[PATCH] Poly1305-AEAD: update to match latest Internet-Draft version
Jussi Kivilinna
jussi.kivilinna at iki.fi
Mon Jun 23 18:01:55 CEST 2014
On 11.06.2014 19:44, Jussi Kivilinna wrote:
> * cipher/cipher-internal.h (gcry_cipher_handle): Use separate byte
> counters for AAD and data in Poly1305.
> * cipher/cipher-poly1305.c (poly1305_fill_bytecount): Remove.
> (poly1305_fill_bytecounts, poly1305_do_padding): New.
> (poly1305_aad_finish): Fill padding to Poly1305 and do not fill AAD
> length.
> (_gcry_cipher_poly1305_authenticate, _gcry_cipher_poly1305_encrypt)
> (_gcry_cipher_poly1305_decrypt): Update AAD and data length separately.
> (_gcry_cipher_poly1305_tag): Fill padding and bytecounts to Poly1305.
> (_gcry_cipher_poly1305_setkey, _gcry_cipher_poly1305_setiv): Reset
> AAD and data byte counts.
> * tests/basic.c (_check_poly1305_cipher): Update test-vectors.
> --
>
> New Internet-Draft version for "ChaCha20 and Poly1305 for IETF protocols"
> added padding to Poly1305-AEAD:
> http://tools.ietf.org/rfcdiff?url2=draft-nir-cfrg-chacha20-poly1305-04.txt
>
> Patch makes Poly1305-AEAD implementation to match the changes.
I'm having second thoughts about this. The Poly1305-AEAD as now implemented in libgcrypt is already used in (Open)SSH and other places, so it might be good idea to support both the old Poly1305-AEAD and the new. But what would be the best way to select between the two Poly1305-AEAD modes?
-Jussi
>
> Signed-off-by: Jussi Kivilinna <jussi.kivilinna at iki.fi>
> ---
> cipher/cipher-internal.h | 7 +++--
> cipher/cipher-poly1305.c | 63 ++++++++++++++++++++++++++++++++------------
> tests/basic.c | 66 ++++++++++++++++++++++++++++++++++------------
> 3 files changed, 100 insertions(+), 36 deletions(-)
>
> diff --git a/cipher/cipher-internal.h b/cipher/cipher-internal.h
> index f6bda66..0e73fde 100644
> --- a/cipher/cipher-internal.h
> +++ b/cipher/cipher-internal.h
> @@ -159,8 +159,11 @@ struct gcry_cipher_handle
>
> /* Mode specific storage for Poly1305 mode. */
> struct {
> - /* byte counter for AAD and data. */
> - u32 bytecount[2];
> + /* byte counter for AAD. */
> + u32 aadcount[2];
> +
> + /* byte counter for data. */
> + u32 datacount[2];
>
> unsigned int aad_finalized:1;
> unsigned int bytecount_over_limits:1;
> diff --git a/cipher/cipher-poly1305.c b/cipher/cipher-poly1305.c
> index a22ffa3..e9e063d 100644
> --- a/cipher/cipher-poly1305.c
> +++ b/cipher/cipher-poly1305.c
> @@ -53,12 +53,14 @@ poly1305_bytecounter_add (u32 ctr[2], size_t add)
>
>
> static void
> -poly1305_fill_bytecount (gcry_cipher_hd_t c)
> +poly1305_fill_bytecounts (gcry_cipher_hd_t c)
> {
> - u32 lenbuf[2];
> + u32 lenbuf[4];
>
> - lenbuf[0] = le_bswap32(c->u_mode.poly1305.bytecount[0]);
> - lenbuf[1] = le_bswap32(c->u_mode.poly1305.bytecount[1]);
> + lenbuf[0] = le_bswap32(c->u_mode.poly1305.aadcount[0]);
