putty/cmdgen.c

/*
 * cmdgen.c - command-line form of PuTTYgen
 */

#define PUTTY_DO_GLOBALS

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>
#include <assert.h>
#include <time.h>
#include <errno.h>
#include <string.h>

#include "putty.h"
#include "ssh.h"

#ifdef TEST_CMDGEN
/*
 * This section overrides some definitions below for test purposes.
 * When compiled with -DTEST_CMDGEN (as cgtest.c will do):
 *
 *  - Calls to get_random_data() are replaced with the diagnostic
 *    function below (I #define the name so that I can still link
 *    with the original set of modules without symbol clash), in
 *    order to avoid depleting the test system's /dev/random
 *    unnecessarily.
 *
 *  - Calls to console_get_userpass_input() are replaced with the
 *    diagnostic function below, so that I can run tests in an
 *    automated manner and provide their interactive passphrase
 *    inputs.
 *
 *  - main() is renamed to cmdgen_main(); at the bottom of the file
 *    I define another main() which calls the former repeatedly to
 *    run tests.
 */
bool cgtest_verbose = false;
#define get_random_data get_random_data_diagnostic
char *get_random_data(int len, const char *device)
{
    char *buf = snewn(len, char);
    memset(buf, 'x', len);
    return buf;
}
#define console_get_userpass_input console_get_userpass_input_diagnostic
int nprompts, promptsgot;
const char *prompts[3];
int console_get_userpass_input(prompts_t *p)
{
    size_t i;
    int ret = 1;
    for (i = 0; i < p->n_prompts; i++) {
        if (promptsgot < nprompts) {
            prompt_set_result(p->prompts[i], prompts[promptsgot++]);
            if (cgtest_verbose)
                printf("  prompt \"%s\": response \"%s\"\n",
                       p->prompts[i]->prompt, p->prompts[i]->result->s);
        } else {
            promptsgot++;           /* track number of requests anyway */
            ret = 0;
            if (cgtest_verbose)
                printf("  prompt \"%s\": no response preloaded\n",
                       p->prompts[i]->prompt);
        }
    }
    return ret;
}
#define main cmdgen_main
#endif

struct progress {
    int phase, current;
};

static void progress_update(void *param, int action, int phase, int iprogress)
{
    struct progress *p = (struct progress *)param;
    if (action != PROGFN_PROGRESS)
        return;
    if (phase > p->phase) {
        if (p->phase >= 0)
            fputc('\n', stderr);
        p->phase = phase;
        if (iprogress >= 0)
            p->current = iprogress - 1;
        else
            p->current = iprogress;
    }
    while (p->current < iprogress) {
        fputc('+', stdout);
        p->current++;
    }
    fflush(stdout);
}

static void no_progress(void *param, int action, int phase, int iprogress)
{
}

/*
 * Stubs to let everything else link sensibly.
 */
char *x_get_default(const char *key)
{
    return NULL;
}
void sk_cleanup(void)
{
}

void showversion(void)
{
    char *buildinfo_text = buildinfo("\n");
    printf("puttygen: %s\n%s\n", ver, buildinfo_text);
    sfree(buildinfo_text);
}

void usage(bool standalone)
{
    fprintf(standalone ? stderr : stdout,
            "Usage: puttygen ( keyfile | -t type [ -b bits ] )\n"
            "                [ -C comment ] [ -P ] [ -q ]\n"
            "                [ -o output-keyfile ] [ -O type | -l | -L"
            " | -p ]\n");
    if (standalone)
        fprintf(stderr,
                "Use \"puttygen --help\" for more detail.\n");
}

void help(void)
{
    /*
     * Help message is an extended version of the usage message. So
     * start with that, plus a version heading.
     */
    printf("PuTTYgen: key generator and converter for the PuTTY tools\n"
           "%s\n", ver);
    usage(false);
    printf("  -t    specify key type when generating (ed25519, ecdsa, rsa, "
                                                        "dsa, rsa1)\n"
           "  -b    specify number of bits when generating key\n"
           "  -C    change or specify key comment\n"
           "  -P    change key passphrase\n"
           "  -q    quiet: do not display progress bar\n"
           "  -O    specify output type:\n"
           "           private             output PuTTY private key format\n"
           "           private-openssh     export OpenSSH private key\n"
           "           private-openssh-new export OpenSSH private key "
                                             "(force new format)\n"
           "           private-sshcom      export ssh.com private key\n"
           "           public              RFC 4716 / ssh.com public key\n"
           "           public-openssh      OpenSSH public key\n"
           "           fingerprint         output the key fingerprint\n"
           "  -o    specify output file\n"
           "  -l    equivalent to `-O fingerprint'\n"
           "  -L    equivalent to `-O public-openssh'\n"
           "  -p    equivalent to `-O public'\n"
           "  --old-passphrase file\n"
           "        specify file containing old key passphrase\n"
           "  --new-passphrase file\n"
           "        specify file containing new key passphrase\n"
           "  --random-device device\n"
           "        specify device to read entropy from (e.g. /dev/urandom)\n"
           );
}

static bool move(char *from, char *to)
{
    int ret;

    ret = rename(from, to);
    if (ret) {
        /*
         * This OS may require us to remove the original file first.
         */
        remove(to);
        ret = rename(from, to);
    }
    if (ret) {
        perror("puttygen: cannot move new file on to old one");
        return false;
    }
    return true;
}

static char *readpassphrase(const char *filename)
{
    FILE *fp;
    char *line;

    fp = fopen(filename, "r");
    if (!fp) {
        fprintf(stderr, "puttygen: cannot open %s: %s\n",
                filename, strerror(errno));
        return NULL;
    }
    line = fgetline(fp);
    if (line)
        line[strcspn(line, "\r\n")] = '\0';
    else if (ferror(fp))
        fprintf(stderr, "puttygen: error reading from %s: %s\n",
                filename, strerror(errno));
    else        /* empty file */
        line = dupstr("");
    fclose(fp);
    return line;
}

#define DEFAULT_RSADSA_BITS 2048

/* For Unix in particular, but harmless if this main() is reused elsewhere */
const bool buildinfo_gtk_relevant = false;

int main(int argc, char **argv)
{
    char *infile = NULL;
    Filename *infilename = NULL, *outfilename = NULL;
    enum { NOKEYGEN, RSA1, RSA2, DSA, ECDSA, ED25519 } keytype = NOKEYGEN;
    char *outfile = NULL, *outfiletmp = NULL;
    enum { PRIVATE, PUBLIC, PUBLICO, FP, OPENSSH_AUTO,
           OPENSSH_NEW, SSHCOM } outtype = PRIVATE;
    int bits = -1;
    const char *comment = NULL;
    char *origcomment = NULL;
    bool change_passphrase = false;
    bool errs = false, nogo = false;
    int intype = SSH_KEYTYPE_UNOPENABLE;
    int sshver = 0;
    ssh2_userkey *ssh2key = NULL;
    RSAKey *ssh1key = NULL;
    strbuf *ssh2blob = NULL;
    char *ssh2alg = NULL;
    char *old_passphrase = NULL, *new_passphrase = NULL;
    bool load_encrypted;
    progfn_t progressfn = is_interactive() ? progress_update : no_progress;
    const char *random_device = NULL;
    int exit_status = 0;

