From d09f26a69f34d624897c800d1fbd0be4ba138bab Mon Sep 17 00:00:00 2001 From: Sean Parkinson Date: Mon, 19 Feb 2018 13:40:18 +1000 Subject: [PATCH] Support indefinite length BER encodings in PKCS #7 --- configure.ac | 15 ++++ wolfcrypt/src/asn.c | 122 ++++++++++++++++++++++++++++++++ wolfcrypt/src/error.c | 3 + wolfcrypt/src/pkcs7.c | 72 ++++++++++++++++++- wolfcrypt/test/test.c | 3 + wolfssl/wolfcrypt/asn.h | 2 + wolfssl/wolfcrypt/error-crypt.h | 4 +- wolfssl/wolfcrypt/pkcs7.h | 3 + 8 files changed, 222 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index 59ae80a72..bf5d630ae 100644 --- a/configure.ac +++ b/configure.ac @@ -217,6 +217,7 @@ then enable_aeskeywrap=yes enable_x963kdf=yes enable_scrypt=yes + enable_indef=yes AM_CFLAGS="-DHAVE_AES_DECRYPT $AM_CFLAGS" fi @@ -2662,6 +2663,19 @@ fi AM_CONDITIONAL([BUILD_SRP], [test "x$ENABLED_SRP" = "xyes"]) +# Indefinite length encoded BER message support +AC_ARG_ENABLE([indef], + [AS_HELP_STRING([--enable-indef],[Enable parsing of indefinite length encoded msgs (default: disabled)])], + [ ENABLED_BER_INDEF=$enableval ], + [ ENABLED_BER_INDEF=no ] + ) + +if test "x$ENABLED_BER_INDEF" = "xyes" +then + AM_CFLAGS="$AM_CFLAGS -DASN_BER_TO_DER" +fi + + # Small Stack AC_ARG_ENABLE([smallstack], @@ -4247,6 +4261,7 @@ echo " * SIGNAL: $ENABLED_SIGNAL" echo " * ERROR_STRINGS: $ENABLED_ERROR_STRINGS" echo " * DTLS: $ENABLED_DTLS" echo " * SCTP: $ENABLED_SCTP" +echo " * Indefinite Length: $ENABLED_BER_INDEF" echo " * Multicast: $ENABLED_MCAST" echo " * Old TLS Versions: $ENABLED_OLD_TLS" echo " * SSL version 3.0: $ENABLED_SSLV3" diff --git a/wolfcrypt/src/asn.c b/wolfcrypt/src/asn.c index 63d842390..d90931ecd 100755 --- a/wolfcrypt/src/asn.c +++ b/wolfcrypt/src/asn.c @@ -786,6 +786,128 @@ static word32 SetBitString(word32 len, byte unusedBits, byte* output) } #endif /* !NO_RSA || HAVE_ECC || HAVE_ED25519 */ +#ifdef ASN_BER_TO_DER +/* Convert a BER encoding with indefinite length items to DER. + * + * ber BER encoded data. + * length Length of BER encoded data. + * der Buffer to hold DER encoded version of data. + * NULL indicates only the length is required. + * returns the length of the DER data on success, ASN_PARSE_E if the BER data is + * invalid and BAD_FUNC_ARG if ber is NULL. + */ +int wc_BerToDer(byte* ber, word32 length, byte* der) +{ + int ret; + word32 i, j, k; + int len, l; + int indef; + int depth = 1; + word32 cnt; + byte lenBytes[4]; + + if (ber == NULL) + return BAD_FUNC_ARG; + + for (i = 0, j = 0; i < length; ) { + if (i + 1 >= length) + return ASN_PARSE_E; + + if (ber[i] == 0 && ber[i+1] == 0) { + if (--depth == 0) + break; + + i += 2; + continue; + } + + indef = ber[i+1] == 0x80; + if (indef && ber[i] < 0x40 && ber[i] != 0x30 && ber[i] != 0x31) { + if (der != NULL) + der[j] = ber[i] & 0x1f; + i++; j++; + i++; + + if (i + 1 >= length) + return ASN_PARSE_E; + + len = 0; + k = i; + while (ber[k] != 0x00) { + k++; + ret = GetLength(ber, &k, &l, length); + if (ret < 0) + return ASN_PARSE_E; + k += l; + len += l; + + if (k + 1 >= length) + return ASN_PARSE_E; + } + + if (der == NULL) { + j += SetLength(len, lenBytes); + j += len; + } + else { + j += SetLength(len, der + j); + k = i; + while (ber[k] != 0x00) { + k++; + ret = GetLength(ber, &k, &l, length); + if (ret < 0) + return ASN_PARSE_E; + XMEMCPY(der + j, ber + k, l); + k += l; j += l; + } + } + i = k + 