Re: [PATCH net 0/2] RDMA/rxe: fix mr_check_range() iova overflow (OOB)

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2026/8/1 2:27, gang.yan@linux.dev 写道:
> July 30, 2026 at 1:15 PM, "Zhu Yanjun" <yanjun.zhu@linux.dev mailto:yanjun.zhu@linux.dev?to=%22Zhu%20Yanjun%22%20%3Cyanjun.zhu%40linux.dev%3E > wrote:
> 
> 
>>
>> 在 2026/7/28 2:11, Gang Yan 写道:
>>
>>>
>>> From: Gang Yan <yangang@kylinos.cn>
>>>
>>>   Hi, Maintainers
>>>
>>>   I've recently started learning RDMA, using soft-RoCE (rxe) as my study
>>>   platform. While pair-programming with an AI assistant during this learning,
>>>   it flagged an integer overflow in mr_check_range(). I dug in, stood up a
>>>   small reproducer, and -- believing the issue is real and worth fixing --
>>>   put together this small series.
>>>
>> Do you have a small reproducer for this issue? If so, could you please share it on the RDMA mailing list?
> 
> Hi,
> 
> Thanks for your review. Here is a small reproducer (attached rxe_overflow_repro.c). I put it together
> quickly with the help of an Claude Code, as I'm still quite new to RDMA.
> 
> Idea: the client posts
> the client posts one RDMA-Write whose remote_addr
>    (0xfffffffffffffff8, len 8) makes iova + length wrap to 0, bypassing the
>    old mr_check_range() comparison; the responder then derives an
>    out-of-bounds page index in rxe_mr_iova_to_index() (the WARN_ON) and
>    reaches mr->page_info[] OOB.
> 
> Build & run (as root):
> 
>   sudo yum install -y libibverbs-devel librdmacm-devel
>   gcc -O2 -o repro rxe_overflow_repro.c -libverbs -lrdmacm
>   sudo modprobe rdma_rxe
>   sudo ip link add dummy0 type dummy
>   sudo ip addr add 192.168.172.1/24 dev dummy0 && sudo ip link set dummy0 up
>   sudo ip link set dummy0 up
>   sudo rdma link add rxe0 type rxe netdev dummy0
>   sudo ./repro 192.168.172.1
> 
> and then check the dmesg:
> [  136.830844] ------------[ cut here ]------------
> [  136.830848] WARNING: drivers/infiniband/sw/rxe/rxe_mr.c:99 at rxe_mr_iova_to_index+0x78/0x90 [rdma_rxe], CPU#188: kworker/u957:0/1368
> [  136.830870] Modules linked in: rdma_ucm ib_uverbs ib_uverbs_support rdma_cm iw_cm ib_cm dummy rdma_rxe ib_core ip6_udp_tunnel udp_tunnel joydev uinput snd_seq_dummy snd_hrtimer rfkill nf_conntrack_netbios_ns nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables sunrpc qrtr snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hda_core snd_intel_dspcfg snd_intel_sdw_acpi snd_hwdep intel_rapl_msr snd_seq intel_rapl_common snd_seq_device snd_pcm virtio_balloon snd_timer snd i2c_piix4 soundcore pcspkr i2c_smbus zram lz4hc_compress vmw_vsock_virtio_transport vmw_vsock_virtio_transport_common vsock qxl serio_raw drm_exec drm_ttm_helper e1000 ttm ata_generic pata_acpi i2c_dev qemu_fw_cfg virtiofs fuse
> [  136.830928] CPU: 188 UID: 0 PID: 1368 Comm: kworker/u957:0 Not tainted 7.2.0-rc5+ #1 PREEMPT(lazy)
> [  136.830931] Hardware name: Red Hat KVM, BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
