X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/bfe9582ec625704c427b441dfa3a57d7a99604b8..refs/heads/tcpdump-4.9:/print-esp.c?ds=inline diff --git a/print-esp.c b/print-esp.c index 247796da..6fabff1e 100644 --- a/print-esp.c +++ b/print-esp.c @@ -21,6 +21,8 @@ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ +/* \summary: IPSEC Encapsulating Security Payload (ESP) printer */ + #ifdef HAVE_CONFIG_H #include "config.h" #endif @@ -117,6 +119,65 @@ struct sa_list { int secretlen; }; +#ifndef HAVE_EVP_CIPHER_CTX_NEW +/* + * Allocate an EVP_CIPHER_CTX. + * Used if we have an older version of OpenSSL that doesn't provide + * routines to allocate and free them. + */ +static EVP_CIPHER_CTX * +EVP_CIPHER_CTX_new(void) +{ + EVP_CIPHER_CTX *ctx; + + ctx = malloc(sizeof(*ctx)); + if (ctx == NULL) + return (NULL); + memset(ctx, 0, sizeof(*ctx)); + return (ctx); +} + +static void +EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx) +{ + EVP_CIPHER_CTX_cleanup(ctx); + free(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! */ @@ -128,8 +189,10 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo, { struct sa_list *sa; const u_char *iv; - int len; - EVP_CIPHER_CTX ctx; + 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; @@ -157,18 +220,60 @@ int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo, if(end <= buf) return 0; - memset(&ctx, 0, sizeof(ctx)); - if (EVP_CipherInit(&ctx, sa->evp, sa->secret, NULL, 0) < 0) + ctx = EVP_CIPHER_CTX_new(); + if (ctx == NULL) + return 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); - EVP_Cipher(&ctx, buf, buf, len); - EVP_CIPHER_CTX_cleanup(&ctx); + 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); + + /* + * 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 @@ -203,7 +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; } } @@ -314,7 +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 @@ -435,8 +539,8 @@ static void esp_print_decode_onesecret(netdissect_options *ndo, char *line, secretfile = fopen(filename, FOPEN_READ_TXT); if (secretfile == NULL) { - perror(filename); - exit(3); + (*ndo->ndo_error)(ndo, "print_esp: can't open %s: %s\n", + filename, strerror(errno)); } while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) { @@ -466,6 +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) { @@ -501,8 +609,14 @@ static void esp_print_decode_onesecret(netdissect_options *ndo, char *line, USES_APPLE_DEPRECATED_API static void esp_init(netdissect_options *ndo _U_) { - + /* + * 0.9.6 doesn't appear to define OPENSSL_API_COMPAT, so + * we check whether it's undefined or it's less than the + * value for 1.1.0. + */ +#if !defined(OPENSSL_API_COMPAT) || OPENSSL_API_COMPAT < 0x10100000L OpenSSL_add_all_algorithms(); +#endif EVP_add_cipher_alias(SN_des_ede3_cbc, "3des"); } USES_APPLE_RST @@ -568,7 +682,9 @@ esp_print(netdissect_options *ndo, int ivlen = 0; const u_char *ivoff; const u_char *p; - EVP_CIPHER_CTX ctx; + EVP_CIPHER_CTX *ctx; + unsigned int block_size, buffer_size; + u_char *input_buffer, *output_buffer; #endif esp = (const struct newesp *)bp; @@ -666,21 +782,70 @@ 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; if (sa->evp) { - memset(&ctx, 0, sizeof(ctx)); - if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0) - (*ndo->ndo_warning)(ndo, "espkey init failed"); - - p = ivoff; - EVP_CipherInit(&ctx, NULL, NULL, p, 0); - EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen)); - EVP_CIPHER_CTX_cleanup(&ctx); - advance = ivoff - (const u_char *)esp + ivlen; + ctx = EVP_CIPHER_CTX_new(); + if (ctx != NULL) { + if (set_cipher_parameters(ctx, sa->evp, secret, NULL, 0) < 0) + (*ndo->ndo_warning)(ndo, "espkey init failed"); + + p = ivoff; + 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); + /* + * 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); } else advance = sizeof(struct newesp);