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 4B84B2F5316; Thu, 13 Nov 2025 16:38:14 +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=1763051894; cv=none; b=o3wjzTDcE4hFzzoMQ6s+nSxL2FH0+fFlWKOWDbcFjOoqJp1GT4hhLyCkwLde7VTfdwLMTvsJ2eM8oaE1Ik0kCmV90ueR0qvixtiHBfPKSrCMV4RQ4RUYRgdAMbNulfYAIGIO3aEI+TRb4Suu5AkPwgM4H8j8Xk1xVwgFVJMOnT8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763051894; c=relaxed/simple; bh=oLWJCOoirB81PvWPQsj4tHBL9mWmJKgCn7/tar7A83U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=AEkJwv5p+fj0OvI5h7AdXuKmVLDstTCtFM6NXajPAKdo4GYcNCG6oMDZVu1zPdXW4xhrMQ1dl1DhbSu8uWFZ8VckmSxaodaa4OavrrnQ/p3AYyIUEFqlN9g2Bk4f8pHaq59HWL8vcdEqVRiTwXBvNqHYPUn40357gLWaFWWFjzA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tnjBYVkj; 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="tnjBYVkj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9B4FC4CEF1; Thu, 13 Nov 2025 16:38:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763051894; bh=oLWJCOoirB81PvWPQsj4tHBL9mWmJKgCn7/tar7A83U=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=tnjBYVkjqYwiLbDq6BRkWz51BFK3Qd+j/ctU5iGSxGFmaC9TNsKXkV+Gh7/EYi8sR Vbez/M1cXRDBAz1WuIODF9/efRrFMqechs7aIyPcjXkoLc5j3tlICJPr4MAfVkQuzD IQtPfaXlFn7uxD4DxeVmEn4ax0gaSHcR+pX1qq8uInGoHK9n97HiaqyFP0XnPSuyxC OaflI6Mslrp9GKs7g1tPifB/4gTBdwL/IT/Z404W2ifJn7OvaAZsRS6YLPPSDGc5tf /E+F7HquQOeiQK6ZYLV7nv+cZM3Ks933EL6wwazkTfQfzwlkSUBtutYhD/Bm6I3PH9 gmvRQ7cN97zbg== From: Christian Brauner Date: Thu, 13 Nov 2025 17:37:29 +0100 Subject: [PATCH v2 24/42] ovl: don't override credentials for ovl_check_whiteouts() Precedence: bulk X-Mailing-List: linux-unionfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20251113-work-ovl-cred-guard-v2-24-c08940095e90@kernel.org> References: <20251113-work-ovl-cred-guard-v2-0-c08940095e90@kernel.org> In-Reply-To: <20251113-work-ovl-cred-guard-v2-0-c08940095e90@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=2721; i=brauner@kernel.org; h=from:subject:message-id; bh=oLWJCOoirB81PvWPQsj4tHBL9mWmJKgCn7/tar7A83U=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSKcbo5aJl41k56+FVdaSPnpRiua7k9gsJMJdeTLr3eE euc+SWgo5SFQYyLQVZMkcWh3SRcbjlPxWajTA2YOaxMIEMYuDgFYCItTgz/nc5kVy26deWP0NRe 5aw/Sg/cb5+yPeG3Ncr186UFWRK9WxgZfhn+KRPdcyz1k62rbbLVDav/Jgt/7gs+LLKnu2Ghkpk SBwA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 The function is only called when rdd->dentry is non-NULL: if (!err && rdd->first_maybe_whiteout && rdd->dentry) err = ovl_check_whiteouts(realpath, rdd); | Caller | Sets rdd->dentry? | Can call ovl_check_whiteouts()? | |-------------------------------|-------------------|---------------------------------| | ovl_dir_read_merged() | ✓ Yes (line 430) | ✓ YES | | ovl_dir_read_impure() | ✗ No | ✗ NO | | ovl_check_d_type_supported() | ✗ No | ✗ NO | | ovl_workdir_cleanup_recurse() | ✗ No | ✗ NO | | ovl_indexdir_cleanup() | ✗ No | ✗ NO | VFS layer (.iterate_shared file operation) → ovl_iterate() [CRED OVERRIDE] → ovl_cache_get() → ovl_dir_read_merged() → ovl_dir_read() → ovl_check_whiteouts() [CRED REVERT] ovl_unlink() → ovl_do_remove() → ovl_check_empty_dir() [CRED OVERRIDE] → ovl_dir_read_merged() → ovl_dir_read() → ovl_check_whiteouts() [CRED REVERT] ovl_rename() → ovl_check_empty_dir() [CRED OVERRIDE] → ovl_dir_read_merged() → ovl_dir_read() → ovl_check_whiteouts() [CRED REVERT] All valid callchains already override credentials so drop the override. Signed-off-by: Christian Brauner --- fs/overlayfs/readdir.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 1e9792cc557b..12f0bb1480d7 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -348,11 +348,7 @@ static bool ovl_fill_merge(struct dir_context *ctx, const char *name, static int ovl_check_whiteouts(const struct path *path, struct ovl_readdir_data *rdd) { - int err = 0; struct dentry *dentry, *dir = path->dentry; - const struct cred *old_cred; - - old_cred = ovl_override_creds(rdd->dentry->d_sb); while (rdd->first_maybe_whiteout) { struct ovl_cache_entry *p = @@ -365,13 +361,11 @@ static int ovl_check_whiteouts(const struct path *path, struct ovl_readdir_data p->is_whiteout = ovl_is_whiteout(dentry); dput(dentry); } else if (PTR_ERR(dentry) == -EINTR) { - err = -EINTR; - break; + return -EINTR; } } - ovl_revert_creds(old_cred); - return err; + return 0; } static inline int ovl_dir_read(const struct path *realpath, -- 2.47.3