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, 35 insertions, 0 deletions

diff --git a/include/misc/altera.h b/include/misc/altera.h
new file mode 100644
index 000000000..60cb5c598
--- /dev/null
+++ b/include/misc/altera.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * altera.h
+ *
+ * altera FPGA driver
+ *
+ * Copyright (C) Altera Corporation 1998-2001
+ * Copyright (C) 2010 NetUP Inc.
+ * Copyright (C) 2010 Igor M. Liplianin <liplianin@netup.ru>
+ */
+
+#ifndef _ALTERA_H_
+#define _ALTERA_H_
+
+struct altera_config {
+	void *dev;
+	u8 *action;
+	int (*jtag_io) (void *dev, int tms, int tdi, int tdo);
+};
+
+#if defined(CONFIG_ALTERA_STAPL) || \
+		(defined(CONFIG_ALTERA_STAPL_MODULE) && defined(MODULE))
+
+extern int altera_init(struct altera_config *config, const struct firmware *fw);
+#else
+
+static inline int altera_init(struct altera_config *config,
+						const struct firmware *fw)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return 0;
+}
+#endif /* CONFIG_ALTERA_STAPL */
+
+#endif /* _ALTERA_H_ */