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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  [PATCH] sanitize locate_fd()
  [PATCH] sanitize unshare_files/reset_files_struct
  [PATCH] sanitize handling of shared descriptor tables in failing execve()
  [PATCH] close race in unshare_files()
  [PATCH] restore sane ->umount_begin() API
  cifs: timeout dfs automounts +little fix.
This commit is contained in:
Linus Torvalds
2008-04-25 19:05:55 -07:00
parent a92910723a f8f95702f0
commit bc84e0a160
16 changed files with 95 additions and 172 deletions
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6
kernel/exit.c
View File

@@ -507,10 +507,9 @@ void put_files_struct(struct files_struct *files)
}
}
EXPORT_SYMBOL(put_files_struct);
void reset_files_struct(struct task_struct *tsk, struct files_struct *files)
void reset_files_struct(struct files_struct *files)
{
struct task_struct *tsk = current;
struct files_struct *old;
old = tsk->files;
@@ -519,7 +518,6 @@ void reset_files_struct(struct task_struct *tsk, struct files_struct *files)
task_unlock(tsk);
put_files_struct(old);
}
EXPORT_SYMBOL(reset_files_struct);
void exit_files(struct task_struct *tsk)
{

58
kernel/fork.c
View File

@@ -805,12 +805,6 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
goto out;
}
/*
* Note: we may be using current for both targets (See exec.c)
* This works because we cache current->files (old) as oldf. Don't
* break this.
*/
tsk->files = NULL;
newf = dup_fd(oldf, &error);
if (!newf)
goto out;
@@ -846,34 +840,6 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
return 0;
}
/*
* Helper to unshare the files of the current task.
* We don't want to expose copy_files internals to
* the exec layer of the kernel.
*/
int unshare_files(void)
{
struct files_struct *files = current->files;
int rc;
BUG_ON(!files);
/* This can race but the race causes us to copy when we don't
need to and drop the copy */
if(atomic_read(&files->count) == 1)
{
atomic_inc(&files->count);
return 0;
}
rc = copy_files(0, current);
if(rc)
current->files = files;
return rc;
}
EXPORT_SYMBOL(unshare_files);
static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
{
struct sighand_struct *sig;
@@ -1811,3 +1777,27 @@ bad_unshare_cleanup_thread:
bad_unshare_out:
return err;
}
/*
* Helper to unshare the files of the current task.
* We don't want to expose copy_files internals to
* the exec layer of the kernel.
*/
int unshare_files(struct files_struct **displaced)
{
struct task_struct *task = current;
struct files_struct *copy;
int error;
error = unshare_fd(CLONE_FILES, &copy);
if (error || !copy) {
*displaced = NULL;
return error;
}
*displaced = task->files;
task_lock(task);
task->files = copy;
task_unlock(task);
return 0;
}