2022-01-22 00:19:26

by Gustavo A. R. Silva

Subject: [PATCH][next] NTB/msi: Use struct_size() helper in devm_kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/ntb/msi.c:46:23: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/ntb/msi.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/ntb/msi.c b/drivers/ntb/msi.c
index dd683cb58d09..6295e55ef85e 100644
--- a/drivers/ntb/msi.c
+++ b/drivers/ntb/msi.c
@@ -33,7 +33,6 @@ int ntb_msi_init(struct ntb_dev *ntb,
{
phys_addr_t mw_phys_addr;
resource_size_t mw_size;
- size_t struct_size;
int peer_widx;
int peers;
int ret;
@@ -43,9 +42,8 @@ int ntb_msi_init(struct ntb_dev *ntb,
if (peers <= 0)
return -EINVAL;

- struct_size = sizeof(*ntb->msi) + sizeof(*ntb->msi->peer_mws) * peers;
-
- ntb->msi = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
+ ntb->msi = devm_kzalloc(&ntb->dev, struct_size(ntb->msi, peer_mws, peers),
+ GFP_KERNEL);
if (!ntb->msi)
return -ENOMEM;

--
2.27.0

2022-01-22 00:24:27

by Kees Cook

Subject: Re: [PATCH][next] NTB/msi: Use struct_size() helper in devm_kzalloc()

On Thu, Jan 20, 2022 at 05:02:47PM -0600, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
>
> Also, address the following sparse warnings:
> drivers/ntb/msi.c:46:23: warning: using sizeof on a flexible structure
>
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Heh, the variable was even named struct_size. ;)

Reviewed-by: Kees Cook <[email protected]>

--
Kees Cook

2022-01-22 01:57:51

by Logan Gunthorpe

Subject: Re: [PATCH][next] NTB/msi: Use struct_size() helper in devm_kzalloc()

On 2022-01-20 4:02 p.m., Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
>
> Also, address the following sparse warnings:
> drivers/ntb/msi.c:46:23: warning: using sizeof on a flexible structure
>
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Thanks, looks good to me.

Reviewed-by: Logan Gunthorpe <[email protected]>