2008-10-18 14:21:41

by Roel Kluin

Subject: [PATCH] ext4: simple_strtol returns signed.

simple_strtol returns signed.

Signed-off-by: Roel Kluin <[email protected]>
---
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9b2b2bc..1789dec 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3516,7 +3516,7 @@ static ssize_t ext4_ui_proc_write(struct file *file, const char __user *buf,
{
unsigned int *p = PDE(file->f_path.dentry->d_inode)->data;
char str[32];
- unsigned long value;
+ long value;

if (cnt >= sizeof(str))
return -EINVAL;

2008-10-18 14:36:12

by Theodore Ts'o

Subject: Re: [PATCH] ext4: simple_strtol returns signed.

On Sat, Oct 18, 2008 at 04:21:44PM -0400, roel kluin wrote:
> simple_strtol returns signed.

Actually the better fix is probably to change the use of
simple_strtol() to simple_strtoul().

- Ted

2008-10-20 20:00:54

by Roel Kluin

Subject: Re: [PATCH] ext4: simple_strtol returns signed.

simple_strtol returns signed, but a negative return values is lost when stored
in an unsigned. As suggested use simple_strtoul() instead.

Signed-off-by: Roel Kluin <[email protected]>
---
Since p is dereferenced with the unsigned long return of simple_strtoul, I think
p should be a pointer to an unsigned long, am I wrong?

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9b2b2bc..0ab6cb4 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3514,18 +3514,15 @@ static int ext4_ui_proc_open(struct inode *inode, struct file *file)
static ssize_t ext4_ui_proc_write(struct file *file, const char __user *buf,
size_t cnt, loff_t *ppos)
{
- unsigned int *p = PDE(file->f_path.dentry->d_inode)->data;
+ unsigned long *p = PDE(file->f_path.dentry->d_inode)->data;
char str[32];
- unsigned long value;

if (cnt >= sizeof(str))
return -EINVAL;
if (copy_from_user(str, buf, cnt))
return -EFAULT;
- value = simple_strtol(str, NULL, 0);
- if (value < 0)
- return -ERANGE;
- *p = value;
+
+ *p = simple_strtoul(str, NULL, 0);
return cnt;
}