tmp_suning_uos_patched/drivers/oprofile/oprofile_files.c
Robert Richter 913050b91e oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
If oprofilefs_ulong_from_user() is called with count equals
zero, *val remains unchanged. Depending on the implementation it
might be uninitialized.

Change oprofilefs_ulong_from_user()'s interface to return count
on success. Thus, we are able to return early if count equals
zero which avoids using *val uninitialized. Fixing all users of
oprofilefs_ulong_ from_user().

This follows write syscall implementation when count is zero:
"If count is zero ... [and if] no errors are detected, 0 will be
returned without causing any other effect." (man 2 write)

Reported-By: Mike Waychison <mikew@google.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Link: http://lkml.kernel.org/r/20111219153830.GH16765@erda.amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-19 17:18:43 +01:00

202 lines
4.7 KiB
C

/**
* @file oprofile_files.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon <levon@movementarian.org>
*/
#include <linux/fs.h>
#include <linux/oprofile.h>
#include <linux/jiffies.h>
#include "event_buffer.h"
#include "oprofile_stats.h"
#include "oprof.h"
#define BUFFER_SIZE_DEFAULT 131072
#define CPU_BUFFER_SIZE_DEFAULT 8192
#define BUFFER_WATERSHED_DEFAULT 32768 /* FIXME: tune */
#define TIME_SLICE_DEFAULT 1
unsigned long oprofile_buffer_size;
unsigned long oprofile_cpu_buffer_size;
unsigned long oprofile_buffer_watershed;
unsigned long oprofile_time_slice;
#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
static ssize_t timeout_read(struct file *file, char __user *buf,
size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(jiffies_to_msecs(oprofile_time_slice),
buf, count, offset);
}
static ssize_t timeout_write(struct file *file, char const __user *buf,
size_t count, loff_t *offset)
{
unsigned long val;
int retval;
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval <= 0)
return retval;
retval = oprofile_set_timeout(val);
if (retval)
return retval;
return count;
}
static const struct file_operations timeout_fops = {
.read = timeout_read,
.write = timeout_write,
.llseek = default_llseek,
};
#endif
static ssize_t depth_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(oprofile_backtrace_depth, buf, count,
offset);
}
static ssize_t depth_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
unsigned long val;
int retval;
if (*offset)
return -EINVAL;
if (!oprofile_ops.backtrace)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval <= 0)
return retval;
retval = oprofile_set_ulong(&oprofile_backtrace_depth, val);
if (retval)
return retval;
return count;
}
static const struct file_operations depth_fops = {
.read = depth_read,
.write = depth_write,
.llseek = default_llseek,
};
static ssize_t pointer_size_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
}
static const struct file_operations pointer_size_fops = {
.read = pointer_size_read,
.llseek = default_llseek,
};
static ssize_t cpu_type_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
}
static const struct file_operations cpu_type_fops = {
.read = cpu_type_read,
.llseek = default_llseek,
};
static ssize_t enable_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
}
static ssize_t enable_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
unsigned long val;
int retval;
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval <= 0)
return retval;
retval = 0;
if (val)
retval = oprofile_start();
else
oprofile_stop();
if (retval)
return retval;
return count;
}
static const struct file_operations enable_fops = {
.read = enable_read,
.write = enable_write,
.llseek = default_llseek,
};
static ssize_t dump_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
wake_up_buffer_waiter();
return count;
}
static const struct file_operations dump_fops = {
.write = dump_write,
.llseek = noop_llseek,
};
void oprofile_create_files(struct super_block *sb, struct dentry *root)
{
/* reinitialize default values */
oprofile_buffer_size = BUFFER_SIZE_DEFAULT;
oprofile_cpu_buffer_size = CPU_BUFFER_SIZE_DEFAULT;
oprofile_buffer_watershed = BUFFER_WATERSHED_DEFAULT;
oprofile_time_slice = msecs_to_jiffies(TIME_SLICE_DEFAULT);
oprofilefs_create_file(sb, root, "enable", &enable_fops);
oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
oprofilefs_create_ulong(sb, root, "buffer_size", &oprofile_buffer_size);
oprofilefs_create_ulong(sb, root, "buffer_watershed", &oprofile_buffer_watershed);
oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &oprofile_cpu_buffer_size);
oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
oprofilefs_create_file(sb, root, "time_slice", &timeout_fops);
#endif
oprofile_create_stats_files(sb, root);
if (oprofile_ops.create_files)
oprofile_ops.create_files(sb, root);
}