From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E81EB34250D for ; Tue, 21 Apr 2026 18:50:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776797418; cv=none; b=jrJHGOL7pRRttLuQFA+vaoQIQyitaZFrSplLSacbhCU24hGIFDUAQw/0HvnduDG0NZPuSGj11X0rDA6JWm6Pq3QSlecWNoTe5ECk6MZR9gAecphrS6Sra7cd+lO1T3iCXqLLXfNYpt/yytQ/nxowAtEsYNCs1KcZVjnTj+LeWUk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776797418; c=relaxed/simple; bh=EPo6FNNjcWhdG4KhP6UIdw5E5GxlSmAr1AfY3wZx2FE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=agI7DS3o1jDjBQX+9V803AwT77G6zjyQhU7ZaI8rafR2/9ElbhZDn7VXCw6uy80KkkeE81wY15FAt6Vr91MHqdtBXwz+pk4HJpPqqs9QMZ5eAo+44//WeVTWyPClohqKjz/OQZgUpYj/EoskiCYOkDOmnvq0KDJjSvdv1bBlock= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ujRXaX55; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ujRXaX55" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40A2AC2BCB0; Tue, 21 Apr 2026 18:50:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776797417; bh=EPo6FNNjcWhdG4KhP6UIdw5E5GxlSmAr1AfY3wZx2FE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ujRXaX55h+MMxB91Emu4iztTsXp8cUOUgmizRCyGw5mTdo0vOqlRUWFrxaBd0Dh8k PfnqXXV0bTVVemQJ6AFQ3ulkslcVYsU7tICnLNROqyN6Nbs+4LnpkWPHZkjy7sZ+X/ j9a6SoZUUHZSyOEfYn+VUTg5vp1RgvlMUzjVYEhfhVQvhOGccCpEz3UyPH9u9QLFLN ZQQIRcMoRrEd/R+NI1HXveAbr15JzUdZQfQceVa0IDhegWqmNlCJfEIkI+NZkLFGVK 46nXYnpBh9FXu73ok8ytTRHY7lRxfiidObBpwLeVNmLa+FG6f5JM57NbHHZ5Ay3jEP rhpLtzi73nq5Q== Date: Tue, 21 Apr 2026 11:50:15 -0700 From: Eric Biggers To: Ard Biesheuvel Cc: linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au Subject: Re: [PATCH] crypto: Drop unused cipher_null crypto_alg Message-ID: <20260421185015.GB2202@quark> References: <20260420094120.5167-1-ardb@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260420094120.5167-1-ardb@kernel.org> On Mon, Apr 20, 2026 at 11:41:20AM +0200, Ard Biesheuvel wrote: > The cipher_null crypto_alg cipher is never used in a meaningful way, > given that it is always wrapped in ecb(), which has its own dedicated > implementation. IOW, the cipher_null crypto_alg should never be used to > implement the ecb(cipher_null) skcipher, and using it for other things > is bogus. > > However, it is accessible from user space, and due to the nature of the > AF_ALG interface, it may be wrapped in arbitrary ways, exposing issues > in template code that wasn't written with block ciphers with a block > size of '1' in mind. > > So drop this code. > > Signed-off-by: Ard Biesheuvel > --- > crypto/crypto_null.c | 35 ++------------------ > 1 file changed, 2 insertions(+), 33 deletions(-) Reviewed-by: Eric Biggers - Eric