net: filter: let unattached filters use sock_fprog_kern
The sk_unattached_filter_create() API is used by BPF filters that
are not directly attached or related to sockets, and are used in
team, ptp, xt_bpf, cls_bpf, etc. As such all users do their own
internal managment of obtaining filter blocks and thus already
have them in kernel memory and set up before calling into
sk_unattached_filter_create(). As a result, due to __user annotation
in sock_fprog, sparse triggers false positives (incorrect type in
assignment [different address space]) when filters are set up before
passing them to sk_unattached_filter_create(). Therefore, let
sk_unattached_filter_create() API use sock_fprog_kern to overcome
this issue.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/xt_bpf.c b/net/netfilter/xt_bpf.c
index 12d4da8..bbffdbd 100644
--- a/net/netfilter/xt_bpf.c
+++ b/net/netfilter/xt_bpf.c
@@ -23,10 +23,11 @@
static int bpf_mt_check(const struct xt_mtchk_param *par)
{
struct xt_bpf_info *info = par->matchinfo;
- struct sock_fprog program;
+ struct sock_fprog_kern program;
program.len = info->bpf_program_num_elem;
- program.filter = (struct sock_filter __user *) info->bpf_program;
+ program.filter = info->bpf_program;
+
if (sk_unattached_filter_create(&info->filter, &program)) {
pr_info("bpf: check failed: parse error\n");
return -EINVAL;