| Message ID | 20240320045106.61875-1-git@jvdsn.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | crypto: ecdh - explicitly zeroize private_key | expand |
On Tue, Mar 19, 2024 at 11:51:06PM -0500, Joachim Vandersmissen wrote: > > diff --git a/crypto/ecdh.c b/crypto/ecdh.c > index 80afee3234fb..ce332b39b705 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; > > + memzero_explicit(ctx->private_key, sizeof(ctx->private_key)); Please use memset instead of memzero_explicit unless it is actually needed (which is not the case here). I know there is another memzero_explicit in this function which should also be memset so it's not your fault. Thanks,
diff --git a/crypto/ecdh.c b/crypto/ecdh.c index 80afee3234fb..ce332b39b705 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; + memzero_explicit(ctx->private_key, sizeof(ctx->private_key)); + if (!params.key || !params.key_size) return ecc_gen_privkey(ctx->curve_id, ctx->ndigits, ctx->private_key);
private_key is overwritten with the key parameter passed in by the caller (if present), or alternatively a newly generated private key. However, it is possible that the caller provides a key (or the newly generated key) which is shorter than the previous key. In that scenario, some key material from the previous key would not be overwritten. The easiest solution is to explicitly zeroize the entire private_key array first. Note that this patch slightly changes the behavior of this function: previously, if the ecc_gen_privkey failed, the old private_key would remain. Now, the private_key is always zeroized. This behavior is consistent with the case where params.key is set and ecc_is_key_valid fails. Signed-off-by: Joachim Vandersmissen <git@jvdsn.com> --- crypto/ecdh.c | 2 ++ 1 file changed, 2 insertions(+)