ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted

When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set,
a user fault may trigger show_pte() without any lock.
If another thread in the same process concurrently calls munmap(),
the page table pages may be freed while show_pte() is still traversing
them, causing a use-after-free in show_pte().

If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
of PMD are freed when show_pte() is running.

Acquire mmap_write_lock() around show_pte() for user faults to fix the
contention.

For user faults, additionally restrict that show_pte() is called only
when the addr is a user-space address (addr < TASK_SIZE). This is because
the lock of tsk->mm only protects the virtual memory of user address space,
furthermore, dumping the page tables of a kernel-space address for user
faults is unnecessary and may have security implications.

Keep everything unchanged for kernel faults, because the kernel is
already in the "oops" state, acquiring a lock may risk a deadlock.

Co-developed-by: Qi Xi <xiqi2@huawei.com>

Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 152 insertions, 0 deletions

diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
new file mode 100644
index 000000000..20034b092
--- /dev/null
+++ b/net/devlink/netlink_gen.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/devlink.yaml */
+/* YNL-GEN kernel header */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#ifndef _LINUX_DEVLINK_GEN_H
+#define _LINUX_DEVLINK_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/devlink.h>
+
+/* Common nested types */
+extern const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1];
+extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_ATTR_BW + 1];
+extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];
+
+/* Ops table for devlink */
+extern const struct genl_split_ops devlink_nl_ops[75];
+
+int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
+			struct genl_info *info);
+int devlink_nl_pre_doit_port(const struct genl_split_ops *ops,
+			     struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
+				      struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_pre_doit_dev_lock(const struct genl_split_ops *ops,
+				 struct sk_buff *skb, struct genl_info *info);
+void
+devlink_nl_post_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
+		     struct genl_info *info);
+void
+devlink_nl_post_doit_dev_lock(const struct genl_split_ops *ops,
+			      struct sk_buff *skb, struct genl_info *info);
+
+int devlink_nl_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int devlink_nl_port_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_port_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_new_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_del_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_split_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_unsplit_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int devlink_nl_sb_pool_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_pool_get_dumpit(struct sk_buff *skb,
+				  struct netlink_callback *cb);
+int devlink_nl_sb_pool_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_port_pool_get_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_sb_port_pool_get_dumpit(struct sk_buff *skb,
+				       struct netlink_callback *cb);
+int devlink_nl_sb_port_pool_set_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_sb_tc_pool_bind_get_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_sb_tc_pool_bind_get_dumpit(struct sk_buff *skb,
+					  struct netlink_callback *cb);
+int devlink_nl_sb_tc_pool_bind_set_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_sb_occ_snapshot_doit(struct sk_buff *skb,
+				    struct genl_info *info);
+int devlink_nl_sb_occ_max_clear_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_eswitch_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_eswitch_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_dpipe_table_get_doit(struct sk_buff *skb,
+				    struct genl_info *info);
+int devlink_nl_dpipe_entries_get_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_dpipe_headers_get_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_dpipe_table_counters_set_doit(struct sk_buff *skb,
+					     struct genl_info *info);
+int devlink_nl_resource_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_resource_dump_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_resource_dump_dumpit(struct sk_buff *skb,
+				    struct netlink_callback *cb);
+int devlink_nl_reload_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_param_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_param_get_dumpit(struct sk_buff *skb,
+				struct netlink_callback *cb);
+int devlink_nl_param_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_get_dumpit(struct sk_buff *skb,
+				 struct netlink_callback *cb);
+int devlink_nl_region_new_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_del_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_read_dumpit(struct sk_buff *skb,
+				  struct netlink_callback *cb);
+int devlink_nl_port_param_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_param_get_dumpit(struct sk_buff *skb,
+				     struct netlink_callback *cb);
+int devlink_nl_port_param_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_info_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_info_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_health_reporter_get_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_health_reporter_get_dumpit(struct sk_buff *skb,
+					  struct netlink_callback *cb);
+int devlink_nl_health_reporter_set_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_health_reporter_recover_doit(struct sk_buff *skb,
+					    struct genl_info *info);
+int devlink_nl_health_reporter_diagnose_doit(struct sk_buff *skb,
+					     struct genl_info *info);
+int devlink_nl_health_reporter_dump_get_dumpit(struct sk_buff *skb,
+					       struct netlink_callback *cb);
+int devlink_nl_health_reporter_dump_clear_doit(struct sk_buff *skb,
+					       struct genl_info *info);
+int devlink_nl_flash_update_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_trap_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_group_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_group_get_dumpit(struct sk_buff *skb,
+				     struct netlink_callback *cb);
+int devlink_nl_trap_group_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_policer_get_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_trap_policer_get_dumpit(struct sk_buff *skb,
+				       struct netlink_callback *cb);
+int devlink_nl_trap_policer_set_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_health_reporter_test_doit(struct sk_buff *skb,
+					 struct genl_info *info);
+int devlink_nl_rate_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_rate_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_rate_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_rate_new_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_rate_del_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_linecard_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_linecard_get_dumpit(struct sk_buff *skb,
+				   struct netlink_callback *cb);
+int devlink_nl_linecard_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_selftests_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_selftests_get_dumpit(struct sk_buff *skb,
+				    struct netlink_callback *cb);
+int devlink_nl_selftests_run_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_notify_filter_set_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+
+#endif /* _LINUX_DEVLINK_GEN_H */