net/sched: potential data corruption
The reset_policy() does:
memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
In the original code, the size of d->tcfd_defdata wasn't fixed and if
strlen(defdata) was less than 31, reset_policy() would cause memory
corruption.
Please Note: The original alloc_defdata() assumes defdata is 32
characters and a NUL terminator while reset_policy() assumes defdata is
31 characters and a NUL. This patch updates alloc_defdata() to match
reset_policy() (ie a shorter string). I'm not very familiar with this
code so please review carefully.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 1b4bc69..4a1d640 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -73,10 +73,10 @@
static int alloc_defdata(struct tcf_defact *d, char *defdata)
{
- d->tcfd_defdata = kstrndup(defdata, SIMP_MAX_DATA, GFP_KERNEL);
+ d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
if (unlikely(!d->tcfd_defdata))
return -ENOMEM;
-
+ strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
return 0;
}