/* $OpenBSD: passwd.c,v 1.14 2023/03/06 14:32:06 tb Exp $ */

#if defined OPENSSL_NO_MD5
#define NO_MD5CRYPT_1
#endif

#if !defined(OPENSSL_NO_DES) || !defined(NO_MD5CRYPT_1)

#include <assert.h>
#include <string.h>

#include "apps.h"

#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/evp.h>

#ifndef OPENSSL_NO_DES
#include <openssl/des.h>
#endif

#ifndef NO_MD5CRYPT_1
#include <openssl/md5.h>
#endif

static unsigned const char cov_2char[64] = {
        /* from crypto/des/fcrypt.c */
        0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35,
        0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44,
        0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C,
        0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54,
        0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x61, 0x62,
        0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A,
        0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72,
        0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A
};

static int
do_passwd(int passed_salt, char **salt_p, char **salt_malloc_p,
    char *passwd, BIO * out, int quiet, int table, int reverse,
    size_t pw_maxlen, int usecrypt, int use1, int useapr1);

static struct {
        char *infile;
        int in_stdin;
        int noverify;
        int quiet;
        int reverse;
        char *salt;
        int table;
        int use1;
        int useapr1;
        int usecrypt;
} cfg;

static const struct option passwd_options[] = {
#ifndef NO_MD5CRYPT_1
        {
                .name = "1",
                .desc = "Use MD5 based BSD password algorithm 1",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.use1,
        },
        {
                .name = "apr1",
                .desc = "Use apr1 algorithm (Apache variant of BSD algorithm)",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.useapr1,
        },
#endif
#ifndef OPENSSL_NO_DES
        {
                .name = "crypt",
                .desc = "Use crypt algorithm (default)",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.usecrypt,
        },
#endif
        {
                .name = "in",
                .argname = "file",
                .desc = "Read passwords from specified file",
                .type = OPTION_ARG,
                .opt.arg = &cfg.infile,
        },
        {
                .name = "noverify",
                .desc = "Do not verify password",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.noverify,
        },
        {
                .name = "quiet",
                .desc = "Do not output warnings",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.quiet,
        },
        {
                .name = "reverse",
                .desc = "Reverse table columns (requires -table)",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.reverse,
        },
        {
                .name = "salt",
                .argname = "string",
                .desc = "Use specified salt",
                .type = OPTION_ARG,
                .opt.arg = &cfg.salt,
        },
        {
                .name = "stdin",
                .desc = "Read passwords from stdin",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.in_stdin,
        },
        {
                .name = "table",
                .desc = "Output cleartext and hashed passwords (tab separated)",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.table,
        },
        { NULL },
};

static void
passwd_usage(void)
{
        fprintf(stderr, "usage: passwd [-1 | -apr1 | -crypt] [-in file] "
            "[-noverify] [-quiet]\n"
            "    [-reverse] [-salt string] [-stdin] [-table] [password]\n\n");
        options_usage(passwd_options);
}

int
passwd_main(int argc, char **argv)
{
        char *passwd = NULL, **passwds = NULL;
        char *salt_malloc = NULL, *passwd_malloc = NULL;
        size_t passwd_malloc_size = 0;
        BIO *in = NULL, *out = NULL;
        int badopt = 0;
        int passed_salt = 0;
        size_t pw_maxlen = 0;
        int argsused;
        int ret = 1;

        if (pledge("stdio cpath wpath rpath tty", NULL) == -1) {
                perror("pledge");
                exit(1);
        }

        memset(&cfg, 0, sizeof(cfg));

        if (options_parse(argc, argv, passwd_options, NULL, &argsused) != 0) {
                passwd_usage();
                goto err;
        }

        if (argsused < argc)
                passwds = &argv[argsused];
        if (cfg.salt != NULL)
                passed_salt = 1;

        if (!cfg.usecrypt && !cfg.use1 &&
            !cfg.useapr1)
                cfg.usecrypt = 1;       /* use default */
        if (cfg.usecrypt + cfg.use1 +
            cfg.useapr1 > 1)
                badopt = 1;     /* conflicting options */

