On Mon, Apr 08, 2024 at 08:26:00PM +0200, Arnd Bergmann wrote:
On Thu, Mar 28, 2024, at 16:00, Dan Carpenter wrote:
On Thu, Mar 28, 2024 at 03:04:54PM +0100, Arnd Bergmann wrote:
Signed-off-by: Arnd Bergmann arnd@arndb.de
This is from randconfig testing with random gcc versions, a .config to reproduce is at https://pastebin.com/r13yezkU
drivers/staging/greybus/fw-management.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/greybus/fw-management.c b/drivers/staging/greybus/fw-management.c index 3054f084d777..35bfdd5f32d2 100644 --- a/drivers/staging/greybus/fw-management.c +++ b/drivers/staging/greybus/fw-management.c @@ -303,13 +303,13 @@ static int fw_mgmt_backend_fw_update_operation(struct fw_mgmt *fw_mgmt, struct gb_fw_mgmt_backend_fw_update_request request; int ret;
- strncpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
- ret = strscpy(request.firmware_tag, tag, GB_FIRMWARE_TAG_MAX_SIZE);
This needs to be strscpy_pad() or it risks an information leak.
Right, I think I misread the code thinking that the strncpy() destination was user provided, but I see now that this copy is from user-provided data into the stack, so the padding is indeed stale stack data.
I could not find out whether this gets copied back to userspace, but adding the padding is safer indeed.
Grey bus is a bus, I'm not sure what's on the other end of the bus but I think we've generally said that the data needs to be zeroed... Although if that is true, why didn't I make this a Smatch warning?
regards, dan carpenter