    #define RETURN(status) do { exit_status = (status); goto out; } while (0)

    /* ------------------------------------------------------------------
     * Parse the command line to figure out what we've been asked to do.
     */

    /*
     * If run with no arguments at all, print the usage message and
     * return success.
     */
    if (argc <= 1) {
        usage(true);
        RETURN(0);
    }

    /*
     * Parse command line arguments.
     */
    while (--argc) {
        char *p = *++argv;
        if (*p == '-') {
            /*
             * An option.
             */
            while (p && *++p) {
                char c = *p;
                switch (c) {
                  case '-':
                    /*
                     * Long option.
                     */
                    {
                        char *opt, *val;
                        opt = p++;     /* opt will have _one_ leading - */
                        while (*p && *p != '=')
                            p++;               /* find end of option */
                        if (*p == '=') {
                            *p++ = '\0';
                            val = p;
                        } else
                            val = NULL;

                        if (!strcmp(opt, "-help")) {
                            if (val) {
                                errs = true;
                                fprintf(stderr, "puttygen: option `-%s'"
                                        " expects no argument\n", opt);
                            } else {
                                help();
                                nogo = true;
                            }
                        } else if (!strcmp(opt, "-version")) {
                            if (val) {
                                errs = true;
                                fprintf(stderr, "puttygen: option `-%s'"
                                        " expects no argument\n", opt);
                            } else {
                                showversion();
                                nogo = true;
                            }
                        } else if (!strcmp(opt, "-pgpfp")) {
                            if (val) {
                                errs = true;
                                fprintf(stderr, "puttygen: option `-%s'"
                                        " expects no argument\n", opt);
                            } else {
                                /* support --pgpfp for consistency */
                                pgp_fingerprints();
                                nogo = true;
                            }
                        } else if (!strcmp(opt, "-old-passphrase")) {
                            if (!val && argc > 1)
                                --argc, val = *++argv;
                            if (!val) {
                                errs = true;
                                fprintf(stderr, "puttygen: option `-%s'"
                                        " expects an argument\n", opt);
                            } else {
                                old_passphrase = readpassphrase(val);
                                if (!old_passphrase)
                                    errs = true;
                            }
                        } else if (!strcmp(opt, "-new-passphrase")) {
                            if (!val && argc > 1)
                                --argc, val = *++argv;
                            if (!val) {
                                errs = true;
                                fprintf(stderr, "puttygen: option `-%s'"
                                        " expects an argument\n", opt);
                            } else {
                                new_passphrase = readpassphrase(val);
                                if (!new_passphrase)
                                    errs = true;
                            }
                        } else if (!strcmp(opt, "-random-device")) {
                            if (!val && argc > 1)
                                --argc, val = *++argv;
                            if (!val) {
                                errs = true;
                                fprintf(stderr, "puttygen: option `-%s'"
                                        " expects an argument\n", opt);
                            } else {
                                random_device = val;
                            }
                        } else {
                            errs = true;
                            fprintf(stderr,
                                    "puttygen: no such option `-%s'\n", opt);
                        }
                    }
                    p = NULL;
                    break;
                  case 'h':
                  case 'V':
                  case 'P':
                  case 'l':
                  case 'L':
                  case 'p':
                  case 'q':
                    /*
                     * Option requiring no parameter.
                     */
                    switch (c) {
                      case 'h':
                        help();
                        nogo = true;
                        break;
                      case 'V':
                        showversion();
                        nogo = true;
                        break;
                      case 'P':
                        change_passphrase = true;
                        break;
                      case 'l':
                        outtype = FP;
                        break;
                      case 'L':
                        outtype = PUBLICO;
                        break;
                      case 'p':
                        outtype = PUBLIC;
                        break;
                      case 'q':
                        progressfn = no_progress;
                        break;
                    }
                    break;
                  case 't':
                  case 'b':
                  case 'C':
                  case 'O':
                  case 'o':
                    /*
                     * Option requiring parameter.
                     */
                    p++;
                    if (!*p && argc > 1)
                        --argc, p = *++argv;
                    else if (!*p) {
                        fprintf(stderr, "puttygen: option `-%c' expects a"
                                " parameter\n", c);
                        errs = true;
                    }
                    /*
                     * Now c is the option and p is the parameter.
                     */
                    switch (c) {
                      case 't':
                        if (!strcmp(p, "rsa") || !strcmp(p, "rsa2"))
                            keytype = RSA2, sshver = 2;
                        else if (!strcmp(p, "rsa1"))
                            keytype = RSA1, sshver = 1;
                        else if (!strcmp(p, "dsa") || !strcmp(p, "dss"))
                            keytype = DSA, sshver = 2;
                        else if (!strcmp(p, "ecdsa"))
                            keytype = ECDSA, sshver = 2;
                        else if (!strcmp(p, "ed25519"))
                            keytype = ED25519, sshver = 2;
                        else {
                            fprintf(stderr,
                                    "puttygen: unknown key type `%s'\n", p);
                            errs = true;
                        }
                        break;
                      case 'b':
                        bits = atoi(p);
                        break;
                      case 'C':
                        comment = p;
                        break;
                      case 'O':
                        if (!strcmp(p, "public"))
                            outtype = PUBLIC;
                        else if (!strcmp(p, "public-openssh"))
                            outtype = PUBLICO;
                        else if (!strcmp(p, "private"))
                            outtype = PRIVATE;
                        else if (!strcmp(p, "fingerprint"))
                            outtype = FP;
                        else if (!strcmp(p, "private-openssh"))
                            outtype = OPENSSH_AUTO, sshver = 2;
                        else if (!strcmp(p, "private-openssh-new"))
                            outtype = OPENSSH_NEW, sshver = 2;
                        else if (!strcmp(p, "private-sshcom"))
                            outtype = SSHCOM, sshver = 2;
                        else {
                            fprintf(stderr,
                                    "puttygen: unknown output type `%s'\n", p);
                            errs = true;
                        }
                        break;
                      case 'o':
                        outfile = p;
                        break;
                    }
                    p = NULL;          /* prevent continued processing */
                    break;
                  default:
                    /*
                     * Unrecognised option.
                     */
                    errs = true;
                    fprintf(stderr, "puttygen: no such option `-%c'\n", c);
                    break;
                }
            }
        } else {
            /*
             * A non-option argument.
             */
            if (!infile)
                infile = p;
            else {
                errs = true;
                fprintf(stderr, "puttygen: cannot handle more than one"
                        " input file\n");
            }
        }
    }