        /* Reject unsupported algorithms */
#ifdef OPENSSL_NO_DES
        if (cfg.usecrypt)
                badopt = 1;
#endif
#ifdef NO_MD5CRYPT_1
        if (cfg.use1 || cfg.useapr1)
                badopt = 1;
#endif

        if (badopt) {
                passwd_usage();
                goto err;
        }

        if ((out = BIO_new(BIO_s_file())) == NULL)
                goto err;
        BIO_set_fp(out, stdout, BIO_NOCLOSE | BIO_FP_TEXT);

        if (cfg.infile != NULL || cfg.in_stdin) {
                if ((in = BIO_new(BIO_s_file())) == NULL)
                        goto err;
                if (cfg.infile != NULL) {
                        assert(cfg.in_stdin == 0);
                        if (BIO_read_filename(in, cfg.infile) <= 0)
                                goto err;
                } else {
                        assert(cfg.in_stdin);
                        BIO_set_fp(in, stdin, BIO_NOCLOSE);
                }
        }
        if (cfg.usecrypt)
                pw_maxlen = 8;
        else if (cfg.use1 || cfg.useapr1)
                pw_maxlen = 256;/* arbitrary limit, should be enough for most
                                 * passwords */

        if (passwds == NULL) {
                /* no passwords on the command line */

                passwd_malloc_size = pw_maxlen + 2;
                /* longer than necessary so that we can warn about truncation */
                passwd = passwd_malloc = malloc(passwd_malloc_size);
                if (passwd_malloc == NULL)
                        goto err;
        }
        if (in == NULL && passwds == NULL) {
                /* build a null-terminated list */
                static char *passwds_static[2] = {NULL, NULL};

                passwds = passwds_static;
                if (in == NULL)
                        if (EVP_read_pw_string(passwd_malloc,
                            passwd_malloc_size, "Password: ",
                            !(passed_salt || cfg.noverify)) != 0)
                                goto err;
                passwds[0] = passwd_malloc;
        }
        if (in == NULL) {
                assert(passwds != NULL);
                assert(*passwds != NULL);

                do {    /* loop over list of passwords */
                        passwd = *passwds++;
                        if (!do_passwd(passed_salt, &cfg.salt,
                            &salt_malloc, passwd, out, cfg.quiet,
                            cfg.table, cfg.reverse,
                            pw_maxlen, cfg.usecrypt,
                            cfg.use1, cfg.useapr1))
                                goto err;
                } while (*passwds != NULL);
        } else {
                int done;

                assert(passwd != NULL);
                do {
                        int r = BIO_gets(in, passwd, pw_maxlen + 1);
                        if (r > 0) {
                                char *c = (strchr(passwd, '\n'));
                                if (c != NULL)
                                        *c = 0; /* truncate at newline */
                                else {
                                        /* ignore rest of line */
                                        char trash[BUFSIZ];
                                        do
                                                r = BIO_gets(in, trash, sizeof trash);
                                        while ((r > 0) && (!strchr(trash, '\n')));
                                }

                                if (!do_passwd(passed_salt, &cfg.salt,
                                    &salt_malloc, passwd, out,
                                    cfg.quiet, cfg.table,
                                    cfg.reverse, pw_maxlen,
                                    cfg.usecrypt, cfg.use1,
                                    cfg.useapr1))
                                        goto err;
                        }
                        done = (r <= 0);
                } while (!done);
        }
        ret = 0;

 err:
        ERR_print_errors(bio_err);

        free(salt_malloc);
        free(passwd_malloc);

