[PATCH] sys_capget should use current if the pid argument is 0

Daniel Jacobowitz
2002-11-19T21:06:40Z

On Fri, Oct 11, 2002 at 07:58:46PM -0700, Linus Torvalds wrote:
>
> On Thu, 10 Oct 2002, Chris Wright wrote:
> >
> > The patch below fixes my oversight. The locking is left the way it was,
> > and just the pid 0 part is fixed as well as the duplicate code removed.
>
> All right, call me stupid, but twhere is the "duplication" in the code you
> removed?
>
> I see the "security/capability.c" thing, yes, but I also look at
> "security/dummy.c", and it appears that at least for that case nobody
> would ever initialize the capabilities that we return to user space at
> all.
>
> So there's a bug somewhere there, and removing the duplication makes
> things worse (admittedly for a case which isn't enabled in the regular
> kernel, but still..)
>
> So I'd ask you to have patience with me, and send a third patch that gets
> this thing right too..

Since this is still broken a month later... I don't know what to do
about the "duplication" question, but I'll leave that to Chris. This
is the uncontroversial portion of Chris's patch; its affect is to
change my zsh shell prompt back to a '%' as I'd expect.

Linus, please apply.

[PATCH] sys_capget should use current if the pid argument is 0

===== kernel/capability.c 1.6 vs edited =====
--- 1.6/kernel/capability.c Sat Sep 14 09:18:49 2002
+++ edited/kernel/capability.c Tue Nov 19 16:10:59 2002
@@ -33,7 +33,7 @@
int ret = 0;
pid_t pid;
__u32 version;
- task_t *target;
+ task_t *target = current;
struct __user_cap_data_struct data;

if (get_user(version, &header->version))
@@ -54,10 +54,12 @@
spin_lock(&task_capability_lock);
read_lock(&tasklist_lock);

- target = find_task_by_pid(pid);
- if (!target) {
- ret = -ESRCH;
- goto out;
+ if (pid && pid != current->pid) {
+ target = find_task_by_pid(pid);
+ if (!target) {
+ ret = -ESRCH;
+ goto out;
+ }
}

data.permitted = cap_t(target->cap_permitted);

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer