From: Dongliang Mu <hidden> Date: 2021-06-14 15:38:39
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
From: Pavel Skripkin <hidden> Date: 2021-06-14 16:02:11
On Mon, 14 Jun 2021 23:37:12 +0800
Dongliang Mu [off-list ref] wrote:
quoted hunk
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch
also removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
Hi, Dongliang!
Just my thougth about this patch:
INIT_WORK(&pdata->set_multicast, smsc75xx_deferred_multicast_write);
does not queue anything, it just initalizes list structure and assigns
callback function. The actual work sheduling happens in
smsc75xx_set_multicast() which is smsc75xx_netdev_ops member.
In case of any error in smsc75xx_bind() the device registration fails
and smsc75xx_netdev_ops won't be registered, so, i guess, there is no
chance of UAF.
Am I missing something? :)
With regards,
Pavel Skripkin
From: Dongliang Mu <hidden> Date: 2021-06-14 23:02:57
On Tue, Jun 15, 2021 at 12:00 AM Pavel Skripkin [off-list ref] wrote:
On Mon, 14 Jun 2021 23:37:12 +0800
Dongliang Mu [off-list ref] wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch
also removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
Hi, Dongliang!
Just my thougth about this patch:
INIT_WORK(&pdata->set_multicast, smsc75xx_deferred_multicast_write);
does not queue anything, it just initalizes list structure and assigns
callback function. The actual work sheduling happens in
smsc75xx_set_multicast() which is smsc75xx_netdev_ops member.
Yes, you are right. However, as written in the commit message,
smsc75xx_set_multicast will be called by smsc75xx_reset [1].
If smsc75xx_set_multicast is called before any check failure occurs,
this work(set_multicast) will be queued into the global list with
schedule_work(&pdata->set_multicast); [2]
At last, if the pdata or dev->data[0] is freed before the
set_multicast really executes, it may lead to a UAF. Is this correct?
BTW, even if the above is true, I don't know if I call the API
``cancel_work_sync(&pdata->set_multicast)'' properly if the
schedule_work is not called.
[1] https://elixir.bootlin.com/linux/latest/source/drivers/net/usb/smsc75xx.c#L1322
[2] https://elixir.bootlin.com/linux/latest/source/drivers/net/usb/smsc75xx.c#L583
In case of any error in smsc75xx_bind() the device registration fails
and smsc75xx_netdev_ops won't be registered, so, i guess, there is no
chance of UAF.
Am I missing something? :)
With regards,
Pavel Skripkin
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted hunk
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
From: Dongliang Mu <hidden> Date: 2021-06-15 07:57:07
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
On Tue, Jun 15, 2021 at 03:56:32PM +0800, Dongliang Mu wrote:
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
quoted
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
From: Dongliang Mu <hidden> Date: 2021-06-15 10:10:48
On Tue, Jun 15, 2021 at 5:44 PM Greg KH [off-list ref] wrote:
On Tue, Jun 15, 2021 at 03:56:32PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
quoted
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
From: Dongliang Mu <hidden> Date: 2021-06-15 10:24:49
On Tue, Jun 15, 2021 at 6:10 PM Dongliang Mu [off-list ref] wrote:
On Tue, Jun 15, 2021 at 5:44 PM Greg KH [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 03:56:32PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
quoted
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
It does not have to. pdata will be useless when the function exits. I
just referred to the implementation of smsc75xx_unbind.
It's wrong there too :)
/: I will fix such two sites in the v2 patch.
Hi gregkh,
If the schedule_work is not invoked, can I call
``cancel_work_sync(&pdata->set_multicast)''? If not, is there any
method to verify if the schedule_work is already called?
Best regards,
Dongliang Mu
On Tue, Jun 15, 2021 at 06:24:17PM +0800, Dongliang Mu wrote:
On Tue, Jun 15, 2021 at 6:10 PM Dongliang Mu [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 5:44 PM Greg KH [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 03:56:32PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
quoted
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
From: Dongliang Mu <hidden> Date: 2021-06-15 12:07:42
On Tue, Jun 15, 2021 at 7:12 PM Greg KH [off-list ref] wrote:
On Tue, Jun 15, 2021 at 06:24:17PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 6:10 PM Dongliang Mu [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 5:44 PM Greg KH [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 03:56:32PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
quoted
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
It does not have to. pdata will be useless when the function exits. I
just referred to the implementation of smsc75xx_unbind.
It's wrong there too :)
/: I will fix such two sites in the v2 patch.
Hi gregkh,
If the schedule_work is not invoked, can I call
``cancel_work_sync(&pdata->set_multicast)''?
Why can you not call this then?
I don't know the internal of schedule_work and cancel_work_sync, so I
ask this question to confirm my patch does not introduce any new
issues.
Did you try it and see?
Yes, I thought up a method and tested it in my local workspace.
First, I reproduced the memory leak in smsc75xx_bind [1] since the PoC
triggered an error before schedule_work.
Then, I merged two patches, and run the PoC. The result showed that my
patch does not trigger any new issues even the schedule_work is not
called.
