// SPDX-License-Identifier: GPL-2.0/* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com * Copyright (c) 2016 Facebook */#include <linux/kernel.h>#include <linux/types.h>#include <linux/slab.h>#include <linux/bpf.h>#include <linux/bpf_perf_event.h>#include <linux/filter.h>#include <linux/uaccess.h>#include <linux/ctype.h>#include <linux/kprobes.h>#include <linux/syscalls.h>#include <linux/error-injection.h> #include <asm/tlb.h> #include "trace_probe.h"#include "trace.h" #define bpf_event_rcu_dereference(p)					\	rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) #ifdef CONFIG_MODULESstruct bpf_trace_module {	struct module *module;	struct list_head list;}; static LIST_HEAD(bpf_trace_modules);static DEFINE_MUTEX(bpf_module_mutex); static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name){	struct bpf_raw_event_map *btp, *ret = NULL;	struct bpf_trace_module *btm;	unsigned int i; 	mutex_lock(&bpf_module_mutex);	list_for_each_entry(btm, &bpf_trace_modules, list) {		for (i = 0; i < btm->module->num_bpf_raw_events; ++i) {			btp = &btm->module->bpf_raw_events[i];			if (!strcmp(btp->tp->name, name)) {				if (try_module_get(btm->module))					ret = btp;				goto out;			}		}	}out:	mutex_unlock(&bpf_module_mutex);	return ret;}#elsestatic struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name){	return NULL;}#endif /* CONFIG_MODULES */ u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); /** * trace_call_bpf - invoke BPF program * @call: tracepoint event * @ctx: opaque context pointer * * kprobe handlers execute BPF programs via this helper. * Can be used from static tracepoints in the future. * * Return: BPF programs always return an integer which is interpreted by * kprobe handler as: * 0 - return from kprobe (event is filtered out) * 1 - store kprobe event into ring buffer * Other values are reserved and currently alias to 1 */unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx){	unsigned int ret; 	if (in_nmi()) /* not supported yet */		return 1; 	preempt_disable(); 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {		/*		 * since some bpf program is already running on this cpu,		 * don't call into another bpf program (same or different)		 * and don't send kprobe event into ring-buffer,		 * so return zero here		 */		ret = 0;		goto out;	} 	/*	 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock	 * to all call sites, we did a bpf_prog_array_valid() there to check	 * whether call->prog_array is empty or not, which is	 * a heurisitc to speed up execution.	 *	 * If bpf_prog_array_valid() fetched prog_array was	 * non-NULL, we go into trace_call_bpf() and do the actual	 * proper rcu_dereference() under RCU lock.	 * If it turns out that prog_array is NULL then, we bail out.	 * For the opposite, if the bpf_prog_array_valid() fetched pointer	 * was NULL, you'll skip the prog_array with the risk of missing	 * out of events when it was updated in between this and the	 * rcu_dereference() which is accepted risk.	 */	ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN);  out:	__this_cpu_dec(bpf_prog_active);	preempt_enable(); 	return ret;}EXPORT_SYMBOL_GPL(trace_call_bpf); #ifdef CONFIG_BPF_KPROBE_OVERRIDEBPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc){	regs_set_return_value(regs, rc);	override_function_with_return(regs);	return 0;} static const struct bpf_func_proto bpf_override_return_proto = {	.func		= bpf_override_return,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_PTR_TO_CTX,	.arg2_type	= ARG_ANYTHING,};#endif BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr){	int ret; 	ret = security_locked_down(LOCKDOWN_BPF_READ);	if (ret < 0)		goto out; 	ret = probe_kernel_read(dst, unsafe_ptr, size);	if (unlikely(ret < 0))out:		memset(dst, 0, size); 	return ret;} static const struct bpf_func_proto bpf_probe_read_proto = {	.func		= bpf_probe_read,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,	.arg3_type	= ARG_ANYTHING,}; BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,	   u32, size){	/*	 * Ensure we're in user context which is safe for the helper to	 * run. This helper has no business in a kthread.	 *	 * access_ok() should prevent writing to non-user memory, but in	 * some situations (nommu, temporary switch, etc) access_ok() does	 * not provide enough validation, hence the check on KERNEL_DS.	 *	 * nmi_uaccess_okay() ensures the probe is not run in an interim	 * state, when the task or mm are switched. This is specifically	 * required to prevent the use of temporary mm.	 */ 	if (unlikely(in_interrupt() ||		     current->flags & (PF_KTHREAD | PF_EXITING)))		return -EPERM;	if (unlikely(uaccess_kernel()))		return -EPERM;	if (unlikely(!nmi_uaccess_okay()))		return -EPERM;	if (!access_ok(unsafe_ptr, size))		return -EPERM; 	return probe_kernel_write(unsafe_ptr, src, size);} static const struct bpf_func_proto bpf_probe_write_user_proto = {	.func		= bpf_probe_write_user,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_ANYTHING,	.arg2_type	= ARG_PTR_TO_MEM,	.arg3_type	= ARG_CONST_SIZE,}; static const struct bpf_func_proto *bpf_get_probe_write_proto(void){	pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",			    current->comm, task_pid_nr(current)); 	return &bpf_probe_write_user_proto;} /* * Only limited trace_printk() conversion specifiers allowed: * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s */BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,	   u64, arg2, u64, arg3){	bool str_seen = false;	int mod[3] = {};	int fmt_cnt = 0;	u64 unsafe_addr;	char buf[64];	int i; 	/*	 * bpf_check()->check_func_arg()->check_stack_boundary()	 * guarantees that fmt points to bpf program stack,	 * fmt_size bytes of it were initialized and fmt_size > 0	 */	if (fmt[--fmt_size] != 0)		return -EINVAL; 	/* check format string for allowed specifiers */	for (i = 0; i < fmt_size; i++) {		if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))			return -EINVAL; 		if (fmt[i] != '%')			continue; 		if (fmt_cnt >= 3)			return -EINVAL; 		/* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */		i++;		if (fmt[i] == 'l') {			mod[fmt_cnt]++;			i++;		} else if (fmt[i] == 'p' || fmt[i] == 's') {			mod[fmt_cnt]++;			/* disallow any further format extensions */			if (fmt[i + 1] != 0 &&			    !isspace(fmt[i + 1]) &&			    !ispunct(fmt[i + 1]))				return -EINVAL;			fmt_cnt++;			if (fmt[i] == 's') {				if (str_seen)					/* allow only one '%s' per fmt string */					return -EINVAL;				str_seen = true; 				switch (fmt_cnt) {				case 1:					unsafe_addr = arg1;					arg1 = (long) buf;					break;				case 2:					unsafe_addr = arg2;					arg2 = (long) buf;					break;				case 3:					unsafe_addr = arg3;					arg3 = (long) buf;					break;				}				buf[0] = 0;				strncpy_from_unsafe(buf,						    (void *) (long) unsafe_addr,						    sizeof(buf));			}			continue;		} 		if (fmt[i] == 'l') {			mod[fmt_cnt]++;			i++;		} 		if (fmt[i] != 'i' && fmt[i] != 'd' &&		    fmt[i] != 'u' && fmt[i] != 'x')			return -EINVAL;		fmt_cnt++;	} /* Horrid workaround for getting va_list handling working with different * argument type combinations generically for 32 and 64 bit archs. */#define __BPF_TP_EMIT()	__BPF_ARG3_TP()#define __BPF_TP(...)							\	__trace_printk(0 /* Fake ip */,					\		       fmt, ##__VA_ARGS__) #define __BPF_ARG1_TP(...)						\	((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64))	\	  ? __BPF_TP(arg1, ##__VA_ARGS__)				\	  : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32))	\	      ? __BPF_TP((long)arg1, ##__VA_ARGS__)			\	      : __BPF_TP((u32)arg1, ##__VA_ARGS__))) #define __BPF_ARG2_TP(...)						\	((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64))	\	  ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__)				\	  : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32))	\	      ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__)		\	      : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) #define __BPF_ARG3_TP(...)						