Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct hv_dr_state.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: "Krzysztof Wilczyński" <kw@linux.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-hyperv@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/pci/controller/pci-hyperv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index bed3cefdaf19..30c7dfeccb16 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -545,7 +545,7 @@ struct hv_pcidev_description {
 struct hv_dr_state {
 	struct list_head list_entry;
 	u32 device_count;
-	struct hv_pcidev_description func[];
+	struct hv_pcidev_description func[] __counted_by(device_count);
 };
 
 struct hv_pci_dev {
-- 
2.34.1

Hello,

> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct hv_dr_state.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Applied to controller/hyperv, thank you!

[1/1] PCI: hv: Annotate struct hv_dr_state with __counted_by
      https://git.kernel.org/pci/pci/c/45538f68b052

	Krzysztof

On Fri, Sep 22, 2023 at 10:52:57AM -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct hv_dr_state.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Dexuan Cui <decui@microsoft.com>
> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
> Cc: "Krzysztof Wilczyński" <kw@linux.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-hyperv@vger.kernel.org
> Cc: linux-pci@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>  drivers/pci/controller/pci-hyperv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index bed3cefdaf19..30c7dfeccb16 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -545,7 +545,7 @@ struct hv_pcidev_description {
>  struct hv_dr_state {
>  	struct list_head list_entry;
>  	u32 device_count;
> -	struct hv_pcidev_description func[];
> +	struct hv_pcidev_description func[] __counted_by(device_count);
>  };
>  
>  struct hv_pci_dev {
> -- 
> 2.34.1
> 
> 

On Fri, Sep 22, 2023 at 10:52:57AM -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct hv_dr_state.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Dexuan Cui <decui@microsoft.com>
> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
> Cc: "Krzysztof Wilczyński" <kw@linux.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-hyperv@vger.kernel.org
> Cc: linux-pci@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Acked-by: Wei Liu <wei.liu@kernel.org>