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 8D7531E1DFC for ; Wed, 25 Mar 2026 00:26:47 +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=1774398407; cv=none; b=dT9dgwI6DnQap2rTC/0BqF7nqK5rrjstsWR8CXXfBJrtSR2HZnOE73PGGct1B1HU7GtNPQAIk/4sKzskScQEn5Ln5LqwihwDI76d4Lj1HiiBnG4/vH2qDC3R54WM0ERD22cBp1U3WAXus/N1COy0GK82Ob0oBTV14kYnZdHQyTw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774398407; c=relaxed/simple; bh=hJ2kdSNKr5aRx0JiqapTGaUoEQaVVO44ElnIUhtEzjk=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=CecIb9xeSx4FbR8qTU27HeJJDkdWTOYs3zmEGF0Of4qpP4XbzV9IXCAKs3tbrgBsSvZBiuc91Cr+Ct7oIJAxgMSBXUiXVgLuV6mn8ldT198ZFXzydga5y6lk+yD/tUIbJoMUsKvU2m1Ik8ck6b1HCrJHV2NxtsJBmgFODhinD+w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H9TMx12i; 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="H9TMx12i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8E33C2BCB1; Wed, 25 Mar 2026 00:26:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774398407; bh=hJ2kdSNKr5aRx0JiqapTGaUoEQaVVO44ElnIUhtEzjk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=H9TMx12i7e1B87tyr+yTuiOc76NcZ1NC3U2gZY5cOl0w9xB8mprM69+zcuiHMIcTr qyKaHaHm6KNPEby0fIi24G3wHFBdGANtMCZ4GAzjH60VXjvE7QswMcNFj5SEQibF3i WHeWemOOxLRmdDoTriSjgUHRU5V/0jvdhZRAmuohWK2yMuYFi9F35/iNEIdhtBRwdd UxRLKuTg5xVn2pXS6sXu6GaytgtpUsskubwgoU3jgfY3caGSHYhnyYLLZTwuWhlVg3 VMiIuSEgOLOXnGRSRTCENYIpVg2hrMHVJSrAZOzcJiKMrbbeh5bXMjihqUH9T73Kp/ jIILz7u/rztWQ== Date: Wed, 25 Mar 2026 09:26:44 +0900 From: Masami Hiramatsu (Google) To: Andy Shevchenko Cc: Petr Mladek , Steven Rostedt , Rasmus Villemoes , Sergey Senozhatsky , Andrew Morton , David Laight , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/2] lib/vsprintf: Fix to check field_width and precision Message-Id: <20260325092644.5a4f84568775c9d1bf89b9d0@kernel.org> In-Reply-To: References: <177410406326.38798.16853803119128725972.stgit@devnote2> <177410407207.38798.2345647618225402693.stgit@devnote2> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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 Mon, 23 Mar 2026 15:27:31 +0200 Andy Shevchenko wrote: > On Sat, Mar 21, 2026 at 11:41:12PM +0900, Masami Hiramatsu (Google) wrote: > > > Check the field_width and presition correctly. Previously it depends > > on the bitfield conversion from int to check out-of-range error. > > However, commit 938df695e98d ("vsprintf: associate the format state > > with the format pointer") changed those fields to int. > > We need to check the out-of-range correctly without bitfield > > conversion. > > ... > > > static void > > set_field_width(struct printf_spec *spec, int width) > > { > > - spec->field_width = width; > > - if (WARN_ONCE(spec->field_width != width, "field width %d too large", width)) { > > - spec->field_width = clamp(width, -FIELD_WIDTH_MAX, FIELD_WIDTH_MAX); > > + if (WARN_ONCE(width > FIELD_WIDTH_MAX || width < -FIELD_WIDTH_MAX, > > + "field width %d too large", width)) { > > + width = clamp(width, -FIELD_WIDTH_MAX, FIELD_WIDTH_MAX); > > } > > + spec->field_width = width; > > } > > > > static void > > set_precision(struct printf_spec *spec, int prec) > > { > > - spec->precision = prec; > > - if (WARN_ONCE(spec->precision != prec, "precision %d too large", prec)) { > > - spec->precision = clamp(prec, 0, PRECISION_MAX); > > + if (WARN_ONCE(prec > PRECISION_MAX || prec < 0, > > + "precision %d too large", prec)) { > > + prec = clamp(prec, 0, PRECISION_MAX); > > } > > + spec->precision = prec; > > } > > Looking at this, perhaps > > #define clamp_WARN_*(...) > ... > > Potential users besides these two: > > arch/powerpc/platforms/pseries/papr-sysparm.c-39- > drivers/gpu/drm/drm_color_mgmt.c-142- > drivers/gpu/drm/i915/display/intel_backlight.c-48- > drivers/media/i2c/vgxy61.c-952- Hmm, that will be an improvement, not a fix. I would like to keep this as small as possible so that we can cleanly apply it to stable trees, and introduce such new macro to for-next. Thank you, > > -- > With Best Regards, > Andy Shevchenko > > -- Masami Hiramatsu (Google)