linux-kernel - [PATCH 04/12] sev-dev: use override credential guards

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Message-Id: <20251103-work-creds-guards-prepare_creds-v1-4-b447b82f2c9b@kernel.org>
Date: Mon, 03 Nov 2025 15:57:30 +0100
From: Christian Brauner <brauner@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-aio@...ck.org, linux-unionfs@...r.kernel.org, 
 linux-erofs@...ts.ozlabs.org, linux-nfs@...r.kernel.org, 
 linux-cifs@...r.kernel.org, samba-technical@...ts.samba.org, 
 cgroups@...r.kernel.org, netdev@...r.kernel.org, 
 linux-crypto@...r.kernel.org, linux-trace-kernel@...r.kernel.org, 
 Christian Brauner <brauner@...nel.org>
Subject: [PATCH 04/12] sev-dev: use override credential guards

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

Signed-off-by: Christian Brauner <brauner@...nel.org>
---
 drivers/crypto/ccp/sev-dev.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 09e4c9490d58..19422f422a59 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -260,7 +260,6 @@ static int sev_cmd_buffer_len(int cmd)
 static struct file *open_file_as_root(const char *filename, int flags, umode_t mode)
 {
 	struct path root __free(path_put) = {};
-	struct file *fp;
 	struct cred *cred;
 	const struct cred *old_cred;
 
@@ -273,13 +272,9 @@ static struct file *open_file_as_root(const char *filename, int flags, umode_t m
 		return ERR_PTR(-ENOMEM);
 
 	cred->fsuid = GLOBAL_ROOT_UID;
-	old_cred = override_creds(cred);
-
-	fp = file_open_root(&root, filename, flags, mode);
-
-	revert_creds(old_cred);
 
-	return fp;
+	with_creds(cred);
+	return file_open_root(&root, filename, flags, mode);
 }
 
 static int sev_read_init_ex_file(void)

-- 
2.47.3