[PATCH] sanitize unshare_files/reset_files_struct
* let unshare_files() give caller the displaced files_struct
* don't bother with grabbing reference only to drop it in the
caller if it hadn't been shared in the first place
* in that form unshare_files() is trivially implemented via
unshare_fd(), so we eliminate the duplicate logics in fork.c
* reset_files_struct() is not just only called for current;
it will break the system if somebody ever calls it for anything
else (we can't modify ->files of somebody else). Lose the
task_struct * argument.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/exec.c b/fs/exec.c
index 4755430..b152029 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1269,19 +1269,13 @@
struct linux_binprm *bprm;
struct file *file;
unsigned long env_p;
- struct files_struct *files;
+ struct files_struct *displaced;
int retval;
- files = current->files;
- retval = unshare_files();
+ retval = unshare_files(&displaced);
if (retval)
goto out_ret;
- if (files == current->files) {
- put_files_struct(files);
- files = NULL;
- }
-
retval = -ENOMEM;
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
if (!bprm)
@@ -1340,8 +1334,8 @@
security_bprm_free(bprm);
acct_update_integrals(current);
kfree(bprm);
- if (files)
- put_files_struct(files);
+ if (displaced)
+ put_files_struct(displaced);
return retval;
}
@@ -1363,8 +1357,8 @@
kfree(bprm);
out_files:
- if (files)
- reset_files_struct(current, files);
+ if (displaced)
+ reset_files_struct(displaced);
out_ret:
return retval;
}