From: Yafang Shao <laoar.shao@gmail.com>
Date: Wed, 23 Jan 2019 12:37:19 +0800
Subject: bpf: sock recvbuff must be limited by rmem_max in bpf_setsockopt()
Patch-mainline: v5.0-rc6
Git-commit: c9e4576743eeda8d24dedc164d65b78877f9a98c
References: bsc#1109837

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/core/filter.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3753,10 +3753,12 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_so
 		/* 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;