Import upstream's tests for DES_ede3_cfb_encrypt Upstream does not actually have any tests for DES-EDE3-CFB, with the exception of a single DES-EDE3-CFB1 test vector, only the single-DES version. But we can gain some coverage by turning 3DES back into single DES with a repeated key. That's good enough for DES. The DES-EDE3-CFB1 test vector is unusable because that tests EVP_des_ede3_cfb1, the real DES-EDE3-CFB1. OpenSSL's low-level APIs do not actually implement CFB correctly for a non-whole-number of bytes! See discussion in the test. I've added coverage for that case by just fabricating a test vector. Change-Id: I9f69cab4d8d1d3accecbeb09f8c1661ce2ecb4ee Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/65689 Reviewed-by: Bob Beck <bbe@google.com> Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/decrepit/des/cfb64ede.c b/decrepit/des/cfb64ede.c index 820c52e..6c51040 100644 --- a/decrepit/des/cfb64ede.c +++ b/decrepit/des/cfb64ede.c
@@ -142,7 +142,7 @@ if (num > 64) { return; - }; + } iv = ivec->bytes; c2l(iv, v0);
diff --git a/decrepit/des/des_test.cc b/decrepit/des/des_test.cc new file mode 100644 index 0000000..0308eb8 --- /dev/null +++ b/decrepit/des/des_test.cc
@@ -0,0 +1,133 @@ +/* + * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +#include <gtest/gtest.h> + +#include <openssl/des.h> +#include <openssl/span.h> + +#include "../../crypto/test/test_util.h" + + +// DES-CFB tests from OpenSSL. OpenSSL has no test vectors for 3DES-CFB at all. +// Instead, we repurpose those tests to cover 3DES-CFB by running the inputs +// through three times. +static const DES_cblock cfb_key = { + {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}}; +static const DES_cblock cfb_iv = { + {0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef}}; +static const uint8_t plain[24] = { + 0x4e, 0x6f, 0x77, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68, 0x65, 0x20, 0x74, + 0x69, 0x6d, 0x65, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x61, 0x6c, 0x6c, 0x20}; +static const uint8_t cfb_cipher8[24] = { + 0xf3, 0x1f, 0xda, 0x07, 0x01, 0x14, 0x62, 0xee, 0x18, 0x7f, 0x43, 0xd8, + 0x0a, 0x7c, 0xd9, 0xb5, 0xb0, 0xd2, 0x90, 0xda, 0x6e, 0x5b, 0x9a, 0x87}; +static const uint8_t cfb_cipher16[24] = { + 0xf3, 0x09, 0x87, 0x87, 0x7f, 0x57, 0xf7, 0x3c, 0x36, 0xb6, 0xdb, 0x70, + 0xd8, 0xd5, 0x34, 0x19, 0xd3, 0x86, 0xb2, 0x23, 0xb7, 0xb2, 0xad, 0x1b}; +static const uint8_t cfb_cipher32[24] = { + 0xf3, 0x09, 0x62, 0x49, 0xa4, 0xdf, 0xa4, 0x9f, 0x33, 0xdc, 0x7b, 0xad, + 0x4c, 0xc8, 0x9f, 0x64, 0xe4, 0x53, 0xe5, 0xec, 0x67, 0x20, 0xda, 0xb6}; +static const uint8_t cfb_cipher48[24] = { + 0xf3, 0x09, 0x62, 0x49, 0xc7, 0xf4, 0x30, 0xb5, 0x15, 0xec, 0xbb, 0x85, + 0x97, 0x5a, 0x13, 0x8c, 0x68, 0x60, 0xe2, 0x38, 0x34, 0x3c, 0xdc, 0x1f}; +static const uint8_t cfb_cipher64[24] = { + 0xf3, 0x09, 0x62, 0x49, 0xc7, 0xf4, 0x6e, 0x51, 0xa6, 0x9e, 0x83, 0x9b, + 0x1a, 0x92, 0xf7, 0x84, 0x03, 0x46, 0x71, 0x33, 0x89, 0x8e, 0xa6, 0x22}; + +// Unlike the above test vectors, this test vector was computed by running the +// existing implementation and saving the output. OpenSSL lacks tests for this +// function, but also implements an incorrect construction in its low-level +// APIs. As a result, importing a standard test vector would only test 1/8 of +// the output. See discussion in the test. +static const uint8_t cfb_cipher1[24] = { + 0xf3, 0x27, 0xff, 0x2d, 0x80, 0xee, 0x12, 0xbe, 0xb6, 0x74, 0xa3, 0xb4, + 