Messages in this thread | | | From | Willem de Bruijn <> | Date | Fri, 25 Jul 2014 09:53:48 -0400 | Subject | Re: [PATCH net-next] net: filter: rename 'struct sk_filter' to 'struct bpf_prog' |
| |
>> >alternative fix for xt_bpf.h could be to replace: >> > /* only used in the kernel */ >> > struct sk_filter *filter __attribute__((aligned(8))); >> >with >> > /* only used in the kernel */ >> > void *filter __attribute__((aligned(8))); >> > >> >but this 'void *' approach may further break broken userspace, >> >whereas the fix implemented here is more seamless. >> >> Yep, that's not good, 'struct sk_filter' should never have been in a uapi >> file actually.
This follows a convention in include/uapi/linux/netfilter/*.h that likely predates the introduction of uapi. A search for "Used internally by the kernel" shows many more examples. I should not have included filter.h, however. The common behavior when using pointers to kernel-internal structures is to have a forward declaration. I suggest making that change, instead of changing to void *. This avoids having to add casts where xt_bpf_info is used in net/netfilter/xt_bpf.c:
-#include <linux/filter.h> #include <linux/types.h>
#define XT_BPF_MAX_NUM_INSTR 64
+struct sk_filter; + struct xt_bpf_info {
I can send this as a separate patch to net-next, if that helps.
> You can just send me a patch to change it to void. It's an internal > kernel pointer as the comment states. There is **no** way that > userspace can lurk with that from iptables at all.
| |