        BIO_free(in);
        BIO_free_all(out);

        return (ret);
}


#ifndef NO_MD5CRYPT_1
/* MD5-based password algorithm (should probably be available as a library
 * function; then the static buffer would not be acceptable).
 * For magic string "1", this should be compatible to the MD5-based BSD
 * password algorithm.
 * For 'magic' string "apr1", this is compatible to the MD5-based Apache
 * password algorithm.
 * (Apparently, the Apache password algorithm is identical except that the
 * 'magic' string was changed -- the laziest application of the NIH principle
 * I've ever encountered.)
 */
static char *
md5crypt(const char *passwd, const char *magic, const char *salt)
{
        static char out_buf[6 + 9 + 24 + 2];    /* "$apr1$..salt..$.......md5h
                                                 * ash..........\0" */
        unsigned char buf[MD5_DIGEST_LENGTH];
        char *salt_out;
        int n;
        unsigned int i;
        EVP_MD_CTX *md = NULL, *md2 = NULL;
        size_t passwd_len, salt_len;

        passwd_len = strlen(passwd);
        out_buf[0] = '$';
        out_buf[1] = 0;
        assert(strlen(magic) <= 4);     /* "1" or "apr1" */
        strlcat(out_buf, magic, sizeof(out_buf));
        strlcat(out_buf, "$", sizeof(out_buf));
        strlcat(out_buf, salt, sizeof(out_buf));
        assert(strlen(out_buf) <= 6 + 8);       /* "$apr1$..salt.." */
        salt_out = out_buf + 2 + strlen(magic);
        salt_len = strlen(salt_out);
        assert(salt_len <= 8);

        if ((md = EVP_MD_CTX_new()) == NULL)
                goto err;
        if (!EVP_DigestInit_ex(md, EVP_md5(), NULL))
                goto err;
        if (!EVP_DigestUpdate(md, passwd, passwd_len))
                goto err;
        if (!EVP_DigestUpdate(md, "$", 1))
                goto err;
        if (!EVP_DigestUpdate(md, magic, strlen(magic)))
                goto err;
        if (!EVP_DigestUpdate(md, "$", 1))
                goto err;
        if (!EVP_DigestUpdate(md, salt_out, salt_len))
                goto err;

        if ((md2 = EVP_MD_CTX_new()) == NULL)
                goto err;
        if (!EVP_DigestInit_ex(md2, EVP_md5(), NULL))
                goto err;
        if (!EVP_DigestUpdate(md2, passwd, passwd_len))
                goto err;
        if (!EVP_DigestUpdate(md2, salt_out, salt_len))
                goto err;
        if (!EVP_DigestUpdate(md2, passwd, passwd_len))
                goto err;
        if (!EVP_DigestFinal_ex(md2, buf, NULL))
                goto err;

        for (i = passwd_len; i > sizeof buf; i -= sizeof buf) {
                if (!EVP_DigestUpdate(md, buf, sizeof buf))
                        goto err;
        }
        if (!EVP_DigestUpdate(md, buf, i))
                goto err;

        n = passwd_len;
        while (n) {
                if (!EVP_DigestUpdate(md, (n & 1) ? "\0" : passwd, 1))
                        goto err;
                n >>= 1;
        }
        if (!EVP_DigestFinal_ex(md, buf, NULL))
                goto err;

        for (i = 0; i < 1000; i++) {
                if (!EVP_DigestInit_ex(md2, EVP_md5(), NULL))
                        goto err;
                if (!EVP_DigestUpdate(md2,
                    (i & 1) ? (unsigned const char *) passwd : buf,
                    (i & 1) ? passwd_len : sizeof buf))
                        goto err;
                if (i % 3) {
                        if (!EVP_DigestUpdate(md2, salt_out, salt_len))
                                goto err;
                }
                if (i % 7) {
                        if (!EVP_DigestUpdate(md2, passwd, passwd_len))
                                goto err;
                }
                if (!EVP_DigestUpdate(md2,
                    (i & 1) ? buf : (unsigned const char *) passwd,
                    (i & 1) ? sizeof buf : passwd_len))
                        goto err;
                if (!EVP_DigestFinal_ex(md2, buf, NULL))
                        goto err;
        }
        EVP_MD_CTX_free(md2);
        md2 = NULL;

        {
                /* transform buf into output string */

                unsigned char buf_perm[sizeof buf];
                int dest, source;
                char *output;

                /* silly output permutation */
                for (dest = 0, source = 0; dest < 14; dest++, source = (source + 6) % 17)
                        buf_perm[dest] = buf[source];
                buf_perm[14] = buf[5];
                buf_perm[15] = buf[11];
                assert(16 == sizeof buf_perm);

                output = salt_out + salt_len;
                assert(output == out_buf + strlen(out_buf));

