Merge tag 'trace-v5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull more tracing updates from Steven Rostedt:
 "Two fixes and one patch that was missed:

  Fixes:

   - Missing __print_hex_dump undef for processing new function in trace
     events

   - Stop WARN_ON messages when lockdown disables tracing on boot up

  Enhancement:

   - Debug option to inject trace events from userspace (for rasdaemon)"

The enhancement has its own config option and is non invasive. It's been
discussed for sever months and should have been added to my original
push, but I never pulled it into my queue.

* tag 'trace-v5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Do not create directories if lockdown is in affect
  tracing: Introduce trace event injection
  tracing: Fix __print_hex_dump scope

7 files changed, 371 insertions, 0 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index cdf5afa87f65..25a0fcfa7a5d 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -671,6 +671,15 @@ config HIST_TRIGGERS
 	  See Documentation/trace/histogram.rst.
 	  If in doubt, say N.
 
+config TRACE_EVENT_INJECT
+	bool "Trace event injection"
+	depends on TRACING
+	help
+	  Allow user-space to inject a specific trace event into the ring
+	  buffer. This is mainly used for testing purpose.
+
+	  If unsure, say N.
+
 config MMIOTRACE_TEST
 	tristate "Test module for mmiotrace"
 	depends on MMIOTRACE && m
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c2b2148bb1d2..0e63db62225f 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
 endif
 obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
 obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
+obj-$(CONFIG_TRACE_EVENT_INJECT) += trace_events_inject.o
 obj-$(CONFIG_HIST_TRIGGERS) += trace_events_hist.o
 obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o
 obj-$(CONFIG_KPROBE_EVENTS) += trace_kprobe.o
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 66358d66c933..4bf050fcfe3b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -11,6 +11,7 @@
 #include <linux/trace_seq.h>
 #include <linux/spinlock.h>
 #include <linux/irq_work.h>
+#include <linux/security.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>	/* for self test */
@@ -5068,6 +5069,11 @@ static __init int test_ringbuffer(void)
 	int cpu;
 	int ret = 0;
 
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warning("Lockdown is enabled, skipping ring buffer tests\n");
+		return 0;
+	}
+
 	pr_info("Running ring buffer tests...\n");
 
 	buffer = ring_buffer_alloc(RB_TEST_BUFFER_SIZE, RB_FL_OVERWRITE);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 02a23a6e5e00..23459d53d576 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1888,6 +1888,12 @@ int __init register_tracer(struct tracer *type)
 		return -1;
 	}
 
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warning("Can not register tracer %s due to lockdown\n",
+			   type->name);
+		return -EPERM;
+	}
+
 	mutex_lock(&trace_types_lock);
 
 	tracing_selftest_running = true;
@@ -8789,6 +8795,11 @@ struct dentry *tracing_init_dentry(void)
 {
 	struct trace_array *tr = &global_trace;
 
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warning("Tracing disabled due to lockdown\n");
+		return ERR_PTR(-EPERM);
+	}
+
 	/* The top level trace array uses  NULL as parent */
 	if (tr->dir)
 		return NULL;
@@ -9231,6 +9242,12 @@ __init static int tracer_alloc_buffers(void)
 	int ring_buf_size;
 	int ret = -ENOMEM;
 
+
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warning("Tracing disabled due to lockdown\n");
+		return -EPERM;
+	}
+
 	/*
 	 * Make sure we don't accidently add more trace options
 	 * than we have bits for.
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index ca7fccafbcbb..63bf60f79398 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1601,6 +1601,7 @@ extern struct list_head ftrace_events;
 
 extern const struct file_operations event_trigger_fops;
 extern const struct file_operations event_hist_fops;
+extern const struct file_operations event_inject_fops;
 
 #ifdef CONFIG_HIST_TRIGGERS
 extern int register_trigger_hist_cmd(void);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6b3a69e9aa6a..c6de3cebc127 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2044,6 +2044,12 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
 	trace_create_file("format", 0444, file->dir, call,
 			  &ftrace_event_format_fops);
 
