commit 0129aaae86be64d293eb64e25c6acb1a57cbd588
author Maciej Żenczykowski <maze@google.com> Wed May 06 14:09:45 2020 -0700
committer Maciej Żenczykowski <maze@google.com> Fri May 08 22:34:37 2020 -0700
tree f6f5ee4d49621998013bd70440dabbfe4309ba16
parent b7f370c0143567f9f475c12ddadb5910b9eb74b7

libnetutils/packet.c - fix a raw socket reception race

A socket created bound to a specific protocol can receive packets before
it's bound to a specific interface/mac.

It's best to rely on the bind().

This replicates the way packet sockets are created in external/android-clat.
See: ring.c ring_create() and clatd.c configure_packet_socket()

Test: builds, atest
Bug: 155297277
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I569d2b81a396f352ab5d1b71bd5ad0d96217aab1

libnetutils/packet.c

diff --git a/libnetutils/packet.c b/libnetutils/packet.c
index 2debc28..b3fa909 100644
--- a/libnetutils/packet.c
+++ b/libnetutils/packet.c
@@ -40,7 +40,7 @@
 int fatal(const char*);
 
 int open_raw_socket(const char* ifname __unused, uint8_t hwaddr[ETH_ALEN], int if_index) {
-    int s = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
+    int s = socket(PF_PACKET, SOCK_DGRAM, 0);
     if (s < 0) return fatal("socket(PF_PACKET)");
 
     struct sockaddr_ll bindaddr = {