maybe not - still confused
On Fri, Aug 16, 2013 at 2:21 AM, Ztatik Light <ztatik.li...@gmail.com>wrote:
> strange i think it has something to do with me using "rb" and "wb" instead
> of "r" and "w"...
>
>
> On Fri, Aug 16, 2013 at 2:14 AM, Ztatik Light <ztatik.li...@gmail.com>wrote:
>
>> So, I'm having a really weird issue... i'm trying simple file
>> encryption/decryption with BIO_*, but if the encrypted file is in a
>> subdirectory.. i get garbage data,
>>
>> I'll post the code i'm using, with a brief elaboration on how i'm using
>> it and what behaviour i'm getting:
>>
>> ///////////////////////////////
>>
>> /*
>>>
>>> Example of ssl read and write to a file
>>>
>>>
>>>> gcc ssl_write_read.c -lssl
>>>
>>> ./a.out
>>>
>>>
>>>>
>>>> */
>>>
>>>
>>>>
>>>>
>>>> #include <openssl/bio.h>
>>>
>>> #include <openssl/err.h>
>>>
>>> #include <openssl/rand.h>
>>>
>>> #include <openssl/ssl.h>
>>>
>>> #include <openssl/x509v3.h>
>>>
>>>
>>>> int read_whole_file( char* filename, char** data ){
>>>
>>> FILE* file = fopen( filename, "rb" );
>>>
>>> fseek( file, 0, SEEK_END );
>>>
>>> long fileSize = ftell( file );
>>>
>>> rewind( file );
>>>
>>> *data = malloc( fileSize );
>>>
>>> fread( *data, fileSize, 1, file );
>>>
>>> fclose( file );
>>>
>>> return fileSize;
>>>
>>> }
>>>
>>> void encrypt_file( char* filename ){
>>>
>>> char new_filename[strlen( filename + 4 )];
>>>
>>> strcpy( new_filename, filename );
>>>
>>> strcat( new_filename, ".enc" );
>>>
>>> char* data;
>>>
>>> int fileSize = read_whole_file( filename, &data );
>>>
>>> write_data( new_filename, data, fileSize, (unsigned char*)"mykey" );
>>>
>>> free( data );
>>>
>>> }
>>>
>>>
>>>> int write_data(const char *filename, char *out, int len, unsigned char
>>>> *key)
>>>
>>> {
>>>
>>> int total, written;
>>>
>>> BIO *cipher, *buffer, *file;
>>>
>>>
>>>
>>> /* Create a buffered file BIO for writing */
>>>
>>> file = BIO_new_file(filename, "wb");
>>>
>>> if (!file)
>>>
>>> return 0;
>>>
>>>
>>>
>>> /* Create a buffering filter BIO to buffer writes to the file */
>>>
>>> buffer = BIO_new(BIO_f_buffer( ));
>>>
>>>
>>>
>>> /* Create a base64 encoding filter BIO */
>>>
>>> // b64 = BIO_new(BIO_f_base64( ));
>>>
>>>
>>>
>>> /* Create the cipher filter BIO and set the key. The last parameter of
>>>
>>> BIO_set_cipher is 1 for encryption and 0 for decryption */
>>>
>>> cipher = BIO_new(BIO_f_cipher( ));
>>>
>>> BIO_set_cipher(cipher, EVP_des_ede3_cbc( ), key, NULL, 1);
>>>
>>>
>>>
>>> /* Assemble the BIO chain to be in the order cipher-b64-buffer-file */
>>>
>>> // BIO_push(cipher, b64);
>>>
>>> // BIO_push(b64, buffer);
>>>
>>> BIO_push(cipher,buffer);
>>>
>>> BIO_push(buffer, file);
>>>
>>>
>>>> /* This loop writes the data to the file. It checks for errors as if
>>>> the
>>>
>>> underlying file were non-blocking */
>>>
>>> for (total = 0; total < len; total += written)
>>>
>>> {
>>>
>>> if ((written = BIO_write(cipher, out + total, len - total)) <= 0)
>>>
>>> {
>>>
>>> if (BIO_should_retry(cipher))
>>>
>>> {
>>>
>>> written = 0;
>>>
>>> continue;
>>>
>>> }
>>>
>>> break;
