X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/06931406d7d50ab93f6457ecf2812695be8adb3c..6c8ef0eb86a39c277d1a43802dd8ea01b51cfb2a:/print-esp.c?ds=sidebyside diff --git a/print-esp.c b/print-esp.c index 9ac7d0be..6fabff1e 100644 --- a/print-esp.c +++ b/print-esp.c @@ -145,6 +145,39 @@ EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx) } #endif +#ifdef HAVE_EVP_CIPHERINIT_EX +/* + * Initialize the cipher by calling EVP_CipherInit_ex(), because + * calling EVP_CipherInit() will reset the cipher context, clearing + * the cipher, so calling it twice, with the second call having a + * null cipher, will clear the already-set cipher. EVP_CipherInit_ex(), + * however, won't reset the cipher context, so you can use it to specify + * the IV oin a second call after a first call to EVP_CipherInit_ex() + * to set the cipher and the key. + * + * XXX - is there some reason why we need to make two calls? + */ +static int +set_cipher_parameters(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, + const unsigned char *key, + const unsigned char *iv, int enc) +{ + return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc); +} +#else +/* + * Initialize the cipher by calling EVP_CipherInit(), because we don't + * have EVP_CipherInit_ex(); we rely on it not trashing the context. + */ +static int +set_cipher_parameters(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, + const unsigned char *key, + const unsigned char *iv, int enc) +{ + return EVP_CipherInit(ctx, cipher, key, iv, enc); +} +#endif + /* * this will adjust ndo_packetp and ndo_snapend to new buffer! */ @@ -156,9 +189,10 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo, { struct sa_list *sa; const u_char *iv; - u_char *buf_mut, *output_buffer; - int len, block_size, cipher_nid, output_buffer_size ; + unsigned int len; EVP_CIPHER_CTX *ctx; + unsigned int block_size, buffer_size; + u_char *input_buffer, *output_buffer; /* initiator arg is any non-zero value */ if(initiator) initiator=1; @@ -189,32 +223,57 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo, ctx = EVP_CIPHER_CTX_new(); if (ctx == NULL) return 0; - if (EVP_CipherInit(ctx, sa->evp, sa->secret, NULL, 0) < 0) + if (set_cipher_parameters(ctx, sa->evp, sa->secret, NULL, 0) < 0) (*ndo->ndo_warning)(ndo, "espkey init failed"); - EVP_CipherInit(ctx, NULL, NULL, iv, 0); - - /* We need a block size */ - block_size = EVP_CIPHER_CTX_block_size(ctx); - /* We need the buffer size to be multiple of a block size */ - output_buffer_size = len + (block_size - len % block_size); - output_buffer = (u_char *)calloc(output_buffer_size, sizeof(u_char)); - /* EVP_Cipher output buffer should be different from the input one. - * Also it should be of size that is multiple of cipher block size. */ - EVP_Cipher(ctx, output_buffer, buf, len); + set_cipher_parameters(ctx, NULL, NULL, iv, 0); + /* + * Allocate buffers for the encrypted and decrypted data. + * Both buffers' sizes must be a multiple of the cipher block + * size, and the output buffer must be separate from the input + * buffer. + */ + block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx); + buffer_size = len + (block_size - len % block_size); + + /* + * Attempt to allocate the input buffer. + */ + input_buffer = (u_char *)malloc(buffer_size); + if (input_buffer == NULL) { + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_error)(ndo, "can't allocate memory for encrypted data buffer"); + } + /* + * Copy the input data to the encrypted data buffer, and pad it + * with zeroes. + */ + memcpy(input_buffer, buf, len); + memset(input_buffer + len, 0, buffer_size - len); + + /* + * Attempt to allocate the output buffer. + */ + output_buffer = (u_char *)malloc(buffer_size); + if (output_buffer == NULL) { + free(input_buffer); + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_error)(ndo, "can't allocate memory for decryption buffer"); + } + EVP_Cipher(ctx, output_buffer, input_buffer, len); EVP_CIPHER_CTX_free(ctx); - buf_mut = (u_char*) buf; - /* Of course this is wrong, because buf is a const buffer, but changing this - * would require more complicated fix. */ - memcpy(buf_mut, output_buffer, len); - free(output_buffer); + /* + * XXX - of course this is wrong, because buf is a const buffer, + * but changing this would require a