This is a note to let you know that I've just added the patch titled

ipv6: fix access to non-linear packet in ndisc_fill_redirect_hdr_option()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: ipv6-fix-access-to-non-linear-packet-in-ndisc_fill_redirect_hdr_option.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Mar 29 08:33:08 CEST 2018

From: Lorenzo Bianconi lorenzo.bianconi@redhat.com Date: Thu, 8 Mar 2018 17:00:02 +0100 Subject: ipv6: fix access to non-linear packet in ndisc_fill_redirect_hdr_option()

From: Lorenzo Bianconi lorenzo.bianconi@redhat.com

[ Upstream commit 9f62c15f28b0d1d746734666d88a79f08ba1e43e ]

Fix the following slab-out-of-bounds kasan report in ndisc_fill_redirect_hdr_option when the incoming ipv6 packet is not linear and the accessed data are not in the linear data region of orig_skb.

[ 1503.122508] ================================================================== [ 1503.122832] BUG: KASAN: slab-out-of-bounds in ndisc_send_redirect+0x94e/0x990 [ 1503.123036] Read of size 1184 at addr ffff8800298ab6b0 by task netperf/1932

[ 1503.123220] CPU: 0 PID: 1932 Comm: netperf Not tainted 4.16.0-rc2+ #124 [ 1503.123347] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-2.fc27 04/01/2014 [ 1503.123527] Call Trace: [ 1503.123579] <IRQ> [ 1503.123638] print_address_description+0x6e/0x280 [ 1503.123849] kasan_report+0x233/0x350 [ 1503.123946] memcpy+0x1f/0x50 [ 1503.124037] ndisc_send_redirect+0x94e/0x990 [ 1503.125150] ip6_forward+0x1242/0x13b0 [...] [ 1503.153890] Allocated by task 1932: [ 1503.153982] kasan_kmalloc+0x9f/0xd0 [ 1503.154074] __kmalloc_track_caller+0xb5/0x160 [ 1503.154198] __kmalloc_reserve.isra.41+0x24/0x70 [ 1503.154324] __alloc_skb+0x130/0x3e0 [ 1503.154415] sctp_packet_transmit+0x21a/0x1810 [ 1503.154533] sctp_outq_flush+0xc14/0x1db0 [ 1503.154624] sctp_do_sm+0x34e/0x2740 [ 1503.154715] sctp_primitive_SEND+0x57/0x70 [ 1503.154807] sctp_sendmsg+0xaa6/0x1b10 [ 1503.154897] sock_sendmsg+0x68/0x80 [ 1503.154987] ___sys_sendmsg+0x431/0x4b0 [ 1503.155078] __sys_sendmsg+0xa4/0x130 [ 1503.155168] do_syscall_64+0x171/0x3f0 [ 1503.155259] entry_SYSCALL_64_after_hwframe+0x42/0xb7

[ 1503.155436] Freed by task 1932: [ 1503.155527] __kasan_slab_free+0x134/0x180 [ 1503.155618] kfree+0xbc/0x180 [ 1503.155709] skb_release_data+0x27f/0x2c0 [ 1503.155800] consume_skb+0x94/0xe0 [ 1503.155889] sctp_chunk_put+0x1aa/0x1f0 [ 1503.155979] sctp_inq_pop+0x2f8/0x6e0 [ 1503.156070] sctp_assoc_bh_rcv+0x6a/0x230 [ 1503.156164] sctp_inq_push+0x117/0x150 [ 1503.156255] sctp_backlog_rcv+0xdf/0x4a0 [ 1503.156346] __release_sock+0x142/0x250 [ 1503.156436] release_sock+0x80/0x180 [ 1503.156526] sctp_sendmsg+0xbb0/0x1b10 [ 1503.156617] sock_sendmsg+0x68/0x80 [ 1503.156708] ___sys_sendmsg+0x431/0x4b0 [ 1503.156799] __sys_sendmsg+0xa4/0x130 [ 1503.156889] do_syscall_64+0x171/0x3f0 [ 1503.156980] entry_SYSCALL_64_after_hwframe+0x42/0xb7

[ 1503.157158] The buggy address belongs to the object at ffff8800298ab600 which belongs to the cache kmalloc-1024 of size 1024 [ 1503.157444] The buggy address is located 176 bytes inside of 1024-byte region [ffff8800298ab600, ffff8800298aba00) [ 1503.157702] The buggy address belongs to the page: [ 1503.157820] page:ffffea0000a62a00 count:1 mapcount:0 mapping:0000000000000000 index:0x0 compound_mapcount: 0 [ 1503.158053] flags: 0x4000000000008100(slab|head) [ 1503.158171] raw: 4000000000008100 0000000000000000 0000000000000000 00000001800e000e [ 1503.158350] raw: dead000000000100 dead000000000200 ffff880036002600 0000000000000000 [ 1503.158523] page dumped because: kasan: bad access detected

[ 1503.158698] Memory state around the buggy address: [ 1503.158816] ffff8800298ab900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 1503.158988] ffff8800298ab980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 1503.159165] >ffff8800298aba00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 1503.159338] ^ [ 1503.159436] ffff8800298aba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 1503.159610] ffff8800298abb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 1503.159785] ================================================================== [ 1503.159964] Disabling lock debugging due to kernel taint

The test scenario to trigger the issue consists of 4 devices: - H0: data sender, connected to LAN0 - H1: data receiver, connected to LAN1 - GW0 and GW1: routers between LAN0 and LAN1. Both of them have an ethernet connection on LAN0 and LAN1 On H{0,1} set GW0 as default gateway while on GW0 set GW1 as next hop for data from LAN0 to LAN1. Moreover create an ip6ip6 tunnel between H0 and H1 and send 3 concurrent data streams (TCP/UDP/SCTP) from H0 to H1 through ip6ip6 tunnel (send buffer size is set to 16K). While data streams are active flush the route cache on HA multiple times. I have not been able to identify a given commit that introduced the issue since, using the reproducer described above, the kasan report has been triggered from 4.14 and I have not gone back further.

Reported-by: Jianlin Shi jishi@redhat.com Reviewed-by: Stefano Brivio sbrivio@redhat.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: Lorenzo Bianconi lorenzo.bianconi@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ndisc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1478,7 +1478,8 @@ static void ndisc_fill_redirect_hdr_opti *(opt++) = (rd_len >> 3); opt += 6;

- memcpy(opt, ipv6_hdr(orig_skb), rd_len - 8); + skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt, + rd_len - 8); }

void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)

Patches currently in stable-queue which might be from lorenzo.bianconi@redhat.com are

queue-4.4/ipv6-fix-access-to-non-linear-packet-in-ndisc_fill_redirect_hdr_option.patch