diff options
Diffstat (limited to 'cipher')
| -rw-r--r-- | cipher/ecc-misc.c | 48 | ||||
| -rw-r--r-- | cipher/ecc.c | 21 |
2 files changed, 52 insertions, 17 deletions
diff --git a/cipher/ecc-misc.c b/cipher/ecc-misc.c index 2f2e5937..67e3b3d8 100644 --- a/cipher/ecc-misc.c +++ b/cipher/ecc-misc.c @@ -292,6 +292,7 @@ _gcry_ecc_compute_public (mpi_point_t Q, mpi_ec_t ec, gpg_err_code_t _gcry_ecc_mont_decodepoint (gcry_mpi_t pk, mpi_ec_t ctx, mpi_point_t result) { + unsigned char *a; unsigned char *rawmpi; unsigned int rawmpilen; @@ -311,8 +312,8 @@ _gcry_ecc_mont_decodepoint (gcry_mpi_t pk, mpi_ec_t ctx, mpi_point_t result) buf++; } - rawmpi = xtrymalloc (rawmpilen? rawmpilen:1); - if (!rawmpi) + a = rawmpi = xtrymalloc (rawmpilen? rawmpilen:1); + if (!a) return gpg_err_code_from_syserror (); p = rawmpi + rawmpilen; @@ -321,16 +322,47 @@ _gcry_ecc_mont_decodepoint (gcry_mpi_t pk, mpi_ec_t ctx, mpi_point_t result) } else { - /* Note: Without using an opaque MPI it is not reliable possible - to find out whether the public key has been given in - uncompressed format. Thus we expect native EdDSA format. */ - rawmpi = _gcry_mpi_get_buffer (pk, ctx->nbits/8, &rawmpilen, NULL); - if (!rawmpi) + a = rawmpi = _gcry_mpi_get_buffer (pk, ctx->nbits/8, &rawmpilen, NULL); + if (!a) return gpg_err_code_from_syserror (); + /* + * It is not reliable to assume that 0x40 means the prefix. + * + * For newer implementation, it is reliable since we always put + * 0x40 for x-only coordinate. + * + * For data with older implementation (non-released development + * version), it is possibe to have the 0x40 as a part of data. + * Besides, when data was parsed as MPI, we might have 0x00 + * prefix. + * + * So, we need to check if it's really the prefix or not. + * Only when it's the prefix, we remove it. + */ + if (ctx->nbits/8 == rawmpilen - 1) + rawmpi++; + else if (rawmpilen < ctx->nbits/8) + {/* + * It is possible for data created by older implementation + * to have shorter length when it was parsed as MPI. + */ + unsigned int new_rawmpilen = ctx->nbits/8; + + rawmpi = xtrymalloc (new_rawmpilen); + if (!rawmpi) + { + gpg_err_code_t err = gpg_err_code_from_syserror (); + xfree (a); + return err; + } + + memset (rawmpi, 0, new_rawmpilen - rawmpilen); + memcpy (rawmpi + new_rawmpilen - rawmpilen, a, rawmpilen); + } } _gcry_mpi_set_buffer (result->x, rawmpi, rawmpilen, 0); - xfree (rawmpi); + xfree (a); mpi_set_ui (result->z, 1); return 0; diff --git a/cipher/ecc.c b/cipher/ecc.c index bd3e7549..51621f8e 100644 --- a/cipher/ecc.c +++ b/cipher/ecc.c @@ -606,17 +606,14 @@ ecc_generate (const gcry_sexp_t genparms, gcry_sexp_t *r_skey) &encpk, &encpklen); else { - int off = !!(flags & PUBKEY_FLAG_COMP); - - encpk = _gcry_mpi_get_buffer_extra (Qx, ctx->nbits/8, off?-1:0, + encpk = _gcry_mpi_get_buffer_extra (Qx, ctx->nbits/8, -1, &encpklen, NULL); if (encpk == NULL) rc = gpg_err_code_from_syserror (); else { - if (off) - encpk[0] = 0x40; - encpklen += off; + encpk[0] = 0x40; + encpklen++; } } if (rc) @@ -1374,11 +1371,13 @@ ecc_encrypt_raw (gcry_sexp_t *r_ciph, gcry_sexp_t s_data, gcry_sexp_t keyparms) mpi_s = _gcry_ecc_ec2os (x, y, pk.E.p); else { - rawmpi = _gcry_mpi_get_buffer (x, ec->nbits/8, &rawmpilen, NULL); + rawmpi = _gcry_mpi_get_buffer_extra (x, ec->nbits/8, -1, + &rawmpilen, NULL); if (!rawmpi) rc = gpg_err_code_from_syserror (); else { + rawmpi[0] = 0x40; mpi_s = mpi_new (0); mpi_set_opaque (mpi_s, rawmpi, rawmpilen*8); } @@ -1393,11 +1392,13 @@ ecc_encrypt_raw (gcry_sexp_t *r_ciph, gcry_sexp_t s_data, gcry_sexp_t keyparms) mpi_e = _gcry_ecc_ec2os (x, y, pk.E.p); else { - rawmpi = _gcry_mpi_get_buffer (x, ec->nbits/8, &rawmpilen, NULL); + rawmpi = _gcry_mpi_get_buffer_extra (x, ec->nbits/8, -1, + &rawmpilen, NULL); if (!rawmpi) rc = gpg_err_code_from_syserror (); else { + rawmpi[0] = 0x40; mpi_e = mpi_new (0); mpi_set_opaque (mpi_e, rawmpi, rawmpilen*8); } @@ -1587,11 +1588,13 @@ ecc_decrypt_raw (gcry_sexp_t *r_plain, gcry_sexp_t s_data, gcry_sexp_t keyparms) unsigned char *rawmpi; unsigned int rawmpilen; - rawmpi = _gcry_mpi_get_buffer (x, ec->nbits/8, &rawmpilen, NULL); + rawmpi = _gcry_mpi_get_buffer_extra (x, ec->nbits/8, -1, + &rawmpilen, NULL); if (!rawmpi) rc = gpg_err_code_from_syserror (); else { + rawmpi[0] = 0x40; r = mpi_new (0); mpi_set_opaque (r, rawmpi, rawmpilen*8); } |