    if (bits == -1) {
        /*
         * No explicit key size was specified. Default varies
         * depending on key type.
         */
        switch (keytype) {
          case ECDSA:
            bits = 384;
            break;
          case ED25519:
            bits = 255;
            break;
          default:
            bits = DEFAULT_RSADSA_BITS;
            break;
        }
    }

    if (keytype == ECDSA && (bits != 256 && bits != 384 && bits != 521)) {
        fprintf(stderr, "puttygen: invalid bits for ECDSA, choose 256, 384 or 521\n");
        errs = true;
    }

    if (keytype == ED25519 && (bits != 255) && (bits != 256)) {
        fprintf(stderr, "puttygen: invalid bits for ED25519, choose 255\n");
        errs = true;
    }

    if (keytype == RSA2 || keytype == RSA1 || keytype == DSA) {
        if (bits < 256) {
            fprintf(stderr, "puttygen: cannot generate %s keys shorter than"
                    " 256 bits\n", (keytype == DSA ? "DSA" : "RSA"));
            errs = true;
        } else if (bits < DEFAULT_RSADSA_BITS) {
            fprintf(stderr, "puttygen: warning: %s keys shorter than"
                    " %d bits are probably not secure\n",
                    (keytype == DSA ? "DSA" : "RSA"), DEFAULT_RSADSA_BITS);
            /* but this is just a warning, so proceed anyway */
        }
    }

    if (errs)
        RETURN(1);

    if (nogo)
        RETURN(0);

    /*
     * If run with at least one argument _but_ not the required
     * ones, print the usage message and return failure.
     */
    if (!infile && keytype == NOKEYGEN) {
        usage(true);
        RETURN(1);
    }

    /* ------------------------------------------------------------------
     * Figure out further details of exactly what we're going to do.
     */

    /*
     * Bomb out if we've been asked to both load and generate a
     * key.
     */
    if (keytype != NOKEYGEN && infile) {
        fprintf(stderr, "puttygen: cannot both load and generate a key\n");
        RETURN(1);
    }

    /*
     * We must save the private part when generating a new key.
     */
    if (keytype != NOKEYGEN &&
        (outtype != PRIVATE && outtype != OPENSSH_AUTO &&
         outtype != OPENSSH_NEW && outtype != SSHCOM)) {
        fprintf(stderr, "puttygen: this would generate a new key but "
                "discard the private part\n");
        RETURN(1);
    }

    /*
     * Analyse the type of the input file, in case this affects our
     * course of action.
     */
    if (infile) {
        infilename = filename_from_str(infile);

        intype = key_type(infilename);

        switch (intype) {
          case SSH_KEYTYPE_UNOPENABLE:
          case SSH_KEYTYPE_UNKNOWN:
            fprintf(stderr, "puttygen: unable to load file `%s': %s\n",
                    infile, key_type_to_str(intype));
            RETURN(1);

          case SSH_KEYTYPE_SSH1:
          case SSH_KEYTYPE_SSH1_PUBLIC:
            if (sshver == 2) {
                fprintf(stderr, "puttygen: conversion from SSH-1 to SSH-2 keys"
                        " not supported\n");
                RETURN(1);
            }
            sshver = 1;
            break;

          case SSH_KEYTYPE_SSH2:
          case SSH_KEYTYPE_SSH2_PUBLIC_RFC4716:
          case SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH:
          case SSH_KEYTYPE_OPENSSH_PEM:
          case SSH_KEYTYPE_OPENSSH_NEW:
          case SSH_KEYTYPE_SSHCOM:
            if (sshver == 1) {
                fprintf(stderr, "puttygen: conversion from SSH-2 to SSH-1 keys"
                        " not supported\n");
                RETURN(1);
            }
            sshver = 2;
            break;

          case SSH_KEYTYPE_OPENSSH_AUTO:
          default:
            unreachable("Should never see these types on an input file");
        }
    }

    /*
     * Determine the default output file, if none is provided.
     *
     * This will usually be equal to stdout, except that if the
     * input and output file formats are the same then the default
     * output is to overwrite the input.
     *
     * Also in this code, we bomb out if the input and output file
     * formats are the same and no other action is performed.
     */
    if ((intype == SSH_KEYTYPE_SSH1 && outtype == PRIVATE) ||
        (intype == SSH_KEYTYPE_SSH2 && outtype == PRIVATE) ||
        (intype == SSH_KEYTYPE_OPENSSH_PEM && outtype == OPENSSH_AUTO) ||
        (intype == SSH_KEYTYPE_OPENSSH_NEW && outtype == OPENSSH_NEW) ||
        (intype == SSH_KEYTYPE_SSHCOM && outtype == SSHCOM)) {
        if (!outfile) {
            outfile = infile;
            outfiletmp = dupcat(outfile, ".tmp");
        }

        if (!change_passphrase && !comment) {
            fprintf(stderr, "puttygen: this command would perform no useful"
                    " action\n");
            RETURN(1);
        }
    } else {
        if (!outfile) {
            /*
             * Bomb out rather than automatically choosing to write
             * a private key file to stdout.
             */
            if (outtype == PRIVATE || outtype == OPENSSH_AUTO ||
                outtype == OPENSSH_NEW || outtype == SSHCOM) {
                fprintf(stderr, "puttygen: need to specify an output file\n");
                RETURN(1);
            }
        }
    }

    /*
     * Figure out whether we need to load the encrypted part of the
     * key. This will be the case if either (a) we need to write
     * out a private key format, or (b) the entire input key file
     * is encrypted.
     */
    if (outtype == PRIVATE || outtype == OPENSSH_AUTO ||
        outtype == OPENSSH_NEW || outtype == SSHCOM ||
        intype == SSH_KEYTYPE_OPENSSH_PEM ||
        intype == SSH_KEYTYPE_OPENSSH_NEW ||
        intype == SSH_KEYTYPE_SSHCOM)
        load_encrypted = true;
    else
        load_encrypted = false;

    if (load_encrypted && (intype == SSH_KEYTYPE_SSH1_PUBLIC ||
                           intype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
                           intype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH)) {
        fprintf(stderr, "puttygen: cannot perform this action on a "
                "public-key-only input file\n");
        RETURN(1);
    }

    /* ------------------------------------------------------------------
     * Now we're ready to actually do some stuff.
     */

