* RE: [PATCH net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit()
2022-11-03 22:00 [PATCH net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit() Nathan Chancellor
@ 2022-11-04 4:29 ` Yoshihiro Shimoda
2022-11-04 19:16 ` Kees Cook
2022-11-05 2:40 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Yoshihiro Shimoda @ 2022-11-04 4:29 UTC (permalink / raw)
To: Nathan Chancellor, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni
Cc: Sergey Shtylyov, netdev@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, Nick Desaulniers, Tom Rix,
Kees Cook, Sami Tolvanen, llvm@lists.linux.dev,
linux-kernel@vger.kernel.org, patches@lists.linux.dev
Hi, Nathan,
> From: Nathan Chancellor, Sent: Friday, November 4, 2022 7:01 AM
>
> With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> indirect call targets are validated against the expected function
> pointer prototype to make sure the call target is valid to help mitigate
> ROP attacks. If they are not identical, there is a failure at run time,
> which manifests as either a kernel panic or thread getting killed. A
> proposed warning in clang aims to catch these at compile time, which
> reveals:
>
> drivers/net/ethernet/renesas/rswitch.c:1533:20: error: incompatible function pointer types initializing 'netdev_tx_t
> (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an
> expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .ndo_start_xmit = rswitch_start_xmit,
> ^~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of
> 'netdev_tx_t', not 'int'. Adjust the return type of rswitch_start_xmit()
> to match the prototype's to resolve the warning and CFI failure.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
Thank you for the patch!
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Best regards,
Yoshihiro Shimoda
> drivers/net/ethernet/renesas/rswitch.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c
> index 20df2020d3e5..f0168fedfef9 100644
> --- a/drivers/net/ethernet/renesas/rswitch.c
> +++ b/drivers/net/ethernet/renesas/rswitch.c
> @@ -1390,7 +1390,7 @@ static int rswitch_stop(struct net_device *ndev)
> return 0;
> };
>
> -static int rswitch_start_xmit(struct sk_buff *skb, struct net_device *ndev)
> +static netdev_tx_t rswitch_start_xmit(struct sk_buff *skb, struct net_device *ndev)
> {
> struct rswitch_device *rdev = netdev_priv(ndev);
> struct rswitch_gwca_queue *gq = rdev->tx_queue;
>
> base-commit: ef2dd61af7366e5a42e828fff04932e32eb0eacc
> --
> 2.38.1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit()
2022-11-03 22:00 [PATCH net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit() Nathan Chancellor
2022-11-04 4:29 ` Yoshihiro Shimoda
@ 2022-11-04 19:16 ` Kees Cook
2022-11-05 2:40 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2022-11-04 19:16 UTC (permalink / raw)
To: Nathan Chancellor
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Sergey Shtylyov, Yoshihiro Shimoda, netdev, linux-renesas-soc,
Nick Desaulniers, Tom Rix, Sami Tolvanen, llvm, linux-kernel,
patches
On Thu, Nov 03, 2022 at 03:00:32PM -0700, Nathan Chancellor wrote:
> With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> indirect call targets are validated against the expected function
> pointer prototype to make sure the call target is valid to help mitigate
> ROP attacks. If they are not identical, there is a failure at run time,
> which manifests as either a kernel panic or thread getting killed. A
> proposed warning in clang aims to catch these at compile time, which
> reveals:
>
> drivers/net/ethernet/renesas/rswitch.c:1533:20: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .ndo_start_xmit = rswitch_start_xmit,
> ^~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of
> 'netdev_tx_t', not 'int'. Adjust the return type of rswitch_start_xmit()
> to match the prototype's to resolve the warning and CFI failure.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit()
2022-11-03 22:00 [PATCH net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit() Nathan Chancellor
2022-11-04 4:29 ` Yoshihiro Shimoda
2022-11-04 19:16 ` Kees Cook
@ 2022-11-05 2:40 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-11-05 2:40 UTC (permalink / raw)
To: Nathan Chancellor
Cc: davem, edumazet, kuba, pabeni, s.shtylyov, yoshihiro.shimoda.uh,
netdev, linux-renesas-soc, ndesaulniers, trix, keescook,
samitolvanen, llvm, linux-kernel, patches
Hello:
This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:
On Thu, 3 Nov 2022 15:00:32 -0700 you wrote:
> With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> indirect call targets are validated against the expected function
> pointer prototype to make sure the call target is valid to help mitigate
> ROP attacks. If they are not identical, there is a failure at run time,
> which manifests as either a kernel panic or thread getting killed. A
> proposed warning in clang aims to catch these at compile time, which
> reveals:
>
> [...]
Here is the summary with links:
- [net-next] net: ethernet: renesas: Fix return type of rswitch_start_xmit()
https://git.kernel.org/netdev/net-next/c/8e0aa1ff44ca
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread