/* * $Id$ * 'OpenSSL for Ruby' project * Copyright (C) 2001-2002 Michal Rokos * All rights reserved. */ /* * This program is licenced under the same licence as Ruby. * (See the file 'LICENCE'.) */ #include "ossl.h" #define GetDigest(obj, ctx) do { \ Data_Get_Struct((obj), EVP_MD_CTX, (ctx)); \ if (!(ctx)) { \ ossl_raise(rb_eRuntimeError, "Digest CTX wasn't initialized!"); \ } \ } while (0) #define SafeGetDigest(obj, ctx) do { \ OSSL_Check_Kind((obj), cDigest); \ GetDigest((obj), (ctx)); \ } while (0) /* * Classes */ VALUE cDigest; VALUE eDigestError; static VALUE ossl_digest_alloc(VALUE klass); /* * Public */ const EVP_MD * GetDigestPtr(VALUE obj) { const EVP_MD *md; ASN1_OBJECT *oid = NULL; if (TYPE(obj) == T_STRING) { const char *name = StringValueCStr(obj); md = EVP_get_digestbyname(name); if (!md) { oid = OBJ_txt2obj(name, 0); md = EVP_get_digestbyobj(oid); ASN1_OBJECT_free(oid); } if(!md) ossl_raise(rb_eRuntimeError, "Unsupported digest algorithm (%s).", name); } else { EVP_MD_CTX *ctx; SafeGetDigest(obj, ctx); md = EVP_MD_CTX_md(ctx); } return md; } VALUE ossl_digest_new(const EVP_MD *md) { VALUE ret; EVP_MD_CTX *ctx; ret = ossl_digest_alloc(cDigest); GetDigest(ret, ctx); if (EVP_DigestInit_ex(ctx, md, NULL) != 1) { ossl_raise(eDigestError, "Digest initialization failed."); } return ret; } /* * Private */ static VALUE ossl_digest_alloc(VALUE klass) { EVP_MD_CTX *ctx; VALUE obj; ctx = EVP_MD_CTX_create(); if (ctx == NULL) ossl_raise(rb_eRuntimeError, "EVP_MD_CTX_create() failed"); obj = Data_Wrap_Struct(klass, 0, EVP_MD_CTX_destroy, ctx); return obj; } VALUE ossl_digest_update(VALUE, VALUE); /* * call-seq: * Digest.new(string [, data]) -> Digest * * Creates a Digest instance based on +string+, which is either the ln * (long name) or sn (short name) of a supported digest algorithm. * If +data+ (a +String+) is given, it is used as the initial input to the * Digest instance, i.e. * digest = OpenSSL::Digest.new('sha256', 'digestdata') * is equal to * digest = OpenSSL::Digest.new('sha256') * digest.update('digestdata') * * === Example * digest = OpenSSL::Digest.new('sha1') * * */ static VALUE ossl_digest_initialize(int argc, VALUE *argv, VALUE self) { EVP_MD_CTX *ctx; const EVP_MD *md; VALUE type, data; rb_scan_args(argc, argv, "11", &type, &data); md = GetDigestPtr(type); if (!NIL_P(data)) StringValue(data); GetDigest(self, ctx); if (EVP_DigestInit_ex(ctx, md, NULL) != 1) { ossl_raise(eDigestError, "Digest initialization failed."); } if (!NIL_P(data)) return ossl_digest_update(self, data); return self; } static VALUE ossl_digest_copy(VALUE self, VALUE other) { EVP_MD_CTX *ctx1, *ctx2; rb_check_frozen(self); if (self == other) return self; GetDigest(self, ctx1); SafeGetDigest(other, ctx2); if (!EVP_MD_CTX_copy(ctx1, ctx2)) { ossl_raise(eDigestError, NULL); } return self; } /* * call-seq: * digest.reset -> self * * Resets the Digest in the sense that any Digest#update that has been * performed is abandoned and the Digest is set to its initial state again. * */ static VALUE ossl_digest_reset(VALUE self) { EVP_MD_CTX *ctx; GetDigest(self, ctx); if (EVP_DigestInit_ex(ctx, EVP_MD_CTX_md(ctx), NULL) != 1) { ossl_raise(eDigestError, "Digest initialization failed."); } return self; } /* * call-seq: * digest.update(string) -> aString * * Not every message digest can be computed in one single pass. If a message * digest is to be computed from several