2003-03-09 20:21:02

by Oleg Drokin

Subject: NCPFS memleak/crazyness?

Hello!

Looking at fs/ncpfs/ioctl.c (latest 2.4 bk tree), I seem to see a place
where we use userspace-pointers directly (And eventually doing kfree on
these). In NCP_IOC_SETOBJECTNAME handler, we allocated space (newname
pointer), copy stuff from userspace to there and then assign userspace
pointer to our internal structure, whoops! Or am I missing something?

Seems that following patch is needed. (Same problem is present in 2.5
and same patch should apply)

Found with help of smatch + enhanced unfree script.

Bye,
Oleg

===== fs/ncpfs/ioctl.c 1.3 vs edited =====
--- 1.3/fs/ncpfs/ioctl.c Mon Sep 9 22:36:07 2002
+++ edited/fs/ncpfs/ioctl.c Sun Mar 9 23:23:12 2003
@@ -434,7 +434,7 @@
oldprivatelen = server->priv.len;
server->auth.auth_type = user.auth_type;
server->auth.object_name_len = user.object_name_len;
- server->auth.object_name = user.object_name;
+ server->auth.object_name = newname;
server->priv.len = 0;
server->priv.data = NULL;
/* leave critical section */

2003-03-09 20:33:19

by Petr Vandrovec

Subject: [PATCH] Re: NCPFS memleak/crazyness?

On Sun, Mar 09, 2003 at 11:30:48PM +0300, Oleg Drokin wrote:
> Hello!
>
> Looking at fs/ncpfs/ioctl.c (latest 2.4 bk tree), I seem to see a place
> where we use userspace-pointers directly (And eventually doing kfree on
> these). In NCP_IOC_SETOBJECTNAME handler, we allocated space (newname
> pointer), copy stuff from userspace to there and then assign userspace
> pointer to our internal structure, whoops! Or am I missing something?
>
> Seems that following patch is needed. (Same problem is present in 2.5
> and same patch should apply)

Definitely. Alan, Linus, Marcelo (alphabetically) please apply...
2.2.x should not be affected as it does not support this ioctl.
Petr Vandrovec

From Oleg Drokin:

In NCP_IOC_SETOBJECTNAME handler, we allocated space (newname pointer),
copy stuff from userspace to there and then assign userspace
pointer to our internal structure, whoops!

===== fs/ncpfs/ioctl.c 1.3 vs edited =====
--- 1.3/fs/ncpfs/ioctl.c Mon Sep 9 22:36:07 2002
+++ edited/fs/ncpfs/ioctl.c Sun Mar 9 23:23:12 2003
@@ -434,7 +434,7 @@
oldprivatelen = server->priv.len;
server->auth.auth_type = user.auth_type;
server->auth.object_name_len = user.object_name_len;
- server->auth.object_name = user.object_name;
+ server->auth.object_name = newname;
server->priv.len = 0;
server->priv.data = NULL;
/* leave critical section */