\	((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64))	\	  ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__)				\	  : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32))	\	      ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__)		\	      : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) 	return __BPF_TP_EMIT();} static const struct bpf_func_proto bpf_trace_printk_proto = {	.func		= bpf_trace_printk,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_PTR_TO_MEM,	.arg2_type	= ARG_CONST_SIZE,}; const struct bpf_func_proto *bpf_get_trace_printk_proto(void){	/*	 * this program might be calling bpf_trace_printk,	 * so allocate per-cpu printk buffers	 */	trace_printk_init_buffers(); 	return &bpf_trace_printk_proto;} static __always_inline intget_map_perf_counter(struct bpf_map *map, u64 flags,		     u64 *value, u64 *enabled, u64 *running){	struct bpf_array *array = container_of(map, struct bpf_array, map);	unsigned int cpu = smp_processor_id();	u64 index = flags & BPF_F_INDEX_MASK;	struct bpf_event_entry *ee; 	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))		return -EINVAL;	if (index == BPF_F_CURRENT_CPU)		index = cpu;	if (unlikely(index >= array->map.max_entries))		return -E2BIG; 	ee = READ_ONCE(array->ptrs[index]);	if (!ee)		return -ENOENT; 	return perf_event_read_local(ee->event, value, enabled, running);} BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags){	u64 value = 0;	int err; 	err = get_map_perf_counter(map, flags, &value, NULL, NULL);	/*	 * this api is ugly since we miss [-22..-2] range of valid	 * counter values, but that's uapi	 */	if (err)		return err;	return value;} static const struct bpf_func_proto bpf_perf_event_read_proto = {	.func		= bpf_perf_event_read,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_CONST_MAP_PTR,	.arg2_type	= ARG_ANYTHING,}; BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags,	   struct bpf_perf_event_value *, buf, u32, size){	int err = -EINVAL; 	if (unlikely(size != sizeof(struct bpf_perf_event_value)))		goto clear;	err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled,				   &buf->running);	if (unlikely(err))		goto clear;	return 0;clear:	memset(buf, 0, size);	return err;} static const struct bpf_func_proto bpf_perf_event_read_value_proto = {	.func		= bpf_perf_event_read_value,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_CONST_MAP_PTR,	.arg2_type	= ARG_ANYTHING,	.arg3_type	= ARG_PTR_TO_UNINIT_MEM,	.arg4_type	= ARG_CONST_SIZE,}; static __always_inline u64__bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,			u64 flags, struct perf_sample_data *sd){	struct bpf_array *array = container_of(map, struct bpf_array, map);	unsigned int cpu = smp_processor_id();	u64 index = flags & BPF_F_INDEX_MASK;	struct bpf_event_entry *ee;	struct perf_event *event; 	if (index == BPF_F_CURRENT_CPU)		index = cpu;	if (unlikely(index >= array->map.max_entries))		return -E2BIG; 	ee = READ_ONCE(array->ptrs[index]);	if (!ee)		return -ENOENT; 	event = ee->event;	if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||		     event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))		return -EINVAL; 	if (unlikely(event->oncpu != cpu))		return -EOPNOTSUPP; 	return perf_event_output(event, sd, regs);} /* * Support executing tracepoints in normal, irq, and nmi context that each call * bpf_perf_event_output */struct bpf_trace_sample_data {	struct perf_sample_data sds[3];}; static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds);static DEFINE_PER_CPU(int, bpf_trace_nest_level);BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,	   u64, flags, void *, data, u64, size){	struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds);	int nest_level = this_cpu_inc_return(bpf_trace_nest_level);	struct perf_raw_record raw = {		.frag = {			.size = size,			.data = data,		},	};	struct perf_sample_data *sd;	int err; 	if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) {		err = -EBUSY;		goto out;	} 	sd = &sds->sds[nest_level - 1]; 	if (unlikely(flags & ~(BPF_F_INDEX_MASK))) {		err = -EINVAL;		goto out;	} 	perf_sample_data_init(sd, 0, 0);	sd->raw = &raw; 	err = __bpf_perf_event_output(regs, map, flags, sd); out:	this_cpu_dec(bpf_trace_nest_level);	return err;} static const struct bpf_func_proto bpf_perf_event_output_proto = {	.func		= bpf_perf_event_output,	.gpl_only	= true,	.ret_type	= RET_INTEGER,

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