From: Kees Cook keescook@chromium.org
[ Upstream commit fb49d9946f96081f9a05d8f305b3f40285afe4a9 ]
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 hdegoede@redhat.com Cc: Mark Gross mgross@linux.intel.com Cc: Mario Limonciello mario.limonciello@dell.com Cc: "Pali Rohár" pali@kernel.org Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: "Uwe Kleine-König" u.kleine-koenig@pengutronix.de Cc: Dell.Client.Kernel@dell.com Cc: platform-driver-x86@vger.kernel.org Reported-by: Andy Lavr andy.lavr@gmail.com Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20210825160749.3891090-1-keescook@chromium.org Reviewed-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/platform/x86/dell-smbios-wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-smbios-wmi.c index c97bd4a45242..32e8c4715d53 100644 --- a/drivers/platform/x86/dell-smbios-wmi.c +++ b/drivers/platform/x86/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]);