a7a12b5a0f
the following command # tc action add action tunnel_key \ > set src_ip 2001:db8::1 dst_ip 2001:db8::2 id 10 erspan_opts 1:6789:0:0 generates the following splat: BUG: KASAN: slab-out-of-bounds in tunnel_key_copy_opts+0xcc9/0x1010 [act_tunnel_key] Write of size 4 at addr ffff88813f5f1cc8 by task tc/873 CPU: 2 PID: 873 Comm: tc Not tainted 5.9.0+ #282 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: dump_stack+0x99/0xcb print_address_description.constprop.7+0x1e/0x230 kasan_report.cold.13+0x37/0x7c tunnel_key_copy_opts+0xcc9/0x1010 [act_tunnel_key] tunnel_key_init+0x160c/0x1f40 [act_tunnel_key] tcf_action_init_1+0x5b5/0x850 tcf_action_init+0x15d/0x370 tcf_action_add+0xd9/0x2f0 tc_ctl_action+0x29b/0x3a0 rtnetlink_rcv_msg+0x341/0x8d0 netlink_rcv_skb+0x120/0x380 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f872a96b338 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 41 89 d4 55 RSP: 002b:00007ffffe367518 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000005f8f5aed RCX: 00007f872a96b338 RDX: 0000000000000000 RSI: 00007ffffe367580 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000000000001c R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000686760 R14: 0000000000000601 R15: 0000000000000000 Allocated by task 873: kasan_save_stack+0x19/0x40 __kasan_kmalloc.constprop.7+0xc1/0xd0 __kmalloc+0x151/0x310 metadata_dst_alloc+0x20/0x40 tunnel_key_init+0xfff/0x1f40 [act_tunnel_key] tcf_action_init_1+0x5b5/0x850 tcf_action_init+0x15d/0x370 tcf_action_add+0xd9/0x2f0 tc_ctl_action+0x29b/0x3a0 rtnetlink_rcv_msg+0x341/0x8d0 netlink_rcv_skb+0x120/0x380 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88813f5f1c00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 200 bytes inside of 256-byte region [ffff88813f5f1c00, ffff88813f5f1d00) The buggy address belongs to the page: page:0000000011b48a19 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13f5f0 head:0000000011b48a19 order:1 compound_mapcount:0 flags: 0x17ffffc0010200(slab|head) raw: 0017ffffc0010200 0000000000000000 0000000d00000001 ffff888107c43400 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88813f5f1b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88813f5f1c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88813f5f1c80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc ^ ffff88813f5f1d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88813f5f1d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc using IPv6 tunnels, act_tunnel_key allocates a fixed amount of memory for the tunnel metadata, but then it expects additional bytes to store tunnel specific metadata with tunnel_key_copy_opts(). Fix the arguments of __ipv6_tun_set_dst(), so that 'md_size' contains the size previously computed by tunnel_key_get_opts_len(), like it's done for IPv4 tunnels. Fixes: 0ed5269f9e41 ("net/sched: add tunnel option support to act_tunnel_key") Reported-by: Shuang Li <shuali@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Link: https://lore.kernel.org/r/36ebe969f6d13ff59912d6464a4356fe6f103766.1603231100.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.