify message signature"}, 
    {"noverify", OPT_NOVERIFY, '-', "Don't verify signers certificate"}, 
    {"nocerts", OPT_NOCERTS, '-', 
     "Don't include signers certificate when signing"}, 
    {"nodetach", OPT_NODETACH, '-', "Use opaque signing"}, 
    {"noattr", OPT_NOATTR, '-', "Don't include any signed attributes"}, 
    {"binary", OPT_BINARY, '-', "Don't translate message to text"}, 
    {"certfile", OPT_CERTFILE, '<', "Other certificates file"}, 
    {"signer", OPT_SIGNER, 's', "Signer certificate file"}, 
    {"recip", OPT_RECIP, '<', "Recipient certificate file for decryption"}, 
    {"in", OPT_IN, '<', "Input file"}, 
    {"inform", OPT_INFORM, 'c', "Input format SMIME (default), PEM or DER"}, 
    {"inkey", OPT_INKEY, 's', 
     "Input private key (if not signer or recipient)"}, 
    {"keyform", OPT_KEYFORM, 'f', "Input private key format (PEM or ENGINE)"}, 
    {"out", OPT_OUT, '>', "Output file"}, 
    {"outform", OPT_OUTFORM, 'c', 
     "Output format SMIME (default), PEM or DER"}, 
    {"content", OPT_CONTENT, '<', 
     "Supply or override content for detached signature"}, 
    {"to", OPT_TO, 's', "To address"}, 
    {"from", OPT_FROM, 's', "From address"}, 
    {"subject", OPT_SUBJECT, 's', "Subject"}, 
    {"text", OPT_TEXT, '-', "Include or delete text MIME headers"}, 
    {"CApath", OPT_CAPATH, '/', "Trusted certificates directory"}, 
    {"CAfile", OPT_CAFILE, '<', "Trusted certificates file"}, 
    {"no-CAfile", OPT_NOCAFILE, '-', 
     "Do not load the default certificates file"}, 
    {"no-CApath", OPT_NOCAPATH, '-', 
     "Do not load certificates from the default certificates directory"}, 
    {"resign", OPT_RESIGN, '-', "Resign a signed message"}, 
    {"nochain", OPT_NOCHAIN, '-', 
     "set PKCS7_NOCHAIN so certificates contained in the message are not used as untrusted CAs" }, 
    {"nosmimecap", OPT_NOSMIMECAP, '-', "Omit the SMIMECapabilities attribute"}, 
    {"stream", OPT_STREAM, '-', "Enable CMS streaming" }, 
    {"indef", OPT_INDEF, '-', "Same as -stream" }, 
    {"noindef", OPT_NOINDEF, '-', "Disable CMS streaming"}, 
    {"crlfeol", OPT_CRLFEOL, '-', "Use CRLF as EOL termination instead of CR only"}, 
    OPT_R_OPTIONS, 
    {"passin", OPT_PASSIN, 's', "Input file pass phrase source"}, 
    {"md", OPT_MD, 's', "Digest algorithm to use when signing or resigning"}, 
    {"", OPT_CIPHER, '-', "Any supported cipher"}, 
    OPT_V_OPTIONS, 
#ifndef OPENSSL_NO_ENGINE 
    {"engine", OPT_ENGINE, 's', "Use engine, possibly a hardware device"}, 
#endif 
    {NULL} 
}; 
 
int smime_main(int argc, char **argv) 
{ 
    BIO *in = NULL, *out = NULL, *indata = NULL; 
    EVP_PKEY *key = NULL; 
    PKCS7 *p7 = NULL; 
    STACK_OF(OPENSSL_STRING) *sksigners = NULL, *skkeys = NULL; 
    STACK_OF(X509) *encerts = NULL, *other = NULL; 
    X509 *cert = NULL, *recip = NULL, *signer = NULL; 
    X509_STORE *store = NULL; 
    X509_VERIFY_PARAM *vpm = NULL; 
    const EVP_CIPHER *cipher = NULL; 
    const EVP_MD *sign_md = NULL; 
    const char *CAfile = NULL, *CApath = NULL, *prog = NULL; 
    char *certfile = NULL, *keyfile = NULL, *contfile = NULL; 
    char *infile = NULL, *outfile = NULL, *signerfile = NULL, *recipfile = NULL; 
    char *passinarg = NULL, *passin = NULL, *to = NULL, *from = NULL, *subject = NULL; 
    OPTION_CHOICE o; 
    int noCApath = 0, noCAfile = 0; 
    int flags = PKCS7_DETACHED, operation = 0, ret = 0, indef = 0; 
    int informat = FORMAT_SMIME, outformat = FORMAT_SMIME, keyform = 
        FORMAT_PEM; 
    int vpmtouched = 0, rv = 0; 
    ENGINE *e = NULL; 
    const char *mime_eol = "\n"; 
 
