OpenSSL 内存泄漏？

我使用以下代码来检查签名。为了简单起见，公钥、消息和签名在中初始化main.

#include <openssl/sha.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>

int main(){
    const unsigned char key[] = "-----BEGIN PUBLIC KEY-----\n"
                "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBALulMfYFyX1kSm7oUxZyCWWhrBBcWrRA\n"
                "V7LSz1PzMPxoxG3KS8H7PRKFkIk42yM8/vhobmcCmj7UM5572wWch50CAwEAAQ==\n"
                "-----END PUBLIC KEY-----\n";
    unsigned int key_len = sizeof(key);

    const unsigned char data[] = {0x6d,0x65,0x73,0x65,0x0a};
    unsigned int data_len = sizeof(data);

    const unsigned char sig[] = {0xa9,0x29,0x81,0x07,0x8c,0xeb,0xf0,0x1b,0x2a,0x31,0xe5,0x60,0x94,0x8a,0x47,0x94,0x3a,0x8f,0x6b,
                0x4e,0x85,0xb9,0xe7,0xe5,0x4a,0x6c,0x56,0x46,0xd1,0x80,0x15,0x57,0xce,0xcb,0x0a,0x3a,0x67,0x15,0xed,
                0x68,0x03,0x58,0x99,0xa4,0x73,0x61,0xe3,0x30,0x85,0xff,0x89,0x7e,0x32,0xef,0x16,0xec,0x23,0x7f,0x14,
                0xde,0xbf,0x53,0xe0,0x3a};
    unsigned int sig_len = sizeof(sig);


    EVP_PKEY* evp_pubkey = EVP_PKEY_new();
        RSA* rsa_pubkey = NULL;
    EVP_MD_CTX ctx;

    BIO* bufio = BIO_new_mem_buf((void*)key, key_len);
    if(bufio == NULL){  
        fprintf(stderr, "BIO not created.\n");
        EVP_PKEY_free(evp_pubkey);
        BIO_free(bufio);
        return 3;
    }

    evp_pubkey = PEM_read_bio_PUBKEY(bufio, NULL, NULL, NULL);
    if(evp_pubkey == NULL){ 
        fprintf(stderr, "evp_pubkey not created.\n");
        EVP_PKEY_free(evp_pubkey);
        BIO_free(bufio);
        return 4;
    }

    EVP_MD_CTX_init(&ctx);  

    if (!EVP_VerifyInit(&ctx, EVP_sha256())) {
            fprintf(stderr, "EVP_SignInit: failed.\n");
            EVP_PKEY_free(evp_pubkey);
            BIO_free(bufio);
            return 5;
        }

        if (!EVP_VerifyUpdate(&ctx, data, data_len)) {
                fprintf(stderr, "EVP_SignUpdate: failed.\n");
                EVP_PKEY_free(evp_pubkey);
                BIO_free(bufio);
                return 6;
        }

        if (!EVP_VerifyFinal(&ctx, sig, sig_len, evp_pubkey)) {
            fprintf(stderr, "EVP_VerifyFinal: failed.\n");
            EVP_PKEY_free(evp_pubkey);
            BIO_free(bufio);
            return 7;
        }

        EVP_PKEY_free(evp_pubkey);
        BIO_free(bufio);

        return 0;
}

编译后用gcc evp.c -lssl -lcrypto和跑步valgrind --tool=memcheck --leak-check=full ./a.out在它上面我得到了一些内存泄漏：

==7492== 56 bytes in 1 blocks are definitely lost in loss record 9 of 12
==7492==    at 0x4C2BBCF: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7492==    by 0x4E9AD77: CRYPTO_malloc (in /lib/x86_64-linux-gnu/libcrypto.so.1.0.0)
==7492==    by 0x4F5D459: EVP_PKEY_new (in /lib/x86_64-linux-gnu/libcrypto.so.1.0.0)
==7492==    by 0x400C4C: main (in a.out)
==7492== 
==7492== 120 bytes in 1 blocks are definitely lost in loss record 10 of 12
==7492==    at 0x4C2BBCF: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7492==    by 0x4E9AD77: CRYPTO_malloc (in /lib/x86_64-linux-gnu/libcrypto.so.1.0.0)
==7492==    by 0x4F55678: EVP_DigestInit_ex (in /lib/x86_64-linux-gnu/libcrypto.so.1.0.0)
==7492==    by 0x400D6A: main (in a.out)

难道我做错了什么？

您正在覆盖此处的指针

evp_pubkey = PEM_read_bio_PUBKEY(bufio, NULL, NULL, NULL);

所以对返回的指针的引用EVP_PKEY_new()第一次已经失去了，你再也无法释放它了。