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, 166 insertions, 0 deletions

diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
new file mode 100644
index 000000000..a65a27dc5
--- /dev/null
+++ b/drivers/s390/cio/css.h
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CSS_H
+#define _CSS_H
+
+#include <linux/mutex.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/types.h>
+
+#include <asm/cio.h>
+#include <asm/chpid.h>
+#include <asm/schid.h>
+
+#include "cio.h"
+
+/*
+ * path grouping stuff
+ */
+#define SPID_FUNC_SINGLE_PATH	   0x00
+#define SPID_FUNC_MULTI_PATH	   0x80
+#define SPID_FUNC_ESTABLISH	   0x00
+#define SPID_FUNC_RESIGN	   0x40
+#define SPID_FUNC_DISBAND	   0x20
+
+#define SNID_STATE1_RESET	   0
+#define SNID_STATE1_UNGROUPED	   2
+#define SNID_STATE1_GROUPED	   3
+
+#define SNID_STATE2_NOT_RESVD	   0
+#define SNID_STATE2_RESVD_ELSE	   2
+#define SNID_STATE2_RESVD_SELF	   3
+
+#define SNID_STATE3_MULTI_PATH	   1
+#define SNID_STATE3_SINGLE_PATH	   0
+
+/*
+ * Miscellaneous constants
+ */
+
+#define CSS_NUM_CUB_PAGES		2
+#define CSS_CUES_PER_PAGE		128
+#define CSS_NUM_ECUB_PAGES		4
+#define CSS_ECUES_PER_PAGE		64
+
+/*
+ * Conditions used to specify which subchannels need evaluation
+ */
+enum css_eval_cond {
+	CSS_EVAL_NO_PATH,		/* Subchannels with no operational paths */
+	CSS_EVAL_NOT_ONLINE	/* sch without an online-device */
+};
+
+struct path_state {
+	__u8  state1 : 2;	/* path state value 1 */
+	__u8  state2 : 2;	/* path state value 2 */
+	__u8  state3 : 1;	/* path state value 3 */
+	__u8  resvd  : 3;	/* reserved */
+} __attribute__ ((packed));
+
+struct extended_cssid {
+	u8 version;
+	u8 cssid;
+} __attribute__ ((packed));
+
+struct pgid {
+	union {
+		__u8 fc;   	/* SPID function code */
+		struct path_state ps;	/* SNID path state */
+	} __attribute__ ((packed)) inf;
+	union {
+		__u32 cpu_addr	: 16;	/* CPU address */
+		struct extended_cssid ext_cssid;
+	} __attribute__ ((packed)) pgid_high;
+	__u32 cpu_id	: 24;	/* CPU identification */
+	__u32 cpu_model : 16;	/* CPU model */
+	__u32 tod_high;		/* high word TOD clock */
+} __attribute__ ((packed));
+
+struct subchannel;
+struct chp_link;
+/**
+ * struct css_driver - device driver for subchannels
+ * @subchannel_type: subchannel type supported by this driver
+ * @drv: embedded device driver structure
+ * @irq: called on interrupts
+ * @chp_event: called for events affecting a channel path
+ * @sch_event: called for events affecting the subchannel
+ * @probe: function called on probe
+ * @remove: function called on remove
+ * @shutdown: called at device shutdown
+ * @settle: wait for asynchronous work to finish
+ */
+struct css_driver {
+	struct css_device_id *subchannel_type;
+	struct device_driver drv;
+	void (*irq)(struct subchannel *);
+	int (*chp_event)(struct subchannel *, struct chp_link *, int);
+	int (*sch_event)(struct subchannel *, int);
+	int (*probe)(struct subchannel *);
+	void (*remove)(struct subchannel *);
+	void (*shutdown)(struct subchannel *);
+	int (*settle)(void);
+};
+
+#define to_cssdriver(n) container_of_const(n, struct css_driver, drv)
+
+extern int css_driver_register(struct css_driver *);
+extern void css_driver_unregister(struct css_driver *);
+
+extern void css_sch_device_unregister(struct subchannel *);
+extern int css_register_subchannel(struct subchannel *);
+extern struct subchannel *css_alloc_subchannel(struct subchannel_id,
+					       struct schib *schib);
+extern struct subchannel *get_subchannel_by_schid(struct subchannel_id);
+extern int css_init_done;
+extern int max_ssid;
+int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
+			       int (*fn_unknown)(struct subchannel_id,
+			       void *), void *data);
+extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
+void css_update_ssd_info(struct subchannel *sch);
+
+struct channel_subsystem {
+	u8 cssid;
+	u8 iid;
+	bool id_valid; /* cssid,iid */
+	struct channel_path *chps[__MAX_CHPID + 1];
+	struct device device;
+	struct pgid global_pgid;
+	struct mutex mutex;
+	/* channel measurement related */
+	int cm_enabled;
+	void *cub[CSS_NUM_CUB_PAGES];
+	void *ecub[CSS_NUM_ECUB_PAGES];
+	/* for orphaned ccw devices */
+	struct subchannel *pseudo_subchannel;
+};
+#define to_css(dev) container_of(dev, struct channel_subsystem, device)
+
+extern struct channel_subsystem *channel_subsystems[];
+
+/* Dummy helper which needs to change once we support more than one css. */
+static inline struct channel_subsystem *css_by_id(u8 cssid)
+{
+	return channel_subsystems[0];
+}
+
+/* Dummy iterator which needs to change once we support more than one css. */
+#define for_each_css(css)						\
+	for ((css) = channel_subsystems[0]; (css); (css) = NULL)
+
+/* Helper functions to build lists for the slow path. */
+void css_schedule_eval(struct subchannel_id schid);
+void css_schedule_eval_all(void);
+void css_schedule_eval_cond(enum css_eval_cond, unsigned long delay);
+int css_complete_work(void);
+
+int sch_is_pseudo_sch(struct subchannel *);
+struct schib;
+int css_sch_is_valid(struct schib *);
+
+extern struct workqueue_struct *cio_work_q;
+void css_wait_for_slow_path(void);
+void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo);
+#endif