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 8AB5C224D6; Fri, 14 Nov 2025 22:45:32 +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=1763160332; cv=none; b=IuUMuUe9wxLQdvj/5s6kzZRAtGJ/27MEYc2uvTQupTkTo94YXnaMFxoLjR5Zz+tlk57ZGrBzyL00lqDPrvjl18ZX1h0QhCr3rcPYKVYUhJYU1Tmjm55vlOxUJ25fqqyhZ4ljXVI03NEW4lh7lTBymnADgDUhrmqcf6SqIFtkpAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763160332; c=relaxed/simple; bh=dyFWzTva0KoeI0S+AEWyVmrx6PoflTe3eM10GlaAFVw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lCWM+D2gbDhU1BdB+JEXJgm7WPsOMMDaxOgMIDUiTprvplniePUgdKQhUxG/jtFhFGlQsUPbwG0Vsuj5S3pIuhmgDBxOjhOiDjpt90C+84eECQ/iAigiA0FCKqwNw1Yo/wOyKkKlPtiBKYNUZylfdkywyYwMx3biRMJFHp/jIHA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BDCMjZSB; 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="BDCMjZSB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5F6DC4CEF1; Fri, 14 Nov 2025 22:45:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763160332; bh=dyFWzTva0KoeI0S+AEWyVmrx6PoflTe3eM10GlaAFVw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=BDCMjZSBR/GXGlgEqu9AUl4zxKa38u2g8Gd9W6c+qfR6tnRf70xTczZZ5LALpzqy5 mjOsFg/NeJhbVd73wbSaziMh5UDClRZUsngm+Op1zwhiW+Rlg6bZQ07cnbAyEOISR2 T+m5RZKk6YAbv1kYVVLKgFMXq54/y5HCxk68xsSkds4A3Pga0ah0ztGQmwrMbXPFT9 DD0wVBw4k68fM4wWKJiMBwy9sHqcozruCs44QZJWbu07ut27T3hdrWWAKwtFrcR/Mh udv/xrDqzrZprTq97tqatVgSAeBPYE8gzr6ZybeN/3C0uSVJ1WJtD2wYLbrleVpo4j 0CHcc8j0IUi2A== From: Christian Brauner Date: Fri, 14 Nov 2025 23:45:22 +0100 Subject: [PATCH 1/5] ovl: add copy up credential guard Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20251114-work-ovl-cred-guard-copyup-v1-1-ea3fb15cf427@kernel.org> References: <20251114-work-ovl-cred-guard-copyup-v1-0-ea3fb15cf427@kernel.org> In-Reply-To: <20251114-work-ovl-cred-guard-copyup-v1-0-ea3fb15cf427@kernel.org> To: Miklos Szeredi , Amir Goldstein Cc: Linus Torvalds , linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christian Brauner X-Mailer: b4 0.15-dev-a6db3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1388; i=brauner@kernel.org; h=from:subject:message-id; bh=dyFWzTva0KoeI0S+AEWyVmrx6PoflTe3eM10GlaAFVw=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSKb+Qo0+hID/gvcbKhTGTOvAuTY6fM/mN5dFuk63+d6 94OvjP5O0pZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACai+I/hf9a/Xx/mLfS6+fNe ffXXqFuWYtzCahWrb1rmP23fUMb+9wPDP3N5iRp1P9cTskIl6z/p6pW1W6Ywczg9ffXwUSmLwop j7AA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Add a credential guard for copy up. This will allows us to waste struct struct ovl_cu_creds and simplify the code. Signed-off-by: Christian Brauner --- fs/overlayfs/copy_up.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index bb0231fc61fc..cc77498fa8ca 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -755,6 +755,33 @@ static void ovl_revert_cu_creds(struct ovl_cu_creds *cc) } } +static const struct cred *ovl_prepare_copy_up_creds(struct dentry *dentry) +{ + struct cred *copy_up_cred = NULL; + int err; + + err = security_inode_copy_up(dentry, ©_up_cred); + if (err < 0) + return ERR_PTR(err); + + if (!copy_up_cred) + return NULL; + + return override_creds(copy_up_cred); +} + +static void ovl_revert_copy_up_creds(const struct cred *orig_cred) +{ + const struct cred *copy_up_cred; + + copy_up_cred = revert_creds(orig_cred); + put_cred(copy_up_cred); +} + +DEFINE_CLASS(copy_up_creds, const struct cred *, + if (!IS_ERR_OR_NULL(_T)) ovl_revert_copy_up_creds(_T), + ovl_prepare_copy_up_creds(dentry), struct dentry *dentry) + /* * Copyup using workdir to prepare temp file. Used when copying up directories, * special files or when upper fs doesn't support O_TMPFILE. -- 2.47.3