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, 102 insertions, 0 deletions

diff --git a/include/trace/events/thp.h b/include/trace/events/thp.h
new file mode 100644
index 000000000..c8fe879d5
--- /dev/null
+++ b/include/trace/events/thp.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM thp
+
+#if !defined(_TRACE_THP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_THP_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+#ifdef CONFIG_PPC_BOOK3S_64
+DECLARE_EVENT_CLASS(hugepage_set,
+
+	    TP_PROTO(unsigned long addr, unsigned long pte),
+	    TP_ARGS(addr, pte),
+	    TP_STRUCT__entry(
+		    __field(unsigned long, addr)
+		    __field(unsigned long, pte)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->addr = addr;
+		    __entry->pte = pte;
+		    ),
+
+	    TP_printk("Set page table entry with 0x%lx with 0x%lx", __entry->addr, __entry->pte)
+);
+
+DEFINE_EVENT(hugepage_set, hugepage_set_pmd,
+	    TP_PROTO(unsigned long addr, unsigned long pmd),
+	    TP_ARGS(addr, pmd)
+);
+
+DEFINE_EVENT(hugepage_set, hugepage_set_pud,
+	    TP_PROTO(unsigned long addr, unsigned long pud),
+	    TP_ARGS(addr, pud)
+);
+
+DECLARE_EVENT_CLASS(hugepage_update,
+
+	    TP_PROTO(unsigned long addr, unsigned long pte, unsigned long clr, unsigned long set),
+	    TP_ARGS(addr, pte, clr, set),
+	    TP_STRUCT__entry(
+		    __field(unsigned long, addr)
+		    __field(unsigned long, pte)
+		    __field(unsigned long, clr)
+		    __field(unsigned long, set)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->addr = addr;
+		    __entry->pte = pte;
+		    __entry->clr = clr;
+		    __entry->set = set;
+
+		    ),
+
+	    TP_printk("hugepage update at addr 0x%lx and pte = 0x%lx clr = 0x%lx, set = 0x%lx", __entry->addr, __entry->pte, __entry->clr, __entry->set)
+);
+
+DEFINE_EVENT(hugepage_update, hugepage_update_pmd,
+	    TP_PROTO(unsigned long addr, unsigned long pmd, unsigned long clr, unsigned long set),
+	    TP_ARGS(addr, pmd, clr, set)
+);
+
+DEFINE_EVENT(hugepage_update, hugepage_update_pud,
+	    TP_PROTO(unsigned long addr, unsigned long pud, unsigned long clr, unsigned long set),
+	    TP_ARGS(addr, pud, clr, set)
+);
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
+DECLARE_EVENT_CLASS(migration_pmd,
+
+		TP_PROTO(unsigned long addr, unsigned long pmd),
+
+		TP_ARGS(addr, pmd),
+
+		TP_STRUCT__entry(
+			__field(unsigned long, addr)
+			__field(unsigned long, pmd)
+		),
+
+		TP_fast_assign(
+			__entry->addr = addr;
+			__entry->pmd = pmd;
+		),
+		TP_printk("addr=%lx, pmd=%lx", __entry->addr, __entry->pmd)
+);
+
+DEFINE_EVENT(migration_pmd, set_migration_pmd,
+	TP_PROTO(unsigned long addr, unsigned long pmd),
+	TP_ARGS(addr, pmd)
+);
+
+DEFINE_EVENT(migration_pmd, remove_migration_pmd,
+	TP_PROTO(unsigned long addr, unsigned long pmd),
+	TP_ARGS(addr, pmd)
+);
+#endif /* _TRACE_THP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>