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: Vincent Li <macli@brc.ubc.ca> Acked-by: David Rientjes <rientjes@google.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Amerigo Wang <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -473,21 +473,20 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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struct task_struct *task;
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char buffer[PROC_NUMBUF], *end;
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char buffer[PROC_NUMBUF];
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struct mm_struct *mm;
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struct vm_area_struct *vma;
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int type;
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long type;
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memset(buffer, 0, sizeof(buffer));
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if (count > sizeof(buffer) - 1)
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count = sizeof(buffer) - 1;
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if (copy_from_user(buffer, buf, count))
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return -EFAULT;
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type = simple_strtol(buffer, &end, 0);
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if (strict_strtol(strstrip(buffer), 10, &type))
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return -EINVAL;
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if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED)
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return -EINVAL;
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if (*end == '\n')
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end++;
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task = get_proc_task(file->f_path.dentry->d_inode);
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if (!task)
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return -ESRCH;
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@ -523,9 +522,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
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mmput(mm);
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}
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put_task_struct(task);
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if (end - buffer == 0)
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return -EIO;
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return end - buffer;
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return count;
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}
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const struct file_operations proc_clear_refs_operations = {
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