/*

 * Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright (c) 2013-2014 Timo Teräs <timo.teras@gmail.com>

 *

 * 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

 */

#include "apps.h"

#include "progs.h"

#if defined(OPENSSL_SYS_UNIX) || defined(__APPLE__) || \

    (defined(__VMS) && defined(__DECC) && __CRTL_VER >= 80300000)

# include <unistd.h>

# include <stdio.h>

# include <limits.h>

# include <errno.h>

# include <string.h>

# include <ctype.h>

# include <sys/stat.h>

/*

 * Make sure that the processing of symbol names is treated the same as when

 * libcrypto is built.  This is done automatically for public headers (see

 * include/openssl/__DECC_INCLUDE_PROLOGUE.H and __DECC_INCLUDE_EPILOGUE.H),

 * but not for internal headers.

 */

# ifdef __VMS

#  pragma names save

#  pragma names as_is,shortened

# endif

# include "internal/o_dir.h"

# ifdef __VMS

#  pragma names restore

# endif

# include <openssl/evp.h>

# include <openssl/pem.h>

# include <openssl/x509.h>

# ifndef PATH_MAX

#  define PATH_MAX 4096

# endif

# ifndef NAME_MAX

#  define NAME_MAX 255

# endif

# define MAX_COLLISIONS  256

# if defined(OPENSSL_SYS_VXWORKS)

/*

 * VxWorks has no symbolic links

 */

#  define lstat(path, buf) stat(path, buf)

int symlink(const char *target, const char *linkpath)

{

    errno = ENOSYS;

    return -1;

}

ssize_t readlink(const char *pathname, char *buf, size_t bufsiz)

{

    errno = ENOSYS;

    return -1;

}

# endif

typedef struct hentry_st {

    struct hentry_st *next;

    char *filename;

    unsigned short old_id;

    unsigned char need_symlink;

    unsigned char digest[EVP_MAX_MD_SIZE];

} HENTRY;

typedef struct bucket_st {

    struct bucket_st *next;

    HENTRY *first_entry, *last_entry;

    unsigned int hash;

    unsigned short type;

    unsigned short num_needed;

} BUCKET;

enum Type {

    /* Keep in sync with |suffixes|, below. */

    TYPE_CERT=0, TYPE_CRL=1

};

enum Hash {

    HASH_OLD, HASH_NEW, HASH_BOTH

};

static int evpmdsize;

static const EVP_MD *evpmd;

static int remove_links = 1;

static int verbose = 0;

static BUCKET *hash_table[257];

static const char *suffixes[] = { "", "r" };

static const char *extensions[] = { "pem", "crt", "cer", "crl" };

static void bit_set(unsigned char *set, unsigned int bit)

{

    set[bit >> 3] |= 1 << (bit & 0x7);

}

static int bit_isset(unsigned char *set, unsigned int bit)

{

    return set[bit >> 3] & (1 << (bit & 0x7));

}

/*

 * Process an entry; return number of errors.

 */

static int add_entry(enum Type type, unsigned int hash, const char *filename,

                      const unsigned char *digest, int need_symlink,

                      unsigned short old_id)

{

    static BUCKET nilbucket;

    static HENTRY nilhentry;

    BUCKET *bp;

    HENTRY *ep, *found = NULL;

    unsigned int ndx = (type + hash) % OSSL_NELEM(hash_table);

    for (bp = hash_table[ndx]; bp; bp = bp->next)

        if (bp->type == type && bp->hash == hash)

            break;

    if (bp == NULL) {

        bp = app_malloc(sizeof(*bp), "hash bucket");

        *bp = nilbucket;

        bp->next = hash_table[ndx];

        bp->type = type;

        bp->hash = hash;

        hash_table[ndx] = bp;

    }

    for (ep = bp->first_entry; ep; ep = ep->next) {

        if (digest && memcmp(digest, ep->digest, evpmdsize) == 0) {

            BIO_printf(bio_err,

                       "%s: warning: skipping duplicate %s in %s\n",

                       opt_getprog(),

                       type == TYPE_CERT ? "certificate" : "CRL", filename);

            return 0;

        }

        if (strcmp(filename, ep->filename) == 0) {

            found = ep;

            if (digest == NULL)

                break;