> + lenbuf[1] = le_bswap32(c->u_mode.poly1305.aadcount[1]);
> + lenbuf[2] = le_bswap32(c->u_mode.poly1305.datacount[0]);
> + lenbuf[3] = le_bswap32(c->u_mode.poly1305.datacount[1]);
> _gcry_poly1305_update (&c->u_mode.poly1305.ctx, (byte*)lenbuf,
> sizeof(lenbuf));
>
> @@ -67,15 +69,33 @@ poly1305_fill_bytecount (gcry_cipher_hd_t c)
>
>
> static void
> +poly1305_do_padding (gcry_cipher_hd_t c, u32 ctr[2])
> +{
> + static const byte zero_padding_buf[15] = {};
> + u32 padding_count;
> +
> + /* Padding to 16 byte boundary. */
> + if (ctr[0] % 16 > 0)
> + {
> + padding_count = 16 - ctr[0] % 16;
> +
> + _gcry_poly1305_update (&c->u_mode.poly1305.ctx, zero_padding_buf,
> + padding_count);
> + }
> +}
> +
> +
> +static void
> poly1305_aad_finish (gcry_cipher_hd_t c)
> {
> - /* Start of encryption marks end of AAD stream. */
> - poly1305_fill_bytecount(c);
> + /* After AAD, feed padding bytes so we get 16 byte alignment. */
> + poly1305_do_padding (c, c->u_mode.poly1305.aadcount);
>
> + /* Start of encryption marks end of AAD stream. */
> c->u_mode.poly1305.aad_finalized = 1;
>
> - c->u_mode.poly1305.bytecount[0] = 0;
> - c->u_mode.poly1305.bytecount[1] = 0;
> + c->u_mode.poly1305.datacount[0] = 0;
> + c->u_mode.poly1305.datacount[1] = 0;
> }
>
>
> @@ -102,7 +122,7 @@ _gcry_cipher_poly1305_authenticate (gcry_cipher_hd_t c,
> if (!c->marks.iv)
> poly1305_set_zeroiv(c);
>
> - if (poly1305_bytecounter_add(c->u_mode.poly1305.bytecount, aadbuflen))
> + if (poly1305_bytecounter_add(c->u_mode.poly1305.aadcount, aadbuflen))
> {
> c->u_mode.poly1305.bytecount_over_limits = 1;
> return GPG_ERR_INV_LENGTH;
> @@ -138,7 +158,7 @@ _gcry_cipher_poly1305_encrypt (gcry_cipher_hd_t c,
> if (!c->u_mode.poly1305.aad_finalized)
> poly1305_aad_finish(c);
>
> - if (poly1305_bytecounter_add(c->u_mode.poly1305.bytecount, inbuflen))
> + if (poly1305_bytecounter_add(c->u_mode.poly1305.datacount, inbuflen))
> {
> c->u_mode.poly1305.bytecount_over_limits = 1;
> return GPG_ERR_INV_LENGTH;
> @@ -176,7 +196,7 @@ _gcry_cipher_poly1305_decrypt (gcry_cipher_hd_t c,
> if (!c->u_mode.poly1305.aad_finalized)
> poly1305_aad_finish(c);
>
> - if (poly1305_bytecounter_add(c->u_mode.poly1305.bytecount, inbuflen))
> + if (poly1305_bytecounter_add(c->u_mode.poly1305.datacount, inbuflen))
> {
> c->u_mode.poly1305.bytecount_over_limits = 1;
> return GPG_ERR_INV_LENGTH;
> @@ -212,8 +232,11 @@ _gcry_cipher_poly1305_tag (gcry_cipher_hd_t c,
>
> if (!c->marks.tag)
> {
> - /* Write data-length to poly1305. */
> - poly1305_fill_bytecount(c);
> + /* After data, feed padding bytes so we get 16 byte alignment. */
> + poly1305_do_padding (c, c->u_mode.poly1305.datacount);
> +
> + /* Write byte counts to poly1305. */
> + poly1305_fill_bytecounts(c);
>
> _gcry_poly1305_finish(&c->u_mode.poly1305.ctx, c->u_iv.iv);
>
