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authorStefan Berger <stefanb@linux.ibm.com>2024-04-18 11:24:44 -0400
committerHerbert Xu <herbert@gondor.apana.org.au>2024-04-26 17:26:09 +0800
commitbd955a4e928f4b3a5b5eb983df1726300c90201c (patch)
tree6652ea583fd094d08ca464e7b31df26c5c522d23 /crypto
parent5ae6d3f5c85cfc8d3ce60da776387062171cc174 (diff)
crypto: ecdh - Pass private key in proper byte order to check valid key
ecc_is_key_valid expects a key with the most significant digit in the last entry of the digit array. Currently ecdh_set_secret passes a reversed key to ecc_is_key_valid that then passes the rather simple test checking whether the private key is in range [2, n-3]. For all current ecdh- supported curves (NIST P192/256/384) the 'n' parameter is a rather large number, therefore easily passing this test. Throughout the ecdh and ecc codebase the variable 'priv' is used for a private_key holding the bytes in proper byte order. Therefore, introduce priv in ecdh_set_secret and copy the bytes from ctx->private_key into priv in proper byte order by using ecc_swap_digits. Pass priv to ecc_is_valid_key. Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Salvatore Benedetto <salvatore.benedetto@intel.com> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/ecdh.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/crypto/ecdh.c b/crypto/ecdh.c
index 3049f147e011..c02c9a2b9682 100644
--- a/crypto/ecdh.c
+++ b/crypto/ecdh.c
@@ -27,7 +27,9 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
unsigned int len)
{
struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+ u64 priv[ECC_MAX_DIGITS];
struct ecdh params;
+ int ret = 0;
if (crypto_ecdh_decode_key(buf, len, &params) < 0 ||
params.key_size > sizeof(u64) * ctx->ndigits)
@@ -40,13 +42,16 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
ctx->private_key);
memcpy(ctx->private_key, params.key, params.key_size);
+ ecc_swap_digits(ctx->private_key, priv, ctx->ndigits);
if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
- ctx->private_key, params.key_size) < 0) {
+ priv, params.key_size) < 0) {
memzero_explicit(ctx->private_key, params.key_size);
- return -EINVAL;
+ ret = -EINVAL;
}
- return 0;
+ memzero_explicit(priv, sizeof(priv));
+
+ return ret;
}
static int ecdh_compute_value(struct kpp_request *req)