Re: [PATCH net v1] net: wwan: fix global oob in wwan_rtnl_policy

[Loic Poulain]

On Tue, 15 Oct 2024 at 15:16, Lin Ma <linma@xxxxxxxxxx> wrote:
>
> The variable wwan_rtnl_link_ops assign a *bigger* maxtype which leads to
> a global out-of-bounds read when parsing the netlink attributes. Exactly
> same bug cause as the oob fixed in commit b33fb5b801c6 ("net: qualcomm:
> rmnet: fix global oob in rmnet_policy").
>
> ==================================================================
> BUG: KASAN: global-out-of-bounds in validate_nla lib/nlattr.c:388 [inline]
> BUG: KASAN: global-out-of-bounds in __nla_validate_parse+0x19d7/0x29a0 lib/nlattr.c:603
> Read of size 1 at addr ffffffff8b09cb60 by task syz.1.66276/323862
>
> CPU: 0 PID: 323862 Comm: syz.1.66276 Not tainted 6.1.70 #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x177/0x231 lib/dump_stack.c:106
>  print_address_description mm/kasan/report.c:284 [inline]
>  print_report+0x14f/0x750 mm/kasan/report.c:395
>  kasan_report+0x139/0x170 mm/kasan/report.c:495
>  validate_nla lib/nlattr.c:388 [inline]
>  __nla_validate_parse+0x19d7/0x29a0 lib/nlattr.c:603
>  __nla_parse+0x3c/0x50 lib/nlattr.c:700
>  nla_parse_nested_deprecated include/net/netlink.h:1269 [inline]
>  __rtnl_newlink net/core/rtnetlink.c:3514 [inline]
>  rtnl_newlink+0x7bc/0x1fd0 net/core/rtnetlink.c:3623
>  rtnetlink_rcv_msg+0x794/0xef0 net/core/rtnetlink.c:6122
>  netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2508
>  netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
>  netlink_unicast+0x74b/0x8c0 net/netlink/af_netlink.c:1352
>  netlink_sendmsg+0x882/0xb90 net/netlink/af_netlink.c:1874
>  sock_sendmsg_nosec net/socket.c:716 [inline]
>  __sock_sendmsg net/socket.c:728 [inline]
>  ____sys_sendmsg+0x5cc/0x8f0 net/socket.c:2499
>  ___sys_sendmsg+0x21c/0x290 net/socket.c:2553
>  __sys_sendmsg net/socket.c:2582 [inline]
>  __do_sys_sendmsg net/socket.c:2591 [inline]
>  __se_sys_sendmsg+0x19e/0x270 net/socket.c:2589
>  do_syscall_x64 arch/x86/entry/common.c:51 [inline]
>  do_syscall_64+0x45/0x90 arch/x86/entry/common.c:81
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f67b19a24ad
> RSP: 002b:00007f67b17febb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f67b1b45f80 RCX: 00007f67b19a24ad
> RDX: 0000000000000000 RSI: 0000000020005e40 RDI: 0000000000000004
> RBP: 00007f67b1a1e01d R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffd2513764f R14: 00007ffd251376e0 R15: 00007f67b17fed40
>  </TASK>
>
> The buggy address belongs to the variable:
>  wwan_rtnl_policy+0x20/0x40
>
> The buggy address belongs to the physical page:
> page:ffffea00002c2700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xb09c
> flags: 0xfff00000001000(reserved|node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000001000 ffffea00002c2708 ffffea00002c2708 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner info is not present (never set?)
>
> Memory state around the buggy address:
>  ffffffff8b09ca00: 05 f9 f9 f9 05 f9 f9 f9 00 01 f9 f9 00 01 f9 f9
>  ffffffff8b09ca80: 00 00 00 05 f9 f9 f9 f9 00 00 03 f9 f9 f9 f9 f9
> >ffffffff8b09cb00: 00 00 00 00 05 f9 f9 f9 00 00 00 00 f9 f9 f9 f9
>                                                        ^
>  ffffffff8b09cb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ==================================================================
>
> According to the comment of `nla_parse_nested_deprecated`, use correct size
> `IFLA_WWAN_MAX` here to fix this issue.
>
> Fixes: 88b710532e53 ("wwan: add interface creation support")
> Signed-off-by: Lin Ma <linma@xxxxxxxxxx>

Reviewed-by: Loic Poulain <loic.poulain@xxxxxxxxxx>