This is a note to let you know that I've just added the patch titled
crypto: ecdh - explicitly zeroize private_key
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
crypto-ecdh-explicitly-zeroize-private_key.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 681352423530110ddf51e788523a08a4310d84b4
Author: Joachim Vandersmissen <git@xxxxxxxxx>
Date: Thu Mar 28 11:24:30 2024 -0500
crypto: ecdh - explicitly zeroize private_key
[ Upstream commit 73e5984e540a76a2ee1868b91590c922da8c24c9 ]
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@xxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/crypto/ecdh.c b/crypto/ecdh.c
index c6f61c2211dc7..865e76e5a51c4 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);