    /*
     * Either load or generate a key.
     */
    if (keytype != NOKEYGEN) {
        char *entropy;
        char default_comment[80];
        struct tm tm;
        struct progress prog;

        prog.phase = -1;
        prog.current = -1;

        tm = ltime();
        if (keytype == DSA)
            strftime(default_comment, 30, "dsa-key-%Y%m%d", &tm);
        else if (keytype == ECDSA)
            strftime(default_comment, 30, "ecdsa-key-%Y%m%d", &tm);
        else if (keytype == ED25519)
            strftime(default_comment, 30, "ed25519-key-%Y%m%d", &tm);
        else
            strftime(default_comment, 30, "rsa-key-%Y%m%d", &tm);

        entropy = get_random_data(bits / 8, random_device);
        if (!entropy) {
            fprintf(stderr, "puttygen: failed to collect entropy, "
                    "could not generate key\n");
            RETURN(1);
        }
        random_setup_special();
        random_reseed(make_ptrlen(entropy, bits / 8));
        smemclr(entropy, bits/8);
        sfree(entropy);

        if (keytype == DSA) {
            struct dss_key *dsskey = snew(struct dss_key);
            dsa_generate(dsskey, bits, progressfn, &prog);
            ssh2key = snew(ssh2_userkey);
            ssh2key->key = &dsskey->sshk;
            ssh1key = NULL;
        } else if (keytype == ECDSA) {
            struct ecdsa_key *ek = snew(struct ecdsa_key);
            ecdsa_generate(ek, bits, progressfn, &prog);
            ssh2key = snew(ssh2_userkey);
            ssh2key->key = &ek->sshk;
            ssh1key = NULL;
        } else if (keytype == ED25519) {
            struct eddsa_key *ek = snew(struct eddsa_key);
            eddsa_generate(ek, bits, progressfn, &prog);
            ssh2key = snew(ssh2_userkey);
            ssh2key->key = &ek->sshk;
            ssh1key = NULL;
        } else {
            RSAKey *rsakey = snew(RSAKey);
            rsa_generate(rsakey, bits, progressfn, &prog);
            rsakey->comment = NULL;
            if (keytype == RSA1) {
                ssh1key = rsakey;
            } else {
                ssh2key = snew(ssh2_userkey);
                ssh2key->key = &rsakey->sshk;
            }
        }
        progressfn(&prog, PROGFN_PROGRESS, INT_MAX, -1);

        if (ssh2key)
            ssh2key->comment = dupstr(default_comment);
        if (ssh1key)
            ssh1key->comment = dupstr(default_comment);

    } else {
        const char *error = NULL;
        bool encrypted;

        assert(infile != NULL);

        sfree(origcomment);
        origcomment = NULL;

        /*
         * Find out whether the input key is encrypted.
         */
        if (intype == SSH_KEYTYPE_SSH1)
            encrypted = rsa1_encrypted_f(infilename, &origcomment);
        else if (intype == SSH_KEYTYPE_SSH2)
            encrypted = ppk_encrypted_f(infilename, &origcomment);
        else
            encrypted = import_encrypted(infilename, intype, &origcomment);

        /*
         * If so, ask for a passphrase.
         */
        if (encrypted && load_encrypted) {
            if (!old_passphrase) {
                prompts_t *p = new_prompts();
                int ret;
                p->to_server = false;
                p->from_server = false;
                p->name = dupstr("SSH key passphrase");
                add_prompt(p, dupstr("Enter passphrase to load key: "), false);
                ret = console_get_userpass_input(p);
                assert(ret >= 0);
                if (!ret) {
                    free_prompts(p);
                    perror("puttygen: unable to read passphrase");
                    RETURN(1);
                } else {
                    old_passphrase = prompt_get_result(p->prompts[0]);
                    free_prompts(p);
                }
            }
        } else {
            old_passphrase = NULL;
        }

        switch (intype) {
            int ret;

          case SSH_KEYTYPE_SSH1:
          case SSH_KEYTYPE_SSH1_PUBLIC:
            ssh1key = snew(RSAKey);
            memset(ssh1key, 0, sizeof(RSAKey));
            if (!load_encrypted) {
                strbuf *blob;
                BinarySource src[1];

                sfree(origcomment);
                origcomment = NULL;

                blob = strbuf_new();

                ret = rsa1_loadpub_f(infilename, BinarySink_UPCAST(blob),
                                     &origcomment, &error);
                BinarySource_BARE_INIT(src, blob->u, blob->len);
                get_rsa_ssh1_pub(src, ssh1key, RSA_SSH1_EXPONENT_FIRST);
                strbuf_free(blob);

                ssh1key->comment = dupstr(origcomment);
                ssh1key->private_exponent = NULL;
                ssh1key->p = NULL;
                ssh1key->q = NULL;
                ssh1key->iqmp = NULL;
            } else {
                ret = rsa1_load_f(infilename, ssh1key, old_passphrase, &error);
            }
            if (ret > 0)
                error = NULL;
            else if (!error)
                error = "unknown error";
            break;

          case SSH_KEYTYPE_SSH2:
          case SSH_KEYTYPE_SSH2_PUBLIC_RFC4716:
          case SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH:
            if (!load_encrypted) {
                sfree(origcomment);
                origcomment = NULL;
                ssh2blob = strbuf_new();
                if (ppk_loadpub_f(infilename, &ssh2alg,
                                  BinarySink_UPCAST(ssh2blob),
                                  &origcomment, &error)) {
                    const ssh_keyalg *alg = find_pubkey_alg(ssh2alg);
                    if (alg)
                        bits = ssh_key_public_bits(
                            alg, ptrlen_from_strbuf(ssh2blob));
                    else
                        bits = -1;
                } else {
                    strbuf_free(ssh2blob);
                    ssh2blob = NULL;
                }
                sfree(ssh2alg);
            } else {
                ssh2key = ppk_load_f(infilename, old_passphrase, &error);
            }
            if ((ssh2key && ssh2key != SSH2_WRONG_PASSPHRASE) || ssh2blob)
                error = NULL;
            else if (!error) {
                if (ssh2key == SSH2_WRONG_PASSPHRASE)
                    error = "wrong passphrase";
                else
                    error = "unknown error";
            }
            break;

          case SSH_KEYTYPE_OPENSSH_PEM:
          case SSH_KEYTYPE_OPENSSH_NEW:
          case SSH_KEYTYPE_SSHCOM:
            ssh2key = import_ssh2(infilename, intype, old_passphrase, &error);
            if (ssh2key) {
                if (ssh2key != SSH2_WRONG_PASSPHRASE)
                    error = NULL;
                else
                    error = "wrong passphrase";
            } else if (!error)
                error = "unknown error";
            break;

          default:
            unreachable("bad input key type");
        }

        if (error) {
            fprintf(stderr, "puttygen: error loading `%s': %s\n",
                    infile, error);
            RETURN(1);
        }
    }

