6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefan Berger stefanb@linux.ibm.com
[ Upstream commit d67c96fb97b5811e15c881d5cb72e293faa5f8e1 ]
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 Tested-by: Lukas Wunner lukas@wunner.de Reviewed-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Stefan Berger stefanb@linux.ibm.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Stable-dep-of: 3b0565c70350 ("crypto: ecdsa - Avoid signed integer overflow on signature decoding") Signed-off-by: Sasha Levin sashal@kernel.org --- 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 3f9ec273a121..e819d0983bd3 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 *