fix icmp6 kernel panic (patch from arch package)

3 files changed, 74 insertions, 1 deletions

diff --git a/.SRCINFO b/.SRCINFO
index 682d83c41333..93521176e065 100644
--- a/.SRCINFO
+++ b/.SRCINFO
@@ -1,5 +1,5 @@
 # Generated by mksrcinfo v8
-# Wed Dec  7 19:54:16 UTC 2016
+# Fri Dec  9 18:39:52 UTC 2016
 pkgbase = linux-linode
 	pkgdesc = Kernel for Linode servers
 	pkgver = 4.8.12
@@ -29,6 +29,7 @@ pkgbase = linux-linode
 	source = https://www.kernel.org/pub/linux/kernel/v4.x/patch-4.8.12.xz
 	source = https://www.kernel.org/pub/linux/kernel/v4.x/patch-4.8.12.sign
 	source = https://git.archlinux.org/svntogit/packages.git/plain/linux/trunk/fix_race_condition_in_packet_set_ring.diff
+	source = net_handle_no_dst_on_skb_in_icmp6_send.patch
 	source = config
 	source = config.x86_64
 	source = menu.lst
@@ -39,6 +40,7 @@ pkgbase = linux-linode
 	sha512sums = 0240bbf602e5c06b4e0be8501c49b4f45e31931e1a50ab49f2c5db7b06af31a20233ea763e12402d4c72a7fa64dfdede9df6af5026936fbfdae436cad1c743f1
 	sha512sums = SKIP
 	sha512sums = fd5800dcc1b9e7825892dfaedf78d9b64f354695992c9a1b0014e66664c6f0f4c80989439df360c994aab03dc4aa1f4e3481f153a6b4383c9e39da93c8d235d0
+	sha512sums = c53bd47527adbd2599a583e05a7d24f930dc4e86b1de017486588205ad6f262a51a4551593bc7a1218c96541ea073ea03b770278d947b1cd0d2801311fcc80e5
 	sha512sums = 211be6cff3c652cf635016f6ea55e95ba8e3dde78f77949f32d7952df389c0dbbaf10b03f813c906b31375e151cff922232c0adb15e7a2948f823ba44345efbd
 	sha512sums = 25bf894092daacf165e471b25d5259e5a21befdf1b06b385ff4d9acec000572a9217caf3ed2c90484031b36b6779ef4a3445261d79331ca06d6c2c81a2e22672
 	sha512sums = 2beaa01dc9679a66ccbbca0f4abeb0f77956651e3f83f114030b2ef344a16240124a549ccee2588b6a1179be6a66b4a8dc931e2c15c4d5282afeb85bb6ada210
diff --git a/PKGBUILD b/PKGBUILD
index f0ec99e5550d..aa5d24ca1f64 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -15,6 +15,7 @@ options=('!strip')
 source=("https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar."{xz,sign}
         "https://www.kernel.org/pub/linux/kernel/v4.x/patch-${pkgver}."{xz,sign}
         'https://git.archlinux.org/svntogit/packages.git/plain/linux/trunk/fix_race_condition_in_packet_set_ring.diff'
+        'net_handle_no_dst_on_skb_in_icmp6_send.patch'
         'config'
         'config.x86_64'
         'menu.lst'
@@ -23,6 +24,7 @@ source=("https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar."{xz,sign}
 sha512sums=('a48a065f21e1c7c4de4cf8ca47b8b8d9a70f86b64e7cfa6e01be490f78895745b9c8790734b1d22182cf1f930fb87eaaa84e62ec8cc1f64ac4be9b949e7c0358' 'SKIP'
             '0240bbf602e5c06b4e0be8501c49b4f45e31931e1a50ab49f2c5db7b06af31a20233ea763e12402d4c72a7fa64dfdede9df6af5026936fbfdae436cad1c743f1' 'SKIP'
             'fd5800dcc1b9e7825892dfaedf78d9b64f354695992c9a1b0014e66664c6f0f4c80989439df360c994aab03dc4aa1f4e3481f153a6b4383c9e39da93c8d235d0'
+            'c53bd47527adbd2599a583e05a7d24f930dc4e86b1de017486588205ad6f262a51a4551593bc7a1218c96541ea073ea03b770278d947b1cd0d2801311fcc80e5'
             '211be6cff3c652cf635016f6ea55e95ba8e3dde78f77949f32d7952df389c0dbbaf10b03f813c906b31375e151cff922232c0adb15e7a2948f823ba44345efbd'
             '25bf894092daacf165e471b25d5259e5a21befdf1b06b385ff4d9acec000572a9217caf3ed2c90484031b36b6779ef4a3445261d79331ca06d6c2c81a2e22672'
             '2beaa01dc9679a66ccbbca0f4abeb0f77956651e3f83f114030b2ef344a16240124a549ccee2588b6a1179be6a66b4a8dc931e2c15c4d5282afeb85bb6ada210'
@@ -43,6 +45,7 @@ prepare() {
   cd "${srcdir}/${_srcname}"
