diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch index bea7bd5a1d5f..a5df9b4910dc 100644 --- a/Documentation/ABI/testing/sysfs-kernel-livepatch +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -55,6 +55,14 @@ Description: The object directory contains subdirectories for each function that is patched within the object. +What: /sys/kernel/livepatch///patched +Date: August 2022 +KernelVersion: 6.1.0 +Contact: live-patching@vger.kernel.org +Description: + An attribute which indicates whether the object is currently + patched. + What: /sys/kernel/livepatch/// Date: Nov 2014 KernelVersion: 3.19.0 diff --git a/fs/proc/kmsg.c b/fs/proc/kmsg.c index 592e6dc7c110..2fc92a13f9f8 100644 --- a/fs/proc/kmsg.c +++ b/fs/proc/kmsg.c @@ -17,8 +17,6 @@ #include -extern wait_queue_head_t log_wait; - static int kmsg_open(struct inode * inode, struct file * file) { return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC); diff --git a/include/linux/printk.h b/include/linux/printk.h index cf7d666ab1f8..8c81806c2e99 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -169,8 +169,6 @@ extern void __printk_safe_exit(void); #define printk_deferred_enter __printk_safe_enter #define printk_deferred_exit __printk_safe_exit -extern bool pr_flush(int timeout_ms, bool reset_on_progress); - /* * Please don't use printk_ratelimit(), because it shares ratelimiting state * with all other unrelated printk_ratelimit() callsites. Instead use @@ -221,11 +219,6 @@ static inline void printk_deferred_exit(void) { } -static inline bool pr_flush(int timeout_ms, bool reset_on_progress) -{ - return true; -} - static inline int printk_ratelimit(void) { return 0; diff --git a/include/linux/syslog.h b/include/linux/syslog.h index 86af908e2663..955f80e34d4f 100644 --- a/include/linux/syslog.h +++ b/include/linux/syslog.h @@ -8,6 +8,8 @@ #ifndef _LINUX_SYSLOG_H #define _LINUX_SYSLOG_H +#include + /* Close the log. Currently a NOP. */ #define SYSLOG_ACTION_CLOSE 0 /* Open the log. Currently a NOP. */ @@ -35,5 +37,6 @@ #define SYSLOG_FROM_PROC 1 int do_syslog(int type, char __user *buf, int count, int source); +extern wait_queue_head_t log_wait; #endif /* _LINUX_SYSLOG_H */ diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index ec06ce59d728..9ada0bc5247b 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -325,6 +325,7 @@ int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs, * /sys/kernel/livepatch//transition * /sys/kernel/livepatch//force * /sys/kernel/livepatch// + * /sys/kernel/livepatch///patched * /sys/kernel/livepatch/// */ static int __klp_disable_patch(struct klp_patch *patch); @@ -431,6 +432,22 @@ static struct attribute *klp_patch_attrs[] = { }; ATTRIBUTE_GROUPS(klp_patch); +static ssize_t patched_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct klp_object *obj; + + obj = container_of(kobj, struct klp_object, kobj); + return sysfs_emit(buf, "%d\n", obj->patched); +} + +static struct kobj_attribute patched_kobj_attr = __ATTR_RO(patched); +static struct attribute *klp_object_attrs[] = { + &patched_kobj_attr.attr, + NULL, +}; +ATTRIBUTE_GROUPS(klp_object); + static void klp_free_object_dynamic(struct klp_object *obj) { kfree(obj->name); @@ -576,6 +593,7 @@ static void klp_kobj_release_object(struct kobject *kobj) static struct kobj_type klp_ktype_object = { .release = klp_kobj_release_object, .sysfs_ops = &kobj_sysfs_ops, + .default_groups = klp_object_groups, }; static void klp_kobj_release_func(struct kobject *kobj) @@ -1171,7 +1189,7 @@ int klp_module_coming(struct module *mod) return -EINVAL; if (!strcmp(mod->name, "vmlinux")) { - pr_err("vmlinux.ko: invalid module name"); + pr_err("vmlinux.ko: invalid module name\n"); return -EINVAL; } diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 5d03a2ad1066..30187b1d8275 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -610,9 +610,23 @@ void klp_reverse_transition(void) /* Called from copy_process() during fork */ void klp_copy_process(struct task_struct *child) { - child->patch_state = current->patch_state; - /* TIF_PATCH_PENDING gets copied in setup_thread_stack() */ + /* + * The parent