subsequent sources, then each may * be passed individually to the Digest instance. * * === Example * digest = OpenSSL::Digest::SHA256.new * digest.update('First input') * digest << 'Second input' # equivalent to digest.update('Second input') * result = digest.digest * */ VALUE ossl_digest_update(VALUE self, VALUE data) { EVP_MD_CTX *ctx; StringValue(data); GetDigest(self, ctx); EVP_DigestUpdate(ctx, RSTRING_PTR(data), RSTRING_LEN(data)); return self; } /* * call-seq: * digest.finish -> aString * */ static VALUE ossl_digest_finish(int argc, VALUE *argv, VALUE self) { EVP_MD_CTX *ctx; VALUE str; rb_scan_args(argc, argv, "01", &str); GetDigest(self, ctx); if (NIL_P(str)) { str = rb_str_new(NULL, EVP_MD_CTX_size(ctx)); } else { StringValue(str); rb_str_resize(str, EVP_MD_CTX_size(ctx)); } EVP_DigestFinal_ex(ctx, (unsigned char *)RSTRING_PTR(str), NULL); return str; } /* * call-seq: * digest.name -> string * * Returns the sn of this Digest instance. * * === Example * digest = OpenSSL::Digest::SHA512.new * puts digest.name # => SHA512 * */ static VALUE ossl_digest_name(VALUE self) { EVP_MD_CTX *ctx; GetDigest(self, ctx); return rb_str_new2(EVP_MD_name(EVP_MD_CTX_md(ctx))); } /* * call-seq: * digest.digest_length -> integer * * Returns the output size of the digest, i.e. the length in bytes of the * final message digest result. * * === Example * digest = OpenSSL::Digest::SHA1.new * puts digest.digest_length # => 20 * */ static VALUE ossl_digest_size(VALUE self) { EVP_MD_CTX *ctx; GetDigest(self, ctx); return INT2NUM(EVP_MD_CTX_size(ctx)); } /* * call-seq: * digest.block_length -> integer * * Returns the block length of the digest algorithm, i.e. the length in bytes * of an individual block. Most modern algorithms partition a message to be * digested into a sequence of fix-sized blocks that are processed * consecutively. * * === Example * digest = OpenSSL::Digest::SHA1.new * puts digest.block_length # => 64 */ static VALUE ossl_digest_block_length(VALUE self) { EVP_MD_CTX *ctx; GetDigest(self, ctx); return INT2NUM(EVP_MD_CTX_block_size(ctx)); } /* * INIT */ void Init_ossl_digest() { rb_require("digest"); #if 0 mOSSL = rb_define_module("OpenSSL"); /* let rdoc know about mOSSL */ #endif /* Document-class: OpenSSL::Digest * * OpenSSL::Digest allows you to compute message digests (sometimes * interchangeably called "hashes") of arbitrary data that are * cryptographically secure, i.e. a Digest implements a secure one-way * function. * * One-way functions offer some useful properties. E.g. given two * distinct inputs the probability that both yield the same output * is highly unlikely. Combined with the fact that every message digest * algorithm has a fixed-length output of just a few bytes, digests are * often used to create unique identifiers for arbitrary data. A common * example is the creation of a unique id for binary documents that are * stored in a database. * * Another useful characteristic of one-way functions (and thus the name) * is that given a digest there is no indication about the original * data that produced it, i.e. the only way to identify the original input * is to "brute-force" through every possible combination of inputs. * * These characteristics make one-way functions also ideal companions * for public key signature algorithms: instead of signing an entire * document, first a hash of the document is produced with a considerably * faster message digest algorithm and only the few bytes of its output * need to be signed using the slower public key algorithm. To validate * the integrity of a signed document, it suffices to re-compute the hash * and verify that it is equal to that in the signature. * * Among the supported message digest algorithms are: * * SHA, SHA1, SHA224, SHA256, SHA384 and SHA512 * * MD2, MD4, MDC2 and MD5 * * RIPEMD160 * * DSS, DSS1 (Pseudo algorithms to be used for DSA signatures. DSS is * equal to SHA and DSS1 is equal to SHA1) * * For each of these algorithms, there is a sub-class of Digest that * can be instantiated as simply as e.g. * * digest = OpenSSL::Digest::SHA1.new * * === Mapping between Digest class and sn/ln * * The sn (short names) and ln (long names) are defined in * and . They are textual * representations of ASN.1 OBJECT IDENTIFIERs. Each supported digest * algorithm has an OBJECT IDENTIFIER associated to it and those again * have short/long names assigned to them. * E.g. the OBJECT IDENTIFIER for SHA-1 is 1.3.14.3.2.26 and its * sn is "SHA1" and its ln is "sha1". * ==== MD2 * * sn: MD2 * * ln: md2 * ==== MD4 * * sn: MD4 * * ln: md4 * ==== MD5 * * sn: MD5 * * ln: md5 * ==== SHA * * sn: SHA * * ln: SHA * ==== SHA-1 * * sn: SHA1 * * ln: sha1 * ==== SHA-224 * * sn: SHA224 * * ln: sha224 * ==== SHA-256 * * sn: SHA256 * * ln: sha256 * ==== SHA-384 * * sn: SHA384 * * ln: sha384 * ==== SHA-512 * * sn: SHA512 * * ln: sha512 * * "Breaking" a message digest algorithm means defying its one-way * function characteristics, i.e. producing a collision or finding a way * to get to the original data by means that are more efficient than * brute-forcing etc. Most of the supported digest algorithms can be * considered broken in this sense, even the very popular MD5 and SHA1 * algorithms. Should security be your highest concern, then you should * probably rely on SHA224, SHA256, SHA384 or SHA512. * * === Hashing a file * * data = File.read('document') * sha256 = OpenSSL::Digest::SHA256.new * digest = sha256.digest(data) * * === Hashing several pieces of data at once * * data1 = File.read('file1') * data2 = File.read('file2') * data3 = File.read('file3') * sha256 = OpenSSL::Digest::SHA256.new * sha256 << data1 * sha256 << data2 * sha256 << data3 * digest = sha256.digest * * === Reuse a Digest instance * * data1 = File.read('file1') * sha256 = OpenSSL::Digest::SHA256.new * digest1 = sha256.digest(data1) * * data2 = File.read('file2') * sha256.reset * digest2 = sha256.digest(data2) * */ cDigest = rb_define_class_under(mOSSL, "Digest", rb_path2class("Digest::Class")); /* Document-class: OpenSSL::Digest::DigestError * * Generic Exception class that is raised if an error occurs during a * Digest operation. */ eDigestError = rb_define_class_under(cDigest, "DigestError", eOSSLError); rb_define_alloc_func(cDigest, ossl_digest_alloc); rb_define_method(cDigest, "initialize", ossl_digest_initialize, -1); rb_define_copy_func(cDigest, ossl_digest_copy); rb_define_method(cDigest, "reset", ossl_digest_reset, 0); rb_define_method(cDigest, "update", ossl_digest_update, 1); rb_define_alias(cDigest, "<<", "update"); rb_define_private_method(cDigest, "finish", ossl_digest_finish, -1); rb_define_method(cDigest, "digest_length", ossl_digest_size, 0); rb_define_method(cDigest, "block_length", ossl_digest_block_length, 0); rb_define_method(cDigest, "name", ossl_digest_name, 0); }