Re: [PATCH 1/1 linux-next] ipc/msg.c: fix memory leak in do_msgsnd()

From: Fabian Frederick
Date: Mon Aug 01 2016 - 07:45:55 EST




> On 31 July 2016 at 16:36 Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> wrote:
>
>
> Hi Fabian,
>
> On 07/29/2016 10:15 AM, Fabian Frederick wrote:
> > Running LTP msgsnd06 with kmemleak gives the following:
> >
> > cat /sys/kernel/debug/kmemleak
> >
> > unreferenced object 0xffff88003c0a11f8 (size 8):
> >Â Â comm "msgsnd06", pid 1645, jiffies 4294672526 (age 6.549s)
> >Â Â hex dump (first 8 bytes):
> >Â Â Â 1b 00 00 00 01 00 00 00Â Â Â Â Â Â Â Â Â Â Â Â Â ........
> >Â Â backtrace:
> >Â Â Â [] kmemleak_alloc+0x23/0x40
> >Â Â Â [] kmem_cache_alloc_trace+0xe1/0x180
> >Â Â Â [] selinux_msg_queue_alloc_security+0x3f/0xd0
> >Â Â Â [] security_msg_queue_alloc+0x2e/0x40
> >Â Â Â [] newque+0x4e/0x150
> >Â Â Â [] ipcget+0x159/0x1b0
> >Â Â Â [] SyS_msgget+0x39/0x40
> >Â Â Â [] entry_SYSCALL_64_fastpath+0x13/0x8f
> >Â Â Â [] 0xffffffffffffffff
> >
> > ipc_rcu_free() was given to ipc_rcu_putref() instead of msg_rcu_free()
> > which does security cleaning.
> Good catch!
>
>Â From a quick look:
> - The same bug appears to exist in sem.c. Do you want to fix it as well?
> - Did you check when it was introduced? I would add cc stable.

Hi Manfred,

Thanks for your advices. I hope the second version is ok. I'll have a look at
sem.c to do the same.

Regards,
Fabian

>
> --
>Â Â Â Manfred
>