bpf: Change bpf_sk_assign to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON

This patch changes the bpf_sk_assign() to take
ARG_PTR_TO_BTF_ID_SOCK_COMMON such that they will work with the pointer
returned by the bpf_skc_to_*() helpers also.

The bpf_sk_lookup_assign() is taking ARG_PTR_TO_SOCKET_"OR_NULL".  Meaning
it specifically takes a literal NULL.  ARG_PTR_TO_BTF_ID_SOCK_COMMON
does not allow a literal NULL, so another ARG type is required
for this purpose and another follow-up patch can be used if
there is such need.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200925000415.3857374-1-kafai@fb.com

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 69b9e30..2d6519a 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3107,7 +3107,7 @@ union bpf_attr {
  *     Return
  *             The id is returned or 0 in case the id could not be retrieved.
  *
- * long bpf_sk_assign(struct sk_buff *skb, struct bpf_sock *sk, u64 flags)
+ * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
  *     Description
  *             Helper is overloaded depending on BPF program type. This
  *             description applies to **BPF_PROG_TYPE_SCHED_CLS** and

diff --git a/net/core/filter.c b/net/core/filter.c
index 1d88e9b..af88935 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6217,7 +6217,7 @@ static const struct bpf_func_proto bpf_tcp_gen_syncookie_proto = {
 
 BPF_CALL_3(bpf_sk_assign, struct sk_buff *, skb, struct sock *, sk, u64, flags)
 {
-       if (flags != 0)
+       if (!sk || flags != 0)
                return -EINVAL;
        if (!skb_at_tc_ingress(skb))
                return -EOPNOTSUPP;
@@ -6241,7 +6241,7 @@ static const struct bpf_func_proto bpf_sk_assign_proto = {
        .gpl_only       = false,
        .ret_type       = RET_INTEGER,
        .arg1_type      = ARG_PTR_TO_CTX,
-       .arg2_type      = ARG_PTR_TO_SOCK_COMMON,
+       .arg2_type      = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
        .arg3_type      = ARG_ANYTHING,
 };
 

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 69b9e30..2d6519a 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3107,7 +3107,7 @@ union bpf_attr {
  *     Return
  *             The id is returned or 0 in case the id could not be retrieved.
  *
- * long bpf_sk_assign(struct sk_buff *skb, struct bpf_sock *sk, u64 flags)
+ * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
  *     Description
  *             Helper is overloaded depending on BPF program type. This
  *             description applies to **BPF_PROG_TYPE_SCHED_CLS** and