    if ((vpm = X509_VERIFY_PARAM_new()) == NULL) 
        return 1; 
 
    prog = opt_init(argc, argv, smime_options); 
    while ((o = opt_next()) != OPT_EOF) { 
        switch (o) { 
        case OPT_EOF: 
        case OPT_ERR: 
 opthelp: 
            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog); 
            goto end; 
        case OPT_HELP: 
            opt_help(smime_options); 
            ret = 0; 
            goto end; 
        case OPT_INFORM: 
            if (!opt_format(opt_arg(), OPT_FMT_PDS, &informat)) 
                goto opthelp; 
            break; 
        case OPT_IN: 
            infile = opt_arg(); 
            break; 
        case OPT_OUTFORM: 
            if (!opt_format(opt_arg(), OPT_FMT_PDS, &outformat)) 
                goto opthelp; 
            break; 
        case OPT_OUT: 
            outfile = opt_arg(); 
            break; 
        case OPT_ENCRYPT: 
            operation = SMIME_ENCRYPT; 
            break; 
        case OPT_DECRYPT: 
            operation = SMIME_DECRYPT; 
            break; 
        case OPT_SIGN: 
            operation = SMIME_SIGN; 
            break; 
        case OPT_RESIGN: 
            operation = SMIME_RESIGN; 
            break; 
        case OPT_VERIFY: 
            operation = SMIME_VERIFY; 
            break; 
        case OPT_PK7OUT: 
            operation = SMIME_PK7OUT; 
            break; 
        case OPT_TEXT: 
            flags |= PKCS7_TEXT; 
            break; 
        case OPT_NOINTERN: 
            flags |= PKCS7_NOINTERN; 
            break; 
        case OPT_NOVERIFY: 
            flags |= PKCS7_NOVERIFY; 
            break; 
        case OPT_NOCHAIN: 
            flags |= PKCS7_NOCHAIN; 
            break; 
        case OPT_NOCERTS: 
            flags |= PKCS7_NOCERTS; 
            break; 
        case OPT_NOATTR: 
            flags |= PKCS7_NOATTR; 
            break; 
        case OPT_NODETACH: 
            flags &= ~PKCS7_DETACHED; 
            break; 
        case OPT_NOSMIMECAP: 
            flags |= PKCS7_NOSMIMECAP; 
            break; 
        case OPT_BINARY: 
            flags |= PKCS7_BINARY; 
            break; 
        case OPT_NOSIGS: 
            flags |= PKCS7_NOSIGS; 
            break; 
        case OPT_STREAM: 
        case OPT_INDEF: 
            indef = 1; 
            break; 
        case OPT_NOINDEF: 
            indef = 0; 
            break; 
        case OPT_CRLFEOL: 
            flags |= PKCS7_CRLFEOL; 
            mime_eol = "\r\n"; 
            break; 
        case OPT_R_CASES: 
            if (!opt_rand(o)) 
                goto end; 
            break; 
        case OPT_ENGINE: 
            e = setup_engine(opt_arg(), 0); 
            break; 
        case OPT_PASSIN: 
            passinarg = opt_arg(); 
            break; 
        case OPT_TO: 
            to = opt_arg(); 
            break; 
        case OPT_FROM: 
            from = opt_arg(); 
            break; 
        case OPT_SUBJECT: 
            subject = opt_arg(); 
            break; 
        case OPT_SIGNER: 
            /* If previous -signer argument add signer to list */ 
            if (signerfile != NULL) { 
                if (sksigners == NULL 
                    && (sksigners = sk_OPENSSL_STRING_new_null()) == NULL) 
                    goto end; 
                sk_OPENSSL_STRING_push(sksigners, signerfile); 
                if (keyfile == NULL) 
                    keyfile = signerfile; 
                if (skkeys == NULL 
                    && (skkeys = sk_OPENSSL_STRING_new_null()) == NULL) 
                    goto end; 
                sk_OPENSSL_STRING_push(skkeys, keyfile); 
                keyfile = NULL; 
            } 
            signerfile = opt_arg(); 
            break; 
        case OPT_RECIP: 
            recipfile = opt_arg(); 
            break; 
        case OPT_MD: 
            if (!opt_md(opt_arg(), &sign_md)) 
                goto opthelp; 
            break; 
        case OPT_CIPHER: 
            if (!opt_cipher(opt_unknown(), &cipher)) 
                goto opthelp; 
            break; 
        case OPT_INKEY: 
            /* If previous -inkey argument add signer to list */ 
            if (keyfile != NULL) { 
                if (signerfile == NULL) { 
                    BIO_printf(bio_err, 
                               "%s: Must have -signer before -inkey\n", prog); 
                    goto opthelp; 
                } 
                if (sksigners == NULL 
                    && (sksigners = sk_OPENSSL_STRING_new_null()) == NULL) 
                    goto end; 
                sk_OPENSSL_STRING_push(sksigners, signerfile); 
                signerfile = NULL; 
                if (skkeys == NULL 
                    && (skkeys = sk_OPENSSL_STRING_new_null()) == NULL) 
                    goto end; 
                sk_OPENSSL_STRING_push(skkeys, keyfile); 
            } 
            keyfile = opt_arg(); 
            break; 
        case OPT_KEYFORM: 
            if (!opt_format(opt_arg(), OPT_FMT_ANY, &keyform)) 
                goto opthelp; 
            break; 
        case OPT_CERTFILE: 
            certfile = opt_arg(); 
            break; 
        case OPT_CAFILE: 
            CAfile = opt_arg(); 
            break; 
        case OPT_CAPATH: 
            CApath = opt_arg(); 
            break; 
        case OPT_NOCAFILE: 
            noCAfile = 1; 
            break; 
        case OPT_NOCAPATH: 
            noCApath = 1; 
            break; 
        case OPT_CONTENT: 
            contfile = opt_arg(); 
            break; 
        case OPT_V_CASES: 
            if (!opt_verify(o, vpm)) 
                goto opthelp; 
            vpmtouched++; 
            break; 
        } 
    } 
    argc = opt_num_rest(); 
    argv = opt_rest(); 
 
