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 3AC57303A2F; Mon, 3 Nov 2025 11:27:30 +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=1762169251; cv=none; b=n6H+3VQlqDSP2wu7doRydDT9DFoXPDIpFFrCs0t05qZTsnQlFbXO4AwyHnPnousMirQmGCwk74ponB0Kiq53SCeCQDUWqn2k1JBhzp1Pk2F7YbjqE25khHOCIdoa1YIov5to58HpptzbTxSgwC+NQKM+B8Yx0ijQUkr0Wh/a6D0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762169251; c=relaxed/simple; bh=mYlstSLu9EjMbm9NKODOYBWD+LPqr6dAu0tzrPktmzQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=SMKBpEnOd0GVyl7nUUGnq72XwAqT82r++iGZciqJv3l/GxIinOiOq8EcBP+7UWv93qoX+4hvDgVkCvEYKlUsJPMQg/3tAcN0CiOyWpUQKLSU+8gCwe7UJ/iOFTafqt3WHeOuM8grDSeFIbfTvUVIbox6m+S3kdc0n/+FUSDQ29k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=STqrMrI4; 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="STqrMrI4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 286ADC4CEE7; Mon, 3 Nov 2025 11:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762169250; bh=mYlstSLu9EjMbm9NKODOYBWD+LPqr6dAu0tzrPktmzQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=STqrMrI4HTdVciHFTQo6X/rWq9AuCwH8cjr9x8+n6+sG8Ivb5pFAr/LHYe5ukSl3Y /xOm63eQeS5pMMZE5xjNg9VDY4XYAN5G6gQqED6X5+od9W9xPQXtK4d8Iv2e02+w0i Wd6O2dhyK3zL3U11rEGhZdsx5Z0pLVA83ls9eVzpGSPPSbL0iICNZDfbyoPPyZ1ZL2 0UPGQZun8LiPfvFilfZkttbHKMGAv17ErlWMEg9EcML+jOM4Mv0+FbKtSqZ3hFRVwg e5YDmEPGlN2ZfqtZWOK6oD41JlWuDosnLjx1hNgTh3glvEN5HiztiFysvvXU3DoIe4 7GNQ753m8/85w== From: Christian Brauner Date: Mon, 03 Nov 2025 12:26:56 +0100 Subject: [PATCH 08/16] binfmt_misc: use credential guards Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251103-work-creds-guards-simple-v1-8-a3e156839e7f@kernel.org> References: <20251103-work-creds-guards-simple-v1-0-a3e156839e7f@kernel.org> In-Reply-To: <20251103-work-creds-guards-simple-v1-0-a3e156839e7f@kernel.org> To: Linus Torvalds Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-aio@kvack.org, linux-unionfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, cgroups@vger.kernel.org, netdev@vger.kernel.org, Christian Brauner X-Mailer: b4 0.15-dev-96507 X-Developer-Signature: v=1; a=openpgp-sha256; l=1225; i=brauner@kernel.org; h=from:subject:message-id; bh=mYlstSLu9EjMbm9NKODOYBWD+LPqr6dAu0tzrPktmzQ=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWRyTGz/+WIFh9nrxRFbP9Uf+F5deo/n7QrmSybR9YfeC tz4fe/fm45SFgYxLgZZMUUWh3aTcLnlPBWbjTI1YOawMoEMYeDiFICJ1OsyMtxbwXNRcorXnde1 VRofdN8wFEYdEtv4JnqO0e+9GibWf2cz/I/OXytfrjPh+IulfbmKUgKiPxLjXAWTRDaHFx95/kj sGDMA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Use credential guards for scoped credential override with automatic restoration on scope exit. Signed-off-by: Christian Brauner --- fs/binfmt_misc.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index a839f960cd4a..558db4bd6c2a 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -782,8 +782,6 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer, return PTR_ERR(e); if (e->flags & MISC_FMT_OPEN_FILE) { - const struct cred *old_cred; - /* * Now that we support unprivileged binfmt_misc mounts make * sure we use the credentials that the register @file was @@ -791,9 +789,8 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer, * didn't matter much as only a privileged process could open * the register file. */ - old_cred = override_creds(file->f_cred); - f = open_exec(e->interpreter); - revert_creds(old_cred); + scoped_with_creds(file->f_cred) + f = open_exec(e->interpreter); if (IS_ERR(f)) { pr_notice("register: failed to install interpreter file %s\n", e->interpreter); -- 2.47.3