dccp: CVE-2017-8824

dccp: use-after-free in DCCP code

References:
https://lists.openwall.net/netdev/2017/12/04/224

Change-Id: I5653c05e22956df9ef614147e79af4f749e4294a
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>

2 files changed, 47 insertions, 0 deletions

diff --git a/patches/cve/4.9.x.scc b/patches/cve/4.9.x.scc
index 4fa6185..96b6bcd 100644
--- a/patches/cve/4.9.x.scc
+++ b/patches/cve/4.9.x.scc
@@ -1,2 +1,3 @@
 #CVEs fixed in 4.9.82:
 patch CVE-2017-18344-posix-timer-Properly-check-sigevent-sigev_notify.patch
+patch CVE-2017-8824-dccp-CVE-2017-8824-use-after-free-in-DCCP-code.patch
diff --git a/patches/cve/CVE-2017-8824-dccp-CVE-2017-8824-use-after-free-in-DCCP-code.patch b/patches/cve/CVE-2017-8824-dccp-CVE-2017-8824-use-after-free-in-DCCP-code.patch
new file mode 100644
index 0000000..4aea4a1
--- /dev/null
+++ b/patches/cve/CVE-2017-8824-dccp-CVE-2017-8824-use-after-free-in-DCCP-code.patch
@@ -0,0 +1,46 @@
+From 69c64866ce072dea1d1e59a0d61e0f66c0dffb76 Mon Sep 17 00:00:00 2001
+From: Mohamed Ghannam <simo.ghannam@gmail.com>
+Date: Tue, 5 Dec 2017 20:58:35 +0000
+Subject: [PATCH] dccp: CVE-2017-8824: use-after-free in DCCP code
+
+Whenever the sock object is in DCCP_CLOSED state,
+dccp_disconnect() must free dccps_hc_tx_ccid and
+dccps_hc_rx_ccid and set to NULL.
+
+CVE: CVE-2017-8824   
+Upstream-Status: Backport  
+
+Signed-off-by: Mohamed Ghannam <simo.ghannam@gmail.com>
+Reviewed-by: Eric Dumazet <edumazet@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
+---
+ net/dccp/proto.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/net/dccp/proto.c b/net/dccp/proto.c
+index b68168f..9d43c1f 100644
+--- a/net/dccp/proto.c
++++ b/net/dccp/proto.c
+@@ -259,6 +259,7 @@ int dccp_disconnect(struct sock *sk, int flags)
+ {
+        struct inet_connection_sock *icsk = inet_csk(sk);
+        struct inet_sock *inet = inet_sk(sk);
++       struct dccp_sock *dp = dccp_sk(sk);
+        int err = 0;
+        const int old_state = sk->sk_state;
+ 
+@@ -278,6 +279,10 @@ int dccp_disconnect(struct sock *sk, int flags)
+                sk->sk_err = ECONNRESET;
+ 
+        dccp_clear_xmit_timers(sk);
++       ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
++       ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
++       dp->dccps_hc_rx_ccid = NULL;
++       dp->dccps_hc_tx_ccid = NULL;
+ 
+        __skb_queue_purge(&sk->sk_receive_queue);
+        __skb_queue_purge(&sk->sk_write_queue);
+-- 
+
+