diff options
Diffstat (limited to 'kernel/cred.c')
| -rw-r--r-- | kernel/cred.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index 45d77284aed0..f9a0ce66c9c3 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -1,12 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* Task credentials management - see Documentation/security/credentials.rst * * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public Licence - * as published by the Free Software Foundation; either version - * 2 of the Licence, or (at your option) any later version. */ #include <linux/export.h> #include <linux/cred.h> @@ -174,6 +170,11 @@ void exit_creds(struct task_struct *tsk) validate_creds(cred); alter_cred_subscribers(cred, -1); put_cred(cred); + +#ifdef CONFIG_KEYS_REQUEST_CACHE + key_put(current->cached_requested_key); + current->cached_requested_key = NULL; +#endif } /** @@ -327,6 +328,10 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) struct cred *new; int ret; +#ifdef CONFIG_KEYS_REQUEST_CACHE + p->cached_requested_key = NULL; +#endif + if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && @@ -450,14 +455,23 @@ int commit_creds(struct cred *new) if (task->mm) set_dumpable(task->mm, suid_dumpable); task->pdeath_signal = 0; + /* + * If a task drops privileges and becomes nondumpable, + * the dumpability change must become visible before + * the credential change; otherwise, a __ptrace_may_access() + * racing with this change may be able to attach to a task it + * shouldn't be able to attach to (as if the task had dropped + * privileges without becoming nondumpable). + * Pairs with a read barrier in __ptrace_may_access(). + */ smp_wmb(); } /* alter the thread keyring */ if (!uid_eq(new->fsuid, old->fsuid)) - key_fsuid_changed(task); + key_fsuid_changed(new); if (!gid_eq(new->fsgid, old->fsgid)) - key_fsgid_changed(task); + key_fsgid_changed(new); /* do it * RLIMIT_NPROC limits on user->processes have already been checked |