Использование openssl на основе pbkdf2 в многопоточном приложении

Question

Я пытаюсь использовать Jan-Piet Mens' pbkdf2 code из своего mosquitto-auth-plug в многопоточном приложении.

Это все отлично работает, когда я запускаю код в одном потоке, но я начала получать Invalid reads (используя Valgrind) для многих в функции pbkdf2_check() внутренней free()s.

Я не использую никаких глобальные общие ресурсы в моем коде и есть установка OpenSSL запирающих обратных вызовов с использованием this libcurl example, но я до сих пор продолжаю получать Invalid reads, в основном с free()s в pbkdf2_check().

Вот мой код:

pbkdf2.c (Основе Jan-Piet Mens' pbkdf2.c code)

/* 
* Copyright (c) 2013 Jan-Piet Mens <jpmens()gmail.com> 
* All rights reserved. 
* 
* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions are met: 
* 
* 1. Redistributions of source code must retain the above copyright notice, 
* this list of conditions and the following disclaimer. 
* 2. Redistributions in binary form must reproduce the above copyright 
* notice, this list of conditions and the following disclaimer in the 
* documentation and/or other materials provided with the distribution. 
* 3. Neither the name of mosquitto nor the names of its 
* contributors may be used to endorse or promote products derived from 
* this software without specific prior written permission. 
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
* POSSIBILITY OF SUCH DAMAGE. 
*/ 

#include "opensslthreadlock.h" 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <openssl/evp.h> 
#include "base64.h" 

#define SEPARATOR  "$" 
#define TRUE (1) 
#define FALSE (0) 
#define NUMT 5 

/* 
* Split PBKDF2$... string into their components. The caller must free() 
* the strings. 
*/ 

static int detoken(char *pbkstr, char **sha, int *iter, char **salt, char **key) 
{ 
    char *p, *s, *save; 
    int rc = 1; 

    save = s = strdup(pbkstr); 

    if ((p = strsep(&s, SEPARATOR)) == NULL) 
     goto out; 
    if (strcmp(p, "PBKDF2") != 0) 
     goto out; 

    if ((p = strsep(&s, SEPARATOR)) == NULL) 
     goto out; 
    *sha = strdup(p); 

    if ((p = strsep(&s, SEPARATOR)) == NULL) 
     goto out; 
    *iter = atoi(p); 

    if ((p = strsep(&s, SEPARATOR)) == NULL) 
     goto out; 
    *salt = strdup(p); 

    if ((p = strsep(&s, SEPARATOR)) == NULL) 
     goto out; 
    *key = strdup(p); 

    rc = 0; 

    out: 
    free(save); 
    return rc; 
} 

int pbkdf2_check(char *password, char *hash) 
{ 
    static char *sha, *salt, *h_pw; 
    int iterations, saltlen, blen; 
    char *b64, *keybuf; 
    unsigned char *out; 
    int match = FALSE; 
    const EVP_MD *evpmd; 
    int keylen, rc; 

    if (detoken(hash, &sha, &iterations, &salt, &h_pw) != 0) 
     return match; 

    /* Determine key length by decoding base64 */ 
    if ((keybuf = malloc(strlen(h_pw) + 1)) == NULL) { 
     fprintf(stderr, "Out of memory\n"); 
     return FALSE; 
    } 
    keylen = base64_decode(h_pw, keybuf); 
    if (keylen < 1) { 
     free(keybuf); 
     return (FALSE); 
    } 
    free(keybuf); 

    if ((out = malloc(keylen)) == NULL) { 
     fprintf(stderr, "Cannot allocate out; out of memory\n"); 
     return (FALSE); 
    } 

#ifdef PWDEBUG 
    fprintf(stderr, "sha  =[%s]\n", sha); 
    fprintf(stderr, "iterations =%d\n", iterations); 
    fprintf(stderr, "salt  =[%s]\n", salt); 
    fprintf(stderr, "h_pw  =[%s]\n", h_pw); 
    fprintf(stderr, "kenlen  =[%d]\n", keylen); 
#endif 

    saltlen = strlen((char *)salt); 

    evpmd = EVP_sha256(); 
    if (strcmp(sha, "sha1") == 0) { 
     evpmd = EVP_sha1(); 
    } else if (strcmp(sha, "sha512") == 0) { 
     evpmd = EVP_sha512(); 
    } 

    rc = PKCS5_PBKDF2_HMAC(password, strlen(password), 
          (unsigned char *)salt, saltlen, 
          iterations, 
          evpmd, keylen, out); 
    if (rc != 1) { 
     goto out; 
    } 

    blen = base64_encode(out, keylen, &b64); 
    if (blen > 0) { 
     int i, diff = 0, hlen = strlen(h_pw); 
#ifdef PWDEBUG 
     fprintf(stderr, "HMAC b64 =[%s]\n", b64); 
#endif 

