| Message ID | 20240320114725.1644921-3-stefanb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v7,01/13] crypto: ecc - Use ECC_CURVE_NIST_P192/256/384_DIGITS where possible | expand |
On Wed Mar 20, 2024 at 1:47 PM EET, Stefan Berger wrote: > For NIST P192/256/384 the public key's x and y parameters could be copied > directly from a given array since both parameters filled 'ndigits' of > digits (a 'digit' is a u64). For support of NIST P521 the key parameters > need to have leading zeros prepended to the most significant digit since > only 2 bytes of the most significant digit are provided. > > Therefore, implement ecc_digits_from_bytes to convert a byte array into an > array of digits and use this function in ecdsa_set_pub_key where an input > byte array needs to be converted into digits. > > Suggested-by: Lukas Wunner <lukas@wunner.de> > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> > Tested-by: Lukas Wunner <lukas@wunner.de> > --- > crypto/ecdsa.c | 14 +++++++++----- > include/crypto/internal/ecc.h | 21 +++++++++++++++++++++ > 2 files changed, 30 insertions(+), 5 deletions(-) > > diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c > index fbd76498aba8..6653dec17327 100644 > --- a/crypto/ecdsa.c > +++ b/crypto/ecdsa.c > @@ -222,9 +222,8 @@ static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx) > static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsigned int keylen) > { > struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); > + unsigned int digitlen, ndigits; > const unsigned char *d = key; > - const u64 *digits = (const u64 *)&d[1]; > - unsigned int ndigits; > int ret; > > ret = ecdsa_ecc_ctx_reset(ctx); > @@ -238,12 +237,17 @@ static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsig > return -EINVAL; > > keylen--; > - ndigits = (keylen >> 1) / sizeof(u64); > + digitlen = keylen >> 1; > + > + ndigits = DIV_ROUND_UP(digitlen, sizeof(u64)); > if (ndigits != ctx->curve->g.ndigits) > return -EINVAL; > > - ecc_swap_digits(digits, ctx->pub_key.x, ndigits); > - ecc_swap_digits(&digits[ndigits], ctx->pub_key.y, ndigits); > + d++; > + > + ecc_digits_from_bytes(d, digitlen, ctx->pub_key.x, ndigits); > + ecc_digits_from_bytes(&d[digitlen], digitlen, ctx->pub_key.y, ndigits); > + > ret = ecc_is_pubkey_valid_full(ctx->curve, &ctx->pub_key); > > ctx->pub_key_set = ret == 0; > diff --git a/include/crypto/internal/ecc.h b/include/crypto/internal/ecc.h > index 4f6c1a68882f..ab722a8986b7 100644 > --- a/include/crypto/internal/ecc.h > +++ b/include/crypto/internal/ecc.h > @@ -56,6 +56,27 @@ static inline void ecc_swap_digits(const void *in, u64 *out, unsigned int ndigit > out[i] = get_unaligned_be64(&src[ndigits - 1 - i]); > } > > +/** > + * ecc_digits_from_bytes() - Create ndigits-sized digits array from byte array > + * @in: Input byte array > + * @nbytes Size of input byte array > + * @out Output digits array > + * @ndigits: Number of digits to create from byte array > + */ > +static inline void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes, > + u64 *out, unsigned int ndigits) > +{ > + unsigned int o = nbytes & 7; > + __be64 msd = 0; > + > + if (o) { > + memcpy((u8 *)&msd + sizeof(msd) - o, in, o); > + out[--ndigits] = be64_to_cpu(msd); > + in += o; > + } > + ecc_swap_digits(in, out, ndigits); > +} > + > /** > * ecc_is_key_valid() - Validate a given ECDH private key > * Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> BR, Jarkko
diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c index fbd76498aba8..6653dec17327 100644 --- a/crypto/ecdsa.c +++ b/crypto/ecdsa.c @@ -222,9 +222,8 @@ static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx) static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsigned int keylen) { struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm); + unsigned int digitlen, ndigits; const unsigned char *d = key; - const u64 *digits = (const u64 *)&d[1]; - unsigned int ndigits; int ret; ret = ecdsa_ecc_ctx_reset(ctx); @@ -238,12 +237,17 @@ static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsig return -EINVAL; keylen--; - ndigits = (keylen >> 1) / sizeof(u64); + digitlen = keylen >> 1; + + ndigits = DIV_ROUND_UP(digitlen, sizeof(u64)); if (ndigits != ctx->curve->g.ndigits) return -EINVAL; - ecc_swap_digits(digits, ctx->pub_key.x, ndigits); - ecc_swap_digits(&digits[ndigits], ctx->pub_key.y, ndigits); + d++; + + ecc_digits_from_bytes(d, digitlen, ctx->pub_key.x, ndigits); + ecc_digits_from_bytes(&d[digitlen], digitlen, ctx->pub_key.y, ndigits); + ret = ecc_is_pubkey_valid_full(ctx->curve, &ctx->pub_key); ctx->pub_key_set = ret == 0; diff --git a/include/crypto/internal/ecc.h b/include/crypto/internal/ecc.h index 4f6c1a68882f..ab722a8986b7 100644 --- a/include/crypto/internal/ecc.h +++ b/include/crypto/internal/ecc.h @@ -56,6 +56,27 @@ static inline void ecc_swap_digits(const void *in, u64 *out, unsigned int ndigit out[i] = get_unaligned_be64(&src[ndigits - 1 - i]); } +/** + * ecc_digits_from_bytes() - Create ndigits-sized digits array from byte array + * @in: Input byte array + * @nbytes Size of input byte array + * @out Output digits array + * @ndigits: Number of digits to create from byte array + */ +static inline void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes, + u64 *out, unsigned int ndigits) +{ + unsigned int o = nbytes & 7; + __be64 msd = 0; + + if (o) { + memcpy((u8 *)&msd + sizeof(msd) - o, in, o); + out[--ndigits] = be64_to_cpu(msd); + in += o; + } + ecc_swap_digits(in, out, ndigits); +} + /** * ecc_is_key_valid() - Validate a given ECDH private key *