On Thu, Jan 20, 2022 at 03:16:00PM -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: sound/usb/mixer_scarlett_gen2.c:1064:28: warning: using sizeof on a flexible structure sound/usb/mixer_scarlett_gen2.c:1065:29: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174 Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org

Looks good to me!

Reviewed-by: Kees Cook keescook@chromium.org

---

Changes in v2:

• Use correct format specifier %zu for type size_t argument.

sound/usb/mixer_scarlett_gen2.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c index 53ebabf42472..7ff8a4817c67 100644 --- a/sound/usb/mixer_scarlett_gen2.c +++ b/sound/usb/mixer_scarlett_gen2.c @@ -1061,9 +1061,9 @@ static int scarlett2_usb( { struct scarlett2_data *private = mixer->private_data; struct usb_device *dev = mixer->chip->dev;

• u16 req_buf_size = sizeof(struct scarlett2_usb_packet) + req_size;
• u16 resp_buf_size = sizeof(struct scarlett2_usb_packet) + resp_size; struct scarlett2_usb_packet *req, *resp = NULL;

• size_t req_buf_size = struct_size(req, data, req_size);

• size_t resp_buf_size = struct_size(resp, data, resp_size); int err;

  req = kmalloc(req_buf_size, GFP_KERNEL);

@@ -1111,7 +1111,7 @@ static int scarlett2_usb( usb_audio_err( mixer->chip, "Scarlett Gen 2/3 USB response result cmd %x was %d "

• 	"expected %d\n",
  

• 	"expected %zu\n",
  cmd, err, resp_buf_size);
  

  err = -EINVAL; goto unlock;

-- 2.27.0