>>>
>>> }
>>>
>>> }
>>>
>>>
>>>
>>> /* Ensure all of our data is pushed all the way to the file */
>>>
>>> BIO_flush(cipher);
>>>
>>>
>>>
>>> BIO_free_all(cipher);
>>>
>>> }
>>>
>>>
>>>> BIO* decrypt_open( const char *filename, unsigned char *key ){
>>>
>>> int total, written;
>>>
>>> BIO *cipher, *buffer, *file;
>>>
>>> //char *b = malloc(len);
>>>
>>>
>>>
>>> /* Create a buffered file BIO for reading */
>>>
>>> file = BIO_new_file(filename, "rb");
>>>
>>> if (!file)
>>>
>>> return 0;
>>>
>>>
>>>
>>> /* Create a buffering filter BIO to buffer writes to the file */
>>>
>>> buffer = BIO_new(BIO_f_buffer( ));
>>>
>>>
>>>
>>> /* Create a base64 encoding filter BIO */
>>>
>>> // b64 = BIO_new(BIO_f_base64( ));
>>>
>>>
>>>
>>> /* Create the cipher filter BIO and set the key. The last parameter of
>>>
>>> BIO_set_cipher is 1 for encryption and 0 for decryption */
>>>
>>> cipher = BIO_new(BIO_f_cipher( ));
>>>
>>> BIO_set_cipher(cipher, EVP_des_ede3_cbc( ), key, NULL, 0);
>>>
>>>
>>>
>>> /* Assemble the BIO chain to be in the order cipher-b64-buffer-file */
>>>
>>> // BIO_push(cipher, b64);
>>>
>>> // BIO_push(b64, buffer);
>>>
>>> BIO_push(cipher,buffer);
>>>
>>> BIO_push(buffer, file);
>>>
>>> return cipher;
>>>
>>> }
>>>
>>> char* decrypt_read( BIO* cipher, int len, char* b ){
>>>
>>> int total, written;
>>>
>>>
>>>> // char b[len + 1];
>>>
>>> for (total = 0; total < len; total += written)
>>>
>>> {
>>>
>>> if ((written = BIO_read(cipher, b, len - total)) <= 0)
>>>
>>> {
>>>
>>> if (BIO_should_retry(cipher))
>>>
>>> {
>>>
>>> written = 0;
>>>
>>> continue;
>>>
>>> }
>>>
>>> break;
>>>
>>> }
>>>
>>> }
>>>
>>>
>>>
>>> b[total] = '\0';
>>>
>>>
>>>
>>> return b;
>>>
>>> }
>>>
>>>
>>>> int main(void)
>>>
>>> {
>>>
>>> //chdir("subdirectory");
>>>
>>> char *file_="test.txt";
>>>
>>> char* data = "howdy\n";
>>>
>>> write_data( file_, data, strlen(data), "mykey");
>>>
>>>
>>>> BIO* cipher = decrypt_open( file_, (unsigned char*)"mykey" );
>>>
>>> char b[999999];
>>>
>>> decrypt_read( cipher, 999999, b );
>>>
>>> BIO_flush( cipher );
>>>
>>> BIO_free_all( cipher );
>>>
>>> printf(">%s\n",b);
>>>
>>>
>>>> //char* test="plain.txt";
>>>
>>> //encrypt_file(test);
>>>
>>>
>>>> }
>>>
>>>
>> ///////////////////////////////////////////////////////////
>>
>> 1. So, first run creates and writes encrypted file "test.txt" and then
>> decrypts and prints out the contents, "howdy",
>>
>> 2. Now, comment out line 141 // write_data( ... re-run to verify "howdy",
>> works fine
>>
>> 3. make directory "temp", move "test.txt" into "temp" and change line 139
>> to reflect that: char *file_="temp/test.txt";.. re-run - I get no results ??
>>
>> 4. Even more weird: change line 139 back to just "test.txt", and replace
>> file_ on line 143 with "temp/test.txt" ... so it reads: BIO* cipher =
>> decrypt_open( "temp/test.txt", (unsigned char*)"mykey" ); // re-run... now
>> it works again all of a sudden. BUT - if you comment out line 139 // char
>> *file_="test.txt";.... then it doesn't work again? Even though *file_ isn't
>> being used???
>>
>
>
