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Commit fb92a4b0 authored by Vincent Li's avatar Vincent Li Committed by Linus Torvalds
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fs/proc/task_mmu.c v1: fix clear_refs_write() input sanity check 



Andrew Morton pointed out similar string hacking and obfuscated check for
zero-length input at the end of the function, David Rientjes suggested to
use strict_strtol to replace simple_strtol, this patch cover above
suggestions, add removing of leading and trailing whitespace from user
input.  It does not change function behavious.

Signed-off-by: default avatarVincent Li <macli@brc.ubc.ca>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Amerigo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent acef82b8

fs/proc/task_mmu.c

+6 −8
Original line number Diff line number Diff line
@@ -473,21 +473,20 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, 
				size_t count, loff_t *ppos)

{

	struct task_struct *task;

	char buffer[PROC_NUMBUF], *end;

	char buffer[PROC_NUMBUF];

	struct mm_struct *mm;

	struct vm_area_struct *vma;

	int type;

	long type;



	memset(buffer, 0, sizeof(buffer));

	if (count > sizeof(buffer) - 1)

		count = sizeof(buffer) - 1;

	if (copy_from_user(buffer, buf, count))

		return -EFAULT;

	type = simple_strtol(buffer, &end, 0);

	if (strict_strtol(strstrip(buffer), 10, &type))

		return -EINVAL;

	if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED)

		return -EINVAL;

	if (*end == '\n')

		end++;

	task = get_proc_task(file->f_path.dentry->d_inode);

	if (!task)

		return -ESRCH;
@@ -523,9 +522,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, 
		mmput(mm);

	}

	put_task_struct(task);

	if (end - buffer == 0)

		return -EIO;

	return end - buffer;



	return count;

}



const struct file_operations proc_clear_refs_operations = {