From: Alistair Popple <alistair@popple•id.au>
To: Neelesh Gupta <neelegup@linux•vnet.ibm.com>
Cc: jk@ozlabs•org, linuxppc-dev@lists•ozlabs.org, minyard@acm•org
Subject: Re: [PATCH] ipmi/powernv: Fix potential invalid pointer dereference
Date: Wed, 29 Jul 2015 03:51:03 +1000 [thread overview]
Message-ID: <2100038.nvIKqFquOH@mexican> (raw)
In-Reply-To: <55B7342F.8080703@linux.vnet.ibm.com>
Hi Neelesh,
This fix looks reasonable to me, although Jeremy would be the best person to
comment if he has time. I wonder why we bother polling at all given that our
event interface should call opal_ipmi_recv() whenever a message is ready?
Also the firmware fix you refer to and this fix are independent of each other
so there's no ordering issues there.
Reviewed-By: Alistair Popple <alistair@popple•id.au>
On Tue, 28 Jul 2015 13:20:07 Neelesh Gupta wrote:
>
> On 07/17/2015 02:12 PM, Neelesh Gupta wrote:
> > Hi Corey,
> >
> > On 07/16/2015 08:31 PM, Corey Minyard wrote:
> >> Ok, this looks fine. A couple of question...
> >>
> >> Do I need to send this upstream right now? How well has this been
tested?
> >
> > I would want either Jeremy or Alistair to review this patch before you
> > send this
> > upstream. There is also firmware piece
> > http://patchwork.ozlabs.org/patch/496645/
> > awaiting review.
> >
> > In the testing front, I manually made the opal_ipmi_recv() function to
> > fail for testing
> > the error path and see if the driver recovers from it and subsequent
> > ipmi commands
> > work all good.
>
> Hi Jeremy/Alistair,
>
> Could you please review it and the corresponding skiboot patch...
>
> Thanks,
> Neelesh.
>
> >
> >> Do you want this backported to 4.0 stable?
> >
> > Yes, I want this to be be backported to 4.0 stable.
> >
> > Thanks,
> > Neelesh.
> >
> >> -corey
> >>
> >> On 07/16/2015 06:16 AM, Neelesh Gupta wrote:
> >>> If the OPAL call to receive the ipmi message fails, then we free up the
> >>> smi message and return. But, the driver still holds the reference to
> >>> old smi message in the 'cur_msg' which can potentially be accessed later
> >>> and freed again leading to kernel oops. To fix it up,
> >>>
> >>> The kernel driver should reset the 'cur_msg' and send reply to the user
> >>> in addition to freeing the message.
> >>>
> >>> Signed-off-by: Neelesh Gupta<neelegup@linux•vnet.ibm.com>
> >>> ---
> >>> drivers/char/ipmi/ipmi_powernv.c | 13 ++++++++++---
> >>> 1 file changed, 10 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/drivers/char/ipmi/ipmi_powernv.c
b/drivers/char/ipmi/ipmi_powernv.c
> >>> index 9b409c0..637486d 100644
> >>> --- a/drivers/char/ipmi/ipmi_powernv.c
> >>> +++ b/drivers/char/ipmi/ipmi_powernv.c
> >>> @@ -143,9 +143,16 @@ static int ipmi_powernv_recv(struct
ipmi_smi_powernv *smi)
> >>> pr_devel("%s: -> %d (size %lld)\n", __func__,
> >>> rc, rc == 0 ? size : 0);
> >>> if (rc) {
> >>> - spin_unlock_irqrestore(&smi->msg_lock, flags);
> >>> - ipmi_free_smi_msg(msg);
> >>> - return 0;
> >>> + /* If came via the poll, and response was not yet ready */
> >>> + if (rc == OPAL_EMPTY) {
> >>> + spin_unlock_irqrestore(&smi->msg_lock, flags);
> >>> + return 0;
> >>> + } else {
> >>> + smi->cur_msg = NULL;
> >>> + spin_unlock_irqrestore(&smi->msg_lock, flags);
> >>> + send_error_reply(smi, msg, IPMI_ERR_UNSPECIFIED);
> >>> + return 0;
> >>> + }
> >>> }
> >>>
> >>> if (size < sizeof(*opal_msg)) {
> >>>
> >
> >
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > Linuxppc-dev@lists•ozlabs.org
> > https://lists.ozlabs.org/listinfo/linuxppc-dev
>
next prev parent reply other threads:[~2015-07-28 17:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 11:16 [PATCH] ipmi/powernv: Fix potential invalid pointer dereference Neelesh Gupta
2015-07-16 15:01 ` Corey Minyard
2015-07-17 8:42 ` Neelesh Gupta
[not found] ` <55B7342F.8080703@linux.vnet.ibm.com>
2015-07-28 17:51 ` Alistair Popple [this message]
2015-07-29 6:05 ` Neelesh Gupta
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2100038.nvIKqFquOH@mexican \
--to=alistair@popple$(echo .)id.au \
--cc=jk@ozlabs$(echo .)org \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=minyard@acm$(echo .)org \
--cc=neelegup@linux$(echo .)vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox