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* [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
@ 2023-04-03  7:54 Ziyang Xuan
  2023-04-03 15:01 ` Manivannan Sadhasivam
  2023-04-08  8:35 ` Manivannan Sadhasivam
  0 siblings, 2 replies; 6+ messages in thread
From: Ziyang Xuan @ 2023-04-03  7:54 UTC (permalink / raw)
  To: mani, davem, edumazet, kuba, pabeni, andersson, luca,
	linux-arm-msm, netdev

Syzbot reported a bug as following:

=====================================================
BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
 qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
 qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
 call_write_iter include/linux/fs.h:2189 [inline]
 aio_write+0x63a/0x950 fs/aio.c:1600
 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
 __do_sys_io_submit fs/aio.c:2078 [inline]
 __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:766 [inline]
 slab_alloc_node mm/slub.c:3452 [inline]
 __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
 __do_kmalloc_node mm/slab_common.c:967 [inline]
 __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
 kmalloc_reserve net/core/skbuff.c:492 [inline]
 __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
 __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
 qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
 call_write_iter include/linux/fs.h:2189 [inline]
 aio_write+0x63a/0x950 fs/aio.c:1600
 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
 __do_sys_io_submit fs/aio.c:2078 [inline]
 __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
scenario. This triggers the uninit variable access bug.

Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
qrtr_endpoint_post() to fix the bug.

Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control")
Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
---
 net/qrtr/af_qrtr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
index 3a70255c8d02..631e81a8a368 100644
--- a/net/qrtr/af_qrtr.c
+++ b/net/qrtr/af_qrtr.c
@@ -498,6 +498,10 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 	if (!size || len != ALIGN(size, 4) + hdrlen)
 		goto err;
 
+	if (cb->type == QRTR_TYPE_RESUME_TX &&
+	    size < sizeof(struct qrtr_ctrl_pkt))
+		goto err;
+
 	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
 	    cb->type != QRTR_TYPE_RESUME_TX)
 		goto err;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
  2023-04-03  7:54 [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume() Ziyang Xuan
@ 2023-04-03 15:01 ` Manivannan Sadhasivam
  2023-04-04  0:38   ` Ziyang Xuan (William)
  2023-04-08  8:35 ` Manivannan Sadhasivam
  1 sibling, 1 reply; 6+ messages in thread
From: Manivannan Sadhasivam @ 2023-04-03 15:01 UTC (permalink / raw)
  To: Ziyang Xuan
  Cc: davem, edumazet, kuba, pabeni, andersson, luca, linux-arm-msm, netdev

On Mon, Apr 03, 2023 at 03:54:17PM +0800, Ziyang Xuan wrote:
> Syzbot reported a bug as following:
> 
> =====================================================
> BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>  qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>  qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>  call_write_iter include/linux/fs.h:2189 [inline]
>  aio_write+0x63a/0x950 fs/aio.c:1600
>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>  __do_sys_io_submit fs/aio.c:2078 [inline]
>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> Uninit was created at:
>  slab_post_alloc_hook mm/slab.h:766 [inline]
>  slab_alloc_node mm/slub.c:3452 [inline]
>  __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
>  __do_kmalloc_node mm/slab_common.c:967 [inline]
>  __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
>  kmalloc_reserve net/core/skbuff.c:492 [inline]
>  __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
>  __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
>  qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>  call_write_iter include/linux/fs.h:2189 [inline]
>  aio_write+0x63a/0x950 fs/aio.c:1600
>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>  __do_sys_io_submit fs/aio.c:2078 [inline]
>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
> in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
> But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
> equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
> scenario. This triggers the uninit variable access bug.
> 

I'm not familiar with syzkaller. Can you please share the data that was fuzzed
by the bot?

