From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 809A53B27E7 for ; Tue, 6 Oct 2026 10:10:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791281430; cv=none; b=ewGYrGZxtJ7ENaKZJtY9il+jR2L+L4jn3GRMO57z23TLQva7FB8tL/3lWhOudfrEnLjnV4skHTZfEJs6pmzsM/2lPoG+rb3xJsjTFxNVFpa/2B72bzlWn9Lgsfclyvmpu5MIpyXACMVOUQ2RE1LW5ivklqyVGKVLgAbha3M7NlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791281430; c=relaxed/simple; bh=wCBKwAO3RldU2ESPFI6THPXILvQkLLbyNG3wUXkZEWo=; h=MIME-Version:Date:From:To:Cc:Message-Id:In-Reply-To:References: Subject:Content-Type; b=EX3I8wyOmVAILSWdKfF1BM3+t1NB/DOQDmm2mVZ9eV4mQ5miPYxvV+GccjxUmKV41so5ew6qyyQJOVnWwpXdLPyO9m+NxCrwDAkbZGrXnAtfwYPlnDOImIto17ML7AgQDctrb64uHTK/rIPYrcFvFVdhjE0AaE+oP4hLTUa/hD4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IVDUfh8n; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IVDUfh8n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB0C51F00893; Tue, 6 Oct 2026 10:10:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791281429; bh=mN1fLUx6U4l11L6MnXB4bhyBo8psXKYYXKG+AATtHRY=; h=Date:From:To:Cc:In-Reply-To:References:Subject; b=IVDUfh8nXRjNdwWnnspKOckVBC1AiAw5MkmIYbWhVv7P2wTzk5HkMj+1YwUFZgIIJ Ndtg/qPwG7blVYnRKYzRSvsm34pJ1aZuodHn+U4FfFZvjWJtRLcbJu4RzsD0TdvgF8 +ne7SoB2NT03Iehbyy+UybpejGQ75i/TYV3QwsJNV0j77F4BzqvirJyDbwPw2aTGKP DNjfBYSpYNM5pTiFnetb1oopM1OJLnUPGq1A2HSLNrMWEg2390UK8nmBrLy9Ogr1dU JRacKobcRveqmBfItkN5R79VVajVP36p8Drca0xLRoUYI6s7FmdN6C0yNxabAvTJFd 7hyfDizUBX0Pg== Received: from ams-compute-02.internal (ams-compute-02.internal [10.64.2.62]) by mailfauth.ams.internal (Postfix) with ESMTP id 67970198003A; Tue, 6 Oct 2026 06:10:27 -0400 (EDT) Received: from ams-imap-11 ([10.64.2.31]) by ams-compute-02.internal (MEProxy); Tue, 06 Oct 2026 06:10:27 -0400 X-ME-Sender: X-ME-Proxy-Cause: dmFkZTF+ynibvRhAiAMRnJcUgqJ6a+xA9WFexSAZHW4HGxJsRcSVNIqtsmNcaUTY1UDF4I u8MBKVSyEqTH81/lAETkaXgb4jhEYHL+MLxq+rqwyyY4+aEhcn9AsF/yzLZdpsc9D0Oko1 l71nfHkL/AGbdZgMSJaz0ucEZBUI1sA6aN/Q7VyNOjA41fNcwMqUUZhhuTaAXSuyDw5kkP 3ZW4cPj30662ajbsHnwtpu+JjzHhOO1XqUNczq8GoAKa/uLQtZCYDX98QCOW56XECpGYzP /1eT5aKoVsgskOBpFD7LBGDPQxaNsDpIjj38BpRGs+UYnRCaESDmvh/qk0pFLMX/wH4yf/ 3yWDQhzUSRshsPr8DIdWWB30L2SbfwfPE3tEd9MWtQBrgn8n74tRCytHcBRHwmUlmCHmZl KKvo22DmjMrAYapiHJP9KqBSmx+aUEa8uDKt+igoFvrzMNtuU328TuuLzTzr52afPynLO+ QI0grAo6NDRi2hsZfQw/REZ1A2+jX1K9TnXbFQTNwc6eUqhM8xTmK4u3noE2ModVSml+ox kScqB2GmK5d0vxGtKlmLv1auOb5jMeV2RTYAWNeUAQUpRhBhuj+07WjqadDb+EtvWiAvti bPwoQcNmcyPKRjpGDTIN3pGbAl48gT2buzU6M6r/uIzSkg3nOhNS4C7JARmA X-ME-Proxy: Feedback-ID: ice86485a:Fastmail Received: by mailuser.ams.internal (Postfix, from userid 501) id 9782CF80096; Tue, 6 Oct 2026 06:10:25 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Tue, 06 Oct 2026 12:10:03 +0200 From: "Ard Biesheuvel" To: "Eric Biggers" , linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Jason A . Donenfeld" , "Herbert Xu" , stable@vger.kernel.org, Sashiko Message-Id: <3631bd3a-2186-4fcf-bceb-28fb4ed97d54@app.fastmail.com> In-Reply-To: <20261006083432.16328-1-ebiggers@kernel.org> References: <20261006083432.16328-1-ebiggers@kernel.org> Subject: Re: [PATCH] lib/crypto: poly1305: Use memzero_explicit() in poly1305_final() Content-Type: text/plain Content-Transfer-Encoding: 7bit On Tue, 6 Oct 2026, at 10:34, Eric Biggers wrote: > Use memzero_explicit() instead of a plain struct assignment to guarantee > zeroization of the 'struct poly1305_desc_ctx'. > > Note that dead store elimination was only theoretically possible with > link-time optimization here. But it's still worth fixing. > > Fixes: a1d93064094c ("crypto: poly1305 - expose init/update/final > library interface") > Cc: stable@vger.kernel.org > Reported-by: Sashiko > Closes: > https://sashiko.dev/#/bug/linux-c3a6bd76-f6ab-4203-892a-cd06f7aa0c34 > Signed-off-by: Eric Biggers > --- > lib/crypto/poly1305.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Reviewed-by: Ard Biesheuvel > diff --git a/lib/crypto/poly1305.c b/lib/crypto/poly1305.c > index f313ccc4b4dd2..048c7afe86138 100644 > --- a/lib/crypto/poly1305.c > +++ b/lib/crypto/poly1305.c > @@ -78,7 +78,7 @@ void poly1305_final(struct poly1305_desc_ctx *desc, u8 *dst) > } > > poly1305_emit(&desc->state.h, dst, desc->s); > - *desc = (struct poly1305_desc_ctx){}; > + memzero_explicit(desc, sizeof(*desc)); > } > EXPORT_SYMBOL(poly1305_final); > > > base-commit: 6a50ce0af5c91fd665d65d357af8ae55db1df7d0 > -- > 2.56.0