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, 47 insertions, 0 deletions

diff --git a/samples/Makefile b/samples/Makefile
new file mode 100644
index 000000000..07641e177
--- /dev/null
+++ b/samples/Makefile
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for Linux samples code
+
+subdir-$(CONFIG_SAMPLE_AUXDISPLAY)	+= auxdisplay
+subdir-$(CONFIG_SAMPLE_ANDROID_BINDERFS) += binderfs
+subdir-$(CONFIG_SAMPLE_CHECK_EXEC)	+= check-exec
+subdir-$(CONFIG_SAMPLE_CGROUP) += cgroup
+obj-$(CONFIG_SAMPLE_CONFIGFS)		+= configfs/
+obj-$(CONFIG_SAMPLE_CONNECTOR)		+= connector/
+obj-$(CONFIG_SAMPLE_FANOTIFY_ERROR)	+= fanotify/
+subdir-$(CONFIG_SAMPLE_HIDRAW)		+= hidraw
+obj-$(CONFIG_SAMPLE_HW_BREAKPOINT)	+= hw_breakpoint/
+obj-$(CONFIG_SAMPLE_KDB)		+= kdb/
+obj-$(CONFIG_SAMPLE_KFIFO)		+= kfifo/
+obj-$(CONFIG_SAMPLE_KOBJECT)		+= kobject/
+obj-$(CONFIG_SAMPLE_KPROBES)		+= kprobes/
+subdir-$(CONFIG_SAMPLE_LANDLOCK)	+= landlock
+obj-$(CONFIG_SAMPLE_LIVEPATCH)		+= livepatch/
+subdir-$(CONFIG_SAMPLE_PIDFD)		+= pidfd
+obj-$(CONFIG_SAMPLE_QMI_CLIENT)		+= qmi/
+obj-$(CONFIG_SAMPLE_RPMSG_CLIENT)	+= rpmsg/
+subdir-$(CONFIG_SAMPLE_SECCOMP)		+= seccomp
+subdir-$(CONFIG_SAMPLE_TIMER)		+= timers
+obj-$(CONFIG_SAMPLE_TRACE_EVENTS)	+= trace_events/
+obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_events/
+obj-$(CONFIG_SAMPLE_TRACE_PRINTK)	+= trace_printk/
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT)	+= ftrace/
+obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace/
+obj-$(CONFIG_SAMPLE_FTRACE_OPS)		+= ftrace/
+obj-$(CONFIG_SAMPLE_TRACE_ARRAY)	+= ftrace/
+subdir-$(CONFIG_SAMPLE_UHID)		+= uhid
+obj-$(CONFIG_VIDEO_PCI_SKELETON)	+= v4l/
+obj-y					+= vfio-mdev/
+subdir-$(CONFIG_SAMPLE_VFS)		+= vfs
+obj-$(CONFIG_SAMPLE_INTEL_MEI)		+= mei/
+obj-$(CONFIG_SAMPLE_TPS6594_PFSM)	+= pfsm/
+subdir-$(CONFIG_SAMPLE_WATCHDOG)	+= watchdog
+subdir-$(CONFIG_SAMPLE_WATCH_QUEUE)	+= watch_queue
+obj-$(CONFIG_SAMPLE_KMEMLEAK)		+= kmemleak/
+obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
+obj-$(CONFIG_SAMPLE_FPROBE)		+= fprobe/
+obj-$(CONFIG_SAMPLES_RUST)		+= rust/
+obj-$(CONFIG_SAMPLE_DAMON_WSSE)		+= damon/
+obj-$(CONFIG_SAMPLE_DAMON_PRCL)		+= damon/
+obj-$(CONFIG_SAMPLE_DAMON_MTIER)	+= damon/
+obj-$(CONFIG_SAMPLE_HUNG_TASK)		+= hung_task/
+obj-$(CONFIG_SAMPLE_TSM_MR)		+= tsm-mr/