From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97AE2347507 for ; Wed, 25 Mar 2026 09:14:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774430093; cv=none; b=itGJ683wbl/9XmRVN4XcQHZ/JYuu0avUu33RHkXKyKZnjv6P4XpZjVWOf28k3jycfkNCUIASZFKc4ep5I0WEZDZYHmKDHNLnnZpq7l+XbesdLt9cOvDxRXlay6S/OyunedFIk8GpYIkFbFUGOofCrhBIm3jtKrbbJ5ef2OYEqc0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774430093; c=relaxed/simple; bh=f6LAJ1cZjCDN2h3rLbF5TG4bubsg5twhIpBTCpNQ0uI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=RilrQvARCrMFjQnKwFZ4B9iQEqTYxNNr22E8ov+QEkM1TO9Cuz7taXhhyAygJDx1DntAYez1pBxkmX87yyS5fXlbQtkZFr2O/G2rYkqNeyDMUP1gp9wH/ktLYo4aCK1skjpuOPKmTyGRQmGFrsoHTT8Kp1+5x7uqLpgHpvwByxg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=EUyum9Ne; arc=none smtp.client-ip=209.85.128.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="EUyum9Ne" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-4853e1ce427so51868635e9.3 for ; Wed, 25 Mar 2026 02:14:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774430090; x=1775034890; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=4UaOpz3+1W+wedEffomJwe2yGeTlmvpj2xZV/k2RXQE=; b=EUyum9Ney3QH7gdd/nvQ6JSF9Zd7V9bb3tBbtArSQjwpJ3nd36n0BsVML/ljX9+Ccn QqKWwuY84vCEDdNL/G1KgP9v88025vaEN1KdVxIWVdoeIFkCNUT/cjldq+Z1eE5X9iNe 5XmN9G74aPmHvdN59Y+gKbiRdfnr7Z22kgnEztovp72Zd2sQwzj1FTZNoqARINY+Ko9r gyYCeKNTAwJStnWOCaUXuHSOlI8t++3a0KXCq49WiYWwXU08CFYwJhM9bARUlR5HU9pZ l5oDk0NpxSZE4qPoMNN9Qf7mZ9bOx7gzfsoly2fFCP4gilSLeqmjmjuvhyrG2DcVpZBj i7Aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774430090; x=1775034890; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=4UaOpz3+1W+wedEffomJwe2yGeTlmvpj2xZV/k2RXQE=; b=IyOEfQquYlOAr9Vn+wVwihXX5ghTNIFg1BdZ5/MXdUkVSjOL7caoesVpPcWmnDmKB+ GDHwMGWYiztc2a7aZagI3uzY4FngXQjztGgNkeMMD922VKE4cPnLQcOnEWuBLoAhVrxv ok3ow6jpgPX57M9Xud+B6sU6lE6/PacyYnVsDXbLzbluafnK/xkDDoaqHAACYC6KN7yf 4mo/D196erADPvszwEIHdRbJk0oDvDji5Vj/gsclTKE8u9SPC8CG+v/5ehgO7uL8gX2u qrqvPr3zVz/I26Knv9F0izFqlqHYrf9JU/cctLAembDFVtLHGO4Qfb+L+QvDdZ8A++Dk GD2A== X-Forwarded-Encrypted: i=1; AJvYcCURt5Qo9Z+w9t+3O0FDzyICrUlWRQVb4QNqmXrXOtSyOg91A6+UFO9p6jHSWwvUL2MavmvUTC55/BQDYJw=@vger.kernel.org X-Gm-Message-State: AOJu0Ywh1diby9h+htP/jTuMB6nk98hrRb+e4zic6Lr5RrlW1OsOIw74 96Z0arPfl1r8BJQ9y0s+1PO3uAIC9BUFhMTO4pMSfGkfkF1F+FAFj5G6 X-Gm-Gg: ATEYQzyNYbQYVV+EOsLxJzaYzQGe6pmVFwSxqmZ8YEB42HqYUU9Y7ndsbFNXVIs6D7P B0o8RbBbRRTA84JPpxNto99rNn381A3Jartj6zkFuAzjvAWlyAkyS/NvwkHfK4jhtHaSJnkAdVx VI9F7WFv1TumzI8OxOYjGy+HUTsr2bXh5QVXIKAVJ9IHrEBCEMaqi1jbvafM5PXtWsqjg0l9D9k 3htTGrTKs6AGJ0wH4W0DyNcq67iyaBa475xEYkQkqLyI4EAHV3T0YSml7onfgoTI3++itcDalBB 44tLAtWqekKqhQ3fcC1qBTVB4Bg+uRJ6UsdsyWHFLNZvrN3gNk503yolHWIQCmsjx3Qwrhqb6fT mkj5AIJ98XuCbeOJXcoNi7Hf7pAl74oJEYDf9JE9w3vP3IadpaFCnQCFNZ8hL1ZvmxrGaq2eLv2 XvzgudOSHRNFtO0HAPXHY0P48H5jJlnE1I9YaxbTcL/qi3JNWyAW+n0yxwF6SYNTxJ X-Received: by 2002:a05:600c:8489:b0:485:5981:1423 with SMTP id 5b1f17b1804b1-48715fbfcc0mr39210235e9.3.1774430089718; Wed, 25 Mar 2026 02:14:49 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4871a937bdfsm52867575e9.9.2026.03.25.02.14.