diff options
| -rw-r--r-- | lib/lib2.c | 9 | ||||
| -rw-r--r-- | set2/task15.c | 35 |
2 files changed, 36 insertions, 8 deletions
@@ -41,7 +41,7 @@ int valid_pkcs7_padding(const char *in, int length_in, char *unpadded, int block } padding_length = length_in - i; - if ((length_in % padding_length) != 0) + if ((length_in % blocksize) != 0) return 0; if(in[length_in-1] != padding_length) @@ -385,7 +385,6 @@ int challenge16_encrypt(char *input, char **encrypted) res[strlen(prepend)+strlen(input)+strlen(append)+2*quote_char+1] = '\0'; // padding unencrypted = pkcs7_padding(res, strlen(res), 16); - printf("%s\n", unencrypted); *encrypted = malloc(strlen(unencrypted)); aes_cbc(unencrypted, strlen(unencrypted), *encrypted, key, iv , 1); return strlen(unencrypted); @@ -398,7 +397,11 @@ void challenge16_decrypt(char *encrypted, int length) aes_cbc(encrypted, length, unencrypted, key, iv, 0); // unpadd - valid_pkcs7_padding(unencrypted, length, unpadd, 16); + int ret = valid_pkcs7_padding(unencrypted, length, unpadd, 16); + if(!ret) { + printf("no valid padding!\n"); + return; + } // look for string ;admin=true; printf("unencrpyted string: %s\n", unpadd); } diff --git a/set2/task15.c b/set2/task15.c index 504eabb..a40ecf3 100644 --- a/set2/task15.c +++ b/set2/task15.c @@ -1,12 +1,7 @@ #include "../lib/lib2.h" - - - int main(int argc, char **Argv) { - - char *padded_text = pkcs7_padding("YELLOW SUBMARINE", 16, 20); char *unpadded = malloc(100); //char *padded_text = "ICE ICE BABY\x01\x02\x03\x04"; @@ -18,4 +13,34 @@ int main(int argc, char **Argv) else printf("invalid padding\n"); + padded_text = pkcs7_padding("YELLOW SUBMARINE", 16, 16); + + //char *padded_text = "ICE ICE BABY\x01\x02\x03\x04"; + printf("padded text: %s\n", padded_text); + result = valid_pkcs7_padding(padded_text, 32,unpadded, 16); + + if(result) + printf("valid padding: %s\n", unpadded); + else + printf("invalid padding\n"); + + padded_text = "ICE ICE BABY\x01\x02\x03\x04"; + printf("padded text: %s\n", padded_text); + result = valid_pkcs7_padding(padded_text, 32,unpadded, 16); + + if(result) + printf("valid padding: %s\n", unpadded); + else + printf("invalid padding\n"); + char *string = "Who let the dogs out"; + padded_text = pkcs7_padding(string, strlen(string), 16); + + printf("%i, %i\n",strlen(string), strlen(padded_text)); + printf("padded text: %s\n", padded_text); + result = valid_pkcs7_padding(padded_text, strlen(padded_text),unpadded, 16); + + if(result) + printf("valid padding: %s\n", unpadded); + else + printf("invalid padding\n"); } |