- Mani

> Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
> qrtr_endpoint_post() to fix the bug.
> 
> Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control")
> Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
> Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540
> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
> ---
>  net/qrtr/af_qrtr.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
> index 3a70255c8d02..631e81a8a368 100644
> --- a/net/qrtr/af_qrtr.c
> +++ b/net/qrtr/af_qrtr.c
> @@ -498,6 +498,10 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
>  	if (!size || len != ALIGN(size, 4) + hdrlen)
>  		goto err;
>  
> +	if (cb->type == QRTR_TYPE_RESUME_TX &&
> +	    size < sizeof(struct qrtr_ctrl_pkt))
> +		goto err;
> +
>  	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
>  	    cb->type != QRTR_TYPE_RESUME_TX)
>  		goto err;
> -- 
> 2.25.1
> 

-- 
மணிவண்ணன் சதாசிவம்

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
  2023-04-03 15:01 ` Manivannan Sadhasivam
@ 2023-04-04  0:38   ` Ziyang Xuan (William)
  2023-04-06  8:34     ` Paolo Abeni
  0 siblings, 1 reply; 6+ messages in thread
From: Ziyang Xuan (William) @ 2023-04-04  0:38 UTC (permalink / raw)
  To: Manivannan Sadhasivam
  Cc: davem, edumazet, kuba, pabeni, andersson, luca, linux-arm-msm, netdev

> On Mon, Apr 03, 2023 at 03:54:17PM +0800, Ziyang Xuan wrote:
>> Syzbot reported a bug as following:
>>
>> =====================================================
>> BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>>  qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>>  qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
>>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>>  call_write_iter include/linux/fs.h:2189 [inline]
>>  aio_write+0x63a/0x950 fs/aio.c:1600
>>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>>  __do_sys_io_submit fs/aio.c:2078 [inline]
>>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> Uninit was created at:
>>  slab_post_alloc_hook mm/slab.h:766 [inline]
>>  slab_alloc_node mm/slub.c:3452 [inline]
>>  __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
>>  __do_kmalloc_node mm/slab_common.c:967 [inline]
>>  __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
>>  kmalloc_reserve net/core/skbuff.c:492 [inline]
>>  __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
>>  __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
>>  qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
>>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>>  call_write_iter include/linux/fs.h:2189 [inline]
>>  aio_write+0x63a/0x950 fs/aio.c:1600
>>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>>  __do_sys_io_submit fs/aio.c:2078 [inline]
>>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
>> in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
>> But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
>> equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
>> scenario. This triggers the uninit variable access bug.
>>
> 
> I'm not familiar with syzkaller. Can you please share the data that was fuzzed
> by the bot?
> 
> - Mani
> 
>> Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
>> qrtr_endpoint_post() to fix the bug.
>>
>> Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control")
>> Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
>> Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540

Hello Manivannan Sadhasivam

See the above link, it's syzkaller dashboard link, you can find a C reproducer that will help you.

William Xuan.

>> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
>> ---
>>  net/qrtr/af_qrtr.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
>> index 3a70255c8d02..631e81a8a368 100644
>> --- a/net/qrtr/af_qrtr.c
>> +++ b/net/qrtr/af_qrtr.c
>> @@ -498,6 +498,10 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
>>  	if (!size || len != ALIGN(size, 4) + hdrlen)
>>  		goto err;
>>  
>> +	if (cb->type == QRTR_TYPE_RESUME_TX &&
>> +	    size < sizeof(struct qrtr_ctrl_pkt))
>> +		goto err;
>> +
>>  	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
>>  	    cb->type != QRTR_TYPE_RESUME_TX)
>>  		goto err;
>> -- 
>> 2.25.1
>>
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
  2023-04-04  0:38   ` Ziyang Xuan (William)
@ 2023-04-06  8:34     ` Paolo Abeni
  0 siblings, 0 replies; 6+ messages in thread
From: Paolo Abeni @ 2023-04-06  8:34 UTC (permalink / raw)
  To: Ziyang Xuan (William), Manivannan Sadhasivam
  Cc: davem, edumazet, kuba, andersson, luca, linux-arm-msm, netdev

