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, 69 insertions, 0 deletions

diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
new file mode 100644
index 000000000..2bc00c67d
--- /dev/null
+++ b/include/asm-generic/Kbuild
@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# asm headers that all architectures except um should have
+# (This file is not included when SRCARCH=um since UML borrows several
+# asm headers from the host architecture.)
+
+mandatory-y += atomic.h
+mandatory-y += archrandom.h
+mandatory-y += barrier.h
+mandatory-y += bitops.h
+mandatory-y += bug.h
+mandatory-y += cacheflush.h
+mandatory-y += cfi.h
+mandatory-y += checksum.h
+mandatory-y += compat.h
+mandatory-y += current.h
+mandatory-y += delay.h
+mandatory-y += device.h
+mandatory-y += div64.h
+mandatory-y += dma-mapping.h
+mandatory-y += dma.h
+mandatory-y += emergency-restart.h
+mandatory-y += exec.h
+mandatory-y += ftrace.h
+mandatory-y += futex.h
+mandatory-y += hardirq.h
+mandatory-y += hw_irq.h
+mandatory-y += io.h
+mandatory-y += irq.h
+mandatory-y += irq_regs.h
+mandatory-y += irq_work.h
+mandatory-y += kdebug.h
+mandatory-y += kmap_size.h
+mandatory-y += kprobes.h
+mandatory-y += kvm_types.h
+mandatory-y += linkage.h
+mandatory-y += local.h
+mandatory-y += local64.h
+mandatory-y += mmiowb.h
+mandatory-y += mmu.h
+mandatory-y += mmu_context.h
+mandatory-y += module.h
+mandatory-y += module.lds.h
+mandatory-y += msi.h
+mandatory-y += pci.h
+mandatory-y += percpu.h
+mandatory-y += percpu_types.h
+mandatory-y += pgalloc.h
+mandatory-y += preempt.h
+mandatory-y += rqspinlock.h
+mandatory-y += runtime-const.h
+mandatory-y += rwonce.h
+mandatory-y += sections.h
+mandatory-y += serial.h
+mandatory-y += shmparam.h
+mandatory-y += simd.h
+mandatory-y += softirq_stack.h
+mandatory-y += switch_to.h
+mandatory-y += timex.h
+mandatory-y += tlbflush.h
+mandatory-y += topology.h
+mandatory-y += trace_clock.h
+mandatory-y += uaccess.h
+mandatory-y += unwind_user.h
+mandatory-y += vdso/clocksource.h
+mandatory-y += vermagic.h
+mandatory-y += vga.h
+mandatory-y += video.h
+mandatory-y += word-at-a-time.h