// 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; 	cant_sleep(); 	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); 	return ret;} #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 static __always_inline intbpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr){	int ret; 	ret = copy_from_user_nofault(dst, unsafe_ptr, size);	if (unlikely(ret < 0))		memset(dst, 0, size);	return ret;} BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size,	   const void __user *, unsafe_ptr){	return bpf_probe_read_user_common(dst, size, unsafe_ptr);} const struct bpf_func_proto bpf_probe_read_user_proto = {	.func		= bpf_probe_read_user,	.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,}; static __always_inline intbpf_probe_read_user_str_common(void *dst, u32 size,			       const void __user *unsafe_ptr){	int ret; 	ret = strncpy_from_user_nofault(dst, unsafe_ptr, size);	if (unlikely(ret < 0))		memset(dst, 0, size);	return ret;} BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size,	   const void __user *, unsafe_ptr){	return bpf_probe_read_user_str_common(dst, size, unsafe_ptr);} const struct bpf_func_proto bpf_probe_read_user_str_proto = {	.func		= bpf_probe_read_user_str,	.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,}; static __always_inline intbpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr){	int ret = security_locked_down(LOCKDOWN_BPF_READ); 	if (unlikely(ret < 0))		goto fail;	ret = copy_from_kernel_nofault(dst, unsafe_ptr, size);	if (unlikely(ret < 0))		goto fail;	return ret;fail:	memset(dst, 0, size);	return ret;} BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size,	   const void *, unsafe_ptr){	return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);} const struct bpf_func_proto bpf_probe_read_kernel_proto = {	.func		= bpf_probe_read_kernel,	.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,}; static __always_inline intbpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr){	int ret = security_locked_down(LOCKDOWN_BPF_READ); 	if (unlikely(ret < 0))		goto fail; 	/*	 * The strncpy_from_kernel_nofault() call will likely not fill the	 * entire buffer, but that's okay in this circumstance as we're probing	 * arbitrary memory anyway similar to bpf_probe_read_*() and might	 * as well probe the stack. Thus, memory is explicitly cleared	 * only in error case, so that improper users ignoring return	 * code altogether don't copy garbage; otherwise length of string	 * is returned that can be used for bpf_perf_event_output() et al.	 */	ret = strncpy_from_kernel_nofault(dst, unsafe_ptr, size);	if (unlikely(ret < 0))		goto fail; 	return ret;fail:	memset(dst, 0, size);	return ret;} BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size,	   const void *, unsafe_ptr){	return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);} const struct bpf_func_proto bpf_probe_read_kernel_str_proto = {	.func		= bpf_probe_read_kernel_str,	.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,}; #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACEBPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size,	   const void *, unsafe_ptr){	if ((unsigned long)unsafe_ptr < TASK_SIZE) {		return bpf_probe_read_user_common(dst, size,				(__force void __user *)unsafe_ptr);	}	return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);} static const struct bpf_func_proto bpf_probe_read_compat_proto = {	.func		= bpf_probe_read_compat,	.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_read_compat_str, void *, dst, u32, size,	   const void *, unsafe_ptr){	if ((unsigned long)unsafe_ptr < TASK_SIZE) {		return bpf_probe_read_user_str_common(dst, size,				(__force void __user *)unsafe_ptr);	}	return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);} static const struct bpf_func_proto bpf_probe_read_compat_str_proto = {	.func		= bpf_probe_read_compat_str,	.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,};#endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */ BPF_CALL_3(bpf_probe_write_user, void __user *, 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; 	return copy_to_user_nofault(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){	if (!capable(CAP_SYS_ADMIN))		return NULL; 	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;} static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,		size_t bufsz){	void __user *user_ptr = (__force void __user *)unsafe_ptr; 	buf[0] = 0; 	switch (fmt_ptype) {	case 's':#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE		if ((unsigned long)unsafe_ptr < TASK_SIZE) {			strncpy_from_user_nofault(buf, user_ptr, bufsz);			break;		}		fallthrough;#endif	case 'k':		strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);		break;	case 'u':		strncpy_from_user_nofault(buf, user_ptr, bufsz);		break;	}} /* * Only limited trace_printk() conversion specifiers allowed: * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s */BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,	   u64, arg2, u64, arg3){	int i, mod[3] = {}, fmt_cnt = 0;	char buf[64], fmt_ptype;	void *unsafe_ptr = NULL;	bool str_seen = false; 	/*	 * 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') {			mod[fmt_cnt]++;			if ((fmt[i + 1] == 'k' ||			     fmt[i + 1] == 'u') &&			    fmt[i + 2] == 's') {				fmt_ptype = fmt[i + 1];				i += 2;				goto fmt_str;			} 			/* disallow any further format extensions */			if (fmt[i + 1] != 0 &&			    !isspace(fmt[i + 1]) &&			    !ispunct(fmt[i + 1]))				return -EINVAL; 			goto fmt_next;		} else if (fmt[i] == 's') {			mod[fmt_cnt]++;			fmt_ptype = fmt[i];fmt_str:			if (str_seen)				/* allow only one '%s' per fmt string */				return -EINVAL;			str_seen = true; 			if (fmt[i + 1] != 0 &&			    !isspace(fmt[i + 1]) &&			    !ispunct(fmt[i + 1]))				return -EINVAL; 			switch (fmt_cnt) {			case 0:				unsafe_ptr = (void *)(long)arg1;				arg1 = (long)buf;				break;			case 1:				unsafe_ptr = (void *)(long)arg2;				arg2 = (long)buf;				break;			case 2:				unsafe_ptr = (void *)(long)arg3;				arg3 = (long)buf;				break;			} 			bpf_trace_copy_string(buf, unsafe_ptr, fmt_ptype,					sizeof(buf));			goto fmt_next;		} 		if (fmt[i] == 'l') {			mod[fmt_cnt]++;			i++;		} 		if (fmt[i] != 'i' && fmt[i] != 'd' &&		    fmt[i] != 'u' && fmt[i] != 'x')			return -EINVAL;fmt_next:		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__)				\

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