2; + + continue; + } + + if (der != NULL) + der[j] = ber[i]; + i++; j++; + + cnt = i; + ret = GetLength(ber, &cnt, &len, length); + if (ret < 0) + return ASN_PARSE_E; + cnt -= i; + if (der != NULL) { + for (k = 0; k < cnt; k++) + der[j + k] = ber[i + k]; + } + i += cnt; j += cnt; + if (cnt == 0) { + i++; + len = wc_BerToDer(ber + i, length - i, NULL); + if (len < 0) + return len; + if (der != NULL) + j += SetLength(len, der + j); + else + j += SetLength(len, lenBytes); + } + + if (!indef) { + if (i + len > length) + return ASN_PARSE_E; + + if (der != NULL) + XMEMCPY(der + j, ber + i, len); + i += len; + j += len; + } + else + depth++; + } + + return j; +} +#endif + #if defined(WOLFSSL_CERT_GEN) || defined(WOLFSSL_KEY_GEN) #if (!defined(NO_RSA) && !defined(HAVE_USER_RSA)) || \ diff --git a/wolfcrypt/src/error.c b/wolfcrypt/src/error.c index 7b52791c9..414b77a3f 100644 --- a/wolfcrypt/src/error.c +++ b/wolfcrypt/src/error.c @@ -449,6 +449,9 @@ const char* wc_GetErrorString(int error) case PRIME_GEN_E: return "Unable to find a prime for RSA key"; + case BER_INDEF_E: + return "Unable to decode an indefinite length encoded message"; + default: return "unknown error number"; diff --git a/wolfcrypt/src/pkcs7.c b/wolfcrypt/src/pkcs7.c index 10287d1ad..9432a09f9 100644 --- a/wolfcrypt/src/pkcs7.c +++ b/wolfcrypt/src/pkcs7.c @@ -338,6 +338,11 @@ void wc_PKCS7_Free(PKCS7* pkcs7) return; wc_PKCS7_FreeDecodedAttrib(pkcs7->decodedAttrib, pkcs7->heap); + +#ifdef ASN_BER_TO_DER + if (pkcs7->der != NULL) + XFREE(pkcs7->der, pkcs7->heap, DYNAMIC_TYPE_PKCS7); +#endif } @@ -1849,6 +1854,28 @@ int wc_PKCS7_VerifySignedData(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz) if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0) return ASN_PARSE_E; + if (length == 0 && pkiMsg[idx-1] == 0x80) { +#ifdef ASN_BER_TO_DER + int len; + + len = wc_BerToDer(pkiMsg, pkiMsgSz, NULL); + if (len < 0) + return len; + pkcs7->der = XMALLOC(len, pkcs7->heap, DYNAMIC_TYPE_PKCS7); + if (pkcs7->der == NULL) + return MEMORY_E; + wc_BerToDer(pkiMsg, pkiMsgSz, pkcs7->der); + + pkiMsg = pkcs7->der; + pkiMsgSz = len; + idx = 0; + if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0) + return ASN_PARSE_E; +#else + return BER_INDEF_E; +#endif + } + /* Get the contentInfo contentType */ if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0) return ASN_PARSE_E; @@ -4299,6 +4326,7 @@ WOLFSSL_API int wc_PKCS7_DecodeEnvelopedData(PKCS7* pkcs7, byte* pkiMsg, int encryptedContentSz; byte padLen; byte* encryptedContent = NULL; + int explicitOctet; if (pkcs7 == NULL || pkcs7->singleCert == NULL || pkcs7->singleCertSz == 0 || pkcs7->privateKey == NULL || @@ -4313,6 +4341,28 @@ WOLFSSL_API int wc_PKCS7_DecodeEnvelopedData(PKCS7* pkcs7, byte* pkiMsg, if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0) return ASN_PARSE_E; + if (length == 0 && pkiMsg[idx-1] == 0x80) { +#ifdef ASN_BER_TO_DER + int len; + + len = wc_BerToDer(pkiMsg, pkiMsgSz, NULL); + if (len < 0) + return len; + pkcs7->der = XMALLOC(len, pkcs7->heap, DYNAMIC_TYPE_PKCS7); + if (pkcs7->der == NULL) + return MEMORY_E; + wc_BerToDer(pkiMsg, pkiMsgSz, pkcs7->der); + + pkiMsg = pkcs7->der; + pkiMsgSz = len; + idx = 0; + if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0) + return ASN_PARSE_E; +#else + return BER_INDEF_E; +#endif + } + if (wc_GetContentType(pkiMsg, &idx, &contentType, pkiMsgSz) < 0) return ASN_PARSE_E; @@ -4435,13 +4485,17 @@ WOLFSSL_API int wc_PKCS7_DecodeEnvelopedData(PKCS7* pkcs7, byte* pkiMsg, XMEMCPY(tmpIv, &pkiMsg[idx], length); idx += length; + explicitOctet = pkiMsg[idx] == (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 0); + /* read encryptedContent, cont[0] */ - if (pkiMsg[idx++] != (ASN_CONTEXT_SPECIFIC | 0)) { + if (pkiMsg[idx] != (ASN_CONTEXT_SPECIFIC | 0) && + pkiMsg[idx] != (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 0)) { #ifdef WOLFSSL_SMALL_STACK XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7); #endif return ASN_PARSE_E; } + idx++; if (GetLength(pkiMsg, &idx, &encryptedContentSz, pkiMsgSz) <= 0) { #ifdef WOLFSSL_SMALL_STACK @@ -4450,6 +4504,22 @@ WOLFSSL_API int wc_PKCS7_DecodeEnvelopedData(PKCS7* pkcs7, byte* pkiMsg, return ASN_PARSE_E; } + if (explicitOctet) { + if (pkiMsg[idx++] != ASN_OCTET_STRING) { +#ifdef WOLFSSL_SMALL_STACK + XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7); +#endif + return ASN_PARSE_E; + } + + if (GetLength(pkiMsg, &idx, &encryptedContentSz, pkiMsgSz) <= 0) { +#ifdef WOLFSSL_SMALL_STACK + XFREE(decryptedKey, NULL, DYNAMIC_TYPE_PKCS7); +#endif + return ASN_PARSE_E; + } + } + encryptedContent = (byte*)XMALLOC(encryptedContentSz, pkcs7->heap, DYNAMIC_TYPE_PKCS7); if (encryptedContent == NULL) { diff --git a/wolfcrypt/test/test.c b/wolfcrypt/test/test.c index f9d58ed21..d26f00957 100644 --- a/wolfcrypt/test/test.c +++ b/wolfcrypt/test/test.c @@ -16702,6 +16702,9 @@ int pkcs7encrypted_test(void) pkcs7.unprotectedAttribs = testVectors[i].attribs; pkcs7.unprotectedAttribsSz = testVectors[i].attribsSz; pkcs7.heap = HEAP_HINT; +#ifdef ASN_BER_TO_DER + pkcs7.der = NULL; +#endif /* encode encryptedData */ encryptedSz = wc_PKCS7_EncodeEncryptedData(&pkcs7, encrypted, diff --git a/wolfssl/wolfcrypt/asn.h b/wolfssl/wolfcrypt/asn.h index 5777e1dd9..8e06317da 100644 --- a/wolfssl/wolfcrypt/asn.h +++ b/wolfssl/wolfcrypt/asn.h @@ -765,6 +765,8 @@ struct TrustedPeerCert { #define WOLFSSL_ASN_API WOLFSSL_LOCAL #endif +WOLFSSL_ASN_API int wc_BerToDer(byte* ber, word32 length, byte* der); + WOLFSSL_ASN_API void FreeAltNames(DNS_entry*, void*); #ifndef IGNORE_NAME_CONSTRAINTS WOLFSSL_ASN_API void FreeNameSubtrees(Base_entry*, void*); diff --git a/wolfssl/wolfcrypt/error-crypt.h b/wolfssl/wolfcrypt/error-crypt.h index c047dfec9..6088bd9cb 100644 --- a/wolfssl/wolfcrypt/error-crypt.h +++ b/wolfssl/wolfcrypt/error-crypt.h @@ -198,7 +198,9 @@ enum { PSS_SALTLEN_E = -250, /* PSS length of salt is to long for hash */ PRIME_GEN_E = -251, /* Failure finding a prime. */ - WC_LAST_E = -251, /* Update this to indicate last error */ + BER_INDEF_E = -252, /* Cannot decode indefinite length BER. */ + + WC_LAST_E = -252, /* Update this to indicate last error */ MIN_CODE_E = -300 /* errors -101 - -299 */ /* add new companion error id strings for any new error codes diff --git a/wolfssl/wolfcrypt/pkcs7.h b/wolfssl/wolfcrypt/pkcs7.h index efa3d7d18..ca6afec7c 100644 --- a/wolfssl/wolfcrypt/pkcs7.h +++ b/wolfssl/wolfcrypt/pkcs7.h @@ -100,6 +100,9 @@ typedef struct PKCS7 { byte* issuer; /* issuer name of singleCert */ byte* privateKey; /* private key, DER, not owner */ void* heap; /* heap hint for dynamic memory */ +#ifdef ASN_BER_TO_DER + byte* der; /* DER encoded version of message */ +#endif byte* cert[MAX_PKCS7_CERTS]; /* Encrypted-data Content Type */