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, 263 insertions, 0 deletions

diff --git a/include/trace/events/cgroup.h b/include/trace/events/cgroup.h
new file mode 100644
index 000000000..b736da063
--- /dev/null
+++ b/include/trace/events/cgroup.h
@@ -0,0 +1,263 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cgroup
+
+#if !defined(_TRACE_CGROUP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CGROUP_H
+
+#include <linux/cgroup.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(cgroup_root,
+
+	TP_PROTO(struct cgroup_root *root),
+
+	TP_ARGS(root),
+
+	TP_STRUCT__entry(
+		__field(	int,		root			)
+		__field(	u32,		ss_mask			)
+		__string(	name,		root->name		)
+	),
+
+	TP_fast_assign(
+		__entry->root = root->hierarchy_id;
+		__entry->ss_mask = root->subsys_mask;
+		__assign_str(name);
+	),
+
+	TP_printk("root=%d ss_mask=%#x name=%s",
+		  __entry->root, __entry->ss_mask, __get_str(name))
+);
+
+DEFINE_EVENT(cgroup_root, cgroup_setup_root,
+
+	TP_PROTO(struct cgroup_root *root),
+
+	TP_ARGS(root)
+);
+
+DEFINE_EVENT(cgroup_root, cgroup_destroy_root,
+
+	TP_PROTO(struct cgroup_root *root),
+
+	TP_ARGS(root)
+);
+
+DEFINE_EVENT(cgroup_root, cgroup_remount,
+
+	TP_PROTO(struct cgroup_root *root),
+
+	TP_ARGS(root)
+);
+
+DECLARE_EVENT_CLASS(cgroup,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path),
+
+	TP_STRUCT__entry(
+		__field(	int,		root			)
+		__field(	int,		level			)
+		__field(	u64,		id			)
+		__string(	path,		path			)
+	),
+
+	TP_fast_assign(
+		__entry->root = cgrp->root->hierarchy_id;
+		__entry->id = cgroup_id(cgrp);
+		__entry->level = cgrp->level;
+		__assign_str(path);
+	),
+
+	TP_printk("root=%d id=%llu level=%d path=%s",
+		  __entry->root, __entry->id, __entry->level, __get_str(path))
+);
+
+DEFINE_EVENT(cgroup, cgroup_mkdir,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path)
+);
+
+DEFINE_EVENT(cgroup, cgroup_rmdir,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path)
+);
+
+DEFINE_EVENT(cgroup, cgroup_release,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path)
+);
+
+DEFINE_EVENT(cgroup, cgroup_rename,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path)
+);
+
+DEFINE_EVENT(cgroup, cgroup_freeze,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path)
+);
+
+DEFINE_EVENT(cgroup, cgroup_unfreeze,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path),
+
+	TP_ARGS(cgrp, path)
+);
+
+DECLARE_EVENT_CLASS(cgroup_migrate,
+
+	TP_PROTO(struct cgroup *dst_cgrp, const char *path,
+		 struct task_struct *task, bool threadgroup),
+
+	TP_ARGS(dst_cgrp, path, task, threadgroup),
+
+	TP_STRUCT__entry(
+		__field(	int,		dst_root		)
+		__field(	int,		dst_level		)
+		__field(	u64,		dst_id			)
+		__field(	int,		pid			)
+		__string(	dst_path,	path			)
+		__string(	comm,		task->comm		)
+	),
+
+	TP_fast_assign(
+		__entry->dst_root = dst_cgrp->root->hierarchy_id;
+		__entry->dst_id = cgroup_id(dst_cgrp);
+		__entry->dst_level = dst_cgrp->level;
+		__assign_str(dst_path);
+		__entry->pid = task->pid;
+		__assign_str(comm);
+	),
+
+	TP_printk("dst_root=%d dst_id=%llu dst_level=%d dst_path=%s pid=%d comm=%s",
+		  __entry->dst_root, __entry->dst_id, __entry->dst_level,
+		  __get_str(dst_path), __entry->pid, __get_str(comm))
+);
+
+DEFINE_EVENT(cgroup_migrate, cgroup_attach_task,
+
+	TP_PROTO(struct cgroup *dst_cgrp, const char *path,
+		 struct task_struct *task, bool threadgroup),
+
+	TP_ARGS(dst_cgrp, path, task, threadgroup)
+);
+
+DEFINE_EVENT(cgroup_migrate, cgroup_transfer_tasks,
+
+	TP_PROTO(struct cgroup *dst_cgrp, const char *path,
+		 struct task_struct *task, bool threadgroup),
+
+	TP_ARGS(dst_cgrp, path, task, threadgroup)
+);
+
+DECLARE_EVENT_CLASS(cgroup_event,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path, int val),
+
+	TP_ARGS(cgrp, path, val),
+
+	TP_STRUCT__entry(
+		__field(	int,		root			)
+		__field(	int,		level			)
+		__field(	u64,		id			)
+		__string(	path,		path			)
+		__field(	int,		val			)
+	),
+
+	TP_fast_assign(
+		__entry->root = cgrp->root->hierarchy_id;
+		__entry->id = cgroup_id(cgrp);
+		__entry->level = cgrp->level;
+		__assign_str(path);
+		__entry->val = val;
+	),
+
+	TP_printk("root=%d id=%llu level=%d path=%s val=%d",
+		  __entry->root, __entry->id, __entry->level, __get_str(path),
+		  __entry->val)
+);
+
+DEFINE_EVENT(cgroup_event, cgroup_notify_populated,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path, int val),
+
+	TP_ARGS(cgrp, path, val)
+);
+
+DEFINE_EVENT(cgroup_event, cgroup_notify_frozen,
+
+	TP_PROTO(struct cgroup *cgrp, const char *path, int val),
+
+	TP_ARGS(cgrp, path, val)
+);
+
+DECLARE_EVENT_CLASS(cgroup_rstat,
+
+	TP_PROTO(struct cgroup *cgrp, int cpu, bool contended),
+
+	TP_ARGS(cgrp, cpu, contended),
+
+	TP_STRUCT__entry(
+		__field(	int,		root			)
+		__field(	int,		level			)
+		__field(	u64,		id			)
+		__field(	int,		cpu			)
+		__field(	bool,		contended		)
+	),
+
+	TP_fast_assign(
+		__entry->root = cgrp->root->hierarchy_id;
+		__entry->id = cgroup_id(cgrp);
+		__entry->level = cgrp->level;
+		__entry->cpu = cpu;
+		__entry->contended = contended;
+	),
+
+	TP_printk("root=%d id=%llu level=%d cpu=%d lock contended:%d",
+		  __entry->root, __entry->id, __entry->level,
+		  __entry->cpu, __entry->contended)
+);
+
+/*
+ * Related to locks:
+ * global rstat_base_lock for base stats
+ * cgroup_subsys::rstat_ss_lock for subsystem stats
+ */
+DEFINE_EVENT(cgroup_rstat, cgroup_rstat_lock_contended,
+
+	TP_PROTO(struct cgroup *cgrp, int cpu, bool contended),
+
+	TP_ARGS(cgrp, cpu, contended)
+);
+
+DEFINE_EVENT(cgroup_rstat, cgroup_rstat_locked,
+
+	TP_PROTO(struct cgroup *cgrp, int cpu, bool contended),
+
+	TP_ARGS(cgrp, cpu, contended)
+);
+
+DEFINE_EVENT(cgroup_rstat, cgroup_rstat_unlock,
+
+	TP_PROTO(struct cgroup *cgrp, int cpu, bool contended),
+
+	TP_ARGS(cgrp, cpu, contended)
+);
+
+#endif /* _TRACE_CGROUP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>