diff mbox series

[next] net: spider_net: Use size_add() in call to struct_size()

Message ID ZQSvsLmJrDsKtLCa@work
State New
Headers
Series [next] net: spider_net: Use size_add() in call to struct_size() |

Commit Message

Gustavo A. R. Silva Sept. 15, 2023, 7:25 p.m. UTC 
  If, for any reason, the open-coded arithmetic causes a wraparound,
the protection that `struct_size()` adds against potential integer
overflows is defeated. Fix this by hardening call to `struct_size()`
with `size_add()`.

Fixes: 3f1071ec39f7 ("net: spider_net: Use struct_size() helper")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/ethernet/toshiba/spider_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kees Cook Sept. 15, 2023, 7:53 p.m. UTC | #1 
On Fri, Sep 15, 2023 at 01:25:36PM -0600, Gustavo A. R. Silva wrote:
> If, for any reason, the open-coded arithmetic causes a wraparound,
> the protection that `struct_size()` adds against potential integer
> overflows is defeated. Fix this by hardening call to `struct_size()`
> with `size_add()`.
> 
> Fixes: 3f1071ec39f7 ("net: spider_net: Use struct_size() helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>
Geoff Levand Sept. 16, 2023, 12:21 a.m. UTC | #2 
On 9/15/23 14:25, Gustavo A. R. Silva wrote:
> If, for any reason, the open-coded arithmetic causes a wraparound,
> the protection that `struct_size()` adds against potential integer
> overflows is defeated. Fix this by hardening call to `struct_size()`
> with `size_add()`.
> 
> Fixes: 3f1071ec39f7 ("net: spider_net: Use struct_size() helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/net/ethernet/toshiba/spider_net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/toshiba/spider_net.c b/drivers/net/ethernet/toshiba/spider_net.c
> index 50d7eacfec58..87e67121477c 100644
> --- a/drivers/net/ethernet/toshiba/spider_net.c
> +++ b/drivers/net/ethernet/toshiba/spider_net.c
> @@ -2332,7 +2332,7 @@ spider_net_alloc_card(void)
>  	struct spider_net_card *card;
>  
>  	netdev = alloc_etherdev(struct_size(card, darray,
> -					    tx_descriptors + rx_descriptors));
> +					    size_add(tx_descriptors, rx_descriptors)));
>  	if (!netdev)
>  		return NULL;
>  

Looks good to me.  Thanks for your fix-up.

Signed-off-by: Geoff Levand <geoff@infradead.org>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/toshiba/spider_net.c b/drivers/net/ethernet/toshiba/spider_net.c
index 50d7eacfec58..87e67121477c 100644
--- a/drivers/net/ethernet/toshiba/spider_net.c
+++ b/drivers/net/ethernet/toshiba/spider_net.c
@@ -2332,7 +2332,7 @@  spider_net_alloc_card(void)
 	struct spider_net_card *card;
 
 	netdev = alloc_etherdev(struct_size(card, darray,
-					    tx_descriptors + rx_descriptors));
+					    size_add(tx_descriptors, rx_descriptors)));
 	if (!netdev)
 		return NULL;