[PATCH 4.20 087/171] bpf: sock recvbuff must be limited by rmem_max in bpf_setsockopt()

Greg Kroah-Hartman
2019-03-12T18:03:57Z

[ Upstream commit c9e4576743eeda8d24dedc164d65b78877f9a98c ]

When sock recvbuff is set by bpf_setsockopt(), the value must by
limited by rmem_max. It is the same with sendbuff.

Fixes: 8c4b4c7e9ff0 ("bpf: Add setsockopt helper function to bpf")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/filter.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 16350f8c8815..821050957aca 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3927,10 +3927,12 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
/* Only some socketops are supported */
switch (optname) {
case SO_RCVBUF:
+ val = min_t(u32, val, sysctl_rmem_max);
sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
sk->sk_rcvbuf = max_t(int, val * 2, SOCK_MIN_RCVBUF);
break;
case SO_SNDBUF:
+ val = min_t(u32, val, sysctl_wmem_max);
sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF);
break;
--
2.19.1