| Message ID | 20240411235157.19801-1-hailmo@amazon.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | [1/2] crypto: ecdh - zeroize crpytographic keys after use | expand |
On Thu, Apr 11, 2024 at 11:51:56PM +0000, Hailey Mothershead wrote: > > @@ -111,7 +113,7 @@ static int ecdh_compute_value(struct kpp_request *req) > free_all: > kfree_sensitive(shared_secret); > free_pubkey: > - kfree(public_key); > + kfree_sensitive(public_key); It makes no sense to zero the public key. Nack.
diff --git a/crypto/ecdh.c b/crypto/ecdh.c index 80afee3234fb..71599cadf0bc 100644 --- a/crypto/ecdh.c +++ b/crypto/ecdh.c @@ -33,6 +33,8 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, params.key_size > sizeof(u64) * ctx->ndigits) return -EINVAL; + memset(ctx->private_key, 0, sizeof(ctx->private_key)); + if (!params.key || !params.key_size) return ecc_gen_privkey(ctx->curve_id, ctx->ndigits, ctx->private_key); @@ -111,7 +113,7 @@ static int ecdh_compute_value(struct kpp_request *req) free_all: kfree_sensitive(shared_secret); free_pubkey: - kfree(public_key); + kfree_sensitive(public_key); return ret; }
Fips 140-3 specifies that Sensitive Security Parameters (SSPs) must be zeroized after use and that overwriting these variables with a new SSP is not sufficient for zeroization. So explicitly zeroize the private key before it is overwritten in ecdh_set_secret. It also requires that variables used in the creation of SSPs be zeroized once they are no longer in use. Zeroize the public key as it is used in the creation of the shared secret. Signed-off-by: Hailey Mothershead <hailmo@amazon.com> --- crypto/ecdh.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)