Re: [PATCH] ipv6: addrlabel: fix infoleak when sending struct ifaddrlblmsg to network

syzbot
2022-11-07T12:31:24Z

> Hello:
>
> This patch was applied to netdev/net.git (master)
> by David S. Miller <davem@davemloft.net>:
>
> On Fri, 4 Nov 2022 11:32:16 +0100 you wrote:
>> When copying a `struct ifaddrlblmsg` to the network, __ifal_reserved
>> remained uninitialized, resulting in a 1-byte infoleak:
>>
>> BUG: KMSAN: kernel-network-infoleak in __netdev_start_xmit ./include/linux/netdevice.h:4841
>> __netdev_start_xmit ./include/linux/netdevice.h:4841
>> netdev_start_xmit ./include/linux/netdevice.h:4857
>> xmit_one net/core/dev.c:3590
>> dev_hard_start_xmit+0x1dc/0x800 net/core/dev.c:3606
>> __dev_queue_xmit+0x17e8/0x4350 net/core/dev.c:4256
>> dev_queue_xmit ./include/linux/netdevice.h:3009
>> __netlink_deliver_tap_skb net/netlink/af_netlink.c:307
>> __netlink_deliver_tap+0x728/0xad0 net/netlink/af_netlink.c:325
>> netlink_deliver_tap net/netlink/af_netlink.c:338
>> __netlink_sendskb net/netlink/af_netlink.c:1263
>> netlink_sendskb+0x1d9/0x200 net/netlink/af_netlink.c:1272
>> netlink_unicast+0x56d/0xf50 net/netlink/af_netlink.c:1360
>> nlmsg_unicast ./include/net/netlink.h:1061
>> rtnl_unicast+0x5a/0x80 net/core/rtnetlink.c:758
>> ip6addrlbl_get+0xfad/0x10f0 net/ipv6/addrlabel.c:628
>> rtnetlink_rcv_msg+0xb33/0x1570 net/core/rtnetlink.c:6082
>> ...
>> Uninit was created at:
>> slab_post_alloc_hook+0x118/0xb00 mm/slab.h:742
>> slab_alloc_node mm/slub.c:3398
>> __kmem_cache_alloc_node+0x4f2/0x930 mm/slub.c:3437
>> __do_kmalloc_node mm/slab_common.c:954
>> __kmalloc_node_track_caller+0x117/0x3d0 mm/slab_common.c:975
>> kmalloc_reserve net/core/skbuff.c:437
>> __alloc_skb+0x27a/0xab0 net/core/skbuff.c:509
>> alloc_skb ./include/linux/skbuff.h:1267
>> nlmsg_new ./include/net/netlink.h:964
>> ip6addrlbl_get+0x490/0x10f0 net/ipv6/addrlabel.c:608
>> rtnetlink_rcv_msg+0xb33/0x1570 net/core/rtnetlink.c:6082
>> netlink_rcv_skb+0x299/0x550 net/netlink/af_netlink.c:2540
>> rtnetlink_rcv+0x26/0x30 net/core/rtnetlink.c:6109
>> netlink_unicast_kernel net/netlink/af_netlink.c:1319
>> netlink_unicast+0x9ab/0xf50 net/netlink/af_netlink.c:1345
>> netlink_sendmsg+0xebc/0x10f0 net/netlink/af_netlink.c:1921
>> ...
>>
>> [...]
>
> Here is the summary with links:
> - ipv6: addrlabel: fix infoleak when sending struct ifaddrlblmsg to network
> https://git.kernel.org/netdev/net/c/c23fb2c82267
>
> You are awesome, thank you!
> --
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