From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9837AC43458 for ; Wed, 8 Jul 2026 15:04:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=N0tnrtHNCdPPaeil/2FJ7xhWeZJlpBvAHaqYCxTjbds=; b=GYXCiCf1RERrXfZldX0Ri76feu NkgbB16fDgCj5Fx2Hol6xBfw6PDGDPsRzn5iqv20ywQC7Rgaq2csCMttA020CGaKZD4eNvWu7cef8 gbyrjjUjAY25dbJNnfAeGD5HGOQECSVeWUUZcyMuSvqPqXjzTd3mfsbvXV4AY8j1GV3Fi5ZQ1IJ/Q QN/dsAjjpgWdgXeIq4MbJJj7gtGqTUUg9nbmxufALVZxCXANXVkxzULEh4G+36Z22knK6oL7E71Xf MVqVBaq94qJaGIBbgQpfhZkOFA1NvP54a6+9n1+ZhSez4TJkxvwlkh0ngTJynw3cBKXFudnvJOXfL 2g+HzGNA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1whTpM-0000000HQtY-0Ohj; Wed, 08 Jul 2026 15:04:44 +0000 Received: from out-174.mta0.migadu.com ([2001:41d0:1004:224b::ae]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1whTpH-0000000HQsJ-3utt for linux-arm-kernel@lists.infradead.org; Wed, 08 Jul 2026 15:04:42 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783523073; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=N0tnrtHNCdPPaeil/2FJ7xhWeZJlpBvAHaqYCxTjbds=; b=hUqtXPlCKELHA6EiN9LfGfbVZe4c7bDuZoHBgOwhbzi72GRUinJRiobYqhbd/jB69TgpCU 8ruYxUGJpT6Umayo14BjAa/WAKGrtjcJUBr2/RxhA/o6dtB6FTwQ6h2kkEurFMzvOVlz71 GbUIvRFoXa2Ntr6oXNd2vuc4M8jkNDo= From: Thorsten Blum To: Thorsten Blum , Herbert Xu , "David S. Miller" , Nicolas Ferre , Alexandre Belloni , Claudiu Beznea Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] crypto: atmel-sha204a - clear RNG data from memory Date: Wed, 8 Jul 2026 17:04:00 +0200 Message-ID: <20260708150359.545852-2-thorsten.blum@linux.dev> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2157; i=thorsten.blum@linux.dev; h=from:subject; bh=q6WzhvHEK1zBLo09d+1w9A+q4i17hzUyPxyhhhNLWOw=; b=owGbwMvMwCUWt7pQ4caZUj3G02pJDFl+afc5ply5Gz+/81i136fpd7unxxkaGBaG3z2zJu7Vu i/3A9YKdZSyMIhxMciKKbI8mPVjhm9pTeUmk4idMHNYmUCGMHBxCsBEJjowMjT3b2z7njlNdvpB rmj3EpuOgM7jv+81Oq4tnj5B2MjIwJmR4U+j5oRbjI4ch1JWbbdb95dp4Z/tQmtMuj92HNvazJ7 Lyg8A X-Developer-Key: i=thorsten.blum@linux.dev; a=openpgp; fpr=1D60735E8AEF3BE473B69D84733678FD8DFEEAD4 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260708_080440_864300_DD6D236F X-CRM114-Status: GOOD ( 11.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In atmel_sha204a_rng_read(), use memzero_explicit() to clear the local stack variable cmd before it goes out of scope, since cmd.data may still hold the last 32 random bytes. Since atmel_sha204a_rng_done() caches work_data in hwrng::priv, and its response data is later used as RNG entropy, use kfree_sensitive() to clear the cached data on transaction failure and device removal. Signed-off-by: Thorsten Blum --- drivers/crypto/atmel-sha204a.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c index 5eb76245347d..21a84c29c9b7 100644 --- a/drivers/crypto/atmel-sha204a.c +++ b/drivers/crypto/atmel-sha204a.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include "atmel-i2c.h" @@ -35,7 +36,7 @@ static void atmel_sha204a_rng_done(struct atmel_i2c_work_data *work_data, dev_warn_ratelimited(&i2c_priv->client->dev, "i2c transaction failed (%d)\n", status); - kfree(work_data); + kfree_sensitive(work_data); atomic_dec(&i2c_priv->tfm_count); return; } @@ -95,12 +96,15 @@ static int atmel_sha204a_rng_read(struct hwrng *rng, void *data, size_t max, ret = atmel_i2c_send_receive(i2c_priv->client, &cmd); if (ret) - return ret; + goto out; max = min(RANDOM_RSP_SIZE - CMD_OVERHEAD_SIZE, max); memcpy(data, &cmd.data[RSP_DATA_IDX], max); + ret = max; - return max; +out: + memzero_explicit(&cmd, sizeof(cmd)); + return ret; } static int atmel_sha204a_otp_read(struct i2c_client *client, u16 addr, u8 *otp) @@ -209,7 +213,7 @@ static void atmel_sha204a_remove(struct i2c_client *client) devm_hwrng_unregister(&client->dev, &i2c_priv->hwrng); atmel_i2c_flush_queue(); - kfree((void *)i2c_priv->hwrng.priv); + kfree_sensitive((void *)i2c_priv->hwrng.priv); } static const struct of_device_id atmel_sha204a_dt_ids[] = { base-commit: e264401ce4776a288524e5b87593d4d864147115