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, 31 insertions, 0 deletions

diff --git a/drivers/resctrl/Kconfig b/drivers/resctrl/Kconfig
new file mode 100644
index 000000000..672abea3b
--- /dev/null
+++ b/drivers/resctrl/Kconfig
@@ -0,0 +1,31 @@
+menuconfig ARM64_MPAM_DRIVER
+	bool "MPAM driver"
+	depends on ARM64 && ARM64_MPAM
+	select ACPI_MPAM if ACPI
+	help
+	  Memory System Resource Partitioning and Monitoring (MPAM) driver for
+	  System IP, e.g. caches and memory controllers.
+
+if ARM64_MPAM_DRIVER
+
+config ARM64_MPAM_DRIVER_DEBUG
+	bool "Enable debug messages from the MPAM driver"
+	help
+	  Say yes here to enable debug messages from the MPAM driver.
+
+config MPAM_KUNIT_TEST
+	bool "KUnit tests for MPAM driver " if !KUNIT_ALL_TESTS
+	depends on KUNIT=y
+	default KUNIT_ALL_TESTS
+	help
+	  Enable this option to run tests in the MPAM driver.
+
+	  If unsure, say N.
+
+endif
+
+config ARM64_MPAM_RESCTRL_FS
+	bool
+	default y if ARM64_MPAM_DRIVER && RESCTRL_FS
+	select RESCTRL_RMID_DEPENDS_ON_CLOSID
+	select RESCTRL_ASSIGN_FIXED