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, 42 insertions, 0 deletions

diff --git a/scripts/git.orderFile b/scripts/git.orderFile
new file mode 100644
index 000000000..5102ba733
--- /dev/null
+++ b/scripts/git.orderFile
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# order file for git, to produce patches which are easier to review
+# by diffing the important stuff like header changes first.
+#
+# one-off usage:
+#   git diff -O scripts/git.orderFile ...
+#
+# add to git config:
+#   git config diff.orderFile scripts/git.orderFile
+#
+
+MAINTAINERS
+
+# Documentation
+Documentation/*
+*.rst
+
+# git-specific
+.gitignore
+scripts/git.orderFile
+
+# build system
+Kconfig*
+*/Kconfig*
+Kbuild*
+*/Kbuild*
+Makefile*
+*/Makefile*
+*.mak
+*.mk
+scripts/*
+
+# semantic patches
+*.cocci
+
+# headers
+*types.h
+*.h
+
+# code
+*.c