From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793804835; b=c7YhSM9VhBPeLUickkXbzCTv7RmbcU/zqP9AMEf4Lmr+v8m+bxhFeTIjjFunYYgR9sdV Kc6+VK64lWYJypG2b1dNs7SGPm/NoIagS8UyUEgpbX1RDYXCH9Lx4kkw07onKrYPlFK+c emi29kevugbt7BRdGZTmiH7s1sU3WQ2Dqn4LurKrzpDyDFU9r0Uxdq1JTP5xsecyvFAHF hRQEiGav7WJSYbqhOdDiquZLXSRhUfOBAysDl5FMaXnTGZtP+28upBbbmaDZ2NH/zGkBL Ri0+O5DZi2iMTW8OQG8niIcyO9fIZtcs1RamsevSK9zUEocNMuK1fjxMt4txva9PoyA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793804835; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=nOOBgT6lRJFU5RRiCRgzoCZj9r5Yz4jAmYGKr2H+qd0=; b=xEsEQS1zLP3K7oNbGFOsP9lZAQIwfsuHPjmD7ZCizzCUx/wq7mB9rZo8tXuSyjX0BUzs f/QgyrbIceNAoj0bFiI7x/S4H7jZqOObfYgT1WYZ/+UCQqFk8D4F04cluxLGOVm6+8FOs yviiB1lywFQ7cVduPLm/T1ZsISG50lveFW3XykvzXwzwvC63Ic2zrZzzEbPyarkcAYiy8 bOSxVCeKNDKN3vnID0XEBp/JJFryDw5DveH8oKEE6Bh2twRG8bq03ieI+n0x5sv4u6wdG PjWnLKPDA+seA0dcjuMZWv3Nbdd2Plm1UV/NI+sXLBxLByPBBOLpE/zoudLQcJivpFg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Oqz5tK03; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B3BA606A31B for ; Wed, 4 Nov 2026 15:07:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Oqz5tK03 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E2A21F00A02; Wed, 4 Nov 2026 15:07:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793804834; bh=nOOBgT6lRJFU5RRiCRgzoCZj9r5Yz4jAmYGKr2H+qd0=; h=Subject:To:Cc:From:Date; b=Oqz5tK03JmumB0E8RzhtaRLCIqMUTP9ki1EgVoVBXFkDgLtnTbfSnVeapUty8mn10 k8oKpVe35AdS37sMHf16jV43k+WeyGuO4QF9k9f3of3gaF+7suHJaUSqcRPRAWD6cF VithZpCXcSmETSOvIUjUxTLDwoEpwd4jWSMyNnfw= Subject: FAILED: patch "[PATCH] ovl: fix mount setup failing when override_creds drops" failed to apply to 6.12-stable tree To: amir73il@gmail.com,brauner@kernel.org,disgoel@linux.ibm.com Cc: From: Date: Wed, 04 Nov 2026 16:07:04 +0100 Message-ID: <2026110404-hamlet-circling-4092@gregkh> X-Mailing-List: stable@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=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 333ad304d4794d6384087ea7fc16e58ab642809b # git commit -s git send-email --to '' --in-reply-to '2026110404-hamlet-circling-4092@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 333ad304d4794d6384087ea7fc16e58ab642809b Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sat, 17 Oct 2026 18:43:30 +0200 Subject: [PATCH] ovl: fix mount setup failing when override_creds drops CAP_SYS_ADMIN When a process drops CAP_SYS_ADMIN and calls fsconfig(FSCONFIG_SET_FLAG, "override_creds"), overlayfs saves those restricted credentials in ofs->creator_cred. ovl_fill_super() then wraps the entire mount setup in with_ovl_creds(), switching to those restricted credentials for the duration. Mount setup calls clone_private_mount(), which checks CAP_SYS_ADMIN against current credentials. With restricted credentials active, this check fails with -EPERM even though the task issuing FSCONFIG_CMD_CREATE is fully privileged. Use the mounter's real credentials only for cloning the private layer mounts. Keep all other backing filesystem operations during mount setup under the stashed credentials. Reported-by: Disha Goel Closes: https://lore.kernel.org/linux-unionfs/20260924112858.51392-1-disgoel@linux.ibm.com Fixes: c28f922c9dcee ("clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns") Cc: stable@vger.kernel.org Reviewed-by: Christian Brauner (Amutable) Signed-off-by: Amir Goldstein diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index cc4b0959faf6..b452b8c5f641 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -503,6 +503,20 @@ static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) } } +/* + * clone_private_mount() checks CAP_SYS_ADMIN in current->cred. + * ovl_fill_super_creds() runs under the stashed creator cred, which + * override_creds may have dropped. + * The task that issued FSCONFIG_CMD_CREATE is still current->real_cred, so + * use that only for the clone. creator_cred stays in effect for every other + * backing-fs operation. + */ +static struct vfsmount *ovl_clone_private_mount(const struct path *path) +{ + scoped_with_creds(current_real_cred()) + return clone_private_mount(path); +} + static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, struct ovl_layer *upper_layer, const struct path *upperpath) @@ -526,7 +540,7 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, if (err) goto out; - upper_mnt = clone_private_mount(upperpath); + upper_mnt = ovl_clone_private_mount(upperpath); err = PTR_ERR(upper_mnt); if (IS_ERR(upper_mnt)) { pr_err("failed to clone upperpath\n"); @@ -1104,7 +1118,7 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, } } - mnt = clone_private_mount(&l->path); + mnt = ovl_clone_private_mount(&l->path); err = PTR_ERR(mnt); if (IS_ERR(mnt)) { pr_err("failed to clone lowerpath\n");