view src/core/ngx_crypt.c @ 8078:5244d3b165ff

SSL: single allocation in session cache on 32-bit platforms. Given the present typical SSL session sizes, on 32-bit platforms it is now beneficial to store all data in a single allocation, since rbtree node + session id + ASN1 representation of a session takes 256 bytes of shared memory (36 + 32 + 150 = about 218 bytes plus SNI server name). Storing all data in a single allocation is beneficial for SNI names up to about 40 characters long and makes it possible to store about 4000 sessions in one megabyte (instead of about 3000 sessions now). This also slightly simplifies the code.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 12 Oct 2022 20:14:40 +0300
parents 1064ea81ed3a
children
line wrap: on
line source


/*
 * Copyright (C) Maxim Dounin
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_crypt.h>
#include <ngx_md5.h>
#include <ngx_sha1.h>


#if (NGX_CRYPT)

static ngx_int_t ngx_crypt_apr1(ngx_pool_t *pool, u_char *key, u_char *salt,
    u_char **encrypted);
static ngx_int_t ngx_crypt_plain(ngx_pool_t *pool, u_char *key, u_char *salt,
    u_char **encrypted);
static ngx_int_t ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt,
    u_char **encrypted);
static ngx_int_t ngx_crypt_sha(ngx_pool_t *pool, u_char *key, u_char *salt,
    u_char **encrypted);


static u_char *ngx_crypt_to64(u_char *p, uint32_t v, size_t n);


ngx_int_t
ngx_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    if (ngx_strncmp(salt, "$apr1$", sizeof("$apr1$") - 1) == 0) {
        return ngx_crypt_apr1(pool, key, salt, encrypted);

    } else if (ngx_strncmp(salt, "{PLAIN}", sizeof("{PLAIN}") - 1) == 0) {
        return ngx_crypt_plain(pool, key, salt, encrypted);

    } else if (ngx_strncmp(salt, "{SSHA}", sizeof("{SSHA}") - 1) == 0) {
        return ngx_crypt_ssha(pool, key, salt, encrypted);

    } else if (ngx_strncmp(salt, "{SHA}", sizeof("{SHA}") - 1) == 0) {
        return ngx_crypt_sha(pool, key, salt, encrypted);
    }

    /* fallback to libc crypt() */

    return ngx_libc_crypt(pool, key, salt, encrypted);
}


static ngx_int_t
ngx_crypt_apr1(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    ngx_int_t          n;
    ngx_uint_t         i;
    u_char            *p, *last, final[16];
    size_t             saltlen, keylen;
    ngx_md5_t          md5, ctx1;

    /* Apache's apr1 crypt is Poul-Henning Kamp's md5 crypt with $apr1$ magic */

    keylen = ngx_strlen(key);

    /* true salt: no magic, max 8 chars, stop at first $ */

    salt += sizeof("$apr1$") - 1;
    last = salt + 8;
    for (p = salt; *p && *p != '$' && p < last; p++) { /* void */ }
    saltlen = p - salt;

    /* hash key and salt */

    ngx_md5_init(&md5);
    ngx_md5_update(&md5, key, keylen);
    ngx_md5_update(&md5, (u_char *) "$apr1$", sizeof("$apr1$") - 1);
    ngx_md5_update(&md5, salt, saltlen);

    ngx_md5_init(&ctx1);
    ngx_md5_update(&ctx1, key, keylen);
    ngx_md5_update(&ctx1, salt, saltlen);
    ngx_md5_update(&ctx1, key, keylen);
    ngx_md5_final(final, &ctx1);

    for (n = keylen; n > 0; n -= 16) {
        ngx_md5_update(&md5, final, n > 16 ? 16 : n);
    }

    ngx_memzero(final, sizeof(final));

    for (i = keylen; i; i >>= 1) {
        if (i & 1) {
            ngx_md5_update(&md5, final, 1);

        } else {
            ngx_md5_update(&md5, key, 1);
        }
    }

    ngx_md5_final(final, &md5);

    for (i = 0; i < 1000; i++) {
        ngx_md5_init(&ctx1);

        if (i & 1) {
            ngx_md5_update(&ctx1, key, keylen);

        } else {
            ngx_md5_update(&ctx1, final, 16);
        }

        if (i % 3) {
            ngx_md5_update(&ctx1, salt, saltlen);
        }

        if (i % 7) {
            ngx_md5_update(&ctx1, key, keylen);
        }

        if (i & 1) {
            ngx_md5_update(&ctx1, final, 16);