                *output++ = '$';

                for (i = 0; i < 15; i += 3) {
                        *output++ = cov_2char[buf_perm[i + 2] & 0x3f];
                        *output++ = cov_2char[((buf_perm[i + 1] & 0xf) << 2) |
                            (buf_perm[i + 2] >> 6)];
                        *output++ = cov_2char[((buf_perm[i] & 3) << 4) |
                            (buf_perm[i + 1] >> 4)];
                        *output++ = cov_2char[buf_perm[i] >> 2];
                }
                assert(i == 15);
                *output++ = cov_2char[buf_perm[i] & 0x3f];
                *output++ = cov_2char[buf_perm[i] >> 6];
                *output = 0;
                assert(strlen(out_buf) < sizeof(out_buf));
        }
        EVP_MD_CTX_free(md);

        return out_buf;
 err:
        EVP_MD_CTX_free(md);
        EVP_MD_CTX_free(md2);

        return NULL;
}
#endif


static int
do_passwd(int passed_salt, char **salt_p, char **salt_malloc_p,
    char *passwd, BIO * out, int quiet, int table, int reverse,
    size_t pw_maxlen, int usecrypt, int use1, int useapr1)
{
        char *hash = NULL;

        assert(salt_p != NULL);
        assert(salt_malloc_p != NULL);

        /* first make sure we have a salt */
        if (!passed_salt) {
#ifndef OPENSSL_NO_DES
                if (usecrypt) {
                        if (*salt_malloc_p == NULL) {
                                *salt_p = *salt_malloc_p = malloc(3);
                                if (*salt_malloc_p == NULL)
                                        goto err;
                        }
                        arc4random_buf(*salt_p, 2);
                        (*salt_p)[0] = cov_2char[(*salt_p)[0] & 0x3f];  /* 6 bits */
                        (*salt_p)[1] = cov_2char[(*salt_p)[1] & 0x3f];  /* 6 bits */
                        (*salt_p)[2] = 0;
                }
#endif                          /* !OPENSSL_NO_DES */

#ifndef NO_MD5CRYPT_1
                if (use1 || useapr1) {
                        int i;

                        if (*salt_malloc_p == NULL) {
                                *salt_p = *salt_malloc_p = malloc(9);
                                if (*salt_malloc_p == NULL)
                                        goto err;
                        }
                        arc4random_buf(*salt_p, 8);

                        for (i = 0; i < 8; i++)
                                (*salt_p)[i] = cov_2char[(*salt_p)[i] & 0x3f];  /* 6 bits */
                        (*salt_p)[8] = 0;
                }
#endif                          /* !NO_MD5CRYPT_1 */
        }
        assert(*salt_p != NULL);

        /* truncate password if necessary */
        if ((strlen(passwd) > pw_maxlen)) {
                if (!quiet)
                        BIO_printf(bio_err,
                            "Warning: truncating password to %zu characters\n",
                            pw_maxlen);
                passwd[pw_maxlen] = 0;
        }
        assert(strlen(passwd) <= pw_maxlen);

        /* now compute password hash */
#ifndef OPENSSL_NO_DES
        if (usecrypt)
                hash = DES_crypt(passwd, *salt_p);
#endif
#ifndef NO_MD5CRYPT_1
        if (use1 || useapr1)
                if ((hash = md5crypt(passwd, (use1 ? "1" : "apr1"), *salt_p)) == NULL)
                        goto err;
#endif
        assert(hash != NULL);

        if (table && !reverse)
                BIO_printf(out, "%s\t%s\n", passwd, hash);
        else if (table && reverse)
                BIO_printf(out, "%s\t%s\n", hash, passwd);
        else
                BIO_printf(out, "%s\n", hash);
        return 1;

 err:
        free(*salt_malloc_p);
        *salt_malloc_p = NULL;
        return 0;
}
#else

int
passwd_main(int argc, char **argv)
{
        fputs("Program not available.\n", stderr)
        return (1);
}
#endif