From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-106113.protonmail.ch (mail-106113.protonmail.ch [79.135.106.113]) (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 8EBFF4183A7; Fri, 5 Jun 2026 09:16:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=79.135.106.113 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780651008; cv=none; b=CFBjtzaWvv/h3jpud4Zyp27LssAObmrFGUUJX4QvbDq4w3094ICylRS0tMmkarNq0SBg9HecTNijYLumc+Di2lmqVLOgeVVYjocm50F9e/isiOds1AEok1yOpdwhyMnKhF9vQhkKJ3EKQv/NVQQwkkRfCf0onSklPX/KcBftibg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780651008; c=relaxed/simple; bh=AkgUWGZkUVsVf7+t/8M3b6jpxqCom0DmtzVegaSQkXE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Oy38V/8p3sw6ZbmSACBU/lK2CxsYKyH5IJ7fzzpYQJWtMcvaYXXodL8FxDl4F+WUQcrY+RUIK1Zoo6/hBqL++yMbejfZd1VxWAUw6xMSWm6z1wLdWymgNHWKe66ymN3wMF3i3h8uMmwzTv0sCzs3kL3kqHx4yC+oTGebToeP2GY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=onurozkan.dev; spf=pass smtp.mailfrom=onurozkan.dev; dkim=pass (2048-bit key) header.d=onurozkan.dev header.i=@onurozkan.dev header.b=Oo3fYQnL; arc=none smtp.client-ip=79.135.106.113 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=onurozkan.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=onurozkan.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=onurozkan.dev header.i=@onurozkan.dev header.b="Oo3fYQnL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=onurozkan.dev; s=protonmail; t=1780650997; x=1780910197; bh=/xY5EtVoI/QL1ZLgCsbM6h32E0Qy+9GKKtlzGcWJLAs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:From:To: Cc:Date:Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=Oo3fYQnLEkd5QO4BE6HYXsxGF2gjwgBMJH/MsLhV+1GDoKwWsRXE+hgqYIPam7m7e Y2LyJV9RNzBO/Ii5cWZa0dZxa8KfZY5IcvA+ayeYP2CaGcAahdaZVgwQHaNi6/MXWk LBR4Drn9kvalGgg41JDU+dlTDt+FJiQoOCgVznlRxLTJLUuGIVpctOKKevsLBtwR7v LIt5ETyT5qNGAlpCd4VpStAHf2Tr7BZp1A1OcrlkL43uyGvu9uoQuxM+MusQkpBttO G28ZQUVKLzouTMvxzTydXMa4PcJl06qr+fppD3SaNoyV1zOvZagc1XW9ig9lfnT0O6 bbTSs5Avg1uJQ== X-Pm-Submission-Id: 4gWwmL44rLz1DF7D From: =?UTF-8?q?Onur=20=C3=96zkan?= To: Gary Guo Cc: Yuan Tan , ojeda@kernel.org, boqun@kernel.org, rust-for-linux@vger.kernel.org, zhiyunq@cs.ucr.edu, ardalan@uci.edu, pgovind2@uci.edu, dzueck@uci.edu, stable@vger.kernel.org Subject: Re: [PATCH] rust: firmware: return empty slice for zero-size firmware Date: Fri, 5 Jun 2026 12:16:31 +0300 Message-ID: <20260605091632.313084-1-work@onurozkan.dev> X-Mailer: git-send-email 2.51.2 In-Reply-To: References: <20260605041134.38290-1-ytan089@ucr.edu> <20260605071104.135675-1-work@onurozkan.dev> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Fri, 05 Jun 2026 09:13:55 +0100=0D Gary Guo wrote:=0D =0D > On Fri Jun 5, 2026 at 8:10 AM BST, Onur =C3=96zkan wrote:=0D > > On Thu, 04 Jun 2026 21:11:34 -0700=0D > > Yuan Tan wrote:=0D > >=0D > >> Firmware::data() builds a Rust slice with core::slice::from_raw_parts(= ).=0D > >> Unlike many C APIs, from_raw_parts() requires its pointer argument to = be=0D > >> non-NULL even when the length is zero.=0D > >> =0D > >> The firmware loader can represent an empty firmware image with size = =3D=3D 0=0D > >=0D > >=0D > > I haven't checked in detail yet but "empty firmware image with size =3D= =3D 0"=0D > > sounds like an invalid image. Can such an image actually make it all th= e way=0D > > to Firmware::data()? I would be surprised if the loader accepted it.=0D > =0D > `kernel_read_file` will return EINVAL if file is of zero size. But I thin= k the=0D > decompression path might produce this? The zstd code just does a=0D > =0D > out_buf =3D vzalloc(out_size);=0D > =0D > which will trigger a WARN but still return NULL.=0D =0D On NULL, it immediately fails with ENOMEM:=0D =0D out_buf =3D vzalloc(out_size);=0D if (!out_buf)=0D return -ENOMEM;=0D =0D Thanks,=0D Onur=0D =0D > =0D > That said, I doubt any valid firmware will be just a compressed empty fil= e.=0D > =0D > Best,=0D > Gary=0D