【发布时间】：2014-09-04 08:35:10
【问题描述】：
我在加密 Apache 日志时遇到问题。我想使用 OpenSSL EVP 函数加密日志（即使用包含在 RSA 公钥中的对称密钥），并将传入日志流加密到磁盘。为此，我认为我需要创建一个二进制文件来加密来自 STDIN 的日志并将它们重定向到磁盘，方法是使用 Apache 中的 ErrorLog 指令。
在另一篇文章中，我认为我的加密工作正常。我的加密代码是：
#include <stdio.h>
#include <stdlib.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/err.h>
#include <arpa/inet.h> /* For htonl() */
int do_evp_seal(FILE *rsa_pkey_file, FILE *in_file, FILE *out_file)
{
int retval = 0;
RSA *rsa_pkey = NULL;
EVP_PKEY *pkey = EVP_PKEY_new();
EVP_CIPHER_CTX ctx;
unsigned char buffer[4096];
unsigned char buffer_out[4096 + EVP_MAX_IV_LENGTH];
size_t len;
int len_out;
unsigned char *ek = NULL;
int eklen;
uint32_t eklen_n;
unsigned char iv[EVP_MAX_IV_LENGTH];
if (!PEM_read_RSA_PUBKEY(rsa_pkey_file, &rsa_pkey, NULL, NULL))
{
fprintf(stderr, "Error loading RSA Public Key File.\n");
ERR_print_errors_fp(stderr);
retval = 2;
goto out;
}
if (!EVP_PKEY_assign_RSA(pkey, rsa_pkey))
{
fprintf(stderr, "EVP_PKEY_assign_RSA: failed.\n");
retval = 3;
goto out;
}
EVP_CIPHER_CTX_init(&ctx);
ek = malloc(EVP_PKEY_size(pkey));
if (!EVP_SealInit(&ctx, EVP_aes_128_cbc(), &ek, &eklen, iv, &pkey, 1))
{
fprintf(stderr, "EVP_SealInit: failed.\n");
retval = 3;
goto out_free;
}
/* First we write out the encrypted key length, then the encrypted key,
* then the iv (the IV length is fixed by the cipher we have chosen).
*/
eklen_n = htonl(eklen);
if (fwrite(&eklen_n, sizeof eklen_n, 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
if (fwrite(ek, eklen, 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
if (fwrite(iv, EVP_CIPHER_iv_length(EVP_aes_128_cbc()), 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
/* Now we process the input file and write the encrypted data to the
* output file. */
while ((len = fread(buffer, 1, sizeof buffer, in_file)) > 0)
{
if (!EVP_SealUpdate(&ctx, buffer_out, &len_out, buffer, len))
{
fprintf(stderr, "EVP_SealUpdate: failed.\n");
retval = 3;
goto out_free;
}
if (fwrite(buffer_out, len_out, 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
}
if (ferror(in_file))
{
perror("input file");
retval = 4;
goto out_free;
}
if (!EVP_SealFinal(&ctx, buffer_out, &len_out))
{
fprintf(stderr, "EVP_SealFinal: failed.\n");
retval = 3;
goto out_free;
}
if (fwrite(buffer_out, len_out, 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
out_free:
EVP_PKEY_free(pkey);
free(ek);
out:
return retval;
}
int main(int argc, char *argv[])
{
FILE *rsa_pkey_file;
int rv;
if (argc < 2)
{
fprintf(stderr, "Usage: %s <PEM RSA Public Key File>\n", argv[0]);
exit(1);
}
rsa_pkey_file = fopen(argv[1], "rb");
if (!rsa_pkey_file)
{
perror(argv[1]);
fprintf(stderr, "Error loading PEM RSA Public Key File.\n");
exit(2);
}
rv = do_evp_seal(rsa_pkey_file, stdin, stdout);
fclose(rsa_pkey_file);
return rv;
}
及解密：
#include <stdio.h>