more complicated fix. + */ + memcpy(buf, output_buffer, len); + free(input_buffer); + free(output_buffer); ndo->ndo_packetp = buf; ndo->ndo_snapend = end; return 1; - - } USES_APPLE_RST @@ -249,7 +308,6 @@ static u_int hexdigit(netdissect_options *ndo, char hex) return (hex - 'a' + 10); else { (*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex); - return 0; } } @@ -360,7 +418,7 @@ espprint_decode_encalgo(netdissect_options *ndo, USES_APPLE_RST /* - * for the moment, ignore the auth algorith, just hard code the authenticator + * for the moment, ignore the auth algorithm, just hard code the authenticator * length. Need to research how openssl looks up HMAC stuff. */ static int @@ -483,7 +541,6 @@ static void esp_print_decode_onesecret(netdissect_options *ndo, char *line, if (secretfile == NULL) { (*ndo->ndo_error)(ndo, "print_esp: can't open %s: %s\n", filename, strerror(errno)); - return; } while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) { @@ -513,6 +570,10 @@ static void esp_print_decode_onesecret(netdissect_options *ndo, char *line, uint32_t spino; spistr = strsep(&spikey, "@"); + if (spistr == NULL) { + (*ndo->ndo_warning)(ndo, "print_esp: failed to find the @ token"); + return; + } spino = strtoul(spistr, &foo, 0); if (spistr == foo || !spikey) { @@ -622,8 +683,8 @@ esp_print(netdissect_options *ndo, const u_char *ivoff; const u_char *p; EVP_CIPHER_CTX *ctx; - u_char *buf_mut, *output_buffer; - int block_size, cipher_nid, output_buffer_size; + unsigned int block_size, buffer_size; + u_char *input_buffer, *output_buffer; #endif esp = (const struct newesp *)bp; @@ -721,7 +782,9 @@ esp_print(netdissect_options *ndo, ep = bp2 + len; } + /* pointer to the IV, if there is one */ ivoff = (const u_char *)(esp + 1) + 0; + /* length of the IV, if there is one; 0, if there isn't */ ivlen = sa->ivlen; secret = sa->secret; ep = ep - sa->authlen; @@ -729,24 +792,57 @@ esp_print(netdissect_options *ndo, if (sa->evp) { ctx = EVP_CIPHER_CTX_new(); if (ctx != NULL) { - if (EVP_CipherInit(ctx, sa->evp, secret, NULL, 0) < 0) + if (set_cipher_parameters(ctx, sa->evp, secret, NULL, 0) < 0) (*ndo->ndo_warning)(ndo, "espkey init failed"); p = ivoff; - EVP_CipherInit(ctx, NULL, NULL, p, 0); - len = ep - (p + ivlen); - - /* We need a block size */ - block_size = EVP_CIPHER_CTX_block_size(ctx); - /* We need the buffer size to be multiple of a block size */ - output_buffer_size = len + (block_size - len % block_size); - output_buffer = (u_char *)calloc(output_buffer_size, sizeof(u_char)); - /* EVP_Cipher output buffer should be different from the input one. - * Also it should be of size that is multiple of cipher block size. */ - EVP_Cipher(ctx, output_buffer, p + ivlen, len); + set_cipher_parameters(ctx, NULL, NULL, p, 0); + len = ep - (p + ivlen); + + /* + * Allocate buffers for the encrypted and decrypted + * data. Both buffers' sizes must be a multiple of + * the cipher block size, and the output buffer must + * be separate from the input buffer. + */ + block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx); + buffer_size = len + (block_size - len % block_size); + + /* + * Attempt to allocate the input buffer. + */ + input_buffer = (u_char *)malloc(buffer_size); + if (input_buffer == NULL) { + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_error)(ndo, "can't allocate memory for encrypted data buffer"); + } + /* + * Copy the input data to the encrypted data buffer, + * and pad it with zeroes. + */ + memcpy(input_buffer, p + ivlen, len); + memset(input_buffer + len, 0, buffer_size - len); + + /* + * Attempt to allocate the output buffer. + */ + output_buffer = (u_char *)malloc(buffer_size); + if (output_buffer == NULL) { + free(input_buffer); + EVP_CIPHER_CTX_free(ctx); + (*ndo->ndo_error)(ndo, "can't allocate memory for decryption buffer"); + } + + EVP_Cipher(ctx, output_buffer, input_buffer, len); + free(input_buffer); EVP_CIPHER_CTX_free(ctx); - memcpy(p + ivlen, output_buffer, len); - free(output_buffer); + /* + * XXX - of course this is wrong, because buf is a + * const buffer, but changing this would require a + * more complicated fix. + */ + memcpy(p + ivlen, output_buffer, len); + free(output_buffer); advance = ivoff - (const u_char *)esp + ivlen; } else advance = sizeof(struct newesp);