+#ifdef CONFIG_TRACE_EVENT_INJECT
+	if (call->event.type && call->class->reg)
+		trace_create_file("inject", 0200, file->dir, file,
+				  &event_inject_fops);
+#endif
+
 	return 0;
 }
 
diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
new file mode 100644
index 000000000000..d43710718ee5
--- /dev/null
+++ b/kernel/trace/trace_events_inject.c
@@ -0,0 +1,331 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_inject - trace event injection
+ *
+ * Copyright (C) 2019 Cong Wang <cwang@twitter.com>
+ */
+
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+
+#include "trace.h"
+
+static int
+trace_inject_entry(struct trace_event_file *file, void *rec, int len)
+{
+	struct trace_event_buffer fbuffer;
+	struct ring_buffer *buffer;
+	int written = 0;
+	void *entry;
+
+	rcu_read_lock_sched();
+	buffer = file->tr->trace_buffer.buffer;
+	entry = trace_event_buffer_reserve(&fbuffer, file, len);
+	if (entry) {
+		memcpy(entry, rec, len);
+		written = len;
+		trace_event_buffer_commit(&fbuffer);
+	}
+	rcu_read_unlock_sched();
+
+	return written;
+}
+
+static int
+parse_field(char *str, struct trace_event_call *call,
+	    struct ftrace_event_field **pf, u64 *pv)
+{
+	struct ftrace_event_field *field;
+	char *field_name;
+	int s, i = 0;
+	int len;
+	u64 val;
+
+	if (!str[i])
+		return 0;
+	/* First find the field to associate to */
+	while (isspace(str[i]))
+		i++;
+	s = i;
+	while (isalnum(str[i]) || str[i] == '_')
+		i++;
+	len = i - s;
+	if (!len)
+		return -EINVAL;
+
+	field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
+	if (!field_name)
+		return -ENOMEM;
+	field = trace_find_event_field(call, field_name);
+	kfree(field_name);
+	if (!field)
+		return -ENOENT;
+
+	*pf = field;
+	while (isspace(str[i]))
+		i++;
+	if (str[i] != '=')
+		return -EINVAL;
+	i++;
+	while (isspace(str[i]))
+		i++;
+	s = i;
+	if (isdigit(str[i]) || str[i] == '-') {
+		char *num, c;
+		int ret;
+
+		/* Make sure the field is not a string */
+		if (is_string_field(field))
+			return -EINVAL;
+
+		if (str[i] == '-')
+			i++;
+
+		/* We allow 0xDEADBEEF */
+		while (isalnum(str[i]))
+			i++;
+		num = str + s;
+		c = str[i];
+		if (c != '\0' && !isspace(c))
+			return -EINVAL;
+		str[i] = '\0';
+		/* Make sure it is a value */
+		if (field->is_signed)
+			ret = kstrtoll(num, 0, &val);
+		else
+			ret = kstrtoull(num, 0, &val);
+		str[i] = c;
+		if (ret)
+			return ret;
+
+		*pv = val;
+		return i;
+	} else if (str[i] == '\'' || str[i] == '"') {
+		char q = str[i];
+
+		/* Make sure the field is OK for strings */
+		if (!is_string_field(field))
+			return -EINVAL;
+
+		for (i++; str[i]; i++) {
+			if (str[i] == '\\' && str[i + 1]) {
+				i++;
+				continue;
+			}
+			if (str[i] == q)
+				break;
+		}
+		if (!str[i])
+			return -EINVAL;
+
+		/* Skip quotes */
+		s++;
+		len = i - s;
+		if (len >= MAX_FILTER_STR_VAL)
+			return -EINVAL;
+
+		*pv = (unsigned long)(str + s);
+		str[i] = 0;
+		/* go past the last quote */
+		i++;
+		return i;
+	}
+
+	return -EINVAL;
+}
+
+static int trace_get_entry_size(struct trace_event_call *call)
+{
+	struct ftrace_event_field *field;
+	struct list_head *head;
+	int size = 0;
+
+	head = trace_get_fields(call);
+	list_for_each_entry(field, head, link) {
+		if (field->size + field->offset > size)
+			size = field->size + field->offset;
+	}
+
+	return size;
+}
+
+static void *trace_alloc_entry(struct trace_event_call *call, int *size)
+{
+	int entry_size = trace_get_entry_size(call);
+	struct ftrace_event_field *field;
+	struct list_head *head;
+	void *entry = NULL;
+
+	/* We need an extra '\0' at the end. */
+	entry = kzalloc(entry_size + 1, GFP_KERNEL);