    /*
     * Change the comment if asked to.
     */
    if (comment) {
        if (sshver == 1) {
            assert(ssh1key);
            sfree(ssh1key->comment);
            ssh1key->comment = dupstr(comment);
        } else {
            assert(ssh2key);
            sfree(ssh2key->comment);
            ssh2key->comment = dupstr(comment);
        }
    }

    /*
     * Unless we're changing the passphrase, the old one (if any) is a
     * reasonable default.
     */
    if (!change_passphrase && old_passphrase && !new_passphrase)
        new_passphrase = dupstr(old_passphrase);

    /*
     * Prompt for a new passphrase if we have been asked to, or if
     * we have just generated a key.
     */
    if (!new_passphrase && (change_passphrase || keytype != NOKEYGEN)) {
        prompts_t *p = new_prompts(NULL);
        int ret;

        p->to_server = false;
        p->from_server = false;
        p->name = dupstr("New SSH key passphrase");
        add_prompt(p, dupstr("Enter passphrase to save key: "), false);
        add_prompt(p, dupstr("Re-enter passphrase to verify: "), false);
        ret = console_get_userpass_input(p);
        assert(ret >= 0);
        if (!ret) {
            free_prompts(p);
            perror("puttygen: unable to read new passphrase");
            RETURN(1);
        } else {
            if (strcmp(prompt_get_result_ref(p->prompts[0]),
                       prompt_get_result_ref(p->prompts[1]))) {
                free_prompts(p);
                fprintf(stderr, "puttygen: passphrases do not match\n");
                RETURN(1);
            }
            new_passphrase = prompt_get_result(p->prompts[0]);
            free_prompts(p);
        }
    }
    if (new_passphrase && !*new_passphrase) {
        sfree(new_passphrase);
        new_passphrase = NULL;
    }

    /*
     * Write output.
     *
     * (In the case where outfile and outfiletmp are both NULL,
     * there is no semantic reason to initialise outfilename at
     * all; but we have to write _something_ to it or some compiler
     * will probably complain that it might be used uninitialised.)
     */
    if (outfiletmp)
        outfilename = filename_from_str(outfiletmp);
    else
        outfilename = filename_from_str(outfile ? outfile : "");

    switch (outtype) {
        bool ret;
        int real_outtype;

      case PRIVATE:
        random_ref(); /* we'll need a few random bytes in the save file */
        if (sshver == 1) {
            assert(ssh1key);
            ret = rsa1_save_f(outfilename, ssh1key, new_passphrase);
            if (!ret) {
                fprintf(stderr, "puttygen: unable to save SSH-1 private key\n");
                RETURN(1);
            }
        } else {
            assert(ssh2key);
            ret = ppk_save_f(outfilename, ssh2key, new_passphrase);
            if (!ret) {
                fprintf(stderr, "puttygen: unable to save SSH-2 private key\n");
                RETURN(1);
            }
        }
        if (outfiletmp) {
            if (!move(outfiletmp, outfile))
                RETURN(1);              /* rename failed */
        }
        break;

      case PUBLIC:
      case PUBLICO:
        {
            FILE *fp;

            if (outfile) {
                fp = f_open(outfilename, "w", false);
                if (!fp) {
                    fprintf(stderr, "unable to open output file\n");
                    exit(1);
                }
            } else {
                fp = stdout;
            }

            if (sshver == 1) {
                ssh1_write_pubkey(fp, ssh1key);
            } else {
                if (!ssh2blob) {
                    assert(ssh2key);
                    ssh2blob = strbuf_new();
                    ssh_key_public_blob(ssh2key->key, BinarySink_UPCAST(ssh2blob));
                }

                ssh2_write_pubkey(fp, ssh2key ? ssh2key->comment : origcomment,
                                  ssh2blob->s, ssh2blob->len,
                                  (outtype == PUBLIC ?
                                   SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 :
                                   SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH));
            }

            if (outfile)
                fclose(fp);
        }
        break;

      case FP:
        {
            FILE *fp;
            char *fingerprint;

            if (sshver == 1) {
                assert(ssh1key);
                fingerprint = rsa_ssh1_fingerprint(ssh1key);
            } else {
                if (ssh2key) {
                    fingerprint = ssh2_fingerprint(ssh2key->key);
                } else {
                    assert(ssh2blob);
                    fingerprint = ssh2_fingerprint_blob(
                        ptrlen_from_strbuf(ssh2blob));
                }
            }

            if (outfile) {
                fp = f_open(outfilename, "w", false);
                if (!fp) {
                    fprintf(stderr, "unable to open output file\n");
                    exit(1);
                }
            } else {
                fp = stdout;
            }
            fprintf(fp, "%s\n", fingerprint);
            if (outfile)
                fclose(fp);

            sfree(fingerprint);
        }
        break;

      case OPENSSH_AUTO:
      case OPENSSH_NEW:
      case SSHCOM:
        assert(sshver == 2);
        assert(ssh2key);
        random_ref(); /* both foreign key types require randomness,
                       * for IV or padding */
        switch (outtype) {
          case OPENSSH_AUTO:
            real_outtype = SSH_KEYTYPE_OPENSSH_AUTO;
            break;
          case OPENSSH_NEW:
            real_outtype = SSH_KEYTYPE_OPENSSH_NEW;
            break;
          case SSHCOM:
            real_outtype = SSH_KEYTYPE_SSHCOM;
            break;
          default:
            unreachable("control flow goof");
        }
        ret = export_ssh2(outfilename, real_outtype, ssh2key, new_passphrase);
        if (!ret) {
            fprintf(stderr, "puttygen: unable to export key\n");
            RETURN(1);
        }
        if (outfiletmp) {
            if (!move(outfiletmp, outfile))
                RETURN(1);              /* rename failed */
        }
        break;
    }

  out:

    #undef RETURN

    if (old_passphrase) {
        smemclr(old_passphrase, strlen(old_passphrase));
        sfree(old_passphrase);
    }
    if (new_passphrase) {
        smemclr(new_passphrase, strlen(new_passphrase));
        sfree(new_passphrase);
    }

    if (ssh1key) {
        freersakey(ssh1key);
        sfree(ssh1key);
    }
    if (ssh2key && ssh2key != SSH2_WRONG_PASSPHRASE) {
        sfree(ssh2key->comment);
        if (ssh2key->key)
            ssh_key_free(ssh2key->key);
        sfree(ssh2key);
    }
    if (ssh2blob)
        strbuf_free(ssh2blob);
    sfree(origcomment);
    if (infilename)
        filename_free(infilename);
    if (outfilename)
        filename_free(outfilename);
    sfree(outfiletmp);

    return exit_status;
}

#ifdef TEST_CMDGEN

#undef main

#include <stdarg.h>

int passes, fails;

void setup_passphrases(char *first, ...)
{
    va_list ap;
    char *next;

