908180f633
[ Upstream commit d047283a7034140ea5da759a494fd2274affdd46 ]
The IPv6 path already drops dst in the daddr changed case, but the IPv4
path does not. This change makes the two code paths consistent.
Further, it is possible that there is already a metadata_dst allocated from
ingress that might already be attached to skbuff->dst while following
the bridge path. If it is not released before setting a new
metadata_dst, it will be leaked. This is similar to what is done in
bpf_set_tunnel_key() or ip6_route_input().
It is important to note that the memory being leaked is not the dst
being set in the bridge code, but rather memory allocated from some
other code path that is not being freed correctly before the skb dst is
overwritten.
An example of the leakage fixed by this commit found using kmemleak:
unreferenced object 0xffff888010112b00 (size 256):
comm "softirq", pid 0, jiffies 4294762496 (age 32.012s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 80 16 f1 83 ff ff ff ff ................
e1 4e f6 82 ff ff ff ff 00 00 00 00 00 00 00 00 .N..............
backtrace:
[<00000000d79567ea>] metadata_dst_alloc+0x1b/0xe0
[<00000000be113e13>] udp_tun_rx_dst+0x174/0x1f0
[<00000000a36848f4>] geneve_udp_encap_recv+0x350/0x7b0
[<00000000d4afb476>] udp_queue_rcv_one_skb+0x380/0x560
[<00000000ac064aea>] udp_unicast_rcv_skb+0x75/0x90
[<000000009a8ee8c5>] ip_protocol_deliver_rcu+0xd8/0x230
[<00000000ef4980bb>] ip_local_deliver_finish+0x7a/0xa0
[<00000000d7533c8c>] __netif_receive_skb_one_core+0x89/0xa0
[<00000000a879497d>] process_backlog+0x93/0x190
[<00000000e41ade9f>] __napi_poll+0x28/0x170
[<00000000b4c0906b>] net_rx_action+0x14f/0x2a0
[<00000000b20dd5d4>] __do_softirq+0xf4/0x305
[<000000003a7d7e15>] __irq_exit_rcu+0xc3/0x140
[<00000000968d39a2>] sysvec_apic_timer_interrupt+0x9e/0xc0
[<000000009e920794>] asm_sysvec_apic_timer_interrupt+0x16/0x20
[<000000008942add0>] native_safe_halt+0x13/0x20
Florian Westphal says: "Original code was likely fine because nothing
ever did set a skb->dst entry earlier than bridge in those days."
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.