+	if (!entry)
+		return NULL;
+
+	head = trace_get_fields(call);
+	list_for_each_entry(field, head, link) {
+		if (!is_string_field(field))
+			continue;
+		if (field->filter_type == FILTER_STATIC_STRING)
+			continue;
+		if (field->filter_type == FILTER_DYN_STRING) {
+			u32 *str_item;
+			int str_loc = entry_size & 0xffff;
+
+			str_item = (u32 *)(entry + field->offset);
+			*str_item = str_loc; /* string length is 0. */
+		} else {
+			char **paddr;
+
+			paddr = (char **)(entry + field->offset);
+			*paddr = "";
+		}
+	}
+
+	*size = entry_size + 1;
+	return entry;
+}
+
+#define INJECT_STRING "STATIC STRING CAN NOT BE INJECTED"
+
+/* Caller is responsible to free the *pentry. */
+static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
+{
+	struct ftrace_event_field *field;
+	unsigned long irq_flags;
+	void *entry = NULL;
+	int entry_size;
+	u64 val;
+	int len;
+
+	entry = trace_alloc_entry(call, &entry_size);
+	*pentry = entry;
+	if (!entry)
+		return -ENOMEM;
+
+	local_save_flags(irq_flags);
+	tracing_generic_entry_update(entry, call->event.type, irq_flags,
+				     preempt_count());
+
+	while ((len = parse_field(str, call, &field, &val)) > 0) {
+		if (is_function_field(field))
+			return -EINVAL;
+
+		if (is_string_field(field)) {
+			char *addr = (char *)(unsigned long) val;
+
+			if (field->filter_type == FILTER_STATIC_STRING) {
+				strlcpy(entry + field->offset, addr, field->size);
+			} else if (field->filter_type == FILTER_DYN_STRING) {
+				int str_len = strlen(addr) + 1;
+				int str_loc = entry_size & 0xffff;
+				u32 *str_item;
+
+				entry_size += str_len;
+				*pentry = krealloc(entry, entry_size, GFP_KERNEL);
+				if (!*pentry) {
+					kfree(entry);
+					return -ENOMEM;
+				}
+				entry = *pentry;
+
+				strlcpy(entry + (entry_size - str_len), addr, str_len);
+				str_item = (u32 *)(entry + field->offset);
+				*str_item = (str_len << 16) | str_loc;
+			} else {
+				char **paddr;
+
+				paddr = (char **)(entry + field->offset);
+				*paddr = INJECT_STRING;
+			}
+		} else {
+			switch (field->size) {
+			case 1: {
+				u8 tmp = (u8) val;
+
+				memcpy(entry + field->offset, &tmp, 1);
+				break;
+			}
+			case 2: {
+				u16 tmp = (u16) val;
+
+				memcpy(entry + field->offset, &tmp, 2);
+				break;
+			}
+			case 4: {
+				u32 tmp = (u32) val;
+
+				memcpy(entry + field->offset, &tmp, 4);
+				break;
+			}
+			case 8:
+				memcpy(entry + field->offset, &val, 8);
+				break;
+			default:
+				return -EINVAL;
+			}
+		}
+
+		str += len;
+	}
+
+	if (len < 0)
+		return len;
+
+	return entry_size;
+}
+
+static ssize_t
+event_inject_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		   loff_t *ppos)
+{
+	struct trace_event_call *call;
+	struct trace_event_file *file;
+	int err = -ENODEV, size;
+	void *entry = NULL;
+	char *buf;
+
+	if (cnt >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = memdup_user_nul(ubuf, cnt);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+	strim(buf);
+
+	mutex_lock(&event_mutex);
+	file = event_file_data(filp);
+	if (file) {
+		call = file->event_call;
+		size = parse_entry(buf, call, &entry);
+		if (size < 0)
+			err = size;
+		else
+			err = trace_inject_entry(file, entry, size);
+	}
+	mutex_unlock(&event_mutex);
+
+	kfree(entry);
+	kfree(buf);
+
+	if (err < 0)
+		return err;
+
+	*ppos += err;
+	return cnt;
+}
+
+static ssize_t
+event_inject_read(struct file *file, char __user *buf, size_t size,
+		  loff_t *ppos)
+{
+	return -EPERM;
+}
+
+const struct file_operations event_inject_fops = {
+	.open = tracing_open_generic,
+	.read = event_inject_read,
+	.write = event_inject_write,
+};