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, 106 insertions, 0 deletions

diff --git a/include/net/smc.h b/include/net/smc.h
new file mode 100644
index 000000000..a2bc3ab88
--- /dev/null
+++ b/include/net/smc.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  Definitions for the SMC module (socket related)
+ *
+ *  Copyright IBM Corp. 2016
+ *
+ *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+#ifndef _SMC_H
+#define _SMC_H
+
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/dibs.h>
+
+struct tcp_sock;
+struct inet_request_sock;
+struct sock;
+
+#define SMC_MAX_PNETID_LEN	16	/* Max. length of PNET id */
+
+struct smc_hashinfo {
+	rwlock_t lock;
+	struct hlist_head ht;
+};
+
+/* SMCD/ISM device driver interface */
+#define ISM_RESERVED_VLANID	0x1FFF
+
+struct smcd_gid {
+	u64	gid;
+	u64	gid_ext;
+};
+
+struct smcd_dev {
+	struct dibs_dev *dibs;
+	struct list_head list;
+	spinlock_t lock;
+	struct list_head vlan;
+	struct workqueue_struct *event_wq;
+	u8 pnetid[SMC_MAX_PNETID_LEN];
+	bool pnetid_by_user;
+	struct list_head lgr_list;
+	spinlock_t lgr_lock;
+	atomic_t lgr_cnt;
+	wait_queue_head_t lgrs_deleted;
+	u8 going_away : 1;
+	struct smc_connection *conn[];
+};
+
+#define SMC_HS_CTRL_NAME_MAX 16
+
+enum {
+	/* ops can be inherit from init_net */
+	SMC_HS_CTRL_FLAG_INHERITABLE = 0x1,
+
+	SMC_HS_CTRL_ALL_FLAGS = SMC_HS_CTRL_FLAG_INHERITABLE,
+};
+
+struct smc_hs_ctrl {
+	/* private */
+
+	struct list_head list;
+	struct module *owner;
+
+	/* public */
+
+	/* unique name */
+	char name[SMC_HS_CTRL_NAME_MAX];
+	int flags;
+
+	/* Invoked before computing SMC option for SYN packets.
+	 * We can control whether to set SMC options by returning various value.
+	 * Return 0 to disable SMC, or return any other value to enable it.
+	 */
+	int (*syn_option)(struct tcp_sock *tp);
+
+	/* Invoked before Set up SMC options for SYN-ACK packets
+	 * We can control whether to respond SMC options by returning various
+	 * value. Return 0 to disable SMC, or return any other value to enable
+	 * it.
+	 */
+	int (*synack_option)(const struct tcp_sock *tp,
+			     struct inet_request_sock *ireq);
+};
+
+#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
+#define smc_call_hsbpf(init_val, tp, func, ...) ({				\
+	typeof(init_val) __ret = (init_val);					\
+	struct smc_hs_ctrl *ctrl;						\
+	rcu_read_lock();							\
+	ctrl = rcu_dereference(sock_net((struct sock *)(tp))->smc.hs_ctrl);	\
+	if (ctrl && ctrl->func)							\
+		__ret = ctrl->func(tp, ##__VA_ARGS__);				\
+	rcu_read_unlock();							\
+	__ret;									\
+})
+#else
+#define smc_call_hsbpf(init_val, tp, ...)  ({ (void)(tp); (init_val); })
+#endif /* CONFIG_SMC_HS_CTRL_BPF */
+
+#endif	/* _SMC_H */