* [PATCH] powerpc/83xx: fix use-after-free on mpc831x_usb_cfg()
@ 2019-07-05 8:58 Wen Yang
2019-07-08 15:21 ` Markus Elfring
0 siblings, 1 reply; 3+ messages in thread
From: Wen Yang @ 2019-07-05 8:58 UTC (permalink / raw)
To: linux-kernel
Cc: wang.yi59, Scott Wood, Paul Mackerras, xue.zhihong, cheng.shengyu,
linuxppc-dev, Wen Yang
The np variable is still being used after the of_node_put() call,
which may result in use-after-free.
We fix this issue by calling of_node_put() after the last usage.
This patatch also do some cleanup.
Fixes: fd066e850351 ("powerpc/mpc8308: fix USB DR controller initialization")
Signed-off-by: Wen Yang <wen.yang99@zte•com.cn>
Cc: Scott Wood <oss@buserror•net>
Cc: Kumar Gala <galak@kernel•crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: Paul Mackerras <paulus@samba•org>
Cc: Michael Ellerman <mpe@ellerman•id.au>
Cc: linuxppc-dev@lists•ozlabs.org
Cc: linux-kernel@vger•kernel.org
---
arch/powerpc/platforms/83xx/usb.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/platforms/83xx/usb.c b/arch/powerpc/platforms/83xx/usb.c
index 3d247d7..56b36fa 100644
--- a/arch/powerpc/platforms/83xx/usb.c
+++ b/arch/powerpc/platforms/83xx/usb.c
@@ -158,14 +158,11 @@ int mpc831x_usb_cfg(void)
iounmap(immap);
- of_node_put(immr_node);
-
/* Map USB SOC space */
ret = of_address_to_resource(np, 0, &res);
- if (ret) {
- of_node_put(np);
- return ret;
- }
+ if (ret)
+ goto out_put_node;
+
usb_regs = ioremap(res.start, resource_size(&res));
/* Using on-chip PHY */
@@ -174,7 +171,7 @@ int mpc831x_usb_cfg(void)
u32 refsel;
if (of_device_is_compatible(immr_node, "fsl,mpc8308-immr"))
- goto out;
+ goto out_unmap;
if (of_device_is_compatible(immr_node, "fsl,mpc8315-immr"))
refsel = CONTROL_REFSEL_24MHZ;
@@ -201,8 +198,10 @@ int mpc831x_usb_cfg(void)
ret = -EINVAL;
}
-out:
+out_unmap:
iounmap(usb_regs);
+out_put_node:
+ of_node_put(immr_node);
of_node_put(np);
return ret;
}
--
2.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: powerpc/83xx: fix use-after-free on mpc831x_usb_cfg()
2019-07-05 8:58 [PATCH] powerpc/83xx: fix use-after-free on mpc831x_usb_cfg() Wen Yang
@ 2019-07-08 15:21 ` Markus Elfring
2019-07-09 2:19 ` wen.yang99
0 siblings, 1 reply; 3+ messages in thread
From: Markus Elfring @ 2019-07-08 15:21 UTC (permalink / raw)
To: Wen Yang, linuxppc-dev
Cc: Yi Wang, Cheng Shengyu, kernel-janitors, linux-kernel, Scott Wood,
Paul Mackerras, Xue Zhihong
> The np variable is still being used after the of_node_put() call,
> which may result in use-after-free.
> We fix this issue by calling of_node_put() after the last usage.
I imagine that this commit description can be improved a bit more
(by mentioning the influence of “immr_node”?).
How do you think about to omit the word “We” here?
> This patatch also do some cleanup.
Should the renaming of a jump label be contributed in a separate update
step of a small patch series besides a wording without a typo?
Regards,
Markus
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: powerpc/83xx: fix use-after-free on mpc831x_usb_cfg()
2019-07-08 15:21 ` Markus Elfring
@ 2019-07-09 2:19 ` wen.yang99
0 siblings, 0 replies; 3+ messages in thread
From: wen.yang99 @ 2019-07-09 2:19 UTC (permalink / raw)
To: Markus.Elfring
Cc: wang.yi59, cheng.shengyu, kernel-janitors, linux-kernel, oss,
paulus, linuxppc-dev
[-- Attachment #1.1: Type: text/plain, Size: 677 bytes --]
> > The np variable is still being used after the of_node_put() call,
>
> > which may result in use-after-free.
>
> > We fix this issue by calling of_node_put() after the last usage.
>
>
> I imagine that this commit description can be improved a bit more
> (by mentioning the influence of “immr_node”?).
> How do you think about to omit the word “We” here?
>
>
> > This patatch also do some cleanup.
>
>
> Should the renaming of a jump label be contributed in a separate update
> step of a small patch series besides a wording without a typo?
Thank you for your comments.
We will improve the commit description and send v2 as soon as possible.
--
Regards,
Wen
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-07-05 8:58 [PATCH] powerpc/83xx: fix use-after-free on mpc831x_usb_cfg() Wen Yang
2019-07-08 15:21 ` Markus Elfring
2019-07-09 2:19 ` wen.yang99
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