        }

    }

    ep = found;

    if (ep == NULL) {

        if (bp->num_needed >= MAX_COLLISIONS) {

            BIO_printf(bio_err,

                       "%s: error: hash table overflow for %s\n",

                       opt_getprog(), filename);

            return 1;

        }

        ep = app_malloc(sizeof(*ep), "collision bucket");

        *ep = nilhentry;

        ep->old_id = ~0;

        ep->filename = OPENSSL_strdup(filename);

        if (bp->last_entry)

            bp->last_entry->next = ep;

        if (bp->first_entry == NULL)

            bp->first_entry = ep;

        bp->last_entry = ep;

    }

    if (old_id < ep->old_id)

        ep->old_id = old_id;

    if (need_symlink && !ep->need_symlink) {

        ep->need_symlink = 1;

        bp->num_needed++;

        memcpy(ep->digest, digest, evpmdsize);

    }

    return 0;

}

/*

 * Check if a symlink goes to the right spot; return 0 if okay.

 * This can be -1 if bad filename, or an error count.

 */

static int handle_symlink(const char *filename, const char *fullpath)

{

    unsigned int hash = 0;

    int i, type, id;

    unsigned char ch;

    char linktarget[PATH_MAX], *endptr;

    ossl_ssize_t n;

    for (i = 0; i < 8; i++) {

        ch = filename[i];

        if (!isxdigit(ch))

            return -1;

        hash <<= 4;

        hash += OPENSSL_hexchar2int(ch);

    }

    if (filename[i++] != '.')

        return -1;

    for (type = OSSL_NELEM(suffixes) - 1; type > 0; type--) {

        const char *suffix = suffixes[type];

        if (strncasecmp(suffix, &filename[i], strlen(suffix)) == 0)

            break;

    }

    i += strlen(suffixes[type]);

    id = strtoul(&filename[i], &endptr, 10);

    if (*endptr != '\0')

        return -1;

    n = readlink(fullpath, linktarget, sizeof(linktarget));

    if (n < 0 || n >= (int)sizeof(linktarget))

        return -1;

    linktarget[n] = 0;

    return add_entry(type, hash, linktarget, NULL, 0, id);

}

/*

 * process a file, return number of errors.

 */

static int do_file(const char *filename, const char *fullpath, enum Hash h)

{

    STACK_OF (X509_INFO) *inf = NULL;

    X509_INFO *x;

    X509_NAME *name = NULL;

    BIO *b;

    const char *ext;

    unsigned char digest[EVP_MAX_MD_SIZE];

    int type, errs = 0;

    size_t i;

    /* Does it end with a recognized extension? */

    if ((ext = strrchr(filename, '.')) == NULL)

        goto end;

    for (i = 0; i < OSSL_NELEM(extensions); i++) {

        if (strcasecmp(extensions[i], ext + 1) == 0)

            break;

    }

    if (i >= OSSL_NELEM(extensions))

        goto end;

    /* Does it have X.509 data in it? */

    if ((b = BIO_new_file(fullpath, "r")) == NULL) {

        BIO_printf(bio_err, "%s: error: skipping %s, cannot open file\n",

                   opt_getprog(), filename);

        errs++;

        goto end;

    }

    inf = PEM_X509_INFO_read_bio(b, NULL, NULL, NULL);

    BIO_free(b);

    if (inf == NULL)

        goto end;

    if (sk_X509_INFO_num(inf) != 1) {

        BIO_printf(bio_err,

                   "%s: warning: skipping %s,"

                   "it does not contain exactly one certificate or CRL\n",

                   opt_getprog(), filename);

        /* This is not an error. */

        goto end;

    }

    x = sk_X509_INFO_value(inf, 0);

    if (x->x509 != NULL) {

        type = TYPE_CERT;

        name = X509_get_subject_name(x->x509);

        if (!X509_digest(x->x509, evpmd, digest, NULL)) {

            BIO_printf(bio_err, "out of memory\n");

            ++errs;

            goto end;

        }

    } else if (x->crl != NULL) {

        type = TYPE_CRL;

        name = X509_CRL_get_issuer(x->crl);

        if (!X509_CRL_digest(x->crl, evpmd, digest, NULL)) {

            BIO_printf(bio_err, "out of memory\n");

            ++errs;

            goto end;

        }

    } else {

        ++errs;

        goto end;

    }

    if (name != NULL) {

        if ((h == HASH_NEW) || (h == HASH_BOTH))

            errs += add_entry(type, X509_NAME_hash(name), filename, digest, 1, ~0);

        if ((h == HASH_OLD) || (h == HASH_BOTH))

            errs += add_entry(type, X509_NAME_hash_old(name), filename, digest, 1, ~0);

    }

end:

    sk_X509_INFO_pop_free(inf, X509_INFO_free);

    return errs;

}

static void str_free(char *s)

{

    OPENSSL_free(s);

}

static int ends_with_dirsep(const char *path)

{

    if (*path != '\0')

        path += strlen(path) - 1;

# if defined __VMS

    if (*path == ']' || *path == '>' || *path == ':')

        return 1;

# elif defined _WIN32

    if (*path == '\\')

        return 1;

# endif

    return *path == '/';

}

/*

 * Process a directory; return number of errors found.

 */

static int do_dir(const char *dirname, enum Hash h)

{

    BUCKET *bp, *nextbp;

    HENTRY *ep, *nextep;

    OPENSSL_DIR_CTX *d = NULL;

    struct stat st;

    unsigned char idmask[MAX_COLLISIONS / 8];

    int n, numfiles, nextid, buflen, errs = 0;

    size_t i;

    const char *pathsep;

    const char *filename;

    char *buf, *copy = NULL;

    STACK_OF(OPENSSL_STRING) *files = NULL;

    if (app_access(dirname, W_OK) < 0) {

        BIO_printf(bio_err, "Skipping %s, can't write\n", dirname);

        return 1;

    }

    buflen = strlen(dirname);

    pathsep = (buflen && !ends_with_dirsep(dirname)) ? "/": "";

    buflen += NAME_MAX + 1 + 1;

    buf = app_malloc(buflen, "filename buffer");

    if (verbose)

        BIO_printf(bio_out, "Doing %s\n", dirname);

    if ((files = sk_OPENSSL_STRING_new_null()) == NULL) {

        BIO_printf(bio_err, "Skipping %s, out of memory\n", dirname);

        errs = 1;

        goto err;

    }

    while ((filename = OPENSSL_DIR_read(&d, dirname)) != NULL) {

        if ((copy = OPENSSL_strdup(filename)) == NULL

                || sk_OPENSSL_STRING_push(files, copy) == 0) {

            OPENSSL_free(copy);

            BIO_puts(bio_err, "out of memory\n");

            errs = 1;

            goto err;

        }

    }

    OPENSSL_DIR_end(&d);

    sk_OPENSSL_STRING_sort(files);

    numfiles = sk_OPENSSL_STRING_num(files);

    for (n = 0; n < numfiles; ++n) {

        filename = sk_OPENSSL_STRING_value(files, n);

        if (BIO_snprintf(buf, buflen, "%s%s%s",

                         dirname, pathsep, filename) >= buflen)

            continue;

        if (lstat(buf, &st) < 0)

            continue;

        if (S_ISLNK(st.st_mode) && handle_symlink(filename, buf) == 0)

            continue;

        errs += do_file(filename, buf, h);

    }

    for (i = 0; i < OSSL_NELEM(hash_table); i++) {

        for (bp = hash_table[i]; bp; bp = nextbp) {

            nextbp = bp->next;

            nextid = 0;

            memset(idmask, 0, (bp->num_needed + 7) / 8);

            for (ep = bp->first_entry; ep; ep = ep->next)

                if (ep->old_id < bp->num_needed)

                    bit_set(idmask, ep->old_id);

            for (ep = bp->first_entry; ep; ep = nextep) {

                nextep = ep->next;

                if (ep->old_id < bp->num_needed) {

                    /* Link exists, and is used as-is */

                    BIO_snprintf(buf, buflen, "%08x.%s%d", bp->hash,

                                 suffixes[bp->type], ep->old_id);

                    if (verbose)

                        BIO_printf(bio_out, "link %s -> %s\n",

                                   ep->filename, buf);

                } else if (ep->need_symlink) {

                    /* New link needed (it may replace something) */

                    while (bit_isset(idmask, nextid))

                        nextid++;

                    BIO_snprintf(buf, buflen, "%s%s%n%08x.%s%d",

                                 dirname, pathsep, &n, bp->hash,

                                 suffixes[bp->type], nextid);

                    if (verbose)

