Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2023-03-06

We've added 8 non-merge commits during the last 7 day(s) which contain
a total of 9 files changed, 64 insertions(+), 18 deletions(-).

The main changes are:

1) Fix BTF resolver for DATASEC sections when a VAR points at a modifier,
   that is, keep resolving such instances instead of bailing out,
   from Lorenz Bauer.

2) Fix BPF test framework with regards to xdp_frame info misplacement
   in the "live packet" code, from Alexander Lobakin.

3) Fix an infinite loop in BPF sockmap code for TCP/UDP/AF_UNIX,
   from Liu Jian.

4) Fix a build error for riscv BPF JIT under PERF_EVENTS=n,
   from Randy Dunlap.

5) Several BPF doc fixes with either broken links or external instead
   of internal doc links, from Bagas Sanjaya.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: check that modifier resolves after pointer
  btf: fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTR
  bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
  bpf, doc: Link to submitting-patches.rst for general patch submission info
  bpf, doc: Do not link to docs.kernel.org for kselftest link
  bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()
  riscv, bpf: Fix patch_text implicit declaration
  bpf, docs: Fix link to BTF doc
====================

Link: https://lore.kernel.org/r/20230306215944.11981-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 9 insertions, 0 deletions

diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index cf26d65ca389..ebf917511937 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -186,6 +186,9 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk,
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return tcp_recvmsg(sk, msg, len, flags, addr_len);
@@ -244,6 +247,9 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return tcp_recvmsg(sk, msg, len, flags, addr_len);
diff --git a/net/ipv4/udp_bpf.c b/net/ipv4/udp_bpf.c
index e5dc91d0e079..0735d820e413 100644
--- a/net/ipv4/udp_bpf.c
+++ b/net/ipv4/udp_bpf.c
@@ -68,6 +68,9 @@ static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
 
+	if (!len)
+		return 0;
+
 	psock = sk_psock_get(sk);
 	if (unlikely(!psock))
 		return sk_udp_recvmsg(sk, msg, len, flags, addr_len);