Question

所以我有3个静态变量：

static char sys_salt[PWORD_SALT_LEN];
static char sys_hash[PWORD_HASH_LEN];
static char *sys_encoded_password;

然后将这3个静态变量发送给该函数：

set_hash_and_salt_for_pword(
    pword, sys_hash, sys_salt, sys_encoded_password);

在此功能内，

通过以下方式设置盐：

arc4random_buf(pword_salt, PWORD_SALT_LEN);
sys_hash已成功设置，并在我的set_hash_and_salt_for_pword被调用后保持设置状态。这是在以下函数内完成的：argon2_hash(...)
我希望像设置static char *sys_encoded_password;一样设置sys_hash：在argon_2hash内，实际上是因为我在函数内部调用了NSLog(...)。（是的。我也正在使用Obejctive-C。但是在函数返回后，指针再次为NULL。

这是怎么回事？为什么该指针不持久？

注意：我看到sys_hash和sys_encoded_password之间有2个区别：

sys_encoded_password的类型为static char*，sys_hash的类型为：static char sys_hash[PWORD_HASH_LEN];（又名-大小由宏定义预先定义，这导致第二个差异：
我通过执行以下sys_encoded_password调用来设置set_hash_and_salt_for_pword中malloc的大小：

encoded_password = malloc(encoded_password_length + 1);

输出如下：

2020-04-22 11:09:16.837705-0400 InsecureApp[31502:3180622] pword inside set_hash_and_salt_for_pword: openSesame
2020-04-22 11:09:16.838315-0400 InsecureApp[31502:3180622] salt inside set_hash_and_salt_for_pword:: \M-}b.\M-1T?\M-4\M^QW#\M^J\M-3\M-y\M-2\^V\M-O\M-E\M-p5\M-M\^R\M^Qii_<L\M-?H\M^F \M-_
2020-04-22 11:09:16.838371-0400 InsecureApp[31502:3180622] hash inside set_hash_and_salt_for_pword:: \M^K)Ϸ\M-R5}v\M-`\^FB&\^W\M^H$'\M-}b.\M-1T?\M-4\M^QW#\M^J\M-3\M-y\M-2\^V\M-O\M-E\M-p5\M-M\^R\M^Qii_<L\M-?H\M^F \M-_
2020-04-22 11:09:16.838435-0400 InsecureApp[31502:3180622] encod inside set_hash_and_salt_for_pword: $argon2id$v=19$m=65536,t=2,p=1$/WIusVQ/tJFXI4qz+bIWz8XwNc0SkWlpXzxMv0iGIN8$iynPt9I1fXbgBkImF4gkJw
2020-04-22 11:09:16.838505-0400 InsecureApp[31502:3180622] pword out: openSesame
2020-04-22 11:09:16.838550-0400 InsecureApp[31502:3180622] salt out:: \M-}b.\M-1T?\M-4\M^QW#\M^J\M-3\M-y\M-2\^V\M-O\M-E\M-p5\M-M\^R\M^Qii_<L\M-?H\M^F \M-_
2020-04-22 11:09:16.838598-0400 InsecureApp[31502:3180622] hash out:: \M^K)Ϸ\M-R5}v\M-`\^FB&\^W\M^H$'\M-}b.\M-1T?\M-4\M^QW#\M^J\M-3\M-y\M-2\^V\M-O\M-E\M-p5\M-M\^R\M^Qii_<L\M-?H\M^F \M-_
2020-04-22 11:09:16.898853-0400 InsecureApp[31502:3180622] encod out: (null)

P.S —这是一个完全不安全的本地应用程序，但我是1）学习C，2）使用argon2 API。

相关代码：

#define PWORD_SALT_LEN 32
#define PWORD_HASH_LEN 16
static char sys_salt[PWORD_SALT_LEN];
static char sys_hash[PWORD_HASH_LEN];
static char *sys_encoded_password;


int set_hash_and_salt_for_pword(
      const char *pword
    , char pword_hash[PWORD_SALT_LEN]
    , char pword_salt[PWORD_HASH_LEN]
    , char *encoded_password
){
    arc4random_buf(pword_salt, PWORD_SALT_LEN);


    uint8_t  *pword_for_argon = (uint8_t*)strdup(pword);
    uint32_t  pword_len       = (uint32_t)strlen((char*)pword_for_argon);

    uint32_t t_cost = 2;            // 1-pass computation
    uint32_t m_cost = (1<<16);      // 64 mebibytes memory usage
    uint32_t lanes  = 1;            // number of threads and lanes

    argon2_type hash_type = Argon2_id;

    size_t encoded_password_length;
    argon2_version version = ARGON2_VERSION_NUMBER;

    encoded_password_length
        = argon2_encodedlen(
              t_cost
            , m_cost
            , lanes
            , (uint32_t)PWORD_SALT_LEN
            , PWORD_HASH_LEN
            , hash_type);

    encoded_password = malloc(encoded_password_length + 1);

    if (!encoded_password) {
        // clear_internal_memory(pword_for_argon, pword_len);
        NSLog(@"could not allocate memory for hash");
    }

    // argon2id_hash_encoded(
    argon2_hash(
          t_cost
        , m_cost
        , lanes
        , pword_for_argon
        , pword_len
        , pword_salt
        , PWORD_SALT_LEN
        , pword_hash               // EXTRA
        , PWORD_HASH_LEN
        , encoded_password
        , encoded_password_length  // )
        , hash_type                // EXTRA
        , version);                // EXTRA


     NSLog(@"pword inside set_hash_and_salt_for_pword: %s", pword);
     NSLog(@"salt inside set_hash_and_salt_for_pword:: %s", pword_salt);
     NSLog(@"hash inside set_hash_and_salt_for_pword:: %s", pword_hash);
     NSLog(@"encod inside set_hash_and_salt_for_pword: %s", encoded_password);

    return 0;
}

int main(){
    /* BLAH CODE */
    char *pword = "openSesame";

    set_hash_and_salt_for_pword(
        pword, sys_hash, sys_salt, sys_encoded_password);

    NSLog(@"pword out: %s", pword);
    NSLog(@"salt out:: %s", sys_salt);
    NSLog(@"hash out:: %s", sys_hash);
    NSLog(@"encod out: %s", sys_encoded_password);

    cleanup();    

    return 0;
}

为什么要设置静态数组，但在函数调用后将静态指针设置为NULL？

0 个答案: