From b66c7af4d86de00db3c28294467bf986083dc963 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Mon, 3 Nov 2025 12:27:03 +0100 Subject: [PATCH] cgroup: use credential guards in cgroup_attach_permissions() Use credential guards for scoped credential override with automatic restoration on scope exit. Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-15-a3e156839e7f@kernel.org Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner --- kernel/cgroup/cgroup.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index fdee387f0d6b..9f61f7cfc8d1 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5363,7 +5363,6 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, struct cgroup_file_ctx *ctx = of->priv; struct cgroup *src_cgrp, *dst_cgrp; struct task_struct *task; - const struct cred *saved_cred; ssize_t ret; enum cgroup_attach_lock_mode lock_mode; @@ -5386,11 +5385,10 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, * permissions using the credentials from file open to protect against * inherited fd attacks. */ - saved_cred = override_creds(of->file->f_cred); - ret = cgroup_attach_permissions(src_cgrp, dst_cgrp, - of->file->f_path.dentry->d_sb, - threadgroup, ctx->ns); - revert_creds(saved_cred); + scoped_with_creds(of->file->f_cred) + ret = cgroup_attach_permissions(src_cgrp, dst_cgrp, + of->file->f_path.dentry->d_sb, + threadgroup, ctx->ns); if (ret) goto out_finish; -- 2.47.3