    nprompts = 0;
    if (first) {
        prompts[nprompts++] = first;
        va_start(ap, first);
        while ((next = va_arg(ap, char *)) != NULL) {
            assert(nprompts < lenof(prompts));
            prompts[nprompts++] = next;
        }
        va_end(ap);
    }
}

void test(int retval, ...)
{
    va_list ap;
    int i, argc, ret;
    char **argv;

    argc = 0;
    va_start(ap, retval);
    while (va_arg(ap, char *) != NULL)
        argc++;
    va_end(ap);

    argv = snewn(argc+1, char *);
    va_start(ap, retval);
    for (i = 0; i <= argc; i++)
        argv[i] = va_arg(ap, char *);
    va_end(ap);

    promptsgot = 0;
    if (cgtest_verbose) {
        printf("run:");
        for (int i = 0; i < argc; i++) {
            static const char okchars[] =
                "0123456789abcdefghijklmnopqrstuvwxyz"
                "ABCDEFGHIJKLMNOPQRSTUVWXYZ%+,-./:=[]^_";
            const char *arg = argv[i];

            printf(" ");
            if (arg[strspn(arg, okchars)]) {
                printf("'");
                for (const char *c = argv[i]; *c; c++) {
                    if (*c == '\'') {
                        printf("'\\''");
                    } else {
                        putchar(*c);
                    }
                }
                printf("'");
            } else {
                fputs(arg, stdout);
            }
        }
        printf("\n");
    }
    ret = cmdgen_main(argc, argv);
    random_clear();

    if (ret != retval) {
        printf("FAILED retval (exp %d got %d):", retval, ret);
        for (i = 0; i < argc; i++)
            printf(" %s", argv[i]);
        printf("\n");
        fails++;
    } else if (promptsgot != nprompts) {
        printf("FAILED nprompts (exp %d got %d):", nprompts, promptsgot);
        for (i = 0; i < argc; i++)
            printf(" %s", argv[i]);
        printf("\n");
        fails++;
    } else {
        passes++;
    }

    sfree(argv);
}

void filecmp(char *file1, char *file2, char *fmt, ...)
{
    /*
     * Ideally I should do file comparison myself, to maximise the
     * portability of this test suite once this application begins
     * running on non-Unix platforms. For the moment, though,
     * calling Unix diff is perfectly adequate.
     */
    char *buf;
    int ret;

    buf = dupprintf("diff -q '%s' '%s'", file1, file2);
    ret = system(buf);
    sfree(buf);

    if (ret) {
        va_list ap;

        printf("FAILED diff (ret=%d): ", ret);

        va_start(ap, fmt);
        vprintf(fmt, ap);
        va_end(ap);

        printf("\n");

        fails++;
    } else
        passes++;
}

/*
 * General-purpose flags word
 */
#define CGT_FLAGS(X)                            \
    X(CGT_TYPE_KNOWN_EARLY)                     \
    X(CGT_OPENSSH)                              \
    X(CGT_SSHCOM)                               \
    X(CGT_SSH_KEYGEN)                           \
    X(CGT_ED25519)                              \
    /* end of list */

#define FLAG_SHIFTS(name) name ## _shift,
enum { CGT_FLAGS(FLAG_SHIFTS) CGT_dummy_shift };
#define FLAG_VALUES(name) name = 1 << name ## _shift,
enum { CGT_FLAGS(FLAG_VALUES) CGT_dummy_flag };

char *cleanup_fp(char *s, unsigned flags)
{
    ptrlen pl = ptrlen_from_asciz(s);
    static const char separators[] = " \n\t";

    /* Skip initial key type word if we find one */
    if (ptrlen_startswith(pl, PTRLEN_LITERAL("ssh-"), NULL) ||
        ptrlen_startswith(pl, PTRLEN_LITERAL("ecdsa-"), NULL))
        ptrlen_get_word(&pl, separators);

    /* Expect two words giving the key length and the hash */
    ptrlen bits = ptrlen_get_word(&pl, separators);
    ptrlen hash = ptrlen_get_word(&pl, separators);

    if (flags & CGT_SSH_KEYGEN) {
        /* Strip "MD5:" prefix if it's present, and do nothing if it isn't */
        ptrlen_startswith(hash, PTRLEN_LITERAL("MD5:"), &hash);

        if (flags & CGT_ED25519) {
            /* OpenSSH ssh-keygen lists ed25519 keys as 256 bits, not 255 */
            if (ptrlen_eq_string(bits, "256"))
                bits = PTRLEN_LITERAL("255");
        }
    }

    return dupprintf("%.*s %.*s", PTRLEN_PRINTF(bits), PTRLEN_PRINTF(hash));
}

char *get_line(char *filename)
{
    FILE *fp;
    char *line;

    fp = fopen(filename, "r");
    if (!fp)
        return NULL;
    line = fgetline(fp);
    fclose(fp);
    return line;
}

char *get_fp(char *filename, unsigned flags)
{
    char *orig = get_line(filename);
    if (!orig)
        return NULL;
    char *toret = cleanup_fp(orig, flags);
    sfree(orig);
    return toret;
}

void check_fp(char *filename, char *fp, char *fmt, ...)
{
    char *newfp;

    if (!fp)
        return;

    newfp = get_fp(filename, 0);

    if (!strcmp(fp, newfp)) {
        passes++;
    } else {
        va_list ap;

        printf("FAILED check_fp ['%s' != '%s']: ", newfp, fp);

        va_start(ap, fmt);
        vprintf(fmt, ap);
        va_end(ap);

        printf("\n");

        fails++;
    }

    sfree(newfp);
}

static const struct cgtest_keytype {
    const char *name;
    unsigned flags;
} cgtest_keytypes[] = {
    { "rsa1", CGT_TYPE_KNOWN_EARLY },
    { "dsa", CGT_OPENSSH | CGT_SSHCOM },
    { "rsa", CGT_OPENSSH | CGT_SSHCOM },
    { "ecdsa", CGT_OPENSSH },
    { "ed25519", CGT_OPENSSH | CGT_ED25519 },
};

int main(int argc, char **argv)
{
    int i;
    int active[lenof(cgtest_keytypes)], active_value;
    bool remove_files = true;

    active_value = 0;
    for (i = 0; i < lenof(cgtest_keytypes); i++)
        active[i] = active_value;