> @@ -247,8 +270,11 @@ _gcry_cipher_poly1305_check_tag (gcry_cipher_hd_t c, const unsigned char *intag,
> void
> _gcry_cipher_poly1305_setkey (gcry_cipher_hd_t c)
> {
> - c->u_mode.poly1305.bytecount[0] = 0;
> - c->u_mode.poly1305.bytecount[1] = 0;
> + c->u_mode.poly1305.aadcount[0] = 0;
> + c->u_mode.poly1305.aadcount[1] = 0;
> +
> + c->u_mode.poly1305.datacount[0] = 0;
> + c->u_mode.poly1305.datacount[1] = 0;
>
> c->u_mode.poly1305.bytecount_over_limits = 0;
> c->u_mode.poly1305.aad_finalized = 0;
> @@ -268,8 +294,11 @@ _gcry_cipher_poly1305_setiv (gcry_cipher_hd_t c, const byte *iv, size_t ivlen)
>
> memset(&c->u_mode.poly1305.ctx, 0, sizeof(c->u_mode.poly1305.ctx));
>
> - c->u_mode.poly1305.bytecount[0] = 0;
> - c->u_mode.poly1305.bytecount[1] = 0;
> + c->u_mode.poly1305.aadcount[0] = 0;
> + c->u_mode.poly1305.aadcount[1] = 0;
> +
> + c->u_mode.poly1305.datacount[0] = 0;
> + c->u_mode.poly1305.datacount[1] = 0;
>
> c->u_mode.poly1305.bytecount_over_limits = 0;
> c->u_mode.poly1305.aad_finalized = 0;
> diff --git a/tests/basic.c b/tests/basic.c
> index 875b36c..bc18aac 100644
> --- a/tests/basic.c
> +++ b/tests/basic.c
> @@ -1625,27 +1625,59 @@ _check_poly1305_cipher (unsigned int step)
> struct tv
> {
> int algo;
> - char key[MAX_DATA_LEN];
> - char iv[MAX_DATA_LEN];
> + const char *key;
> + const char *iv;
> int ivlen;
> - unsigned char aad[MAX_DATA_LEN];
> + const char *aad;
> int aadlen;
> - unsigned char plaintext[MAX_DATA_LEN];
> + const char *plaintext;
> int inlen;
> - char out[MAX_DATA_LEN];
> - char tag[MAX_DATA_LEN];
> + const char *out;
> + const char *tag;
> } tv[] =
> {
> - /* draft-agl-tls-chacha20poly1305-04 */
> + /* draft-nir-cfrg-chacha20-poly1305-04 */
> { GCRY_CIPHER_CHACHA20,
> - "\x42\x90\xbc\xb1\x54\x17\x35\x31\xf3\x14\xaf\x57\xf3\xbe\x3b\x50"
> - "\x06\xda\x37\x1e\xce\x27\x2a\xfa\x1b\x5d\xbd\xd1\x10\x0a\x10\x07",
> - "\xcd\x7c\xf6\x7b\xe3\x9c\x79\x4a", 8,
> - "\x87\xe2\x29\xd4\x50\x08\x45\xa0\x79\xc0", 10,
> - "\x86\xd0\x99\x74\x84\x0b\xde\xd2\xa5\xca", 10,
> - "\xe3\xe4\x46\xf7\xed\xe9\xa1\x9b\x62\xa4",
> - "\x67\x7d\xab\xf4\xe3\xd2\x4b\x87\x6b\xb2\x84\x75\x38\x96\xe1\xd6" },
> - /* draft-nir-cfrg-chacha20-poly1305-03 */
> + "\x1c\x92\x40\xa5\xeb\x55\xd3\x8a\xf3\x33\x88\x86\x04\xf6\xb5\xf0"
> + "\x47\x39\x17\xc1\x40\x2b\x80\x09\x9d\xca\x5c\xbc\x20\x70\x75\xc0",
> + "\x00\x00\x00\x00\x01\x02\x03\x04\x05\x06\x07\x08", 12,
> + "\xf3\x33\x88\x86\x00\x00\x00\x00\x00\x00\x4e\x91", 12,
> + "\x49\x6e\x74\x65\x72\x6e\x65\x74\x2d\x44\x72\x61\x66\x74\x73\x20"
> + "\x61\x72\x65\x20\x64\x72\x61\x66\x74\x20\x64\x6f\x63\x75\x6d\x65"
> + "\x6e\x74\x73\x20\x76\x61\x6c\x69\x64\x20\x66\x6f\x72\x20\x61\x20"
> + "\x6d\x61\x78\x69\x6d\x75\x6d\x20\x6f\x66\x20\x73\x69\x78\x20\x6d"
> + "\x6f\x6e\x74\x68\x73\x20\x61\x6e\x64\x20\x6d\x61\x79\x20\x62\x65"
> + "\x20\x75\x70\x64\x61\x74\x65\x64\x2c\x20\x72\x65\x70\x6c\x61\x63"
