selftests/bpf: Test packet range of pointers sharing an idgrafted

Add tests where two packet pointers share an id and tightening one
pointer's umax from its var_off would put it less than their constant
distance from the other's umax: with an index & 0x38 capped at 50, the
base pointer keeps umax 50, so the pointer 8 bytes further on must keep
umax 58, even though its known bits allow at most 56.

These refused a valid program or accepted an out-of-bounds access before
the fix:

- check the advanced copy, load through the base: valid, was refused;
- check the base, load the byte at base + 1 through a copy advanced by
  8: was accepted;
- check base + 4, load 4 bytes at base + 2 through base + 8: reads two
  bytes past the checked range, was accepted;
- the same as the second with data_meta pointers checked against data:
  was accepted.

These pass with and without the fix and cover nearby paths:

- subtract an unknown scalar from a checked pointer and load below it
  (the range is kept across a new id);
- reach a load through two paths whose checks cover 8 and 7 bytes after
  the loaded pointer; the second path must not be pruned by the first;
- spill a copy of a pointer, check the pointer, fill the copy and load
  one byte past the checked range: the load is refused, and the copy
  has the range of the check.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/usb/class/Kconfig b/drivers/usb/class/Kconfig
new file mode 100644
index 000000000..d3f5162bd
--- /dev/null
+++ b/drivers/usb/class/Kconfig
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB Class driver configuration
+#
+comment "USB Device Class drivers"
+
+config USB_ACM
+	tristate "USB Modem (CDC ACM) support"
+	depends on TTY
+	help
+	  This driver supports USB modems and ISDN adapters which support the
+	  Communication Device Class Abstract Control Model interface.
+	  Please read <file:Documentation/usb/acm.rst> for details.
+
+	  If your modem only reports "Cls=ff(vend.)" in the descriptors in
+	  /sys/kernel/debug/usb/devices, then your modem will not work with this
+	  driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cdc-acm.
+
+config USB_PRINTER
+	tristate "USB Printer support"
+	help
+	  Say Y here if you want to connect a USB printer to your computer's
+	  USB port.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usblp.
+
+config USB_WDM
+	tristate "USB Wireless Device Management support"
+	help
+	  This driver supports the WMC Device Management functionality
+	  of cell phones compliant to the CDC WMC specification. You can use
+	  AT commands over this device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cdc-wdm.
+
+config USB_TMC
+	tristate "USB Test and Measurement Class support"
+	help
+	  Say Y here if you want to connect a USB device that follows
+	  the USB.org specification for USB Test and Measurement devices
+	  to your computer's USB port.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usbtmc.