From: Christian Brauner <brauner@kernel.org>
Date: Mon, 3 Nov 2025 11:26:53 +0000 (+0100)
Subject: backing-file: use credential guards for splice read
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c3076d146e312af1ee2eff0287e298cf20774b39;p=thirdparty%2Flinux.git

backing-file: use credential guards for splice read

Use credential guards for scoped credential override with automatic
restoration on scope exit.

Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-5-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---

diff --git a/fs/backing-file.c b/fs/backing-file.c
index 2ba0f3c7f203..4d4edf906ef3 100644
--- a/fs/backing-file.c
+++ b/fs/backing-file.c
@@ -283,15 +283,13 @@ ssize_t backing_file_splice_read(struct file *in, struct kiocb *iocb,
 				 unsigned int flags,
 				 struct backing_file_ctx *ctx)
 {
-	const struct cred *old_cred;
 	ssize_t ret;
 
 	if (WARN_ON_ONCE(!(in->f_mode & FMODE_BACKING)))
 		return -EIO;
 
-	old_cred = override_creds(ctx->cred);
-	ret = vfs_splice_read(in, &iocb->ki_pos, pipe, len, flags);
-	revert_creds(old_cred);
+	scoped_with_creds(ctx->cred)
+		ret = vfs_splice_read(in, &iocb->ki_pos, pipe, len, flags);
 
 	if (ctx->accessed)
 		ctx->accessed(iocb->ki_filp);