Module: kamailio Branch: master Commit: 40d9289977b97becc4d4bd948bcde57ea320cf0e URL: https://github.com/kamailio/kamailio/commit/40d9289977b97becc4d4bd948bcde57… Author: Daniel-Constantin Mierla &lt;miconda(a)gmail.com&gt; Committer: Daniel-Constantin Mierla &lt;miconda(a)gmail.com&gt; Date: 2020-06-02T07:57:34+02:00 crypto: saved functions in crypto_aes.c --- Modified: src/modules/crypto/crypto_aes.c --- Diff: https://github.com/kamailio/kamailio/commit/40d9289977b97becc4d4bd948bcde57… Patch: https://github.com/kamailio/kamailio/commit/40d9289977b97becc4d4bd948bcde57… --- diff --git a/src/modules/crypto/crypto_aes.c b/src/modules/crypto/crypto_aes.c index 9573c7264d..777d43502b 100644 --- a/src/modules/crypto/crypto_aes.c +++ b/src/modules/crypto/crypto_aes.c @@ -19,3 +19,122 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +/** + * Create an 256 bit key and IV using the supplied key_data and salt. + * Fills in the encryption and decryption ctx objects and returns 0 on success + */ +int crypto_aes_init(unsigned char *key_data, int key_data_len, + unsigned char *salt, EVP_CIPHER_CTX *e_ctx, EVP_CIPHER_CTX *d_ctx) +{ + int i, nrounds = 5; + int x; + unsigned char key[32], iv[32]; + + /* + * Gen key & IV for AES 256 CBC mode. A SHA1 digest is used to hash + * the supplied key material. + * nrounds is the number of times the we hash the material. More rounds + * are more secure but slower. + */ + i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha1(), salt, + key_data, key_data_len, nrounds, key, iv); + if (i != 32) { + LM_ERR("key size is %d bits - should be 256 bits\n", i); + return -1; + } + + for(x = 0; x<32; ++x) + LM_DBG("key: %x iv: %x \n", key[x], iv[x]); + + for(x = 0; x<8; ++x) + LM_DBG("salt: %x\n", salt[x]); + + if(e_ctx) { + EVP_CIPHER_CTX_init(e_ctx); + EVP_EncryptInit_ex(e_ctx, EVP_aes_256_cbc(), NULL, key, iv); + } + if(d_ctx) { + EVP_CIPHER_CTX_init(d_ctx); + EVP_DecryptInit_ex(d_ctx, EVP_aes_256_cbc(), NULL, key, iv); + } + + return 0; +} + +/* + * Encrypt *len bytes of data + * All data going in & out is considered binary (unsigned char[]) + */ +unsigned char *crypto_aes_encrypt(EVP_CIPHER_CTX *e, unsigned char *plaintext, + int *len) +{ + /* max ciphertext len for a n bytes of plaintext is + * n + AES_BLOCK_SIZE -1 bytes */ + int c_len = *len + AES_BLOCK_SIZE - 1, f_len = 0; + unsigned char *ciphertext = (unsigned char *)malloc(c_len); + + if(ciphertext == NULL) { + LM_ERR("no more system memory\n"); + return NULL; + } + /* allows reusing of 'e' for multiple encryption cycles */ + if(!EVP_EncryptInit_ex(e, NULL, NULL, NULL, NULL)){ + LM_ERR("failure in EVP_EncryptInit_ex \n"); + free(ciphertext); + return NULL; + } + + /* update ciphertext, c_len is filled with the length of ciphertext + * generated, *len is the size of plaintext in bytes */ + if(!EVP_EncryptUpdate(e, ciphertext, &c_len, plaintext, *len)){ + LM_ERR("failure in EVP_EncryptUpdate \n"); + free(ciphertext); + return NULL; + } + + /* update ciphertext with the final remaining bytes */ + if(!EVP_EncryptFinal_ex(e, ciphertext+c_len, &f_len)){ + LM_ERR("failure in EVP_EncryptFinal_ex \n"); + free(ciphertext); + return NULL; + } + + *len = c_len + f_len; + return ciphertext; +} + +/* + * Decrypt *len bytes of ciphertext + */ +unsigned char *crypto_aes_decrypt(EVP_CIPHER_CTX *e, unsigned char *ciphertext, + int *len) +{ + /* plaintext will always be equal to or lesser than length of ciphertext*/ + int p_len = *len, f_len = 0; + unsigned char *plaintext = (unsigned char *)malloc(p_len); + + if(plaintext==NULL) { + LM_ERR("no more system memory\n"); + return NULL; + } + if(!EVP_DecryptInit_ex(e, NULL, NULL, NULL, NULL)){ + LM_ERR("failure in EVP_DecryptInit_ex \n"); + free(plaintext); + return NULL; + } + + if(!EVP_DecryptUpdate(e, plaintext, &p_len, ciphertext, *len)){ + LM_ERR("failure in EVP_DecryptUpdate\n"); + free(plaintext); + return NULL; + } + + if(!EVP_DecryptFinal_ex(e, plaintext+p_len, &f_len)){ + LM_ERR("failure in EVP_DecryptFinal_ex\n"); + free(plaintext); + return NULL; + } + + *len = p_len + f_len; + return plaintext; +} \ No newline at end of file