'datalen' is unsigned, use 'ret' instead to catch a negative return value.
Signed-off-by: Roel Kluin <12o3l@tiscali.nl>

---

diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c

index fbde461..b78d015 100644

--- a/net/sched/act_simple.c

+++ b/net/sched/act_simple.c

@@ -114,9 +114,10 @@ static int tcf_simp_init(struct nlattr *nla, struct nlattr *est,

 	if (defdata == NULL)

 		return -EINVAL;
-	datalen = nla_len(tb[TCA_DEF_DATA]);

-	if (datalen <= 0)

+	ret = nla_len(tb[TCA_DEF_DATA]);

+	if (ret <= 0)

 		return -EINVAL;

+	datalen = ret;
 	pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);

 	if (!pc) {

--

From: Roel Kluin <12o3l@tiscali.nl>
This clobbers 'ret' which is compared to ACT_P_CREATED

later in the function.  If the !pc branch below this code

is not taken, ret must be left at it's initial value of

zero.  Now, it will take on some non-zero positive value

which is not correct.
--

The change is also unnecessary because the attribute was

already validated and the length can not be less than zero.
This patch changes it to only check for zero length.
Signed-off-by: Patrick McHardy <kaber@trash.net>

From: Patrick McHardy <kaber@trash.net>
Even though there have been discussions to do other things,

this patch moves things in the forward direction so I have

applied it.
Thanks.
--

Since act_simple is an academic example:

I think that a better solution is to add TCA_DEF_DATA (which is a

string) to the nla_policy. nla_policy is defined but at the moment it is

not used in the call to nla_parse_nested() - might as well use it.
Roel, would you like to take a crack at that? You will need to define

the max size of the string that TCA_DEF_DATA can hold (if you want to do

it cleanly then define it in include/linux/tc_act/tc_defact.h). This MAX

size will appear in the nla_policy.
cheers,

jamal
--

Basic validity checks are always performed. But I agree, better

to provide a good example.

--