    while (--argc > 0) {
        ptrlen arg = ptrlen_from_asciz(*++argv);
        if (ptrlen_eq_string(arg, "-v") ||
            ptrlen_eq_string(arg, "--verbose")) {
            cgtest_verbose = true;
        } else if (ptrlen_eq_string(arg, "--keep")) {
            remove_files = false;
        } else if (ptrlen_eq_string(arg, "--help")) {
            printf("usage:     cgtest [options] [key types]\n");
            printf("options:   -v, --verbose         "
                   "print more output during tests\n");
            printf("           --keep                "
                   "do not delete the temporary output files\n");
            printf("           --help                "
                   "display this help text\n");
            printf("key types: ");
            for (i = 0; i < lenof(cgtest_keytypes); i++)
                printf("%s%s", i ? ", " : "", cgtest_keytypes[i].name);
            printf("\n");
            return 0;
        } else if (!ptrlen_startswith(arg, PTRLEN_LITERAL("-"), NULL)) {
            for (i = 0; i < lenof(cgtest_keytypes); i++)
                if (ptrlen_eq_string(arg, cgtest_keytypes[i].name))
                    break;
            if (i == lenof(cgtest_keytypes)) {
                fprintf(stderr, "cgtest: unrecognised key type '%.*s'\n",
                        PTRLEN_PRINTF(arg));
                return 1;
            }
            active_value = 1; /* disables all keys not explicitly enabled */
            active[i] = active_value;
        } else {
            fprintf(stderr, "cgtest: unrecognised option '%.*s'\n",
                    PTRLEN_PRINTF(arg));
            return 1;
        }
    }

    passes = fails = 0;

    for (i = 0; i < lenof(cgtest_keytypes); i++) {
        if (active[i] != active_value)
            continue;

        const struct cgtest_keytype *keytype = &cgtest_keytypes[i];
        bool supports_openssh = keytype->flags & CGT_OPENSSH;
        bool supports_sshcom = keytype->flags & CGT_SSHCOM;
        bool type_known_early = keytype->flags & CGT_TYPE_KNOWN_EARLY;

        char filename[128], osfilename[128], scfilename[128];
        char pubfilename[128], tmpfilename1[128], tmpfilename2[128];
        char *fp = NULL;

        sprintf(filename, "test-%s.ppk", keytype->name);
        sprintf(pubfilename, "test-%s.pub", keytype->name);
        sprintf(osfilename, "test-%s.os", keytype->name);
        sprintf(scfilename, "test-%s.sc", keytype->name);
        sprintf(tmpfilename1, "test-%s.tmp1", keytype->name);
        sprintf(tmpfilename2, "test-%s.tmp2", keytype->name);

        /*
         * Create an encrypted key.
         */
        setup_passphrases("sponge", "sponge", NULL);
        test(0, "puttygen", "-t", keytype->name, "-o", filename, NULL);

        /*
         * List the public key in OpenSSH format.
         */
        setup_passphrases(NULL);
        test(0, "puttygen", "-L", filename, "-o", pubfilename, NULL);
        {
            char *cmdbuf;
            fp = NULL;
            cmdbuf = dupprintf("ssh-keygen -E md5 -l -f '%s' > '%s'",
                    pubfilename, tmpfilename1);
            if (cgtest_verbose)
                printf("OpenSSH fp check: %s\n", cmdbuf);
            if (system(cmdbuf) ||
                (fp = get_fp(tmpfilename1,
                             CGT_SSH_KEYGEN | keytype->flags)) == NULL) {
                printf("UNABLE to test fingerprint matching against OpenSSH");
            }
            sfree(cmdbuf);
            if (fp && cgtest_verbose) {
                char *line = get_line(tmpfilename1);
                printf("OpenSSH fp: %s\n", line);
                printf("Cleaned up: %s\n", fp);
                sfree(line);
            }
        }

        /*
         * List the public key in IETF/ssh.com format.
         */
        setup_passphrases(NULL);
        test(0, "puttygen", "-p", filename, NULL);

        /*
         * List the fingerprint of the key.
         */
        setup_passphrases(NULL);
        test(0, "puttygen", "-l", filename, "-o", tmpfilename1, NULL);
        if (!fp) {
            /*
             * If we can't test fingerprints against OpenSSH, we
             * can at the very least test equality of all the
             * fingerprints we generate of this key throughout
             * testing.
             */
            fp = get_fp(tmpfilename1, 0);
        } else {
            check_fp(tmpfilename1, fp, "%s initial fp", keytype->name);
        }

        /*
         * Change the comment of the key; this _does_ require a
         * passphrase owing to the tamperproofing.
         *
         * NOTE: In SSH-1, this only requires a passphrase because
         * of inadequacies of the loading and saving mechanisms. In
         * _principle_, it should be perfectly possible to modify
         * the comment on an SSH-1 key without requiring a
         * passphrase; the only reason I can't do it is because my
         * loading and saving mechanisms don't include a method of
         * loading all the key data without also trying to decrypt
         * the private section.
         *
         * I don't consider this to be a problem worth solving,
         * because (a) to fix it would probably end up bloating
         * PuTTY proper, and (b) SSH-1 is on the way out anyway so
         * it shouldn't be highly significant. If it seriously
         * bothers anyone then perhaps I _might_ be persuadable.
         */
        setup_passphrases("sponge", NULL);
        test(0, "puttygen", "-C", "new-comment", filename, NULL);

        /*
         * Change the passphrase to nothing.
         */
        setup_passphrases("sponge", "", "", NULL);
        test(0, "puttygen", "-P", filename, NULL);

        /*
         * Change the comment of the key again; this time we expect no
         * passphrase to be required.
         */
        setup_passphrases(NULL);
        test(0, "puttygen", "-C", "new-comment-2", filename, NULL);

        /*
         * Export the private key into OpenSSH format; no passphrase
         * should be required since the key is currently unencrypted.
         */
        setup_passphrases(NULL);
        test(supports_openssh ? 0 : 1,
             "puttygen", "-O", "private-openssh", "-o", osfilename,
             filename, NULL);

        if (supports_openssh) {
            /*
             * List the fingerprint of the OpenSSH-formatted key.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-l", osfilename, "-o", tmpfilename1, NULL);
            check_fp(tmpfilename1, fp, "%s openssh clear fp", keytype->name);

            /*
             * List the public half of the OpenSSH-formatted key in
             * OpenSSH format.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-L", osfilename, NULL);

            /*
             * List the public half of the OpenSSH-formatted key in
             * IETF/ssh.com format.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-p", osfilename, NULL);
        }

        /*
         * Export the private key into ssh.com format; no passphrase
         * should be required since the key is currently unencrypted.
         */
        setup_passphrases(NULL);
        test(supports_sshcom ? 0 : 1,
             "puttygen", "-O", "private-sshcom",
             "-o", scfilename, filename, NULL);

        if (supports_sshcom) {
            /*
             * List the fingerprint of the ssh.com-formatted key.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-l", scfilename, "-o", tmpfilename1, NULL);
            check_fp(tmpfilename1, fp, "%s ssh.com clear fp", keytype->name);

