On 9/15/23 12:52, Kees Cook wrote:
On Fri, Sep 15, 2023 at 12:43:20PM -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: 40e1a70b4aed ("drm: Add GUD USB Display driver")
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/gpu/drm/gud/gud_pipe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
index d2f199ea3c11..a02f75be81f0 100644
--- a/drivers/gpu/drm/gud/gud_pipe.c
+++ b/drivers/gpu/drm/gud/gud_pipe.c
@@ -503,7 +503,7 @@ int gud_pipe_check(struct drm_simple_display_pipe *pipe,
return -ENOENT;
len = struct_size(req, properties,
- GUD_PROPERTIES_MAX_NUM + GUD_CONNECTOR_PROPERTIES_MAX_NUM);
+ size_add(GUD_PROPERTIES_MAX_NUM, GUD_CONNECTOR_PROPERTIES_MAX_NUM));
There are both constant expressions, so there's not too much value in
wrapping them with size_add(), but for maintaining a common coding style
for dealing with allocation sizes, I can be convinced of the change. :)
Yep; I've found a mix of constant expressions and variables doing open-coded arithmetic
in `struct_size()`, so I'm sending them all.
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Thanks!
--
Gustavo
req = kzalloc(len, GFP_KERNEL);
if (!req)
return -ENOMEM;
--
2.34.1
