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, 71 insertions, 0 deletions

diff --git a/include/trace/events/hwmon.h b/include/trace/events/hwmon.h
new file mode 100644
index 000000000..3865098f2
--- /dev/null
+++ b/include/trace/events/hwmon.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM hwmon
+
+#if !defined(_TRACE_HWMON_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HWMON_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(hwmon_attr_class,
+
+	TP_PROTO(int index, const char *attr_name, long long val),
+
+	TP_ARGS(index, attr_name, val),
+
+	TP_STRUCT__entry(
+		__field(int, index)
+		__string(attr_name, attr_name)
+		__field(long long, val)
+	),
+
+	TP_fast_assign(
+		__entry->index = index;
+		__assign_str(attr_name);
+		__entry->val = val;
+	),
+
+	TP_printk("index=%d, attr_name=%s, val=%lld",
+		  __entry->index,  __get_str(attr_name), __entry->val)
+);
+
+DEFINE_EVENT(hwmon_attr_class, hwmon_attr_show,
+
+	TP_PROTO(int index, const char *attr_name, long long val),
+
+	TP_ARGS(index, attr_name, val)
+);
+
+DEFINE_EVENT(hwmon_attr_class, hwmon_attr_store,
+
+	TP_PROTO(int index, const char *attr_name, long long val),
+
+	TP_ARGS(index, attr_name, val)
+);
+
+TRACE_EVENT(hwmon_attr_show_string,
+
+	TP_PROTO(int index, const char *attr_name, const char *s),
+
+	TP_ARGS(index, attr_name, s),
+
+	TP_STRUCT__entry(
+		__field(int, index)
+		__string(attr_name, attr_name)
+		__string(label, s)
+	),
+
+	TP_fast_assign(
+		__entry->index = index;
+		__assign_str(attr_name);
+		__assign_str(label);
+	),
+
+	TP_printk("index=%d, attr_name=%s, val=%s",
+		  __entry->index, __get_str(attr_name), __get_str(label))
+);
+
+#endif /* _TRACE_HWMON_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>