Hi,

On Tue, 2023-04-04 at 08:38 +0800, Ziyang Xuan (William) wrote:
> > On Mon, Apr 03, 2023 at 03:54:17PM +0800, Ziyang Xuan wrote:
> > > Syzbot reported a bug as following:
> > > 
> > > =====================================================
> > > BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0
> > > net/qrtr/af_qrtr.c:230
> > >  qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
> > >  qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
> > >  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
> > >  call_write_iter include/linux/fs.h:2189 [inline]
> > >  aio_write+0x63a/0x950 fs/aio.c:1600
> > >  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
> > >  __do_sys_io_submit fs/aio.c:2078 [inline]
> > >  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
> > >  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
> > >  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > >  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
> > >  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > > 
> > > Uninit was created at:
> > >  slab_post_alloc_hook mm/slab.h:766 [inline]
> > >  slab_alloc_node mm/slub.c:3452 [inline]
> > >  __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
> > >  __do_kmalloc_node mm/slab_common.c:967 [inline]
> > >  __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
> > >  kmalloc_reserve net/core/skbuff.c:492 [inline]
> > >  __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
> > >  __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
> > >  qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
> > >  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
> > >  call_write_iter include/linux/fs.h:2189 [inline]
> > >  aio_write+0x63a/0x950 fs/aio.c:1600
> > >  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
> > >  __do_sys_io_submit fs/aio.c:2078 [inline]
> > >  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
> > >  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
> > >  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > >  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
> > >  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > > 
> > > It is because that skb->len requires at least sizeof(struct
> > > qrtr_ctrl_pkt)
> > > in qrtr_tx_resume(). And skb->len equals to size in
> > > qrtr_endpoint_post().
> > > But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb-
> > > >type
> > > equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the
> > > syzbot
> > > scenario. This triggers the uninit variable access bug.
> > > 
> > 
> > I'm not familiar with syzkaller. Can you please share the data that
> > was fuzzed
> > by the bot?
> > 
> > - Mani
> > 
> > > Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX
> > > in
> > > qrtr_endpoint_post() to fix the bug.
> > > 
> > > Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow
> > > control")
> > > Reported-by:
> > > syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
> > > Link:
> > > https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540
> 
> Hello Manivannan Sadhasivam
> 
> See the above link, it's syzkaller dashboard link, you can find a C
> reproducer that will help you.

Hi Mani,

Are you satisfied with the information above? The patch LGTM and the
syzkaller report looks quite clear.

Thanks!

Paolo


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
  2023-04-03  7:54 [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume() Ziyang Xuan
  2023-04-03 15:01 ` Manivannan Sadhasivam
@ 2023-04-08  8:35 ` Manivannan Sadhasivam
  2023-04-10  0:58   ` Ziyang Xuan (William)
  1 sibling, 1 reply; 6+ messages in thread
From: Manivannan Sadhasivam @ 2023-04-08  8:35 UTC (permalink / raw)
  To: Ziyang Xuan
  Cc: davem, edumazet, kuba, pabeni, andersson, luca, linux-arm-msm, netdev

On Mon, Apr 03, 2023 at 03:54:17PM +0800, Ziyang Xuan wrote:
> Syzbot reported a bug as following:
> 
> =====================================================
> BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>  qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>  qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>  call_write_iter include/linux/fs.h:2189 [inline]
>  aio_write+0x63a/0x950 fs/aio.c:1600
>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>  __do_sys_io_submit fs/aio.c:2078 [inline]
>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> Uninit was created at:
>  slab_post_alloc_hook mm/slab.h:766 [inline]
>  slab_alloc_node mm/slub.c:3452 [inline]
>  __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
>  __do_kmalloc_node mm/slab_common.c:967 [inline]
>  __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
>  kmalloc_reserve net/core/skbuff.c:492 [inline]
>  __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
>  __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
>  qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>  call_write_iter include/linux/fs.h:2189 [inline]
>  aio_write+0x63a/0x950 fs/aio.c:1600
>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>  __do_sys_io_submit fs/aio.c:2078 [inline]
>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
> in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
> But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
> equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
> scenario. This triggers the uninit variable access bug.
> 
> Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
> qrtr_endpoint_post() to fix the bug.
> 
> Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control")
> Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
> Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540
> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>

Looks good to me. But I have a small suggestion below.

> ---
>  net/qrtr/af_qrtr.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
> index 3a70255c8d02..631e81a8a368 100644
> --- a/net/qrtr/af_qrtr.c
> +++ b/net/qrtr/af_qrtr.c
> @@ -498,6 +498,10 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
>  	if (!size || len != ALIGN(size, 4) + hdrlen)
>  		goto err;
>  
> +	if (cb->type == QRTR_TYPE_RESUME_TX &&
> +	    size < sizeof(struct qrtr_ctrl_pkt))

There is already a check for QRTR_TYPE_NEW_SERVER below. So you can combine both:

	if ((cb->type == QRTR_TYPE_NEW_SERVER ||
	     cb->type == QRTR_TYPE_RESUME_TX)
	     && size < sizeof(struct qrtr_ctrl_pkt))
		goto err;

- Mani

> +		goto err;
> +
>  	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
>  	    cb->type != QRTR_TYPE_RESUME_TX)
>  		goto err;
> -- 
> 2.25.1
> 

-- 
மணிவண்ணன் சதாசிவம்

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
  2023-04-08  8:35 ` Manivannan Sadhasivam
@ 2023-04-10  0:58   ` Ziyang Xuan (William)
  0 siblings, 0 replies; 6+ messages in thread
From: Ziyang Xuan (William) @ 2023-04-10  0:58 UTC (permalink / raw)
  To: Manivannan Sadhasivam
  Cc: davem, edumazet, kuba, pabeni, andersson, luca, linux-arm-msm, netdev

> On Mon, Apr 03, 2023 at 03:54:17PM +0800, Ziyang Xuan wrote:
>> Syzbot reported a bug as following:
>>
>> =====================================================
>> BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>>  qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
>>  qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
>>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>>  call_write_iter include/linux/fs.h:2189 [inline]
>>  aio_write+0x63a/0x950 fs/aio.c:1600
>>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>>  __do_sys_io_submit fs/aio.c:2078 [inline]
>>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> Uninit was created at:
>>  slab_post_alloc_hook mm/slab.h:766 [inline]
>>  slab_alloc_node mm/slub.c:3452 [inline]
>>  __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
>>  __do_kmalloc_node mm/slab_common.c:967 [inline]
>>  __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
>>  kmalloc_reserve net/core/skbuff.c:492 [inline]
>>  __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
>>  __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
>>  qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
>>  qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
>>  call_write_iter include/linux/fs.h:2189 [inline]
>>  aio_write+0x63a/0x950 fs/aio.c:1600
>>  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
>>  __do_sys_io_submit fs/aio.c:2078 [inline]
>>  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
>>  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
>> in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
>> But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
>> equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
>> scenario. This triggers the uninit variable access bug.
>>
>> Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
>> qrtr_endpoint_post() to fix the bug.
>>
>> Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control")
>> Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
>> Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540
>> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
> 
> Looks good to me. But I have a small suggestion below.
> 
>> ---
>>  net/qrtr/af_qrtr.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
>> index 3a70255c8d02..631e81a8a368 100644
>> --- a/net/qrtr/af_qrtr.c
>> +++ b/net/qrtr/af_qrtr.c
>> @@ -498,6 +498,10 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
>>  	if (!size || len != ALIGN(size, 4) + hdrlen)
>>  		goto err;
>>  
>> +	if (cb->type == QRTR_TYPE_RESUME_TX &&
>> +	    size < sizeof(struct qrtr_ctrl_pkt))
> 
> There is already a check for QRTR_TYPE_NEW_SERVER below. So you can combine both:
> 
> 	if ((cb->type == QRTR_TYPE_NEW_SERVER ||
> 	     cb->type == QRTR_TYPE_RESUME_TX)
> 	     && size < sizeof(struct qrtr_ctrl_pkt))
> 		goto err;
> 
> - Mani
That's good. Thank you for your suggestion!

v2 will be sent.

William Xuan
> 
>> +		goto err;
>> +
>>  	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
>>  	    cb->type != QRTR_TYPE_RESUME_TX)
>>  		goto err;
>> -- 
>> 2.25.1
>>
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2023-04-10  0:58 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-04-03  7:54 [PATCH net] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume() Ziyang Xuan
2023-04-03 15:01 ` Manivannan Sadhasivam
2023-04-04  0:38   ` Ziyang Xuan (William)
2023-04-06  8:34     ` Paolo Abeni
2023-04-08  8:35 ` Manivannan Sadhasivam
2023-04-10  0:58   ` Ziyang Xuan (William)

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