X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/bfe9582ec625704c427b441dfa3a57d7a99604b8..1a04b92e365f5ed01ca38619b41bcc4fc9cbd63c:/print-esp.c?ds=sidebyside diff --git a/print-esp.c b/print-esp.c index 247796da..ade700a2 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, output_buffer_size; + u_char *output_buffer; /* initiator arg is any non-zero value */ if(initiator) initiator=1; @@ -157,18 +220,39 @@ 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 a buffer for the decrypted data. + * The output buffer must be separate from the input buffer, and + * its size must be a multiple of the cipher block size. + */ + block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx); + output_buffer_size = len + (block_size - len % block_size); + output_buffer = (u_char *)malloc(output_buffer_size); + if (output_buffer == NULL) { + (*ndo->ndo_warning)(ndo, "can't allocate memory for decryption buffer"); + EVP_CIPHER_CTX_free(ctx); + return 0; + } + EVP_Cipher(ctx, output_buffer, buf, 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(output_buffer); ndo->ndo_packetp = buf; ndo->ndo_snapend = end; return 1; - } USES_APPLE_RST @@ -435,8 +519,9 @@ 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)); + return; } while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) { @@ -501,8 +586,14 @@ 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 @@ -545,19 +636,19 @@ esp_print(netdissect_options *ndo, _U_ #endif , - int *nhdr + u_int *nhdr #ifndef HAVE_LIBCRYPTO _U_ #endif , - int *padlen + u_int *padlen #ifndef HAVE_LIBCRYPTO _U_ #endif ) { - register const struct newesp *esp; - register const u_char *ep; + const struct newesp *esp; + const u_char *ep; #ifdef HAVE_LIBCRYPTO const struct ip *ip; struct sa_list *sa = NULL; @@ -568,7 +659,9 @@ 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, output_buffer_size; + u_char *output_buffer; #endif esp = (const struct newesp *)bp; @@ -590,8 +683,8 @@ esp_print(netdissect_options *ndo, ND_PRINT((ndo, "[|ESP]")); goto fail; } - ND_PRINT((ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi))); - ND_PRINT((ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq))); + ND_PRINT((ndo, "ESP(spi=0x%08x", EXTRACT_BE_U_4(&esp->esp_spi))); + ND_PRINT((ndo, ",seq=0x%x)", EXTRACT_BE_U_4(&esp->esp_seq))); ND_PRINT((ndo, ", length %u", length)); #ifndef HAVE_LIBCRYPTO @@ -613,14 +706,14 @@ esp_print(netdissect_options *ndo, case 6: ip6 = (const struct ip6_hdr *)bp2; /* we do not attempt to decrypt jumbograms */ - if (!EXTRACT_16BITS(&ip6->ip6_plen)) + if (!EXTRACT_BE_U_2(&ip6->ip6_plen)) goto fail; /* if we can't get nexthdr, we do not need to decrypt it */ - len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen); + len = sizeof(struct ip6_hdr) + EXTRACT_BE_U_2(&ip6->ip6_plen); /* see if we can find the SA, and if so, decode it */ for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) { - if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) && + if (sa->spi == EXTRACT_BE_U_4(&esp->esp_spi) && sa->daddr_version == 6 && UNALIGNED_MEMCMP(&sa->daddr.in6, &ip6->ip6_dst, sizeof(struct in6_addr)) == 0) { @@ -630,13 +723,13 @@ esp_print(netdissect_options *ndo, break; case 4: /* nexthdr & padding are in the last fragment */ - if (EXTRACT_16BITS(&ip->ip_off) & IP_MF) + if (EXTRACT_BE_U_2(&ip->ip_off) & IP_MF) goto fail; - len = EXTRACT_16BITS(&ip->ip_len); + len = EXTRACT_BE_U_2(&ip->ip_len); /* see if we can find the SA, and if so, decode it */ for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) { - if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) && + if (sa->spi == EXTRACT_BE_U_4(&esp->esp_spi) && sa->daddr_version == 4 && UNALIGNED_MEMCMP(&sa->daddr.in4, &ip->ip_dst, sizeof(struct in_addr)) == 0) { @@ -666,33 +759,62 @@ 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 a buffer for the decrypted data. + * The output buffer must be separate from the + * input buffer, and its size must be a multiple + * of the cipher block size. + */ + block_size = (unsigned int)EVP_CIPHER_CTX_block_size(ctx); + output_buffer_size = len + (block_size - len % block_size); + output_buffer = (u_char *)malloc(output_buffer_size); + if (output_buffer == NULL) { + (*ndo->ndo_warning)(ndo, "can't allocate memory for decryption buffer"); + EVP_CIPHER_CTX_free(ctx); + return -1; + } + + EVP_Cipher(ctx, output_buffer, p + ivlen, 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(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); /* sanity check for pad length */ - if (ep - bp < *(ep - 2)) + if (ep - bp < EXTRACT_U_1(ep - 2)) goto fail; if (padlen) - *padlen = *(ep - 2) + 2; + *padlen = EXTRACT_U_1(ep - 2) + 2; if (nhdr) - *nhdr = *(ep - 1); + *nhdr = EXTRACT_U_1(ep - 1); ND_PRINT((ndo, ": ")); return advance;