#include <stdlib.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/err.h>
#include <arpa/inet.h> /* For htonl() */
int do_evp_unseal(FILE *rsa_pkey_file, FILE *in_file, FILE *out_file)
{
int retval = 0;
RSA *rsa_pkey = NULL;
EVP_PKEY *pkey = EVP_PKEY_new();
EVP_CIPHER_CTX ctx;
unsigned char buffer[4096];
unsigned char buffer_out[4096 + EVP_MAX_IV_LENGTH];
size_t len;
int len_out;
unsigned char *ek;
unsigned int eklen;
uint32_t eklen_n;
unsigned char iv[EVP_MAX_IV_LENGTH];
if (!PEM_read_RSAPrivateKey(rsa_pkey_file, &rsa_pkey, NULL, NULL))
{
fprintf(stderr, "Error loading RSA Private Key File.\n");
ERR_print_errors_fp(stderr);
retval = 2;
goto out;
}
if (!EVP_PKEY_assign_RSA(pkey, rsa_pkey))
{
fprintf(stderr, "EVP_PKEY_assign_RSA: failed.\n");
retval = 3;
goto out;
}
EVP_CIPHER_CTX_init(&ctx);
ek = malloc(EVP_PKEY_size(pkey));
/* First need to fetch the encrypted key length, encrypted key and IV */
if (fread(&eklen_n, sizeof eklen_n, 1, in_file) != 1)
{
perror("input file");
retval = 4;
goto out_free;
}
eklen = ntohl(eklen_n);
if (eklen > EVP_PKEY_size(pkey))
{
fprintf(stderr, "Bad encrypted key length (%u > %d)\n", eklen,
EVP_PKEY_size(pkey));
retval = 4;
goto out_free;
}
if (fread(ek, eklen, 1, in_file) != 1)
{
perror("input file");
retval = 4;
goto out_free;
}
if (fread(iv, EVP_CIPHER_iv_length(EVP_aes_128_cbc()), 1, in_file) != 1)
{
perror("input file");
retval = 4;
goto out_free;
}
if (!EVP_OpenInit(&ctx, EVP_aes_128_cbc(), ek, eklen, iv, pkey))
{
fprintf(stderr, "EVP_OpenInit: failed.\n");
retval = 3;
goto out_free;
}
while ((len = fread(buffer, 1, sizeof buffer, in_file)) > 0)
{
if (!EVP_OpenUpdate(&ctx, buffer_out, &len_out, buffer, len))
{
fprintf(stderr, "EVP_OpenUpdate: failed.\n");
retval = 3;
goto out_free;
}
if (fwrite(buffer_out, len_out, 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
}
if (ferror(in_file))
{
perror("input file");
retval = 4;
goto out_free;
}
if (!EVP_OpenFinal(&ctx, buffer_out, &len_out))
{
fprintf(stderr, "EVP_SealFinal: failed.\n");
retval = 3;
goto out_free;
}
if (fwrite(buffer_out, len_out, 1, out_file) != 1)
{
perror("output file");
retval = 5;
goto out_free;
}
out_free:
EVP_PKEY_free(pkey);
free(ek);
out:
return retval;
}
int main(int argc, char *argv[])
{
FILE *rsa_pkey_file;
int rv;
if (argc < 2)
{
fprintf(stderr, "Usage: %s <PEM RSA Private Key File>\n", argv[0]);
exit(1);
}
rsa_pkey_file = fopen(argv[1], "rb");
if (!rsa_pkey_file)
{
perror(argv[1]);
fprintf(stderr, "Error loading PEM RSA Private Key File.\n");
exit(2);
}
rv = do_evp_unseal(rsa_pkey_file, stdin, stdout);
fclose(rsa_pkey_file);
return rv;
}
我在 Apache 中的指令是：
ErrorLog "|/home/Desktop/encrypt /home/Desktop/public.pem > /home/Desktop/output.log"
但是当我重新启动 Apache 并开始浏览时，没有出现 output.log 文件。从 shell 提示符运行加密函数会产生预期的结果。
救命！
【问题讨论】：
标签： c apache encryption rsa