0xd6, 0xfb, 0x5d, 0x0d, 0x49, 0x18, 0x84, 0xed, 0xfe, 0xca, 0x17, 0x5f}; + +TEST(DESTest, CFB) { + DES_key_schedule ks; + DES_set_key(&cfb_key, &ks); + + struct { + int numbits; + const uint8_t (&ciphertext)[24]; + } kTests[] = { + {1, cfb_cipher1}, {8, cfb_cipher8}, {16, cfb_cipher16}, + {32, cfb_cipher32}, {48, cfb_cipher48}, {64, cfb_cipher64}, + }; + for (const auto &t : kTests) { + SCOPED_TRACE(t.numbits); + + // |DES_ede3_cfb_encrypt| only supports streaming at segment boundaries. + // Segments, however, are measured in bits, not bytes. When the segment is + // not a whole number of bytes, OpenSSL's low-level functions do not + // implement CFB correctly. CFB-n ultimately computes a sequence of E(I_i) + // blocks, extracts n bits from each block to XOR into the next n bits of + // plaintext. OpenSSL computes the correct sequence of blocks, but then + // rounds n up to a byte boundary when consuming input. + // + // It essentially interprets CFB-1 as a funny CFB-8, with the wrong amount + // of cipher feedback. To get the real CFB-1 out of OpenSSL's CFB-1, you put + // each plaintext bit as into its byte, with bit at the MSB, then mask off + // all but the MSB of each ciphertext byte. OpenSSL's |EVP_des_ede3_cfb1| + // does this transformation internally, to work around this bug. + // + // In case anyone is relying on the remaining bits, we test all the output + // bits of the OpenSSL version. However, for such callers, it is unclear if + // this version has been sufficiently analyzed. + size_t offset = (t.numbits + 7) / 8; + for (size_t split = 0; split < sizeof(plain); split += offset) { + SCOPED_TRACE(split); + uint8_t out[sizeof(plain)]; + DES_cblock iv = cfb_iv; + DES_ede3_cfb_encrypt(plain, out, t.numbits, split, &ks, &ks, &ks, &iv, + DES_ENCRYPT); + DES_ede3_cfb_encrypt(plain + split, out + split, t.numbits, + sizeof(plain) - split, &ks, &ks, &ks, &iv, + DES_ENCRYPT); + EXPECT_EQ(Bytes(out), Bytes(t.ciphertext)); + + iv = cfb_iv; + DES_ede3_cfb_encrypt(t.ciphertext, out, t.numbits, split, &ks, &ks, &ks, + &iv, DES_DECRYPT); + DES_ede3_cfb_encrypt(t.ciphertext + split, out + split, t.numbits, + sizeof(plain) - split, &ks, &ks, &ks, &iv, + DES_DECRYPT); + EXPECT_EQ(Bytes(out), Bytes(plain)); + } + } +} + +TEST(DESTest, CFB64) { + DES_key_schedule ks; + DES_set_key(&cfb_key, &ks); + + // Unlike the generic CFB API, the CFB64 API can be split within a block + // boundary. + for (size_t split = 0; split <= sizeof(plain); split++) { + SCOPED_TRACE(split); + uint8_t out[sizeof(plain)]; + DES_cblock iv = cfb_iv; + int n = 0; + DES_ede3_cfb64_encrypt(plain, out, split, &ks, &ks, &ks, &iv, &n, + DES_ENCRYPT); + DES_ede3_cfb64_encrypt(plain + split, out + split, sizeof(plain) - split, + &ks, &ks, &ks, &iv, &n, DES_ENCRYPT); + EXPECT_EQ(Bytes(out), Bytes(cfb_cipher64)); + + n = 0; + iv = cfb_iv; + DES_ede3_cfb64_encrypt(cfb_cipher64, out, split, &ks, &ks, &ks, &iv, &n, + DES_DECRYPT); + DES_ede3_cfb64_encrypt(cfb_cipher64 + split, out + split, + sizeof(cfb_cipher64) - split, &ks, &ks, &ks, &iv, &n, + DES_DECRYPT); + EXPECT_EQ(Bytes(out), Bytes(plain)); + } +}
diff --git a/sources.cmake b/sources.cmake index 2a4a03e..c65afb9 100644 --- a/sources.cmake +++ b/sources.cmake
@@ -346,6 +346,7 @@ decrepit/blowfish/blowfish_test.cc decrepit/cast/cast_test.cc decrepit/cfb/cfb_test.cc + decrepit/des/des_test.cc decrepit/evp/evp_test.cc decrepit/ripemd/ripemd_test.cc decrepit/xts/xts_test.cc