   patch -p1 -i "${srcdir}/patch-${pkgver}"
   patch -p1 -i "${srcdir}/fix_race_condition_in_packet_set_ring.diff"
+  patch -p1 -i "${srcdir}/net_handle_no_dst_on_skb_in_icmp6_send.patch"
   if [ "${CARCH}" = "x86_64" ]; then
     cat "${srcdir}/config.x86_64" > ./.config
   else
diff --git a/net_handle_no_dst_on_skb_in_icmp6_send.patch b/net_handle_no_dst_on_skb_in_icmp6_send.patch
new file mode 100644
index 000000000000..06448a90affe
--- /dev/null
+++ b/net_handle_no_dst_on_skb_in_icmp6_send.patch
@@ -0,0 +1,68 @@
+From 79dc7e3f1cd323be4c81aa1a94faa1b3ed987fb2 Mon Sep 17 00:00:00 2001
+From: David Ahern <dsa@cumulusnetworks.com>
+Date: Sun, 27 Nov 2016 18:52:53 -0800
+Subject: [PATCH] net: handle no dst on skb in icmp6_send
+
+Andrey reported the following while fuzzing the kernel with syzkaller:
+
+kasan: CONFIG_KASAN_INLINE enabled
+kasan: GPF could be caused by NULL-ptr deref or user memory access
+general protection fault: 0000 [#1] SMP KASAN
+Modules linked in:
+CPU: 0 PID: 3859 Comm: a.out Not tainted 4.9.0-rc6+ #429
+Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
+task: ffff8800666d4200 task.stack: ffff880067348000
+RIP: 0010:[<ffffffff833617ec>]  [<ffffffff833617ec>]
+icmp6_send+0x5fc/0x1e30 net/ipv6/icmp.c:451
+RSP: 0018:ffff88006734f2c0  EFLAGS: 00010206
+RAX: ffff8800666d4200 RBX: 0000000000000000 RCX: 0000000000000000
+RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000000018
+RBP: ffff88006734f630 R08: ffff880064138418 R09: 0000000000000003
+R10: dffffc0000000000 R11: 0000000000000005 R12: 0000000000000000
+R13: ffffffff84e7e200 R14: ffff880064138484 R15: ffff8800641383c0
+FS:  00007fb3887a07c0(0000) GS:ffff88006cc00000(0000) knlGS:0000000000000000
+CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+CR2: 0000000020000000 CR3: 000000006b040000 CR4: 00000000000006f0
+Stack:
+ ffff8800666d4200 ffff8800666d49f8 ffff8800666d4200 ffffffff84c02460
+ ffff8800666d4a1a 1ffff1000ccdaa2f ffff88006734f498 0000000000000046
+ ffff88006734f440 ffffffff832f4269 ffff880064ba7456 0000000000000000
+Call Trace:
+ [<ffffffff83364ddc>] icmpv6_param_prob+0x2c/0x40 net/ipv6/icmp.c:557
+ [<     inline     >] ip6_tlvopt_unknown net/ipv6/exthdrs.c:88
+ [<ffffffff83394405>] ip6_parse_tlv+0x555/0x670 net/ipv6/exthdrs.c:157
+ [<ffffffff8339a759>] ipv6_parse_hopopts+0x199/0x460 net/ipv6/exthdrs.c:663
+ [<ffffffff832ee773>] ipv6_rcv+0xfa3/0x1dc0 net/ipv6/ip6_input.c:191
+ ...
+
+icmp6_send / icmpv6_send is invoked for both rx and tx paths. In both
+cases the dst->dev should be preferred for determining the L3 domain
+if the dst has been set on the skb. Fallback to the skb->dev if it has
+not. This covers the case reported here where icmp6_send is invoked on
+Rx before the route lookup.
+
+Fixes: 5d41ce29e ("net: icmp6_send should use dst dev to determine L3 domain")
+Reported-by: Andrey Konovalov <andreyknvl@google.com>
+Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/ipv6/icmp.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
+index 7370ad2..2772004 100644
+--- a/net/ipv6/icmp.c
++++ b/net/ipv6/icmp.c
+@@ -447,8 +447,10 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
+ 
+ 	if (__ipv6_addr_needs_scope_id(addr_type))
+ 		iif = skb->dev->ifindex;
+-	else
+-		iif = l3mdev_master_ifindex(skb_dst(skb)->dev);
++	else {
++		dst = skb_dst(skb);
++		iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev);
++	}
+ 
+ 	/*
+ 	 *	Must not send error if the source does not uniquely