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umh: creds: kill subprocess_info->cred logic 

Now that nobody ever changes subprocess_info->cred we can kill this member
and related code.  ____call_usermodehelper() always runs in the context of
freshly forked kernel thread, it has the proper ->cred copied from its
parent kthread, keventd.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
wifi-calibration
Oleg Nesterov 2010-05-26 14:43:01 -07:00 committed by Linus Torvalds
parent 685bfd2c48
commit c70a626d3e
4 changed files with 0 additions and 81 deletions
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1
include/linux/cred.h
View File

@ -156,7 +156,6 @@ extern int copy_creds(struct task_struct *, unsigned long);
extern struct cred *cred_alloc_blank(void);
extern struct cred *prepare_creds(void);
extern struct cred *prepare_exec_creds(void);
extern struct cred *prepare_usermodehelper_creds(void);
extern int commit_creds(struct cred *);
extern void abort_creds(struct cred *);
extern const struct cred *override_creds(const struct cred *);

1
include/linux/kmod.h
View File

@ -56,7 +56,6 @@ enum umh_wait {
struct subprocess_info {
struct work_struct work;
struct completion *complete;
struct cred *cred;
char *path;
char **argv;
char **envp;

60
kernel/cred.c
View File

@ -346,66 +346,6 @@ struct cred *prepare_exec_creds(void)
return new;
}
/*
* prepare new credentials for the usermode helper dispatcher
*/
struct cred *prepare_usermodehelper_creds(void)
{
#ifdef CONFIG_KEYS
struct thread_group_cred *tgcred = NULL;
#endif
struct cred *new;
#ifdef CONFIG_KEYS
tgcred = kzalloc(sizeof(*new->tgcred), GFP_ATOMIC);
if (!tgcred)
return NULL;
#endif
new = kmem_cache_alloc(cred_jar, GFP_ATOMIC);
if (!new)
goto free_tgcred;
kdebug("prepare_usermodehelper_creds() alloc %p", new);
memcpy(new, &init_cred, sizeof(struct cred));
atomic_set(&new->usage, 1);
set_cred_subscribers(new, 0);
get_group_info(new->group_info);
get_uid(new->user);
#ifdef CONFIG_KEYS
new->thread_keyring = NULL;
new->request_key_auth = NULL;
new->jit_keyring = KEY_REQKEY_DEFL_DEFAULT;
atomic_set(&tgcred->usage, 1);
spin_lock_init(&tgcred->lock);
new->tgcred = tgcred;
#endif
#ifdef CONFIG_SECURITY
new->security = NULL;
#endif
if (security_prepare_creds(new, &init_cred, GFP_ATOMIC) < 0)
goto error;
validate_creds(new);
BUG_ON(atomic_read(&new->usage) != 1);
return new;
error:
put_cred(new);
return NULL;
free_tgcred:
#ifdef CONFIG_KEYS
kfree(tgcred);
#endif
return NULL;
}
/*
* Copy credentials for the new process created by fork()
*

19
kernel/kmod.c
View File

@ -134,8 +134,6 @@ static int ____call_usermodehelper(void *data)
struct subprocess_info *sub_info = data;
int retval;
BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
/* Unblock all signals */
spin_lock_irq(&current->sighand->siglock);
flush_signal_handlers(current, 1);
@ -143,10 +141,6 @@ static int ____call_usermodehelper(void *data)
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
/* Install the credentials */
commit_creds(sub_info->cred);
sub_info->cred = NULL;
/* We can run anywhere, unlike our parent keventd(). */
set_cpus_allowed_ptr(current, cpu_all_mask);
@ -174,8 +168,6 @@ void call_usermodehelper_freeinfo(struct subprocess_info *info)
{
if (info->cleanup)
(*info->cleanup)(info);
if (info->cred)
put_cred(info->cred);
kfree(info);
}
EXPORT_SYMBOL(call_usermodehelper_freeinfo);
@ -231,8 +223,6 @@ static void __call_usermodehelper(struct work_struct *work)
pid_t pid;
enum umh_wait wait = sub_info->wait;
BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
/* CLONE_VFORK: wait until the usermode helper has execve'd
* successfully We need the data structures to stay around
* until that is done. */
@ -355,12 +345,6 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
sub_info->path = path;
sub_info->argv = argv;
sub_info->envp = envp;
sub_info->cred = prepare_usermodehelper_creds();
if (!sub_info->cred) {
kfree(sub_info);
return NULL;
}
out:
return sub_info;
}
@ -411,9 +395,6 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
validate_creds(sub_info->cred);
helper_lock();
if (sub_info->path[0] == '\0')
goto out;