process may have gone through a KLP transition since + * the thread flag was copied in setup_thread_stack earlier. Bring + * the task flag up to date with the parent here. + * + * The operation is serialized against all klp_*_transition() + * operations by the tasklist_lock. The only exception is + * klp_update_patch_state(current), but we cannot race with + * that because we are current. + */ + if (test_tsk_thread_flag(current, TIF_PATCH_PENDING)) + set_tsk_thread_flag(child, TIF_PATCH_PENDING); + else + clear_tsk_thread_flag(child, TIF_PATCH_PENDING); + + child->patch_state = current->patch_state; } /* diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index b36c110d39e7..580d26c5f5e7 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -222,9 +222,6 @@ int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, } #endif /* CONFIG_PRINTK && CONFIG_SYSCTL */ -/* Number of registered extended console drivers. */ -static int nr_ext_console_drivers; - /* * Helper macros to handle lockdep when locking/unlocking console_sem. We use * macros instead of functions so that _RET_IP_ contains useful information. @@ -435,7 +432,7 @@ static struct printk_ringbuffer *prb = &printk_rb_static; * per_cpu_areas are initialised. This variable is set to true when * it's safe to access per-CPU data. */ -static bool __printk_percpu_data_ready __read_mostly; +static bool __printk_percpu_data_ready __ro_after_init; bool printk_percpu_data_ready(void) { @@ -2298,6 +2295,7 @@ asmlinkage __visible int _printk(const char *fmt, ...) } EXPORT_SYMBOL(_printk); +static bool pr_flush(int timeout_ms, bool reset_on_progress); static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress); #else /* CONFIG_PRINTK */ @@ -2332,6 +2330,7 @@ static void call_console_driver(struct console *con, const char *text, size_t le { } static bool suppress_message_printing(int level) { return false; } +static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; } static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; } #endif /* CONFIG_PRINTK */ @@ -3194,9 +3193,6 @@ void register_console(struct console *newcon) console_drivers->next = newcon; } - if (newcon->flags & CON_EXTENDED) - nr_ext_console_drivers++; - newcon->dropped = 0; if (newcon->flags & CON_PRINTBUFFER) { /* Get a consistent copy of @syslog_seq. */ @@ -3221,9 +3217,6 @@ void register_console(struct console *newcon) if (bootcon_enabled && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && !keep_bootcon) { - /* We need to iterate through all boot consoles, to make - * sure we print everything out, before we unregister them. - */ for_each_console(con) if (con->flags & CON_BOOT) unregister_console(con); @@ -3262,9 +3255,6 @@ int unregister_console(struct console *console) if (res) goto out_disable_unlock; - if (console->flags & CON_EXTENDED) - nr_ext_console_drivers--; - /* * If this isn't the last console and it has CON_CONSDEV set, we * need to set it on the next preferred console. @@ -3446,11 +3436,10 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre * Context: Process context. May sleep while acquiring console lock. * Return: true if all enabled printers are caught up. */ -bool pr_flush(int timeout_ms, bool reset_on_progress) +static bool pr_flush(int timeout_ms, bool reset_on_progress) { return __pr_flush(NULL, timeout_ms, reset_on_progress); } -EXPORT_SYMBOL(pr_flush); /* * Delayed printk version, for scheduler-internal messages: diff --git a/lib/vsprintf.c b/lib/vsprintf.c index c414a8d9f1ea..24f37bab8bc1 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -750,37 +750,42 @@ static int __init debug_boot_weak_hash_enable(char *str) } early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable); -static DEFINE_STATIC_KEY_FALSE(filled_random_ptr_key); +static bool filled_random_ptr_key __read_mostly; +static siphash_key_t ptr_key __read_mostly; +static void fill_ptr_key_workfn(struct work_struct *work); +static DECLARE_DELAYED_WORK(fill_ptr_key_work, fill_ptr_key_workfn); -static void enable_ptr_key_workfn(struct work_struct *work) +static void fill_ptr_key_workfn(struct work_struct *work) { - static_branch_enable(&filled_random_ptr_key); + if (!rng_is_initialized()) { + queue_delayed_work(system_unbound_wq, &fill_ptr_key_work, HZ * 2); + return; + } + + get_random_bytes(&ptr_key, sizeof(ptr_key)); + + /* Pairs with smp_rmb() before reading ptr_key. */ + smp_wmb(); + WRITE_ONCE(filled_random_ptr_key, true); } +static int __init vsprintf_init_hashval(void) +{ + fill_ptr_key_workfn(NULL); + return 0; +} +subsys_initcall(vsprintf_init_hashval) + /* Maps a pointer to a 32 bit unique identifier. */ static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out) { - static siphash_key_t ptr_key __read_mostly; unsigned long hashval; - if (!static_branch_likely(&filled_random_ptr_key)) { - static bool filled = false; - static DEFINE_SPINLOCK(filling); - static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn); - unsigned long flags; - - if (!system_unbound_wq || !rng_is_initialized() || - !spin_trylock_irqsave(&filling, flags)) - return -EAGAIN; - - if (!filled) { - get_random_bytes(&ptr_key, sizeof(ptr_key)); - queue_work(system_unbound_wq, &enable_ptr_key_work); - filled = true; - } - spin_unlock_irqrestore(&filling, flags); - } + if (!READ_ONCE(filled_random_ptr_key)) + return -EBUSY; + /* Pairs with smp_wmb() after writing ptr_key. */ + smp_rmb(); #ifdef CONFIG_64BIT hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); @@ -1189,7 +1194,7 @@ char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec, } static noinline_for_stack -char *bitmap_string(char *buf, char *end, unsigned long *bitmap, +char *bitmap_string(char *buf, char *end, const unsigned long *bitmap, struct printf_spec spec, const char *fmt) { const int CHUNKSZ = 32; @@ -1233,7 +1238,7 @@ char *bitmap_string(char *buf, char *end, unsigned long *bitmap, } static noinline_for_stack -char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap, +char *bitmap_list_string(char *buf, char *end, const unsigned long *bitmap, struct printf_spec spec, const char *fmt) { int nr_bits = max_t(int, spec.field_width, 0); diff --git a/tools/testing/selftests/livepatch/Makefile b/tools/testing/selftests/livepatch/Makefile index 1acc9e1fa3fb..02fadc9d55e0 100644 --- a/tools/testing/selftests/livepatch/Makefile +++ b/tools/testing/selftests/livepatch/Makefile @@ -6,7 +6,8 @@ TEST_PROGS := \ test-callbacks.sh \ test-shadow-vars.sh \ test-state.sh \ - test-ftrace.sh + test-ftrace.sh \ + test-sysfs.sh TEST_FILES := settings diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh index 9230b869371d..c8416c54b463 100644 --- a/tools/testing/selftests/livepatch/functions.sh +++ b/tools/testing/selftests/livepatch/functions.sh @@ -6,6 +6,7 @@ MAX_RETRIES=600 RETRY_INTERVAL=".1" # seconds +KLP_SYSFS_DIR="/sys/kernel/livepatch" # Kselftest framework requirement - SKIP code is 4 ksft_skip=4 @@ -86,7 +87,7 @@ function set_ftrace_enabled() { if [[ "$result" != "$1" ]] ; then if [[ $can_fail -eq 1 ]] ; then - echo "livepatch: $err" > /dev/kmsg + echo "livepatch: $err" | sed 's#/proc/sys/kernel/#kernel.#' > /dev/kmsg return fi @@ -308,3 +309,36 @@ function check_result { cleanup_dmesg_file } + +# check_sysfs_rights(modname, rel_path, expected_rights) - check sysfs +# path permissions +# modname - livepatch module creating the sysfs interface +# rel_path - relative path of the sysfs interface +# expected_rights - expected access rights +function check_sysfs_rights() { + local mod="$1"; shift + local rel_path="$1"; shift + local expected_rights="$1"; shift + + local path="$KLP_SYSFS_DIR/$mod/$rel_path" + local rights=$(/bin/stat --format '%A' "$path") + if test "$rights" != "$expected_rights" ; then + die "Unexpected access rights of $path: $expected_rights vs. $rights" + fi +} + +# check_sysfs_value(modname, rel_path, expected_value) - check sysfs value +# modname - livepatch module creating the sysfs interface +# rel_path - relative path of the sysfs interface +# expected_value - expected value read from the file +function check_sysfs_value() { + local mod="$1"; shift + local rel_path="$1"; shift + local expected_value="$1"; shift + + local path="$KLP_SYSFS_DIR/$mod/$rel_path" + local value=`cat $path` + if test "$value" != "$expected_value" ; then + die "Unexpected value in $path: $expected_value vs. $value" + fi +} diff --git a/tools/testing/selftests/livepatch/test-sysfs.sh b/tools/testing/selftests/livepatch/test-sysfs.sh new file mode 100755 index 000000000000..7f76f280189a --- /dev/null +++ b/tools/testing/selftests/livepatch/test-sysfs.sh @@ -0,0 +1,86 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2022 Song Liu + +. $(dirname $0)/functions.sh + +MOD_LIVEPATCH=test_klp_livepatch + +setup_config + +# - load a livepatch and verifies the sysfs entries work as expected + +start_test "sysfs test" + +load_lp $MOD_LIVEPATCH + +check_sysfs_rights "$MOD_LIVEPATCH" "" "drwxr-xr-x" +check_sysfs_rights "$MOD_LIVEPATCH" "enabled" "-rw-r--r--" +check_sysfs_value "$MOD_LIVEPATCH" "enabled" "1" +check_sysfs_rights "$MOD_LIVEPATCH" "force" "--w-------" +check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--" +check_sysfs_value "$MOD_LIVEPATCH" "transition" "0" +check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--" +check_sysfs_value "$MOD_LIVEPATCH" "vmlinux/patched" "1" + +disable_lp $MOD_LIVEPATCH + +unload_lp $MOD_LIVEPATCH + +check_result "% modprobe $MOD_LIVEPATCH +livepatch: enabling patch '$MOD_LIVEPATCH' +livepatch: '$MOD_LIVEPATCH': initializing patching transition +livepatch: '$MOD_LIVEPATCH': starting patching transition +livepatch: '$MOD_LIVEPATCH': completing patching transition +livepatch: '$MOD_LIVEPATCH': patching complete +% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled +livepatch: '$MOD_LIVEPATCH': initializing unpatching transition +livepatch: '$MOD_LIVEPATCH': starting unpatching transition +livepatch: '$MOD_LIVEPATCH': completing unpatching transition +livepatch: '$MOD_LIVEPATCH': unpatching complete +% rmmod $MOD_LIVEPATCH" + +start_test "sysfs test object/patched" + +MOD_LIVEPATCH=test_klp_callbacks_demo +MOD_TARGET=test_klp_callbacks_mod +load_lp $MOD_LIVEPATCH + +# check the "patch" file changes as target module loads/unloads +check_sysfs_value "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0" +load_mod $MOD_TARGET +check_sysfs_value "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "1" +unload_mod $MOD_TARGET +check_sysfs_value "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0" + +disable_lp $MOD_LIVEPATCH +unload_lp $MOD_LIVEPATCH + +check_result "% modprobe test_klp_callbacks_demo +livepatch: enabling patch 'test_klp_callbacks_demo' +livepatch: 'test_klp_callbacks_demo': initializing patching transition +test_klp_callbacks_demo: pre_patch_callback: vmlinux +livepatch: 'test_klp_callbacks_demo': starting patching transition +livepatch: 'test_klp_callbacks_demo': completing patching transition +test_klp_callbacks_demo: post_patch_callback: vmlinux +livepatch: 'test_klp_callbacks_demo': patching complete +% modprobe test_klp_callbacks_mod +livepatch: applying patch 'test_klp_callbacks_demo' to loading module 'test_klp_callbacks_mod' +test_klp_callbacks_demo: pre_patch_callback: test_klp_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init +test_klp_callbacks_demo: post_patch_callback: test_klp_callbacks_mod -> [MODULE_STATE_COMING] Full formed, running module_init +test_klp_callbacks_mod: test_klp_callbacks_mod_init +% rmmod test_klp_callbacks_mod +test_klp_callbacks_mod: test_klp_callbacks_mod_exit +test_klp_callbacks_demo: pre_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away +livepatch: reverting patch 'test_klp_callbacks_demo' on unloading module 'test_klp_callbacks_mod' +test_klp_callbacks_demo: post_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away +% echo 0 > /sys/kernel/livepatch/test_klp_callbacks_demo/enabled +livepatch: 'test_klp_callbacks_demo': initializing unpatching transition +test_klp_callbacks_demo: pre_unpatch_callback: vmlinux +livepatch: 'test_klp_callbacks_demo': starting unpatching transition +livepatch: 'test_klp_callbacks_demo': completing unpatching transition +test_klp_callbacks_demo: post_unpatch_callback: vmlinux +livepatch: 'test_klp_callbacks_demo': unpatching complete +% rmmod test_klp_callbacks_demo" + +exit 0