From fb49d9946f96081f9a05d8f305b3f40285afe4a9 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 25 Aug 2021 09:07:49 -0700 Subject: [PATCH] platform/x86: dell-smbios-wmi: Avoid false-positive memcpy() warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Since all the size checking has already happened, use input.pointer (void *) so memcpy() doesn't get confused about how much is being written. Avoids this false-positive warning when run-time memcpy() strict bounds checking is enabled: memcpy: detected field-spanning write (size 4096) of single field (size 36) WARNING: CPU: 0 PID: 357 at drivers/platform/x86/dell/dell-smbios-wmi.c:74 run_smbios_call+0x110/0x1e0 [dell_smbios] Cc: Hans de Goede Cc: Mark Gross Cc: Mario Limonciello Cc: "Pali Rohár" Cc: Andy Shevchenko Cc: "Uwe Kleine-König" Cc: Dell.Client.Kernel@dell.com Cc: platform-driver-x86@vger.kernel.org Reported-by: Andy Lavr Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210825160749.3891090-1-keescook@chromium.org Reviewed-by: Hans de Goede Signed-off-by: Hans de Goede --- drivers/platform/x86/dell/dell-smbios-wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/platform/x86/dell/dell-smbios-wmi.c b/drivers/platform/x86/dell/dell-smbios-wmi.c index 33f8237727335..01ea4bb958aff 100644 --- a/drivers/platform/x86/dell/dell-smbios-wmi.c +++ b/drivers/platform/x86/dell/dell-smbios-wmi.c @@ -71,7 +71,7 @@ static int run_smbios_call(struct wmi_device *wdev) obj->integer.value); return -EIO; } - memcpy(&priv->buf->std, obj->buffer.pointer, obj->buffer.length); + memcpy(input.pointer, obj->buffer.pointer, obj->buffer.length); dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n", priv->buf->std.output[0], priv->buf->std.output[1], priv->buf->std.output[2], priv->buf->std.output[3]);