* [PATCH] nfc: st21nfca: fix possible double free in st21nfca_im_recv_dep_res_cb()
@ 2022-06-22 6:51 Hangyu Hua
2022-06-23 9:42 ` Paolo Abeni
0 siblings, 1 reply; 3+ messages in thread
From: Hangyu Hua @ 2022-06-22 6:51 UTC (permalink / raw)
To: krzysztof.kozlowski, sameo, christophe.ricard
Cc: netdev, linux-kernel, Hangyu Hua
nfc_tm_data_received will free skb internally when it fails. There is no
need to free skb in st21nfca_im_recv_dep_res_cb again.
Fix this by setting skb to NULL when nfc_tm_data_received fails.
Fixes: 1892bf844ea0 ("NFC: st21nfca: Adding P2P support to st21nfca in Initiator & Target mode")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
drivers/nfc/st21nfca/dep.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nfc/st21nfca/dep.c b/drivers/nfc/st21nfca/dep.c
index 1ec651e31064..07ac5688011c 100644
--- a/drivers/nfc/st21nfca/dep.c
+++ b/drivers/nfc/st21nfca/dep.c
@@ -594,7 +594,8 @@ static void st21nfca_im_recv_dep_res_cb(void *context, struct sk_buff *skb,
ST21NFCA_NFC_DEP_PFB_PNI(dep_res->pfb + 1);
size++;
skb_pull(skb, size);
- nfc_tm_data_received(info->hdev->ndev, skb);
+ if (nfc_tm_data_received(info->hdev->ndev, skb))
+ skb = NULL;
break;
case ST21NFCA_NFC_DEP_PFB_SUPERVISOR_PDU:
pr_err("Received a SUPERVISOR PDU\n");
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] nfc: st21nfca: fix possible double free in st21nfca_im_recv_dep_res_cb()
2022-06-22 6:51 [PATCH] nfc: st21nfca: fix possible double free in st21nfca_im_recv_dep_res_cb() Hangyu Hua
@ 2022-06-23 9:42 ` Paolo Abeni
2022-06-23 10:47 ` Hangyu Hua
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Abeni @ 2022-06-23 9:42 UTC (permalink / raw)
To: Hangyu Hua, krzysztof.kozlowski, sameo, christophe.ricard
Cc: netdev, linux-kernel
On Wed, 2022-06-22 at 14:51 +0800, Hangyu Hua wrote:
> nfc_tm_data_received will free skb internally when it fails. There is no
> need to free skb in st21nfca_im_recv_dep_res_cb again.
>
> Fix this by setting skb to NULL when nfc_tm_data_received fails.
>
> Fixes: 1892bf844ea0 ("NFC: st21nfca: Adding P2P support to st21nfca in Initiator & Target mode")
> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
> ---
> drivers/nfc/st21nfca/dep.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nfc/st21nfca/dep.c b/drivers/nfc/st21nfca/dep.c
> index 1ec651e31064..07ac5688011c 100644
> --- a/drivers/nfc/st21nfca/dep.c
> +++ b/drivers/nfc/st21nfca/dep.c
> @@ -594,7 +594,8 @@ static void st21nfca_im_recv_dep_res_cb(void *context, struct sk_buff *skb,
> ST21NFCA_NFC_DEP_PFB_PNI(dep_res->pfb + 1);
> size++;
> skb_pull(skb, size);
> - nfc_tm_data_received(info->hdev->ndev, skb);
> + if (nfc_tm_data_received(info->hdev->ndev, skb))
> + skb = NULL;
Note that 'skb' not used (nor freed) by this function after this point:
the next 'break' statement refears to the inner switch, and land to the
execution flow to the 'return' statement a few lines below.
kfree_skb(skb) is never reached.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] nfc: st21nfca: fix possible double free in st21nfca_im_recv_dep_res_cb()
2022-06-23 9:42 ` Paolo Abeni
@ 2022-06-23 10:47 ` Hangyu Hua
0 siblings, 0 replies; 3+ messages in thread
From: Hangyu Hua @ 2022-06-23 10:47 UTC (permalink / raw)
To: Paolo Abeni, krzysztof.kozlowski, sameo, christophe.ricard
Cc: netdev, linux-kernel
On 2022/6/23 17:42, Paolo Abeni wrote:
> On Wed, 2022-06-22 at 14:51 +0800, Hangyu Hua wrote:
>> nfc_tm_data_received will free skb internally when it fails. There is no
>> need to free skb in st21nfca_im_recv_dep_res_cb again.
>>
>> Fix this by setting skb to NULL when nfc_tm_data_received fails.
>>
>> Fixes: 1892bf844ea0 ("NFC: st21nfca: Adding P2P support to st21nfca in Initiator & Target mode")
>> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
>> ---
>> drivers/nfc/st21nfca/dep.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/nfc/st21nfca/dep.c b/drivers/nfc/st21nfca/dep.c
>> index 1ec651e31064..07ac5688011c 100644
>> --- a/drivers/nfc/st21nfca/dep.c
>> +++ b/drivers/nfc/st21nfca/dep.c
>> @@ -594,7 +594,8 @@ static void st21nfca_im_recv_dep_res_cb(void *context, struct sk_buff *skb,
>> ST21NFCA_NFC_DEP_PFB_PNI(dep_res->pfb + 1);
>> size++;
>> skb_pull(skb, size);
>> - nfc_tm_data_received(info->hdev->ndev, skb);
>> + if (nfc_tm_data_received(info->hdev->ndev, skb))
>> + skb = NULL;
>
> Note that 'skb' not used (nor freed) by this function after this point:
> the next 'break' statement refears to the inner switch, and land to the
> execution flow to the 'return' statement a few lines below.
> kfree_skb(skb) is never reached.
>
> Paolo
>
My fault. I messed up two switch statements. I will be more careful next
time.
hangyu
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-06-23 10:47 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-22 6:51 [PATCH] nfc: st21nfca: fix possible double free in st21nfca_im_recv_dep_res_cb() Hangyu Hua
2022-06-23 9:42 ` Paolo Abeni
2022-06-23 10:47 ` Hangyu Hua
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