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Subject[PATCH] fs/proc/task_mmu.c v1: fix clear_refs_write() input sanity check
Date
v1 fix the compiling errors and keep the type variable name.

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.

This patch is rebased on mmotm-2009-08-04-14-22.

Signed-off-by: Vincent Li <macli@brc.ubc.ca>
---
fs/proc/task_mmu.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2079969..c7cf8f3 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -491,21 +491,20 @@ 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;
@@ -541,9 +540,8 @@ 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 = {
--
1.6.0.4


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