Hi, On 8/25/21 6:07 PM, Kees Cook wrote: > 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] > > Note: is there a missed kfree() in the marked error path? > > Cc: Hans de Goede <hdegoede@xxxxxxxxxx> > Cc: Mark Gross <mgross@xxxxxxxxxxxxxxx> > Cc: Mario Limonciello <mario.limonciello@xxxxxxxx> > Cc: "Pali Rohár" <pali@xxxxxxxxxx> > Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Cc: "Uwe Kleine-König" <u.kleine-koenig@xxxxxxxxxxxxxx> > Cc: Dell.Client.Kernel@xxxxxxxx > Cc: platform-driver-x86@xxxxxxxxxxxxxxx > Reported-by: Andy Lavr <andy.lavr@xxxxxxxxx> > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Thank you, I've applied the patch, minus the: /* output.pointer memory allocation leak? */ Comment, instead I'll submit (and also apply right-away) a patch to add the missing kfree() Regards, Hans > --- > drivers/platform/x86/dell/dell-smbios-wmi.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/platform/x86/dell/dell-smbios-wmi.c b/drivers/platform/x86/dell/dell-smbios-wmi.c > index 33f823772733..c410d6d920b8 100644 > --- a/drivers/platform/x86/dell/dell-smbios-wmi.c > +++ b/drivers/platform/x86/dell/dell-smbios-wmi.c > @@ -69,9 +69,10 @@ static int run_smbios_call(struct wmi_device *wdev) > if (obj->type == ACPI_TYPE_INTEGER) > dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n", > obj->integer.value); > + /* output.pointer memory allocation leak? */ > 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]); >