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Mar 2026 02:14:49 -0700 (PDT) Date: Wed, 25 Mar 2026 09:14:47 +0000 From: David Laight To: "Masami Hiramatsu (Google)" Cc: Petr Mladek , Rasmus Villemoes , Andy Shevchenko , Steven Rostedt , Sergey Senozhatsky , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/2] lib/vsprintf: Fix to check field_width and precision Message-ID: <20260325091447.74e419df@pumpkin> In-Reply-To: <20260325101704.f31e0ba4c13ebb1b63b701aa@kernel.org> References: <177410406326.38798.16853803119128725972.stgit@devnote2> <177410407207.38798.2345647618225402693.stgit@devnote2> <20260323135905.5272127b@pumpkin> <20260324172433.05292942@pumpkin> <20260325093320.5bc786394face92aadbe4e4b@kernel.org> <20260325101704.f31e0ba4c13ebb1b63b701aa@kernel.org> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 25 Mar 2026 10:17:04 +0900 Masami Hiramatsu (Google) wrote: > On Wed, 25 Mar 2026 09:33:20 +0900 > Masami Hiramatsu (Google) wrote: > > > On Tue, 24 Mar 2026 17:24:33 +0000 > > David Laight wrote: > > > > > On Tue, 24 Mar 2026 17:45:49 +0100 > > > Petr Mladek wrote: > > > > > > > On Mon 2026-03-23 13:59:05, David Laight wrote: > > > ... > > > > > I've also just fixed nolibc's handling of %*.*s (which is in 'next' since > > > > > I only wrote it recently), the above is actually broken. > > > > > Negative 'precision' (all values) are fine, they just request the default. > > > > > > > > Great catch! We should clamp the precision to (0, PRECISION_MAX). But we > > > > should warn only when it is outside of (-PRECISION_MAX, PRECISION_MAX). > > > > > > No, you are going to clamp it needs to be to (-1, PRECISION_MAX); > > > but max(precision, PRECISION_MAX) if fine now the value is being saved > > > in an int. > > > And there is no need to warn about changing negative values - they > > > all mean exactly the same thing. > > > > Ah, indeed. > > > > "A negative precision is taken as if the precision were omitted." > > Hmm, and format_decode() does not accept -1 precision. We need > another patch to fix it. > > spec->precision = -1; > if (unlikely(*fmt.str == '.')) { > fmt.str++; > if (isdigit(*fmt.str)) { <---- isdigit() accepts '0'-'9', not '-'. > spec->precision = skip_atoi(&fmt.str); <--- this only returns positive value. > if (spec->precision < 0) > spec->precision = 0; That is fine, you aren't allowed a negative value there - just for "%.*d". David > } else if (*fmt.str == '*') { > > Thanks, >