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authorStefan Berger <stefanb@linux.ibm.com>2024-04-04 17:18:45 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2024-04-12 10:07:51 +0300
commitd67c96fb97b5811e15c881d5cb72e293faa5f8e1 (patch)
tree4ad18dc03d5e111c8e8baf10d6d86347fa0235db /crypto
parent526d23fc2dd03a749297f5ef5edcbfb8c492dcfd (diff)
downloadlinux-d67c96fb97b5811e15c881d5cb72e293faa5f8e1.tar.xz
crypto: ecdsa - Convert byte arrays with key coordinates to digits
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>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/ecdsa.c14
1 files changed, 9 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;