From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793111946; b=TxMEnlDTKNtJTGAjRDPBTgtFrSVDeQ/3ksOCw1zgZJP+HJlWzFD7EVpXwKoMh74rPn90 HVMH3egBkD2Hb7j8Ii07G4Y3UwzdthDf0qPb/uZQcLJHh/gIAHoLHNrBoVGNcdQvaH3OR uvToax7rIqAod0x4SgA+UU/PFfVmpWnkrbZ0mN1GXCo8VOC1gvxaOUrCn10GnCTVQBAu8 IO8nJrtEvkADhok3BBPrAVN7+cTJjrLzleMxdR4tM4ezlV/kmSIO7ONTLo2xwfkkZAHge xBWMXFe9SGnc2VUFFUasZNS5KeEx7i3h3zNhFxL06/RdfQY9Q8BOrFjsNmBQBYERJ7A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793111946; h=DMARC-Filter:Received:Received:DKIM-Signature:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=oxYYXzuA+KjDDtWBG7XEQK2PA3jUu3Ip09CfAk+HxQw=; b=irg7ci3t7gSSmUh0J/KV9ox0dH/R0YnDQAPpZCTr8SkQJPWlYt9yXmJYy5wuaOZ9nvNC 1EVNhy9RPqMvO0PRlL7F+eCZBwkgyANzX/8esF0twMQ5DM7nRbHHzyotZNhmubfQcroMx lXVWvHgDkrkGX7sgu7rgpI6PYpXmRQE9CA9aDls+4Z4oPPQ4h+fGoGIEyGnNV0vzWtp/l gfvN1M5Wlon/wQFzAItxgb8etrKvjG4LcEvC33G7j7+sJG9LEgez5opnZ7P2JnOMv2ISl NZPbivE30tzpbt+HCULzdArUq3h6LnDYr73ibnoQuzkkN/dbn038nwTD96tR434BFeQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=Tuu0f2NG; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DBD75606A31D for ; Tue, 27 Oct 2026 14:39:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org DBD75606A31D Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=Tuu0f2NG Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E33B515A1; Tue, 27 Oct 2026 07:39:01 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B347E3F7B4; Tue, 27 Oct 2026 07:39:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793111945; bh=n8NvRega0eGpWWLCqhMnQOQTEFhQaD4mJqw4M2cZC0I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Tuu0f2NGiSDtPpXzfxeF+d4TpQ+fcWm20gBIEXsO0TrAwfwSpBAajHfZIBBXglDR9 sCtiuyFp1Yw2vQ0AHV85TbuVm/Lcg5uEOpJs3qWEwOQjdq4hNf9gJ4qCyyivsfuhmO SZCZG941AeMqFBwQdBA+pZDN7BbJlYuVgXupkXt8= Date: Tue, 27 Oct 2026 14:39:00 +0000 From: Catalin Marinas To: Thorsten Blum Cc: Will Deacon , Mark Rutland , Oliver Upton , Robin Murphy , Yureka Lilian , Marc Zyngier , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: idreg-override: Use property length in get_bootargs_cmdline() Message-ID: References: <20261015192810.395975-2-blum@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261015192810.395975-2-blum@kernel.org> On Thu, Oct 15, 2026 at 09:28:08PM +0200, Thorsten Blum wrote: > fdt_getprop() already provides the length of the bootargs property. Use > it to reject a zero-length property before dereferencing it, and test > the first byte directly instead of calling strlen(). > > Signed-off-by: Thorsten Blum > --- > arch/arm64/kernel/pi/idreg-override.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c > index acaf56234973..588c8af2a567 100644 > --- a/arch/arm64/kernel/pi/idreg-override.c > +++ b/arch/arm64/kernel/pi/idreg-override.c > @@ -383,15 +383,17 @@ static __init const u8 *get_bootargs_cmdline(const void *fdt, int node) > { > static char const bootargs[] __initconst = "bootargs"; > const u8 *prop; > + int len; > > if (node < 0) > return NULL; > > - prop = fdt_getprop(fdt, node, bootargs, NULL); > - if (!prop) > + prop = fdt_getprop(fdt, node, bootargs, &len); > + /* No bootargs for a missing, zero-length, or empty-string property. */ > + if (!prop || !len || !*prop) > return NULL; > > - return strlen(prop) ? prop : NULL; > + return prop; I think the patch makes sense. In theory we may have a value-less bootargs property and prop points to the next token (or some FDT_END_NODE) but they would all have 0 as the first byte, so the strlen() check would catch it. Anyway, the above is clearer, so: Reviewed-by: Catalin Marinas