[PATCH 3.18 18/29] osf_getdomainname(): use copy_to_user()

From: Greg Kroah-Hartman
Date: Fri Sep 07 2018 - 17:43:33 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit 9ba3eb5103cf56f0daaf07de4507df76e7813ed7 upstream.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/alpha/kernel/osf_sys.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)

--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -560,25 +560,20 @@ SYSCALL_DEFINE0(getdtablesize)
*/
SYSCALL_DEFINE2(osf_getdomainname, char __user *, name, int, namelen)
{
- unsigned len;
- int i;
+ int len, err = 0;
+ char *kname;

- if (!access_ok(VERIFY_WRITE, name, namelen))
- return -EFAULT;
-
- len = namelen;
- if (len > 32)
- len = 32;
+ if (namelen > 32)
+ namelen = 32;

down_read(&uts_sem);
- for (i = 0; i < len; ++i) {
- __put_user(utsname()->domainname[i], name + i);
- if (utsname()->domainname[i] == '\0')
- break;
- }
+ kname = utsname()->domainname;
+ len = strnlen(kname, namelen);
+ if (copy_to_user(name, kname, min(len + 1, namelen)))
+ err = -EFAULT;
up_read(&uts_sem);

- return 0;
+ return err;
}

/*