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, 95 insertions, 0 deletions

diff --git a/include/trace/events/kyber.h b/include/trace/events/kyber.h
new file mode 100644
index 000000000..9d44781ef
--- /dev/null
+++ b/include/trace/events/kyber.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM kyber
+
+#if !defined(_TRACE_KYBER_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KYBER_H
+
+#include <linux/blkdev.h>
+#include <linux/tracepoint.h>
+
+#define DOMAIN_LEN		16
+#define LATENCY_TYPE_LEN	8
+
+TRACE_EVENT(kyber_latency,
+
+	TP_PROTO(dev_t dev, const char *domain, const char *type,
+		 unsigned int percentile, unsigned int numerator,
+		 unsigned int denominator, unsigned int samples),
+
+	TP_ARGS(dev, domain, type, percentile, numerator, denominator, samples),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev				)
+		__array(	char,	domain,	DOMAIN_LEN		)
+		__array(	char,	type,	LATENCY_TYPE_LEN	)
+		__field(	u8,	percentile			)
+		__field(	u8,	numerator			)
+		__field(	u8,	denominator			)
+		__field(	unsigned int,	samples			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= dev;
+		strscpy(__entry->domain, domain, sizeof(__entry->domain));
+		strscpy(__entry->type, type, sizeof(__entry->type));
+		__entry->percentile	= percentile;
+		__entry->numerator	= numerator;
+		__entry->denominator	= denominator;
+		__entry->samples	= samples;
+	),
+
+	TP_printk("%d,%d %s %s p%u %u/%u samples=%u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->domain,
+		  __entry->type, __entry->percentile, __entry->numerator,
+		  __entry->denominator, __entry->samples)
+);
+
+TRACE_EVENT(kyber_adjust,
+
+	TP_PROTO(dev_t dev, const char *domain, unsigned int depth),
+
+	TP_ARGS(dev, domain, depth),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__array(	char,	domain,	DOMAIN_LEN	)
+		__field(	unsigned int,	depth		)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= dev;
+		strscpy(__entry->domain, domain, sizeof(__entry->domain));
+		__entry->depth		= depth;
+	),
+
+	TP_printk("%d,%d %s %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->domain,
+		  __entry->depth)
+);
+
+TRACE_EVENT(kyber_throttled,
+
+	TP_PROTO(dev_t dev, const char *domain),
+
+	TP_ARGS(dev, domain),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__array(	char,	domain,	DOMAIN_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= dev;
+		strscpy(__entry->domain, domain, sizeof(__entry->domain));
+	),
+
+	TP_printk("%d,%d %s", MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->domain)
+);
+
+#define _TRACE_KYBER_H
+#endif /* _TRACE_KYBER_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>