net: CVE-2016-9793

net: avoid signed overflows for SO_{SND|RCV}BUFFORCE

References:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.1.y&id=f99fb439e6aff4e9f8b91a80d48b2a2d97aa2248

Change-Id: Idb0b4aa03389ed4bc6385a32bef14211bca809f9
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>

2 files changed, 60 insertions, 0 deletions

diff --git a/patches/cve/4.1.x.scc b/patches/cve/4.1.x.scc
index 47341b8..3d8e1ae 100644
--- a/patches/cve/4.1.x.scc
+++ b/patches/cve/4.1.x.scc
@@ -33,4 +33,8 @@ patch CVE-2017-7184-xfrm_user-validate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch
 
 #fixed in 4.1.50
 patch CVE-2016-10318-fscrypto-add-authorization-check-for-setting-encrypt.patch
+patch CVE-2016-9793-net-avoid-signed-overflows-for-SO_-SND-RCV-BUFFORCE.patch
+
+
+
 
diff --git a/patches/cve/CVE-2016-9793-net-avoid-signed-overflows-for-SO_-SND-RCV-BUFFORCE.patch b/patches/cve/CVE-2016-9793-net-avoid-signed-overflows-for-SO_-SND-RCV-BUFFORCE.patch
new file mode 100644
index 0000000..5329cc7
--- /dev/null
+++ b/patches/cve/CVE-2016-9793-net-avoid-signed-overflows-for-SO_-SND-RCV-BUFFORCE.patch
@@ -0,0 +1,56 @@
+From f99fb439e6aff4e9f8b91a80d48b2a2d97aa2248 Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Fri, 2 Dec 2016 09:44:53 -0800
+Subject: [PATCH] net: avoid signed overflows for SO_{SND|RCV}BUFFORCE
+
+[ Upstream commit b98b0bc8c431e3ceb4b26b0dfc8db509518fb290 ]
+
+CAP_NET_ADMIN users should not be allowed to set negative
+sk_sndbuf or sk_rcvbuf values, as it can lead to various memory
+corruptions, crashes, OOM...
+
+Note that before commit 82981930125a ("net: cleanups in
+sock_setsockopt()"), the bug was even more serious, since SO_SNDBUF
+and SO_RCVBUF were vulnerable.
+
+This needs to be backported to all known linux kernels.
+
+Again, many thanks to syzkaller team for discovering this gem.
+
+CVE: CVE-2016-9793 
+Upstream-Status: Backport  
+
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Reported-by: Andrey Konovalov <andreyknvl@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
+Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
+---
+ net/core/sock.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/net/core/sock.c b/net/core/sock.c
+index 76e0b87..7697148 100644
+--- a/net/core/sock.c
++++ b/net/core/sock.c
+@@ -729,7 +729,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
+                val = min_t(u32, val, sysctl_wmem_max);
+ set_sndbuf:
+                sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
+-               sk->sk_sndbuf = max_t(u32, val * 2, SOCK_MIN_SNDBUF);
++               sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF);
+                /* Wake up sending tasks if we upped the value. */
+                sk->sk_write_space(sk);
+                break;
+@@ -765,7 +765,7 @@ set_rcvbuf:
+                 * returning the value we actually used in getsockopt
+                 * is the most desirable behavior.
+                 */
+-               sk->sk_rcvbuf = max_t(u32, val * 2, SOCK_MIN_RCVBUF);
++               sk->sk_rcvbuf = max_t(int, val * 2, SOCK_MIN_RCVBUF);
+                break;
+ 
+        case SO_RCVBUFFORCE:
+-- 
+2.7.4
+