binfmt_misc: use credential guards

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

Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-8-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2025-11-03 12:26:56 +01:00
parent 6e1d1c1fa7
commit ff2044cd27
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 2 additions and 5 deletions

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@ -782,8 +782,6 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
return PTR_ERR(e);
if (e->flags & MISC_FMT_OPEN_FILE) {
const struct cred *old_cred;
/*
* Now that we support unprivileged binfmt_misc mounts make
* sure we use the credentials that the register @file was
@ -791,9 +789,8 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
* didn't matter much as only a privileged process could open
* the register file.
*/
old_cred = override_creds(file->f_cred);
scoped_with_creds(file->f_cred)
f = open_exec(e->interpreter);
revert_creds(old_cred);
if (IS_ERR(f)) {
pr_notice("register: failed to install interpreter file %s\n",
e->interpreter);