            /*
             * List the public half of the ssh.com-formatted key in
             * OpenSSH format.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-L", scfilename, NULL);

            /*
             * List the public half of the ssh.com-formatted key in
             * IETF/ssh.com format.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-p", scfilename, NULL);
        }

        if (supports_openssh && supports_sshcom) {
            /*
             * Convert from OpenSSH into ssh.com.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", osfilename, "-o", tmpfilename1,
                 "-O", "private-sshcom", NULL);

            /*
             * Convert from ssh.com back into a PuTTY key,
             * supplying the same comment as we had before we
             * started to ensure the comparison works.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", tmpfilename1, "-C", "new-comment-2",
                 "-o", tmpfilename2, NULL);

            /*
             * See if the PuTTY key thus generated is the same as
             * the original.
             */
            filecmp(filename, tmpfilename2,
                    "p->o->s->p clear %s", keytype->name);

            /*
             * Convert from ssh.com to OpenSSH.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", scfilename, "-o", tmpfilename1,
                 "-O", "private-openssh", NULL);

            /*
             * Convert from OpenSSH back into a PuTTY key,
             * supplying the same comment as we had before we
             * started to ensure the comparison works.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", tmpfilename1, "-C", "new-comment-2",
                 "-o", tmpfilename2, NULL);

            /*
             * See if the PuTTY key thus generated is the same as
             * the original.
             */
            filecmp(filename, tmpfilename2,
                    "p->s->o->p clear %s", keytype->name);

            /*
             * Finally, do a round-trip conversion between PuTTY
             * and ssh.com without involving OpenSSH, to test that
             * the key comment is preserved in that case.
             */
            setup_passphrases(NULL);
            test(0, "puttygen", "-O", "private-sshcom", "-o", tmpfilename1,
                 filename, NULL);
            setup_passphrases(NULL);
            test(0, "puttygen", tmpfilename1, "-o", tmpfilename2, NULL);
            filecmp(filename, tmpfilename2,
                    "p->s->p clear %s", keytype->name);
        }

        /*
         * Check that mismatched passphrases cause an error.
         */
        setup_passphrases("sponge2", "sponge3", NULL);
        test(1, "puttygen", "-P", filename, NULL);

        /*
         * Put a passphrase back on.
         */
        setup_passphrases("sponge2", "sponge2", NULL);
        test(0, "puttygen", "-P", filename, NULL);

        /*
         * Export the private key into OpenSSH format, this time
         * while encrypted.
         */
        if (!supports_openssh && type_known_early) {
            /* We'll know far enough in advance that this combination
             * is going to fail that we never ask for the passphrase */
            setup_passphrases(NULL);
        } else {
            setup_passphrases("sponge2", NULL);
        }

        test(supports_openssh ? 0 : 1,
             "puttygen", "-O", "private-openssh", "-o", osfilename,
             filename, NULL);

        if (supports_openssh) {
            /*
             * List the fingerprint of the OpenSSH-formatted key.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-l", osfilename, "-o", tmpfilename1, NULL);
            check_fp(tmpfilename1, fp, "%s openssh encrypted fp",
                     keytype->name);

            /*
             * List the public half of the OpenSSH-formatted key in
             * OpenSSH format.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-L", osfilename, NULL);

            /*
             * List the public half of the OpenSSH-formatted key in
             * IETF/ssh.com format.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-p", osfilename, NULL);
        }

        /*
         * Export the private key into ssh.com format, this time
         * while encrypted. For RSA1 keys, this should give an
         * error.
         */
        if (!supports_sshcom && type_known_early) {
            /* We'll know far enough in advance that this combination
             * is going to fail that we never ask for the passphrase */
            setup_passphrases(NULL);
        } else {
            setup_passphrases("sponge2", NULL);
        }

        test(supports_sshcom ? 0 : 1,
             "puttygen", "-O", "private-sshcom", "-o", scfilename,
             filename, NULL);

        if (supports_sshcom) {
            /*
             * List the fingerprint of the ssh.com-formatted key.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-l", scfilename, "-o", tmpfilename1, NULL);
            check_fp(tmpfilename1, fp, "%s ssh.com encrypted fp",
                     keytype->name);

            /*
             * List the public half of the ssh.com-formatted key in
             * OpenSSH format.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-L", scfilename, NULL);

            /*
             * List the public half of the ssh.com-formatted key in
             * IETF/ssh.com format.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-p", scfilename, NULL);
        }

        if (supports_openssh && supports_sshcom) {
            /*
             * Convert from OpenSSH into ssh.com.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", osfilename, "-o", tmpfilename1,
                 "-O", "private-sshcom", NULL);

            /*
             * Convert from ssh.com back into a PuTTY key,
             * supplying the same comment as we had before we
             * started to ensure the comparison works.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", tmpfilename1, "-C", "new-comment-2",
                 "-o", tmpfilename2, NULL);

            /*
             * See if the PuTTY key thus generated is the same as
             * the original.
             */
            filecmp(filename, tmpfilename2,
                    "p->o->s->p encrypted %s", keytype->name);

            /*
             * Convert from ssh.com to OpenSSH.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", scfilename, "-o", tmpfilename1,
                 "-O", "private-openssh", NULL);

            /*
             * Convert from OpenSSH back into a PuTTY key,
             * supplying the same comment as we had before we
             * started to ensure the comparison works.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", tmpfilename1, "-C", "new-comment-2",
                 "-o", tmpfilename2, NULL);

            /*
             * See if the PuTTY key thus generated is the same as
             * the original.
             */
            filecmp(filename, tmpfilename2,
                    "p->s->o->p encrypted %s", keytype->name);

            /*
             * Finally, do a round-trip conversion between PuTTY
             * and ssh.com without involving OpenSSH, to test that
             * the key comment is preserved in that case.
             */
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", "-O", "private-sshcom", "-o", tmpfilename1,
                 filename, NULL);
            setup_passphrases("sponge2", NULL);
            test(0, "puttygen", tmpfilename1, "-o", tmpfilename2, NULL);
            filecmp(filename, tmpfilename2,
                    "p->s->p encrypted %s", keytype->name);
        }

        /*
         * Load with the wrong passphrase.
         */
        setup_passphrases("sponge8", NULL);
        test(1, "puttygen", "-C", "spurious-new-comment", filename, NULL);

        /*
         * Load a totally bogus file.
         */
        setup_passphrases(NULL);
        test(1, "puttygen", "-C", "spurious-new-comment", pubfilename, NULL);

        sfree(fp);

        if (remove_files) {
            remove(filename);
            remove(pubfilename);
            remove(osfilename);
            remove(scfilename);
            remove(tmpfilename1);
            remove(tmpfilename2);
        }
    }
    printf("%d passes, %d fails\n", passes, fails);
    return fails == 0 ? 0 : 1;
}

#endif