filter: refactor common filter attach code into __sk_attach_prog

Both sk_attach_filter() and sk_attach_bpf() are setting up sk_filter,
charging skmem and attaching it to the socket after we got the eBPF
prog up and ready. Lets refactor that into a common helper.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/filter.c b/net/core/filter.c
index ff000cb25e0aac712b6287ce350f5948d5ff3a31..7a4eb7030dba9085aa8c25151fcca62173002e33 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1019,6 +1019,32 @@ void bpf_prog_destroy(struct bpf_prog *fp)
 }
 EXPORT_SYMBOL_GPL(bpf_prog_destroy);
 
+static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk)
+{
+       struct sk_filter *fp, *old_fp;
+
+       fp = kmalloc(sizeof(*fp), GFP_KERNEL);
+       if (!fp)
+               return -ENOMEM;
+
+       fp->prog = prog;
+       atomic_set(&fp->refcnt, 0);
+
+       if (!sk_filter_charge(sk, fp)) {
+               kfree(fp);
+               return -ENOMEM;
+       }
+
+       old_fp = rcu_dereference_protected(sk->sk_filter,
+                                          sock_owned_by_user(sk));
+       rcu_assign_pointer(sk->sk_filter, fp);
+
+       if (old_fp)
+               sk_filter_uncharge(sk, old_fp);
+
+       return 0;
+}
+
 /**
  *     sk_attach_filter - attach a socket filter
  *     @fprog: the filter program
@@ -1031,7 +1057,6 @@ EXPORT_SYMBOL_GPL(bpf_prog_destroy);
  */
 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
 {
-       struct sk_filter *fp, *old_fp;
        unsigned int fsize = bpf_classic_proglen(fprog);
        unsigned int bpf_fsize = bpf_prog_size(fprog->len);
        struct bpf_prog *prog;
@@ -1068,35 +1093,20 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
        if (IS_ERR(prog))
                return PTR_ERR(prog);
 
-       fp = kmalloc(sizeof(*fp), GFP_KERNEL);
-       if (!fp) {
+       err = __sk_attach_prog(prog, sk);
+       if (err < 0) {
                __bpf_prog_release(prog);
-               return -ENOMEM;
-       }
-       fp->prog = prog;
-
-       atomic_set(&fp->refcnt, 0);
-
-       if (!sk_filter_charge(sk, fp)) {
-               __sk_filter_release(fp);
-               return -ENOMEM;
+               return err;
        }
 
-       old_fp = rcu_dereference_protected(sk->sk_filter,
-                                          sock_owned_by_user(sk));
-       rcu_assign_pointer(sk->sk_filter, fp);
-
-       if (old_fp)
-               sk_filter_uncharge(sk, old_fp);
-
        return 0;
 }
 EXPORT_SYMBOL_GPL(sk_attach_filter);
 
 int sk_attach_bpf(u32 ufd, struct sock *sk)
 {
-       struct sk_filter *fp, *old_fp;
        struct bpf_prog *prog;
+       int err;
 
        if (sock_flag(sk, SOCK_FILTER_LOCKED))
                return -EPERM;
@@ -1110,27 +1120,12 @@ int sk_attach_bpf(u32 ufd, struct sock *sk)
                return -EINVAL;
        }
 
-       fp = kmalloc(sizeof(*fp), GFP_KERNEL);
-       if (!fp) {
+       err = __sk_attach_prog(prog, sk);
+       if (err < 0) {
                bpf_prog_put(prog);
-               return -ENOMEM;
-       }
-
-       fp->prog = prog;
-       atomic_set(&fp->refcnt, 0);
-
-       if (!sk_filter_charge(sk, fp)) {
-               __sk_filter_release(fp);
-               return -ENOMEM;
+               return err;
        }
 
-       old_fp = rcu_dereference_protected(sk->sk_filter,
-                                          sock_owned_by_user(sk));
-       rcu_assign_pointer(sk->sk_filter, fp);
-
-       if (old_fp)
-               sk_filter_uncharge(sk, old_fp);
-
        return 0;
 }