selinuxfs: switch to memdup_user_nul()
Nothing in there gives a damn about the buffer alignment - it
just parses its contents. So the use of get_zeroed_page()
doesn't buy us anything - might as well had been kmalloc(),
which makes that code equivalent to open-coded memdup_user_nul()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index c02da25..73c60ba 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -147,23 +147,16 @@
ssize_t length;
int new_value;
- length = -ENOMEM;
if (count >= PAGE_SIZE)
- goto out;
+ return -ENOMEM;
/* No partial writes. */
- length = -EINVAL;
if (*ppos != 0)
- goto out;
+ return -EINVAL;
- length = -ENOMEM;
- page = (char *)get_zeroed_page(GFP_KERNEL);
- if (!page)
- goto out;
-
- length = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
@@ -186,7 +179,7 @@
}
length = count;
out:
- free_page((unsigned long) page);
+ kfree(page);
return length;
}
#else
@@ -275,27 +268,20 @@
size_t count, loff_t *ppos)
{
- char *page = NULL;
+ char *page;
ssize_t length;
int new_value;
- length = -ENOMEM;
if (count >= PAGE_SIZE)
- goto out;
+ return -ENOMEM;
/* No partial writes. */
- length = -EINVAL;
if (*ppos != 0)
- goto out;
+ return -EINVAL;
- length = -ENOMEM;
- page = (char *)get_zeroed_page(GFP_KERNEL);
- if (!page)
- goto out;
-
- length = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
@@ -313,7 +299,7 @@
length = count;
out:
- free_page((unsigned long) page);
+ kfree(page);
return length;
}
#else
@@ -611,31 +597,24 @@
static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- char *page = NULL;
+ char *page;
ssize_t length;
unsigned int new_value;
length = task_has_security(current, SECURITY__SETCHECKREQPROT);
if (length)
- goto out;
+ return length;
- length = -ENOMEM;
if (count >= PAGE_SIZE)
- goto out;
+ return -ENOMEM;
/* No partial writes. */
- length = -EINVAL;
if (*ppos != 0)
- goto out;
+ return -EINVAL;
- length = -ENOMEM;
- page = (char *)get_zeroed_page(GFP_KERNEL);
- if (!page)
- goto out;
-
- length = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
length = -EINVAL;
if (sscanf(page, "%u", &new_value) != 1)
@@ -644,7 +623,7 @@
selinux_checkreqprot = new_value ? 1 : 0;
length = count;
out:
- free_page((unsigned long) page);
+ kfree(page);
return length;
}
static const struct file_operations sel_checkreqprot_ops = {
@@ -1100,14 +1079,12 @@
if (*ppos != 0)
goto out;
- length = -ENOMEM;
- page = (char *)get_zeroed_page(GFP_KERNEL);
- if (!page)
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page)) {
+ length = PTR_ERR(page);
+ page = NULL;
goto out;
-
- length = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
+ }
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
@@ -1121,7 +1098,7 @@
out:
mutex_unlock(&sel_mutex);
- free_page((unsigned long) page);
+ kfree(page);
return length;
}
@@ -1154,14 +1131,12 @@
if (*ppos != 0)
goto out;
- length = -ENOMEM;
- page = (char *)get_zeroed_page(GFP_KERNEL);
- if (!page)
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page)) {
+ length = PTR_ERR(page);
+ page = NULL;
goto out;
-
- length = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
+ }
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
@@ -1176,7 +1151,7 @@
out:
mutex_unlock(&sel_mutex);
- free_page((unsigned long) page);
+ kfree(page);
return length;
}
@@ -1292,31 +1267,24 @@
size_t count, loff_t *ppos)
{
- char *page = NULL;
+ char *page;
ssize_t ret;
int new_value;
ret = task_has_security(current, SECURITY__SETSECPARAM);
if (ret)
- goto out;
+ return ret;
- ret = -ENOMEM;
if (count >= PAGE_SIZE)
- goto out;
+ return -ENOMEM;
/* No partial writes. */
- ret = -EINVAL;
if (*ppos != 0)
- goto out;
+ return -EINVAL;
- ret = -ENOMEM;
- page = (char *)get_zeroed_page(GFP_KERNEL);
- if (!page)
- goto out;
-
- ret = -EFAULT;
- if (copy_from_user(page, buf, count))
- goto out;
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
ret = -EINVAL;
if (sscanf(page, "%u", &new_value) != 1)
@@ -1326,7 +1294,7 @@
ret = count;
out:
- free_page((unsigned long)page);
+ kfree(page);
return ret;
}