> + "\x65\x64\x2c\x20\x6f\x72\x20\x6f\x62\x73\x6f\x6c\x65\x74\x65\x64"
> + "\x20\x62\x79\x20\x6f\x74\x68\x65\x72\x20\x64\x6f\x63\x75\x6d\x65"
> + "\x6e\x74\x73\x20\x61\x74\x20\x61\x6e\x79\x20\x74\x69\x6d\x65\x2e"
> + "\x20\x49\x74\x20\x69\x73\x20\x69\x6e\x61\x70\x70\x72\x6f\x70\x72"
> + "\x69\x61\x74\x65\x20\x74\x6f\x20\x75\x73\x65\x20\x49\x6e\x74\x65"
> + "\x72\x6e\x65\x74\x2d\x44\x72\x61\x66\x74\x73\x20\x61\x73\x20\x72"
> + "\x65\x66\x65\x72\x65\x6e\x63\x65\x20\x6d\x61\x74\x65\x72\x69\x61"
> + "\x6c\x20\x6f\x72\x20\x74\x6f\x20\x63\x69\x74\x65\x20\x74\x68\x65"
> + "\x6d\x20\x6f\x74\x68\x65\x72\x20\x74\x68\x61\x6e\x20\x61\x73\x20"
> + "\x2f\xe2\x80\x9c\x77\x6f\x72\x6b\x20\x69\x6e\x20\x70\x72\x6f\x67"
> + "\x72\x65\x73\x73\x2e\x2f\xe2\x80\x9d", 265,
> + "\x64\xa0\x86\x15\x75\x86\x1a\xf4\x60\xf0\x62\xc7\x9b\xe6\x43\xbd"
> + "\x5e\x80\x5c\xfd\x34\x5c\xf3\x89\xf1\x08\x67\x0a\xc7\x6c\x8c\xb2"
> + "\x4c\x6c\xfc\x18\x75\x5d\x43\xee\xa0\x9e\xe9\x4e\x38\x2d\x26\xb0"
> + "\xbd\xb7\xb7\x3c\x32\x1b\x01\x00\xd4\xf0\x3b\x7f\x35\x58\x94\xcf"
> + "\x33\x2f\x83\x0e\x71\x0b\x97\xce\x98\xc8\xa8\x4a\xbd\x0b\x94\x81"
> + "\x14\xad\x17\x6e\x00\x8d\x33\xbd\x60\xf9\x82\xb1\xff\x37\xc8\x55"
> + "\x97\x97\xa0\x6e\xf4\xf0\xef\x61\xc1\x86\x32\x4e\x2b\x35\x06\x38"
> + "\x36\x06\x90\x7b\x6a\x7c\x02\xb0\xf9\xf6\x15\x7b\x53\xc8\x67\xe4"
> + "\xb9\x16\x6c\x76\x7b\x80\x4d\x46\xa5\x9b\x52\x16\xcd\xe7\xa4\xe9"
> + "\x90\x40\xc5\xa4\x04\x33\x22\x5e\xe2\x82\xa1\xb0\xa0\x6c\x52\x3e"
> + "\xaf\x45\x34\xd7\xf8\x3f\xa1\x15\x5b\x00\x47\x71\x8c\xbc\x54\x6a"
> + "\x0d\x07\x2b\x04\xb3\x56\x4e\xea\x1b\x42\x22\x73\xf5\x48\x27\x1a"
> + "\x0b\xb2\x31\x60\x53\xfa\x76\x99\x19\x55\xeb\xd6\x31\x59\x43\x4e"
> + "\xce\xbb\x4e\x46\x6d\xae\x5a\x10\x73\xa6\x72\x76\x27\x09\x7a\x10"
> + "\x49\xe6\x17\xd9\x1d\x36\x10\x94\xfa\x68\xf0\xff\x77\x98\x71\x30"
> + "\x30\x5b\xea\xba\x2e\xda\x04\xdf\x99\x7b\x71\x4d\x6c\x6f\x2c\x29"
> + "\xa6\xad\x5c\xb4\x02\x2b\x02\x70\x9b",
> + "\xee\xad\x9d\x67\x89\x0c\xbb\x22\x39\x23\x36\xfe\xa1\x85\x1f\x38" },
> + /* draft-nir-cfrg-chacha20-poly1305-04 */
> { GCRY_CIPHER_CHACHA20,
> "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
> "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f",
> @@ -1661,11 +1693,11 @@ _check_poly1305_cipher (unsigned int step)
> "\xfa\xb3\x24\xe4\xfa\xd6\x75\x94\x55\x85\x80\x8b\x48\x31\xd7\xbc"
> "\x3f\xf4\xde\xf0\x8e\x4b\x7a\x9d\xe5\x76\xd2\x65\x86\xce\xc6\x4b"
> "\x61\x16",
> - "\x18\xfb\x11\xa5\x03\x1a\xd1\x3a\x7e\x3b\x03\xd4\x6e\xe3\xa6\xa7" }
> + "\x1a\xe1\x0b\x59\x4f\x09\xe2\x6a\x7e\x90\x2e\xcb\xd0\x60\x06\x91" },
> };
>
> gcry_cipher_hd_t hde, hdd;
> - unsigned char out[MAX_DATA_LEN];
> + unsigned char out[1024];
> unsigned char tag[16];
> int i, keylen;
> gcry_error_t err = 0;
>
>
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