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, 44 insertions, 0 deletions

diff --git a/include/clocksource/timer-davinci.h b/include/clocksource/timer-davinci.h
new file mode 100644
index 000000000..1dcc1333f
--- /dev/null
+++ b/include/clocksource/timer-davinci.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * TI DaVinci clocksource driver
+ *
+ * Copyright (C) 2019 Texas Instruments
+ * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ */
+
+#ifndef __TIMER_DAVINCI_H__
+#define __TIMER_DAVINCI_H__
+
+#include <linux/clk.h>
+#include <linux/ioport.h>
+
+enum {
+	DAVINCI_TIMER_CLOCKEVENT_IRQ,
+	DAVINCI_TIMER_CLOCKSOURCE_IRQ,
+	DAVINCI_TIMER_NUM_IRQS,
+};
+
+/**
+ * struct davinci_timer_cfg - davinci clocksource driver configuration struct
+ * @reg:        register range resource
+ * @irq:        clockevent and clocksource interrupt resources
+ * @cmp_off:    if set - it specifies the compare register used for clockevent
+ *
+ * Note: if the compare register is specified, the driver will use the bottom
+ * clock half for both clocksource and clockevent and the compare register
+ * to generate event irqs. The user must supply the correct compare register
+ * interrupt number.
+ *
+ * This is only used by da830 the DSP of which uses the top half. The timer
+ * driver still configures the top half to run in free-run mode.
+ */
+struct davinci_timer_cfg {
+	struct resource reg;
+	struct resource irq[DAVINCI_TIMER_NUM_IRQS];
+	unsigned int cmp_off;
+};
+
+int __init davinci_timer_register(struct clk *clk,
+				  const struct davinci_timer_cfg *data);
+
+#endif /* __TIMER_DAVINCI_H__ */