While looking into a CONFIG_FORTIFY=y related bug, I noticed that
hid_allocate calls strlen() on a local C string variable. This variable
can only have literal string values. There is no benefit to having
FORTIFY have this be a checked strlen call, because these are literal
values. By calling strlen() explicitly in the branches of a switch, the
compiler can evaluate strlen("literal value") at compile time, rather
than at runtime.
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
drivers/hid/hid-input.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 48c1c02c69f4..9ad3cc88c26b 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -1922,12 +1922,15 @@ static struct hid_input *hidinput_allocate(struct hid_device *hid,
switch (application) {
case HID_GD_KEYBOARD:
suffix = "Keyboard";
+ suffix_len = strlen(suffix);
break;
case HID_GD_KEYPAD:
suffix = "Keypad";
+ suffix_len = strlen(suffix);
break;
case HID_GD_MOUSE:
suffix = "Mouse";
+ suffix_len = strlen(suffix);
break;
case HID_DG_PEN:
/*
@@ -1938,36 +1941,44 @@ static struct hid_input *hidinput_allocate(struct hid_device *hid,
* will have to change it and the test suite will not be happy.
*/
suffix = "Stylus";
+ suffix_len = strlen(suffix);
break;
case HID_DG_STYLUS:
suffix = "Pen";
+ suffix_len = strlen(suffix);
break;
case HID_DG_TOUCHSCREEN:
suffix = "Touchscreen";
+ suffix_len = strlen(suffix);
break;
case HID_DG_TOUCHPAD:
suffix = "Touchpad";
+ suffix_len = strlen(suffix);
break;
case HID_GD_SYSTEM_CONTROL:
suffix = "System Control";
+ suffix_len = strlen(suffix);
break;
case HID_CP_CONSUMER_CONTROL:
suffix = "Consumer Control";
+ suffix_len = strlen(suffix);
break;
case HID_GD_WIRELESS_RADIO_CTLS:
suffix = "Wireless Radio Control";
+ suffix_len = strlen(suffix);
break;
case HID_GD_SYSTEM_MULTIAXIS:
suffix = "System Multi Axis";
+ suffix_len = strlen(suffix);
break;
default:
+ suffix_len = 0;
break;
}
}
if (suffix) {
name_len = strlen(hid->name);
- suffix_len = strlen(suffix);
if ((name_len < suffix_len) ||
strcmp(hid->name + name_len - suffix_len, suffix)) {
hidinput->name = kasprintf(GFP_KERNEL, "%s %s",
--
2.37.2.672.g94769d06f0-goog