        } else {
            ngx_md5_update(&ctx1, key, keylen);
        }

        ngx_md5_final(final, &ctx1);
    }

    /* output */

    *encrypted = ngx_pnalloc(pool, sizeof("$apr1$") - 1 + saltlen + 1 + 22 + 1);
    if (*encrypted == NULL) {
        return NGX_ERROR;
    }

    p = ngx_cpymem(*encrypted, "$apr1$", sizeof("$apr1$") - 1);
    p = ngx_copy(p, salt, saltlen);
    *p++ = '$';

    p = ngx_crypt_to64(p, (final[ 0]<<16) | (final[ 6]<<8) | final[12], 4);
    p = ngx_crypt_to64(p, (final[ 1]<<16) | (final[ 7]<<8) | final[13], 4);
    p = ngx_crypt_to64(p, (final[ 2]<<16) | (final[ 8]<<8) | final[14], 4);
    p = ngx_crypt_to64(p, (final[ 3]<<16) | (final[ 9]<<8) | final[15], 4);
    p = ngx_crypt_to64(p, (final[ 4]<<16) | (final[10]<<8) | final[ 5], 4);
    p = ngx_crypt_to64(p, final[11], 2);
    *p = '\0';

    return NGX_OK;
}


static u_char *
ngx_crypt_to64(u_char *p, uint32_t v, size_t n)
{
    static u_char   itoa64[] =
        "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    while (n--) {
        *p++ = itoa64[v & 0x3f];
        v >>= 6;
    }

    return p;
}


static ngx_int_t
ngx_crypt_plain(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    size_t   len;
    u_char  *p;

    len = ngx_strlen(key);

    *encrypted = ngx_pnalloc(pool, sizeof("{PLAIN}") - 1 + len + 1);
    if (*encrypted == NULL) {
        return NGX_ERROR;
    }

    p = ngx_cpymem(*encrypted, "{PLAIN}", sizeof("{PLAIN}") - 1);
    ngx_memcpy(p, key, len + 1);

    return NGX_OK;
}


static ngx_int_t
ngx_crypt_ssha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    size_t       len;
    ngx_int_t    rc;
    ngx_str_t    encoded, decoded;
    ngx_sha1_t   sha1;

    /* "{SSHA}" base64(SHA1(key salt) salt) */

    /* decode base64 salt to find out true salt */

    encoded.data = salt + sizeof("{SSHA}") - 1;
    encoded.len = ngx_strlen(encoded.data);

    len = ngx_max(ngx_base64_decoded_length(encoded.len), 20);

    decoded.data = ngx_pnalloc(pool, len);
    if (decoded.data == NULL) {
        return NGX_ERROR;
    }

    rc = ngx_decode_base64(&decoded, &encoded);

    if (rc != NGX_OK || decoded.len < 20) {
        decoded.len = 20;
    }

    /* update SHA1 from key and salt */

    ngx_sha1_init(&sha1);
    ngx_sha1_update(&sha1, key, ngx_strlen(key));
    ngx_sha1_update(&sha1, decoded.data + 20, decoded.len - 20);
    ngx_sha1_final(decoded.data, &sha1);

    /* encode it back to base64 */

    len = sizeof("{SSHA}") - 1 + ngx_base64_encoded_length(decoded.len) + 1;

    *encrypted = ngx_pnalloc(pool, len);
    if (*encrypted == NULL) {
        return NGX_ERROR;
    }

    encoded.data = ngx_cpymem(*encrypted, "{SSHA}", sizeof("{SSHA}") - 1);
    ngx_encode_base64(&encoded, &decoded);
    encoded.data[encoded.len] = '\0';

    return NGX_OK;
}


static ngx_int_t
ngx_crypt_sha(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
{
    size_t      len;
    ngx_str_t   encoded, decoded;
    ngx_sha1_t  sha1;
    u_char      digest[20];

    /* "{SHA}" base64(SHA1(key)) */

    decoded.len = sizeof(digest);
    decoded.data = digest;

    ngx_sha1_init(&sha1);
    ngx_sha1_update(&sha1, key, ngx_strlen(key));
    ngx_sha1_final(digest, &sha1);

    len = sizeof("{SHA}") - 1 + ngx_base64_encoded_length(decoded.len) + 1;

    *encrypted = ngx_pnalloc(pool, len);
    if (*encrypted == NULL) {
        return NGX_ERROR;
    }

    encoded.data = ngx_cpymem(*encrypted, "{SHA}", sizeof("{SHA}") - 1);
    ngx_encode_base64(&encoded, &decoded);
    encoded.data[encoded.len] = '\0';

    return NGX_OK;
}

#endif /* NGX_CRYPT */