Re: [PATCH][next] drm/i915/guc: Use struct_size() helper in kmalloc()

[Tvrtko Ursulin]

On 25/01/2022 18:07, 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/gpu/drm/i915/gt/uc/intel_guc_ct.c:792:23: warning: using sizeof on a 
flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org>
---
  drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c 
b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
index aa6dd6415202..e352a1aad228 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
@@ -789,7 +789,7 @@ static struct ct_incoming_msg *ct_alloc_msg(u32 num_dwords)
  {
        struct ct_incoming_msg *msg;

- msg = kmalloc(sizeof(*msg) + sizeof(u32) * num_dwords, GFP_ATOMIC);

+       msg = kmalloc(struct_size(msg, msg, num_dwords), GFP_ATOMIC);
        if (msg)
                msg->size = num_dwords;
        return msg;

Reviewed-by: Tvrtko Ursulin <tvrtko.ursu...@intel.com>

Thanks for the patch, will merge shortly.

Regards,

Tvrtko