[PATCH V2] net/nfc/nci: fix infoleak in struct nci_set_config_param

[PATCH V2] net/nfc/nci: fix infoleak in struct nci_set_config_param

[cgel.zte]

From: "Minghao Chi (CGEL ZTE)" <chi.minghao@zte.com.cn>

On 64-bit systems, struct nci_set_config_param has
an added padding of 7 bytes between struct members
id and len. Even though all struct members are initialized,
the 7-byte hole will contain data from the kernel stack.
This patch zeroes out struct nci_set_config_param before
usage, preventing infoleaks to userspace.

v1->v2:
  -Modify the title.
  -Add explanatory information.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi (CGEL ZTE) <chi.minghao@zte.com.cn>
---
 net/nfc/nci/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index d2537383a3e8..32be42be1152 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -641,6 +641,7 @@ int nci_set_config(struct nci_dev *ndev, __u8 id, size_t len, const __u8 *val)
 	if (!val || !len)
 		return 0;
 
+	memset(&param, 0x0, sizeof(param));
 	param.id = id;
 	param.len = len;
 	param.val = val;
-- 
2.25.1

Re: [PATCH V2] net/nfc/nci: fix infoleak in struct nci_set_config_param

[weiyongjun (A)]

> From: "Minghao Chi (CGEL ZTE)" <chi.minghao@zte.com.cn>
>
> On 64-bit systems, struct nci_set_config_param has
> an added padding of 7 bytes between struct members
> id and len. Even though all struct members are initialized,
> the 7-byte hole will contain data from the kernel stack.
> This patch zeroes out struct nci_set_config_param before
> usage, preventing infoleaks to userspace.


How this info leaks to userspace?


nci_set_config_req() convert to use packed 'struct nci_core_set_config_cmd'

to send data, which does not contain hole.

Re: [PATCH V2] net/nfc/nci: fix infoleak in struct nci_set_config_param

[Krzysztof Kozlowski]

On 02/03/2022 04:33, cgel.zte@gmail.com wrote:
> From: "Minghao Chi (CGEL ZTE)" <chi.minghao@zte.com.cn>
> 
> On 64-bit systems, struct nci_set_config_param has
> an added padding of 7 bytes between struct members
> id and len. Even though all struct members are initialized,
> the 7-byte hole will contain data from the kernel stack.
> This patch zeroes out struct nci_set_config_param before
> usage, preventing infoleaks to userspace.
> 
> v1->v2:
>   -Modify the title.
>   -Add explanatory information.

Changelog goes below ---.

> Reported-by: Zeal Robot <zealci@zte.com.cn>

Why do you ignore the comment about missing report?

> Signed-off-by: Minghao Chi (CGEL ZTE) <chi.minghao@zte.com.cn>
> ---
>  net/nfc/nci/core.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
> index d2537383a3e8..32be42be1152 100644
> --- a/net/nfc/nci/core.c
> +++ b/net/nfc/nci/core.c
> @@ -641,6 +641,7 @@ int nci_set_config(struct nci_dev *ndev, __u8 id, size_t len, const __u8 *val)
>  	if (!val || !len)
>  		return 0;
>  
> +	memset(&param, 0x0, sizeof(param));

You ignored the comment here as well. That's not how a v2 should be
sent...  if you don't agree with comments, we need to keep discussing.

>  	param.id = id;
>  	param.len = len;
>  	param.val = val;


Best regards,
Krzysztof