linux-kernel - [PATCH RFC 4/6] fhandle: pull CAP_DAC_READ_SEARCH check into may_decode

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Message-ID: <20241129-work-pidfs-file_handle-v1-4-87d803a42495@kernel.org>
Date: Fri, 29 Nov 2024 14:38:03 +0100
From: Christian Brauner <brauner@...nel.org>
To: Erin Shepherd <erin.shepherd@....eu>,
	Amir Goldstein <amir73il@...il.com>,
	Jeff Layton <jlayton@...nel.org>
Cc: Christian Brauner <brauner@...nel.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Jan Kara <jack@...e.cz>,
	Chuck Lever <chuck.lever@...cle.com>,
	linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-nfs@...r.kernel.org
Subject: [PATCH RFC 4/6] fhandle: pull CAP_DAC_READ_SEARCH check into may_decode_fh()

There's no point in keeping it outside of that helper. This way we have
all the permission pieces in one place.

Signed-off-by: Christian Brauner <brauner@...nel.org>
---
 fs/fhandle.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/fhandle.c b/fs/fhandle.c
index c00d88fb14e16654b5cbbb71760c0478eac20384..031ad5592a0beabcc299436f037ad5fe626332e6 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -298,6 +298,9 @@ static inline bool may_decode_fh(struct handle_to_path_ctx *ctx,
 {
 	struct path *root = &ctx->root;
 
+	if (capable(CAP_DAC_READ_SEARCH))
+		return true;
+
 	/*
 	 * Restrict to O_DIRECTORY to provide a deterministic API that avoids a
 	 * confusing api in the face of disconnected non-dir dentries.
@@ -337,7 +340,7 @@ static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
 	if (retval)
 		goto out_err;
 
-	if (!capable(CAP_DAC_READ_SEARCH) && !may_decode_fh(&ctx, o_flags)) {
+	if (!may_decode_fh(&ctx, o_flags)) {
 		retval = -EPERM;
 		goto out_path;
 	}

-- 
2.45.2