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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2010-10-27 15:34:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-27 18:03:12 -0700
commit9b1bf12d5d51bca178dea21b04a0805e29d60cf1 (patch)
tree902a2c0e5882a2152da59a589958d6426dc84643 /fs
parentb84011508360d6885a9d95a235ec77d56f133377 (diff)
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signals: move cred_guard_mutex from task_struct to signal_struct
Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec itself and we can reuse ->cred_guard_mutex for it. Yes, concurrent execve() has no worth. Let's move ->cred_guard_mutex from task_struct to signal_struct. It naturally prevent multiple-threads-inside-exec. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.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>
Diffstat (limited to 'fs')
-rw-r--r--fs/exec.c10
-rw-r--r--fs/proc/base.c8
2 files changed, 9 insertions, 9 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 3aa75b8888a1..9722909c4d88 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1083,14 +1083,14 @@ EXPORT_SYMBOL(setup_new_exec);
*/
int prepare_bprm_creds(struct linux_binprm *bprm)
{
- if (mutex_lock_interruptible(&current->cred_guard_mutex))
+ if (mutex_lock_interruptible(&current->signal->cred_guard_mutex))
return -ERESTARTNOINTR;
bprm->cred = prepare_exec_creds();
if (likely(bprm->cred))
return 0;
- mutex_unlock(&current->cred_guard_mutex);
+ mutex_unlock(&current->signal->cred_guard_mutex);
return -ENOMEM;
}
@@ -1098,7 +1098,7 @@ void free_bprm(struct linux_binprm *bprm)
{
free_arg_pages(bprm);
if (bprm->cred) {
- mutex_unlock(&current->cred_guard_mutex);
+ mutex_unlock(&current->signal->cred_guard_mutex);
abort_creds(bprm->cred);
}
kfree(bprm);
@@ -1119,13 +1119,13 @@ void install_exec_creds(struct linux_binprm *bprm)
* credentials; any time after this it may be unlocked.
*/
security_bprm_committed_creds(bprm);
- mutex_unlock(&current->cred_guard_mutex);
+ mutex_unlock(&current->signal->cred_guard_mutex);
}
EXPORT_SYMBOL(install_exec_creds);
/*
* determine how safe it is to execute the proposed program
- * - the caller must hold current->cred_guard_mutex to protect against
+ * - the caller must hold ->cred_guard_mutex to protect against
* PTRACE_ATTACH
*/
int check_unsafe_exec(struct linux_binprm *bprm)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9b094c1c8465..f3d02ca461ec 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -226,7 +226,7 @@ struct mm_struct *mm_for_maps(struct task_struct *task)
{
struct mm_struct *mm;
- if (mutex_lock_killable(&task->cred_guard_mutex))
+ if (mutex_lock_killable(&task->signal->cred_guard_mutex))
return NULL;
mm = get_task_mm(task);
@@ -235,7 +235,7 @@ struct mm_struct *mm_for_maps(struct task_struct *task)
mmput(mm);
mm = NULL;
}
- mutex_unlock(&task->cred_guard_mutex);
+ mutex_unlock(&task->signal->cred_guard_mutex);
return mm;
}
@@ -2354,14 +2354,14 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
goto out_free;
/* Guard against adverse ptrace interaction */
- length = mutex_lock_interruptible(&task->cred_guard_mutex);
+ length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
if (length < 0)
goto out_free;
length = security_setprocattr(task,
(char*)file->f_path.dentry->d_name.name,
(void*)page, count);
- mutex_unlock(&task->cred_guard_mutex);
+ mutex_unlock(&task->signal->cred_guard_mutex);
out_free:
free_page((unsigned long) page);
out: