diff options
Diffstat (limited to 'main/busybox/0014-ntpd-respond-only-to-client-and-symmetric-active-pac.patch')
| -rw-r--r-- | main/busybox/0014-ntpd-respond-only-to-client-and-symmetric-active-pac.patch | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/main/busybox/0014-ntpd-respond-only-to-client-and-symmetric-active-pac.patch b/main/busybox/0014-ntpd-respond-only-to-client-and-symmetric-active-pac.patch new file mode 100644 index 0000000000..24dc0e890c --- /dev/null +++ b/main/busybox/0014-ntpd-respond-only-to-client-and-symmetric-active-pac.patch @@ -0,0 +1,41 @@ +From c87fd50857e07450e8868730293f2af7063d263a Mon Sep 17 00:00:00 2001 +From: Miroslav Lichvar <mlichvar@redhat.com> +Date: Mon, 1 Aug 2016 20:24:24 +0200 +Subject: [PATCH 14/15] ntpd: respond only to client and symmetric active + packets + +The busybox NTP implementation doesn't check the NTP mode of packets +received on the server port and responds to any packet with the right +size. This includes responses from another NTP server. An attacker can +send a packet with a spoofed source address in order to create an +infinite loop of responses between two busybox NTP servers. Adding +more packets to the loop increases the traffic between the servers +until one of them has a fully loaded CPU and/or network. + +Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> +Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> +--- + networking/ntpd.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/networking/ntpd.c b/networking/ntpd.c +index 7f7d69e..182dd58 100644 +--- a/networking/ntpd.c ++++ b/networking/ntpd.c +@@ -2042,6 +2042,13 @@ recv_and_process_client_pkt(void /*int fd*/) + goto bail; + } + ++ /* Respond only to client and symmetric active packets */ ++ if ((msg.m_status & MODE_MASK) != MODE_CLIENT ++ && (msg.m_status & MODE_MASK) != MODE_SYM_ACT ++ ) { ++ goto bail; ++ } ++ + query_status = msg.m_status; + query_xmttime = msg.m_xmttime; + +-- +2.9.1 + |