     /* "manual" strcmp() to ensure constant time */ 
     for (i = 0; (i < blen) && (i < hlen); i++) { 
      diff |= h_pw[i]^b64[i]; 
     } 

     match = diff == 0; 
     if (hlen != blen) 
      match = 0; 

     free(b64); 
    } 

    out: 
    free(sha); 
    free(salt); 
    free(h_pw); 
    free(out); 

    return match; 
} 

void *test_pbkdf2(void *argt) { 
    int i; 
    for (i = 0; i < 3; ++i) { 
     char password[] = "password"; 
     char pbkstr[] = "PBKDF2$sha1$98$XaIs9vQgmLujKHZG4/B3dNTbeP2PyaVKySTirZznBrE=$2DX/HZDTojVbfgAIdozBi6CihjWP1+akYnh/h9uQfIVl6pLoAiwJe1ey2WW2BnT+"; 
     int match; 

     printf("Checking password [%s] for %s\n", password, pbkstr); 

     match = pbkdf2_check(password, pbkstr); 
     printf("match == %d\n", match); 
    } 
    pthread_exit(); 
} 

int main(int argc, char **argv) 
{ 
    pthread_t tid[NUMT]; 
    int i; 
    int error; 
    (void)argc; /* we don't use any arguments in this example */ 
    (void)argv; 

    thread_setup(); 

    for(i=0; i< NUMT; i++) { 
     error = pthread_create(&tid[i], 
           NULL, /* default attributes please */ 
           test_pbkdf2, 
           NULL); 
     if(0 != error) 
      fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error); 
    } 

    /* now wait for all threads to terminate */ 
    for(i=0; i< NUMT; i++) { 
     error = pthread_join(tid[i], NULL); 
     fprintf(stderr, "Thread %d terminated\n", i); 
    } 

    thread_cleanup(); 
    return 0; 
} 

opensslthreadlock.h:

/*************************************************************************** 
*         _ _ ____ _ 
* Project      ___| | | | _ \| | 
*       /__| | | | |_) | | 
*       | (__| |_| | _ <| |___ 
*        \___|\___/|_| \_\_____| 
* 
* Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al. 
* 
* This software is licensed as described in the file COPYING, which 
* you should have received as part of this distribution. The terms 
* are also available at https://curl.haxx.se/docs/copyright.html. 
* 
* You may opt to use, copy, modify, merge, publish, distribute and/or sell 
* copies of the Software, and permit persons to whom the Software is 
* furnished to do so, under the terms of the COPYING file. 
* 
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 
* KIND, either express or implied. 
* 
***************************************************************************/ 
/* <DESC> 
* one way to set the necessary OpenSSL locking callbacks if you want to do 
* multi-threaded transfers with HTTPS/FTPS with libcurl built to use OpenSSL. 
* </DESC> 
*/ 
/* 
* This is not a complete stand-alone example. 
* 
* Author: Jeremy Brown 
*/ 

int thread_setup(void); 

int thread_cleanup(void); 

Реализация здесь (opensslthreadlock.c). Код здесь: base64.c/h.

Я использую это для создания и испытания:

gcc -o pbkdf2test pbkdf2.c opensslthreadlock.c base64.c -lcrypto -lpthread 

valgrind --tool=memcheck --leak-check=full --track-origins=yes -v ./pbkdf2test 

Answer 1

Это все отлично работает, когда я запускаю код в одном потоке, но я начала получать Invalid чтения (с помощью Valgrind) для многих внутренние свободные() s в функции pbkdf2_check().

Это, как представляется, из-за:

static char *sha, *salt, *h_pw; 

Это всегда будет страдать состояние гонки, как pbkdf2_check написано.

Кроме того, как только эти бега:

out: 
    free(sha); 
    free(salt); 
    free(h_pw); 
    free(out); 

оборванные указатели повторно из-за статический класс памяти.

Вы, вероятно, следует удалить класс static для хранения sha, salt и h_pw и инициализировать все, чтобы NULL или 0. Использование C99 (-std=c99), и вы можете:

char *sha=NULL, *salt=NULL, *h_pw=NULL; 
int iterations=0, saltlen=0, blen=0; 
char *b64=NULL, *keybuf=NULL; 
unsigned char *out=NULL; 
int match = FALSE; 
const EVP_MD *evpmd=NULL; 
int keylen=0, rc=-1; 

Затем оптимизатор удалит Инициализаторы/записи, которые не нужны.