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authorLinus Torvalds <torvalds@linux-foundation.org>2008-04-25 19:05:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-25 19:05:55 -0700
commitbc84e0a160e383deb56568f4e03bc51b1ce16775 (patch)
tree3c8cf1ae23c2f9c165bd7ce63a40b1d5c3aee275 /kernel
parenta92910723a5af54f81373875fd95133c88df94bd (diff)
parentf8f95702f0c4529b0f59488f4509608f0c160e77 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* '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.
Diffstat (limited to 'kernel')
-rw-r--r--kernel/exit.c6
-rw-r--r--kernel/fork.c58
2 files changed, 26 insertions, 38 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index cece89f80ab..97f609f574b 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -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)
{
diff --git a/kernel/fork.c b/kernel/fork.c
index 89fe414645e..efb618fc8ff 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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;
+}