This is just a cleanup.
My testing version of Smatch warns about this:
net/core/filter.c +380 check_load_and_stores(6)
warn: check 'flen' for negative values
flen comes from the user. We try to clamp the values here between 1
and BPF_MAXINSNS but the clamp doesn't work because it could be
negative. This is a bug, but it's not exploitable.
Signed-off-by: Dan Carpenter <redacted>
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 741956f..8eeb205 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -155,7 +155,7 @@ extern unsigned int sk_run_filter(const struct sk_buff *skb,
const struct sock_filter *filter);
extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
extern int sk_detach_filter(struct sock *sk);
-extern int sk_chk_filter(struct sock_filter *filter, int flen);
+extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
#ifdef CONFIG_BPF_JIT
extern void bpf_jit_compile(struct sk_filter *fp);
diff --git a/net/core/filter.c b/net/core/filter.c
index 8fcc2d7..5dea452 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -436,7 +436,7 @@ error:
*
* Returns 0 if the rule set is legal or -EINVAL if not.
*/
-int sk_chk_filter(struct sock_filter *filter, int flen)
+int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
{
/*
* Valid instructions are initialized to non-0.