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, 28 insertions, 0 deletions

diff --git a/scripts/remove-stale-files b/scripts/remove-stale-files
new file mode 100755
index 000000000..6e39fa854
--- /dev/null
+++ b/scripts/remove-stale-files
@@ -0,0 +1,28 @@
+#!/bin/sh
+
+set -e
+
+# When you move, remove or rename generated files, you probably also update
+# .gitignore and cleaning rules in the Makefile. This is the right thing
+# to do. However, people usually do 'git pull', 'git bisect', etc. without
+# running 'make clean'. Then, the stale generated files are left over, often
+# causing build issues.
+#
+# Also, 'git status' shows such stale build artifacts as untracked files.
+# What is worse, some people send a wrong patch to get them back to .gitignore
+# without checking the commit history.
+#
+# So, when you (re)move generated files, please move the cleaning rules from
+# the Makefile to this script. This is run before Kbuild starts building
+# anything, so people will not be annoyed by such garbage files.
+#
+# This script is not intended to grow endlessly. Rather, it is a temporary scrap
+# yard. Stale files stay in this file for a while (for some release cycles?),
+# then will be really dead and removed from the code base entirely.
+
+# moved to security/selinux/genheaders
+rm -f scripts/selinux/genheaders/genheaders
+
+rm -f *.spec
+
+rm -f lib/test_fortify.log