                        BIO_printf(bio_out, "link %s -> %s\n",

                                   ep->filename, &buf[n]);

                    if (unlink(buf) < 0 && errno != ENOENT) {

                        BIO_printf(bio_err,

                                   "%s: Can't unlink %s, %s\n",

                                   opt_getprog(), buf, strerror(errno));

                        errs++;

                    }

                    if (symlink(ep->filename, buf) < 0) {

                        BIO_printf(bio_err,

                                   "%s: Can't symlink %s, %s\n",

                                   opt_getprog(), ep->filename,

                                   strerror(errno));

                        errs++;

                    }

                    bit_set(idmask, nextid);

                } else if (remove_links) {

                    /* Link to be deleted */

                    BIO_snprintf(buf, buflen, "%s%s%n%08x.%s%d",

                                 dirname, pathsep, &n, bp->hash,

                                 suffixes[bp->type], ep->old_id);

                    if (verbose)

                        BIO_printf(bio_out, "unlink %s\n",

                                   &buf[n]);

                    if (unlink(buf) < 0 && errno != ENOENT) {

                        BIO_printf(bio_err,

                                   "%s: Can't unlink %s, %s\n",

                                   opt_getprog(), buf, strerror(errno));

                        errs++;

                    }

                }

                OPENSSL_free(ep->filename);

                OPENSSL_free(ep);

            }

            OPENSSL_free(bp);

        }

        hash_table[i] = NULL;

    }

 err:

    sk_OPENSSL_STRING_pop_free(files, str_free);

    OPENSSL_free(buf);

    return errs;

}

typedef enum OPTION_choice {

    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,

    OPT_COMPAT, OPT_OLD, OPT_N, OPT_VERBOSE

} OPTION_CHOICE;

const OPTIONS rehash_options[] = {

    {OPT_HELP_STR, 1, '-', "Usage: %s [options] [cert-directory...]\n"},

    {OPT_HELP_STR, 1, '-', "Valid options are:\n"},

    {"help", OPT_HELP, '-', "Display this summary"},

    {"h", OPT_HELP, '-', "Display this summary"},

    {"compat", OPT_COMPAT, '-', "Create both new- and old-style hash links"},

    {"old", OPT_OLD, '-', "Use old-style hash to generate links"},

    {"n", OPT_N, '-', "Do not remove existing links"},

    {"v", OPT_VERBOSE, '-', "Verbose output"},

    {NULL}

};

int rehash_main(int argc, char **argv)

{

    const char *env, *prog;

    char *e, *m;

    int errs = 0;

    OPTION_CHOICE o;

    enum Hash h = HASH_NEW;

    prog = opt_init(argc, argv, rehash_options);

    while ((o = opt_next()) != OPT_EOF) {

        switch (o) {

        case OPT_EOF:

        case OPT_ERR:

            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);

            goto end;

        case OPT_HELP:

            opt_help(rehash_options);

            goto end;

        case OPT_COMPAT:

            h = HASH_BOTH;

            break;

        case OPT_OLD:

            h = HASH_OLD;

            break;

        case OPT_N:

            remove_links = 0;

            break;

        case OPT_VERBOSE:

            verbose = 1;

            break;

        }

    }

    argc = opt_num_rest();

    argv = opt_rest();

    evpmd = EVP_sha1();

    evpmdsize = EVP_MD_size(evpmd);

    if (*argv != NULL) {

        while (*argv != NULL)

            errs += do_dir(*argv++, h);

    } else if ((env = getenv(X509_get_default_cert_dir_env())) != NULL) {

        char lsc[2] = { LIST_SEPARATOR_CHAR, '\0' };

        m = OPENSSL_strdup(env);

        for (e = strtok(m, lsc); e != NULL; e = strtok(NULL, lsc))

            errs += do_dir(e, h);

        OPENSSL_free(m);

    } else {

        errs += do_dir(X509_get_default_cert_dir(), h);

    }

 end:

    return errs;

}

#else

const OPTIONS rehash_options[] = {

    {NULL}

};

int rehash_main(int argc, char **argv)

{

    BIO_printf(bio_err, "Not available; use c_rehash script\n");

    return 1;

}

#endif /* defined(OPENSSL_SYS_UNIX) || defined(__APPLE__) */