Commit f1d3cbfa authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

tracing: Move duplicate code of trace_kprobe/eprobe.c into header 

The functions:

  fetch_store_strlen_user()
  fetch_store_strlen()
  fetch_store_string_user()
  fetch_store_string()

are identical in both trace_kprobe.c and trace_eprobe.c. Move them into
a new header file trace_probe_kernel.h to share it. This code will later
be used by the synthetic events as well.

Marked for stable as a fix for a crash in synthetic events requires it.

Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org



Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: default avatarTom Zanussi <zanussi@kernel.org>
Fixes: bd82631d ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent b7085b6f

kernel/trace/trace_eprobe.c

+5 −55
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include "trace_dynevent.h"

#include "trace_probe.h"

#include "trace_probe_tmpl.h"

#include "trace_probe_kernel.h"



#define EPROBE_EVENT_SYSTEM "eprobes"
@@ -456,29 +457,14 @@ NOKPROBE_SYMBOL(process_fetch_insn) 
static nokprobe_inline int

fetch_store_strlen_user(unsigned long addr)

{

	const void __user *uaddr =  (__force const void __user *)addr;



	return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);

	return kern_fetch_store_strlen_user(addr);

}



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

fetch_store_strlen(unsigned long addr)

{

	int ret, len = 0;

	u8 c;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if (addr < TASK_SIZE)

		return fetch_store_strlen_user(addr);

#endif



	do {

		ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);

		len++;

	} while (c && ret == 0 && len < MAX_STRING_SIZE);



	return (ret < 0) ? ret : len;

	return kern_fetch_store_strlen(addr);

}



/*
@@ -488,21 +474,7 @@ fetch_store_strlen(unsigned long addr) 
static nokprobe_inline int

fetch_store_string_user(unsigned long addr, void *dest, void *base)

{

	const void __user *uaddr =  (__force const void __user *)addr;

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;

	long ret;



	if (unlikely(!maxlen))

		return -ENOMEM;



	__dest = get_loc_data(dest, base);



	ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);

	if (ret >= 0)

		*(u32 *)dest = make_data_loc(ret, __dest - base);



	return ret;

	return kern_fetch_store_string_user(addr, dest, base);

}



/*
@@ -512,29 +484,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) 
static nokprobe_inline int

fetch_store_string(unsigned long addr, void *dest, void *base)

{

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;

	long ret;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)addr < TASK_SIZE)

		return fetch_store_string_user(addr, dest, base);

#endif



	if (unlikely(!maxlen))

		return -ENOMEM;



	__dest = get_loc_data(dest, base);



	/*

	 * Try to get string again, since the string can be changed while

	 * probing.

	 */

	ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);

	if (ret >= 0)

		*(u32 *)dest = make_data_loc(ret, __dest - base);



	return ret;

	return kern_fetch_store_string(addr, dest, base);

}



static nokprobe_inline int

kernel/trace/trace_kprobe.c

+5 −55
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include "trace_kprobe_selftest.h"

#include "trace_probe.h"

#include "trace_probe_tmpl.h"

#include "trace_probe_kernel.h"



#define KPROBE_EVENT_SYSTEM "kprobes"

#define KRETPROBE_MAXACTIVE_MAX 4096
@@ -1223,29 +1224,14 @@ static const struct file_operations kprobe_profile_ops = { 
static nokprobe_inline int

fetch_store_strlen_user(unsigned long addr)

{

	const void __user *uaddr =  (__force const void __user *)addr;



	return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);

	return kern_fetch_store_strlen_user(addr);

}



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

fetch_store_strlen(unsigned long addr)

{

	int ret, len = 0;

	u8 c;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if (addr < TASK_SIZE)

		return fetch_store_strlen_user(addr);

#endif



	do {

		ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);

		len++;

	} while (c && ret == 0 && len < MAX_STRING_SIZE);



	return (ret < 0) ? ret : len;

	return kern_fetch_store_strlen(addr);

}



/*
@@ -1255,21 +1241,7 @@ fetch_store_strlen(unsigned long addr) 
static nokprobe_inline int

fetch_store_string_user(unsigned long addr, void *dest, void *base)

{

	const void __user *uaddr =  (__force const void __user *)addr;

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;

	long ret;



	if (unlikely(!maxlen))

		return -ENOMEM;



	__dest = get_loc_data(dest, base);



	ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);

	if (ret >= 0)

		*(u32 *)dest = make_data_loc(ret, __dest - base);



	return ret;

	return kern_fetch_store_string_user(addr, dest, base);

}



/*
@@ -1279,29 +1251,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) 
static nokprobe_inline int

fetch_store_string(unsigned long addr, void *dest, void *base)

{

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;

	long ret;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)addr < TASK_SIZE)

		return fetch_store_string_user(addr, dest, base);

#endif



	if (unlikely(!maxlen))

		return -ENOMEM;



	__dest = get_loc_data(dest, base);



	/*

	 * Try to get string again, since the string can be changed while

	 * probing.

	 */

	ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);

	if (ret >= 0)

		*(u32 *)dest = make_data_loc(ret, __dest - base);



	return ret;

	return kern_fetch_store_string(addr, dest, base);

}



static nokprobe_inline int

kernel/trace/trace_probe_kernel.h

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __TRACE_PROBE_KERNEL_H_

#define __TRACE_PROBE_KERNEL_H_



/*

 * This depends on trace_probe.h, but can not include it due to

 * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.

 * Which means that any other user must include trace_probe.h before including

 * this file.

 */

/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

kern_fetch_store_strlen_user(unsigned long addr)

{

	const void __user *uaddr =  (__force const void __user *)addr;



	return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);

}



/* Return the length of string -- including null terminal byte */

static nokprobe_inline int

kern_fetch_store_strlen(unsigned long addr)

{

	int ret, len = 0;

	u8 c;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if (addr < TASK_SIZE)

		return kern_fetch_store_strlen_user(addr);

#endif



	do {

		ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);

		len++;

	} while (c && ret == 0 && len < MAX_STRING_SIZE);



	return (ret < 0) ? ret : len;

}



/*

 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf

 * with max length and relative data location.

 */

static nokprobe_inline int

kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)

{

	const void __user *uaddr =  (__force const void __user *)addr;

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;

	long ret;



	if (unlikely(!maxlen))

		return -ENOMEM;



	__dest = get_loc_data(dest, base);



	ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);

	if (ret >= 0)

		*(u32 *)dest = make_data_loc(ret, __dest - base);



	return ret;

}



/*

 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max

 * length and relative data location.

 */

static nokprobe_inline int

kern_fetch_store_string(unsigned long addr, void *dest, void *base)

{

	int maxlen = get_loc_len(*(u32 *)dest);

	void *__dest;

	long ret;



#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	if ((unsigned long)addr < TASK_SIZE)

		return kern_fetch_store_string_user(addr, dest, base);

#endif



	if (unlikely(!maxlen))

		return -ENOMEM;



	__dest = get_loc_data(dest, base);



	/*

	 * Try to get string again, since the string can be changed while

	 * probing.

	 */

	ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);

	if (ret >= 0)

		*(u32 *)dest = make_data_loc(ret, __dest - base);



	return ret;

}



#endif /* __TRACE_PROBE_KERNEL_H_ */