[1] https://syzkaller.appspot.com/bug?id=c978ec308a1b89089a17ff48183d70b4c840dfb0
On Tue, Jun 15, 2021 at 08:07:10PM +0800, Dongliang Mu wrote:
On Tue, Jun 15, 2021 at 7:12 PM Greg KH [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 06:24:17PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 6:10 PM Dongliang Mu [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 5:44 PM Greg KH [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 03:56:32PM +0800, Dongliang Mu wrote:
quoted
On Tue, Jun 15, 2021 at 3:38 PM Greg KH [off-list ref] wrote:
quoted
On Mon, Jun 14, 2021 at 11:37:12PM +0800, Dongliang Mu wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
fails to clean up the work scheduled in smsc75xx_reset->
smsc75xx_set_multicast, which leads to use-after-free if the work is
scheduled to start after the deallocation. In addition, this patch also
removes one dangling pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and set
the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
From: Pavel Skripkin <hidden> Date: 2021-06-15 13:31:32
On Tue, 15 Jun 2021 07:01:13 +0800
Dongliang Mu [off-list ref] wrote:
On Tue, Jun 15, 2021 at 12:00 AM Pavel Skripkin
[off-list ref] wrote:
quoted
On Mon, 14 Jun 2021 23:37:12 +0800
Dongliang Mu [off-list ref] wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in
smsc75xx_bind") fails to clean up the work scheduled in
smsc75xx_reset-> smsc75xx_set_multicast, which leads to
use-after-free if the work is scheduled to start after the
deallocation. In addition, this patch also removes one dangling
pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and
set the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/usb/smsc75xx.c
b/drivers/net/usb/smsc75xx.c index b286993da67c..f81740fcc8d5
100644 --- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -1504,7 +1504,10 @@ static int smsc75xx_bind(struct usbnet
Hi, Dongliang!
Just my thougth about this patch:
INIT_WORK(&pdata->set_multicast, smsc75xx_deferred_multicast_write);
does not queue anything, it just initalizes list structure and
assigns callback function. The actual work sheduling happens in
smsc75xx_set_multicast() which is smsc75xx_netdev_ops member.
Yes, you are right. However, as written in the commit message,
smsc75xx_set_multicast will be called by smsc75xx_reset [1].
If smsc75xx_set_multicast is called before any check failure occurs,
this work(set_multicast) will be queued into the global list with
schedule_work(&pdata->set_multicast); [2]
Ah, I missed it, sorry :)
Maybe, small optimization for error handling path like:
cancel_work:
cancel_work_sync(&pdata->set_multicast);
dev->data[0] = 0;
free_pdata:
kfree(pdata);
return ret;
is suitbale here.
At last, if the pdata or dev->data[0] is freed before the
set_multicast really executes, it may lead to a UAF. Is this correct?
BTW, even if the above is true, I don't know if I call the API
``cancel_work_sync(&pdata->set_multicast)'' properly if the
schedule_work is not called.
In case of any error in smsc75xx_bind() the device registration
fails and smsc75xx_netdev_ops won't be registered, so, i guess,
there is no chance of UAF.
Am I missing something? :)
With regards,
Pavel Skripkin
From: Dongliang Mu <hidden> Date: 2021-06-16 02:17:14
On Tue, Jun 15, 2021 at 9:31 PM Pavel Skripkin [off-list ref] wrote:
On Tue, 15 Jun 2021 07:01:13 +0800
Dongliang Mu [off-list ref] wrote:
quoted
On Tue, Jun 15, 2021 at 12:00 AM Pavel Skripkin
[off-list ref] wrote:
quoted
On Mon, 14 Jun 2021 23:37:12 +0800
Dongliang Mu [off-list ref] wrote:
quoted
The commit 46a8b29c6306 ("net: usb: fix memory leak in
smsc75xx_bind") fails to clean up the work scheduled in
smsc75xx_reset-> smsc75xx_set_multicast, which leads to
use-after-free if the work is scheduled to start after the
deallocation. In addition, this patch also removes one dangling
pointer - dev->data[0].
This patch calls cancel_work_sync to cancel the schedule work and
set the dangling pointer to NULL.
Fixes: 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind")
Signed-off-by: Dongliang Mu <redacted>
---
drivers/net/usb/smsc75xx.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/usb/smsc75xx.c
b/drivers/net/usb/smsc75xx.c index b286993da67c..f81740fcc8d5
100644 --- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -1504,7 +1504,10 @@ static int smsc75xx_bind(struct usbnet
Hi, Dongliang!
Just my thougth about this patch:
INIT_WORK(&pdata->set_multicast, smsc75xx_deferred_multicast_write);
does not queue anything, it just initalizes list structure and
assigns callback function. The actual work sheduling happens in
smsc75xx_set_multicast() which is smsc75xx_netdev_ops member.
Yes, you are right. However, as written in the commit message,
smsc75xx_set_multicast will be called by smsc75xx_reset [1].
If smsc75xx_set_multicast is called before any check failure occurs,
this work(set_multicast) will be queued into the global list with
schedule_work(&pdata->set_multicast); [2]
Ah, I missed it, sorry :)
Maybe, small optimization for error handling path like:
cancel_work:
cancel_work_sync(&pdata->set_multicast);
dev->data[0] = 0;
free_pdata:
kfree(pdata);
return ret;
is suitbale here.
I agree with this style of error handling. However, I need to adjust
the location of dev->data[0] = 0 after kfree(pdata) because if there
still leaves a dangling pointer it directly goes to free_pdata.
quoted
At last, if the pdata or dev->data[0] is freed before the
set_multicast really executes, it may lead to a UAF. Is this correct?
BTW, even if the above is true, I don't know if I call the API
``cancel_work_sync(&pdata->set_multicast)'' properly if the
schedule_work is not called.
Yeah, it will be ok.
Thanks for the confirmation. I've tested it under the previous kernel
crash. It works fine.
I will send a v2 patch quickly.
In case of any error in smsc75xx_bind() the device registration
fails and smsc75xx_netdev_ops won't be registered, so, i guess,
there is no chance of UAF.
Am I missing something? :)
With regards,
Pavel Skripkin