    if (!(operation & SMIME_SIGNERS) && (skkeys != NULL || sksigners != NULL)) { 
        BIO_puts(bio_err, "Multiple signers or keys not allowed\n"); 
        goto opthelp; 
    } 
 
    if (operation & SMIME_SIGNERS) { 
        /* Check to see if any final signer needs to be appended */ 
        if (keyfile && !signerfile) { 
            BIO_puts(bio_err, "Illegal -inkey without -signer\n"); 
            goto opthelp; 
        } 
        if (signerfile != NULL) { 
            if (sksigners == NULL 
                && (sksigners = sk_OPENSSL_STRING_new_null()) == NULL) 
                goto end; 
            sk_OPENSSL_STRING_push(sksigners, signerfile); 
            if (!skkeys && (skkeys = sk_OPENSSL_STRING_new_null()) == NULL) 
                goto end; 
            if (!keyfile) 
                keyfile = signerfile; 
            sk_OPENSSL_STRING_push(skkeys, keyfile); 
        } 
        if (sksigners == NULL) { 
            BIO_printf(bio_err, "No signer certificate specified\n"); 
            goto opthelp; 
        } 
        signerfile = NULL; 
        keyfile = NULL; 
    } else if (operation == SMIME_DECRYPT) { 
        if (recipfile == NULL && keyfile == NULL) { 
            BIO_printf(bio_err, 
                       "No recipient certificate or key specified\n"); 
            goto opthelp; 
        } 
    } else if (operation == SMIME_ENCRYPT) { 
        if (argc == 0) { 
            BIO_printf(bio_err, "No recipient(s) certificate(s) specified\n"); 
            goto opthelp; 
        } 
    } else if (!operation) { 
        goto opthelp; 
    } 
 
    if (!app_passwd(passinarg, NULL, &passin, NULL)) { 
        BIO_printf(bio_err, "Error getting password\n"); 
        goto end; 
    } 
 
    ret = 2; 
 
    if (!(operation & SMIME_SIGNERS)) 
        flags &= ~PKCS7_DETACHED; 
 
    if (!(operation & SMIME_OP)) { 
        if (flags & PKCS7_BINARY) 
            outformat = FORMAT_BINARY; 
    } 
 
    if (!(operation & SMIME_IP)) { 
        if (flags & PKCS7_BINARY) 
            informat = FORMAT_BINARY; 
    } 
 
    if (operation == SMIME_ENCRYPT) { 
        if (cipher == NULL) { 
#ifndef OPENSSL_NO_DES 
            cipher = EVP_des_ede3_cbc(); 
#else 
            BIO_printf(bio_err, "No cipher selected\n"); 
            goto end; 
#endif 
        } 
        encerts = sk_X509_new_null(); 
        if (encerts == NULL) 
            goto end; 
        while (*argv != NULL) { 
            cert = load_cert(*argv, FORMAT_PEM, 
                             "recipient certificate file"); 
            if (cert == NULL) 
                goto end; 
            sk_X509_push(encerts, cert); 
            cert = NULL; 
            argv++; 
        } 
    } 
 
    if (certfile != NULL) { 
        if (!load_certs(certfile, &other, FORMAT_PEM, NULL, 
                        "certificate file")) { 
            ERR_print_errors(bio_err); 
            goto end; 
        } 
    } 
 
    if (recipfile != NULL && (operation == SMIME_DECRYPT)) { 
        if ((recip = load_cert(recipfile, FORMAT_PEM, 
                               "recipient certificate file")) == NULL) { 
            ERR_print_errors(bio_err); 
            goto end; 
        } 
    } 
 
    if (operation == SMIME_DECRYPT) { 
        if (keyfile == NULL) 
            keyfile = recipfile; 
    } else if (operation == SMIME_SIGN) { 
        if (keyfile == NULL) 
            keyfile = signerfile; 
    } else { 
        keyfile = NULL; 
    } 
 
    if (keyfile != NULL) { 
        key = load_key(keyfile, keyform, 0, passin, e, "signing key file"); 
        if (key == NULL) 
            goto end; 
    } 
 
    in = bio_open_default(infile, 'r', informat); 
    if (in == NULL) 
        goto end; 
 
    if (operation & SMIME_IP) { 
        if (informat == FORMAT_SMIME) { 
            p7 = SMIME_read_PKCS7(in, &indata); 
        } else if (informat == FORMAT_PEM) { 
            p7 = PEM_read_bio_PKCS7(in, NULL, NULL, NULL); 
        } else if (informat == FORMAT_ASN1) { 
            p7 = d2i_PKCS7_bio(in, NULL); 
        } else { 
            BIO_printf(bio_err, "Bad input format for PKCS#7 file\n"); 
            goto end; 
        } 
 
        if (p7 == NULL) { 
            BIO_printf(bio_err, "Error reading S/MIME message\n"); 
            goto end; 
        } 
        if (contfile != NULL) { 
            BIO_free(indata); 
            if ((indata = BIO_new_file(contfile, "rb")) == NULL) { 
                BIO_printf(bio_err, "Can't read content file %s\n", contfile); 
                goto end; 
            } 
        } 
    } 
 
    out = bio_open_default(outfile, 'w', outformat); 
    if (out == NULL) 
        goto end; 
 
    if (operation == SMIME_VERIFY) { 
        if ((store = setup_verify(CAfile, CApath, noCAfile, noCApath)) == NULL) 
            goto end; 
        X509_STORE_set_verify_cb(store, smime_cb); 
        if (vpmtouched) 
            X509_STORE_set1_param(store, vpm); 
    } 
 
    ret = 3; 
 
    if (operation == SMIME_ENCRYPT) { 
        if (indef) 
            flags |= PKCS7_STREAM; 
        p7 = PKCS7_encrypt(encerts, in, cipher, flags); 
    } else if (operation & SMIME_SIGNERS) { 
        int i; 
        /* 
         * If detached data content we only enable streaming if S/MIME output 
         * format. 
         */ 
        if (operation == SMIME_SIGN) { 
            if (flags & PKCS7_DETACHED) { 
                if (outformat == FORMAT_SMIME) 
                    flags |= PKCS7_STREAM; 
            } else if (indef) { 
                flags |= PKCS7_STREAM; 
            } 
            flags |= PKCS7_PARTIAL; 
            p7 = PKCS7_sign(NULL, NULL, other, in, flags); 
            if (p7 == NULL) 
                goto end; 
            if (flags & PKCS7_NOCERTS) { 
                for (i = 0; i < sk_X509_num(other); i++) { 
                    X509 *x = sk_X509_value(other, i); 
                    PKCS7_add_certificate(p7, x); 
                } 
            } 
        } else { 
            flags |= PKCS7_REUSE_DIGEST; 
        } 
        for (i = 0; i < sk_OPENSSL_STRING_num(sksigners); i++) { 
            signerfile = sk_OPENSSL_STRING_value(sksigners, i); 
            keyfile = sk_OPENSSL_STRING_value(skkeys, i); 
            signer = load_cert(signerfile, FORMAT_PEM, 
                               "signer certificate"); 
            if (signer == NULL) 
                goto end; 
            key = load_key(keyfile, keyform, 0, passin, e, "signing key file"); 
            if (key == NULL) 
                goto end; 
            if (!PKCS7_sign_add_signer(p7, signer, key, sign_md, flags)) 
                goto end; 
            X509_free(signer); 
            signer = NULL; 
            EVP_PKEY_free(key); 
            key = NULL; 
        } 
        /* If not streaming or resigning finalize structure */ 
        if ((operation == SMIME_SIGN) && !(flags & PKCS7_STREAM)) { 
            if (!PKCS7_final(p7, in, flags)) 
                goto end; 
        } 
    } 
 
    if (p7 == NULL) { 
        BIO_printf(bio_err, "Error creating PKCS#7 structure\n"); 
        goto end; 
    } 
 
    ret = 4; 
    if (operation == SMIME_DECRYPT) { 
        if (!PKCS7_decrypt(p7, key, recip, out, flags)) { 
            BIO_printf(bio_err, "Error decrypting PKCS#7 structure\n"); 
            goto end; 
        } 
    } else if (operation == SMIME_VERIFY) { 
        STACK_OF(X509) *signers; 
        if (PKCS7_verify(p7, other, store, indata, out, flags)) 
            BIO_printf(bio_err, "Verification successful\n"); 
        else { 
            BIO_printf(bio_err, "Verification failure\n"); 
            goto end; 
        } 
        signers = PKCS7_get0_signers(p7, other, flags); 
        if (!save_certs(signerfile, signers)) { 
            BIO_printf(bio_err, "Error writing signers to %s\n", signerfile); 
            ret = 5; 
            goto end; 
        } 
        sk_X509_free(signers); 
    } else if (operation == SMIME_PK7OUT) { 
        PEM_write_bio_PKCS7(out, p7); 
    } else { 
        if (to) 
            BIO_printf(out, "To: %s%s", to, mime_eol); 
        if (from) 
            BIO_printf(out, "From: %s%s", from, mime_eol); 
        if (subject) 
            BIO_printf(out, "Subject: %s%s", subject, mime_eol); 
        if (outformat == FORMAT_SMIME) { 
            if (operation == SMIME_RESIGN) 
                rv = SMIME_write_PKCS7(out, p7, indata, flags); 
            else 
                rv = SMIME_write_PKCS7(out, p7, in, flags); 
        } else if (outformat == FORMAT_PEM) { 
            rv = PEM_write_bio_PKCS7_stream(out, p7, in, flags); 
        } else if (outformat == FORMAT_ASN1) { 
            rv = i2d_PKCS7_bio_stream(out, p7, in, flags); 
        } else { 
            BIO_printf(bio_err, "Bad output format for PKCS#7 file\n"); 
            goto end; 
        } 
        if (rv == 0) { 
            BIO_printf(bio_err, "Error writing output\n"); 
            ret = 3; 
            goto end; 
        } 
    } 
    ret = 0; 
 end: 
    if (ret) 
        ERR_print_errors(bio_err); 
    sk_X509_pop_free(encerts, X509_free); 
    sk_X509_pop_free(other, X509_free); 
    X509_VERIFY_PARAM_free(vpm); 
    sk_OPENSSL_STRING_free(sksigners); 
    sk_OPENSSL_STRING_free(skkeys); 
    X509_STORE_free(store); 
    X509_free(cert); 
    X509_free(recip); 
    X509_free(signer); 
    EVP_PKEY_free(key); 
    PKCS7_free(p7); 
    release_engine(e); 
    BIO_free(in); 
    BIO_free(indata); 
    BIO_free_all(out); 
    OPENSSL_free(passin); 
    return ret; 
} 
 
static int save_certs(char *signerfile, STACK_OF(X509) *signers) 
{ 
    int i; 
    BIO *tmp; 
 
    if (signerfile == NULL) 
        return 1; 
    tmp = BIO_new_file(signerfile, "w"); 
    if (tmp == NULL) 
        return 0; 
    for (i = 0; i < sk_X509_num(signers); i++) 
        PEM_write_bio_X509(tmp, sk_X509_value(signers, i)); 
    BIO_free(tmp); 
    return 1; 
} 
 
/* Minimal callback just to output policy info (if any) */ 
 
static int smime_cb(int ok, X509_STORE_CTX *ctx) 
{ 
    int error; 
 
    error = X509_STORE_CTX_get_error(ctx); 
 
    if ((error != X509_V_ERR_NO_EXPLICIT_POLICY) 
        && ((error != X509_V_OK) || (ok != 2))) 
        return ok; 
 
    policies_print(ctx); 
 
    return ok; 
}