Prev: rcu: more careful check for the last non-dyntick-idle CPU
Next: rcu: only raise softirq when need
From: Eric W. Biederman on 30 Mar 2010 12:30
Dan Carpenter <error27(a)gmail.com> writes:

> "len" hasn't been properly range checked so we shouldn't use it as an
> array offset. This can only be written to by root but it would still be
> annoying to accidentally write more than 3 characters and corrupt your
> memory.
>
> Signed-off-by: Dan Carpenter <error27(a)gmail.com>
> ---
> I don't have a cross compile environment to compile this. Sorry. :/
>
> diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c
> index f449c69..72c2e90 100644
> --- a/drivers/s390/char/sclp_async.c
> +++ b/drivers/s390/char/sclp_async.c
> @@ -84,7 +84,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write,
> rc = copy_from_user(buf, buffer, sizeof(buf));
> if (rc != 0)
> return -EFAULT;
> - buf[len - 1] = '\0';
> + buf[sizeof(buf) - 1] = '\0';
> if (strict_strtoul(buf, 0, &val) != 0)
> return -EINVAL;
> if (val != 0 && val != 1)
> @@ -99,6 +99,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write,
> static struct ctl_table callhome_table[] = {
> {
> .procname = "callhome",
> + .maxlen = 3,
> .mode = 0644,
> .proc_handler = proc_handler_callhome,
> },

Setting maxlen won't do any good as proc_handler_callhome doesn't look at it.

Eric

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: rcu: more careful check for the last non-dyntick-idle CPU
Next: rcu: only raise softirq when need