Commit a205b082 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
parents 455ba0c0 913050b9
......@@ -88,7 +88,7 @@ static ssize_t hwsampler_write(struct file *file, char const __user *buf,
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
if (retval <= 0)
return retval;
if (oprofile_started)
......
......@@ -45,7 +45,7 @@ static ssize_t timeout_write(struct file *file, char const __user *buf,
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
if (retval <= 0)
return retval;
retval = oprofile_set_timeout(val);
......@@ -84,7 +84,7 @@ static ssize_t depth_write(struct file *file, char const __user *buf, size_t cou
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
if (retval <= 0)
return retval;
retval = oprofile_set_ulong(&oprofile_backtrace_depth, val);
......@@ -141,9 +141,10 @@ static ssize_t enable_write(struct file *file, char const __user *buf, size_t co
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
if (retval <= 0)
return retval;
retval = 0;
if (val)
retval = oprofile_start();
else
......
......@@ -60,6 +60,13 @@ ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t cou
}
/*
* Note: If oprofilefs_ulong_from_user() returns 0, then *val remains
* unchanged and might be uninitialized. 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)
*/
int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
{
char tmpbuf[TMPBUFSIZE];
......@@ -79,7 +86,7 @@ int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_
raw_spin_lock_irqsave(&oprofilefs_lock, flags);
*val = simple_strtoul(tmpbuf, NULL, 0);
raw_spin_unlock_irqrestore(&oprofilefs_lock, flags);
return 0;
return count;
}
......@@ -99,7 +106,7 @@ static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_
return -EINVAL;
retval = oprofilefs_ulong_from_user(&value, buf, count);
if (retval)
if (retval <= 0)
return retval;
retval = oprofile_set_ulong(file->private_data, value);
......
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