From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from todd.t-8ch.de (todd.t-8ch.de [159.69.126.157]) (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 150F914265 for ; Sun, 12 May 2024 07:22:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.69.126.157 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715498540; cv=none; b=UpFSAQqHBI65wJuTY/mw1JOH3yOjAFhb+moYtyE7o4F4Ul9Ei2cgIGpvjhIAUAMJXrVVItuHFM9TbX5dYClCR6Zr7tRSmrsoyH5QM4u9wN73wmCPOr8hY++f9jjmKbXdz0N3aEwd3uv7lB+NHFD02V/81SEYLPpkuqYW9A+IXfE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715498540; c=relaxed/simple; bh=9ioxjcM/LgA4IkV8XhTL6DxF8jZt95CIPT9t08Xev7k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RTo6ncjyNcPLlAm6YxT4/gsITDzca0Uc3czB9m0/Yoi33qW1lWf/oIRAcxuu6DcSDVLe9OxE0NgcwWUkLs67X3laEkZdo0gfgXHoVGgoA6sqpLB1mvrDqE3gfrLY582S6jedX2k6KZXmcPmQu1745B7nrcX28X8WRlsKiParyxA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=weissschuh.net; spf=pass smtp.mailfrom=weissschuh.net; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b=sWF2dRQo; arc=none smtp.client-ip=159.69.126.157 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b="sWF2dRQo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1715498534; bh=9ioxjcM/LgA4IkV8XhTL6DxF8jZt95CIPT9t08Xev7k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sWF2dRQoLhbcsauQ5Dt8C5bj0ol9Xy0i7+eGP0/uVDcI9dDDLQIYD24wgrUgxHEwJ KVh9Mbg/XEUfdk0INhTwPIsEhei46xkJZ2JXPIg5QzhJxkBZzMTpSE0lf3cSCxGwK8 gqCS7Wf1Pc93cZ6XChOZxIuwlkVp2hb1sVgShlEU= Date: Sun, 12 May 2024 09:22:13 +0200 From: Thomas =?utf-8?Q?Wei=C3=9Fschuh?= To: linux-kernel@vger.kernel.org Cc: Joel Granados , Luis Chamberlain , "Eric W. Biederman" Subject: Re: [PATCH] ucounts: constify usage of ctl_table_header::ctl_table_arg Message-ID: References: <20240511-sysctl-const-table-arg-ucount-v1-1-a00ad8f6f233@weissschuh.net> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240511-sysctl-const-table-arg-ucount-v1-1-a00ad8f6f233@weissschuh.net> On 2024-05-11 21:28:10+0000, Thomas Weißschuh wrote: > The sysctl core is preparing to only expose instances of > struct ctl_table as "const". > This will also affect the member > ctl_table_header::ctl_table_arg. > > Prepare for that change to "struct ctl_table_header", > and already constify the usage of ctl_table_arg. Please disregard this patch. Apparently Dave already picked it up as part of [0] through the net-next tree, which makes sense the ctl_table_arg changes are in net/ for the largest part. See commit bfa858f220ab ("sysctl: treewide: constify ctl_table_header::ctl_table_arg"). [0] https://lore.kernel.org/lkml/20240418-sysctl-const-table-arg-v2-1-4012abc31311@weissschuh.net/ > > No functional change. > > Signed-off-by: Thomas Weißschuh > --- > Motivation > ========== > > Moving structures containing function pointers into unmodifiable .rodata > prevents attackers or bugs from corrupting and diverting those pointers. > > Also the "struct ctl_table" exposed by the sysctl core were never meant > to be mutated by users. > > Process > ======= > > * Drop ctl_table modifications from the sysctl core ([0], in -next) > * Constify arguments to ctl_table_root::{set_ownership,permissions} > ([1], in -next) > * Migrate users of "ctl_table_header::ctl_table_arg" to "const". > (in progress, this patch) > * Afterwards convert "ctl_table_header::ctl_table_arg" itself to const. > (to be done) > * Prepare helpers used to implement proc_handlers throughout the tree to > use "const struct ctl_table *". ([2], in progress) > * Afterwards switch over all proc_handlers callbacks to use > "const struct ctl_table *" in one commit. ([2], in progress) > Only custom handlers will be affected, the big commit avoids a > disruptive and messy transition phase. > * Switch over the internals of the sysctl core to "const struct ctl_table *" (to be done) > * Switch include/linux/sysctl.h to "const struct ctl_table *" (to be done) > * Transition instances of "struct ctl_table" through the tree to const (to be done) > > A work-in-progress view containging all the outlined changes can be found at > https://git.sr.ht/~t-8ch/linux sysctl-constfy > > [0] https://lore.kernel.org/lkml/20240322-sysctl-empty-dir-v2-0-e559cf8ec7c0@weissschuh.net/ > [1] https://lore.kernel.org/lkml/20240315-sysctl-const-ownership-v3-0-b86680eae02e@weissschuh.net/ > [2] https://lore.kernel.org/lkml/20240423-sysctl-const-handler-v3-0-e0beccb836e2@weissschuh.net/ > > Cc: Joel Granados > Cc: Luis Chamberlain > Cc: Eric W. Biederman > --- > kernel/ucount.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/ucount.c b/kernel/ucount.c > index 4aa6166cb856..d9e283600f5c 100644 > --- a/kernel/ucount.c > +++ b/kernel/ucount.c > @@ -119,7 +119,7 @@ bool setup_userns_sysctls(struct user_namespace *ns) > void retire_userns_sysctls(struct user_namespace *ns) > { > #ifdef CONFIG_SYSCTL > - struct ctl_table *tbl; > + const struct ctl_table *tbl; > > tbl = ns->sysctls->ctl_table_arg; > unregister_sysctl_table(ns->sysctls); > > --- > base-commit: cf87f46fd34d6c19283d9625a7822f20d90b64a4 > change-id: 20240511-sysctl-const-table-arg-ucount-75027ec3fbf4 > > Best regards, > -- > Thomas Weißschuh >