> [  136.830935] Workqueue: rxe_wq do_work [rdma_rxe]
> [  136.830944] RIP: 0010:rxe_mr_iova_to_index+0x78/0x90 [rdma_rxe]
> [  136.830953] Code: 48 83 c4 28 e9 f9 1d 79 d2 48 8b 4f 68 48 23 8f 48 01 00 00 48 29 c8 48 89 c2 48 c1 ea 0c 48 63 c2 41 3b 90 58 01 00 00 72 d6 <0f> 0b 48 83 c4 28 e9 cd 1d 79 d2 66 90 66 66 2e 0f 1f 84 00 00 00
> [  136.830954] RSP: 0018:ffffd0c5833c7d38 EFLAGS: 00010286
> [  136.830957] RAX: ffffffffffff332d RBX: 0000000000000008 RCX: 000000000000000c
> [  136.830958] RDX: 00000000ffff332d RSI: 000000000000ccd2 RDI: ffff8d8ddc8b7e00
> [  136.830960] RBP: fffffffffffffff8 R08: ffff8d8ddc8b7e00 R09: 000000000000000c
> [  136.830961] R10: 0000000000000008 R11: ffff8d8d0ab96e56 R12: ffff8d8ddc8b7e00
> [  136.830962] R13: ffff8d8d0ab96e56 R14: 0000000000000286 R15: ffff8d8cd1a80428
> [  136.830966] FS:  0000000000000000(0000) GS:ffff8d9bcc89a000(0000) knlGS:0000000000000000
> [  136.830968] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  136.830969] CR2: 000000000ccd39b8 CR3: 00000001061fe000 CR4: 0000000000350ef0
> [  136.830973] Call Trace:
> [  136.830975]  <TASK>
> [  136.830978]  ? rxe_pool_get_index+0x4b/0x70 [rdma_rxe]
> [  136.830986]  rxe_mr_copy_xarray+0xb4/0x170 [rdma_rxe]
> [  136.830994]  execute+0x27e/0x320 [rdma_rxe]
> [  136.831002]  rxe_receiver+0x4f9/0xce0 [rdma_rxe]
> [  136.831009]  ? __pfx_rxe_receiver+0x10/0x10 [rdma_rxe]
> [  136.831015]  do_task+0x70/0x220 [rdma_rxe]
> [  136.831023]  process_one_work+0x19e/0x370
> [  136.831028]  worker_thread+0x1a6/0x310
> [  136.831030]  ? __pfx_worker_thread+0x10/0x10
> [  136.831032]  kthread+0xe4/0x120
> [  136.831035]  ? __pfx_kthread+0x10/0x10
> [  136.831038]  ret_from_fork+0x1a1/0x270
> [  136.831058]  ? __pfx_kthread+0x10/0x10
> [  136.831060]  ret_from_fork_asm+0x1a/0x30
> [  136.831066]  </TASK>
> [  136.831067] ---[ end trace 0000000000000000 ]---
> [  136.831077] rxe0: qp#17 make_send_cqe: non-flush error status = 10
> [  207.516233] dummy0 speed is unknown, defaulting to 1000
> 
> I tried it on a Fedora guest running 7.2.0-rc5: it reliably reproduces the WARNING
> at rxe_mr_iova_to_index() (i.e. the responder accepting an out-of-bounds index).
> 
> I'm still learning the RDMA stack, so my understanding of some of the details may not
> be fully thorough — apologies if anything above is unclear, and I'm happy to correct
> or expand on whatever is needed.

Thanks a lot. I have made tests with this commit and the test program in 
the attachment. In my test environment, I can verify this commit can fix 
the mentioned problem.

Thanks a lot.
Zhu Yanjun

> 
> Thanks
> Gang
> 
>>
>> I’d like to use it to reproduce the problem and confirm that this commit fixes the reported issue.
>>
>> Thanks a lot.
>>
>> Zhu Yanjun
>>
>>>
>>> Thanks
>>>   Gang
>>>
>>>   Gang Yan (2):
>>>   RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB
>>>   access
>>>   DO-NOT-MERGE: selftest: add rxe mr_check_range() overflow reproducer
>>>
>>>   drivers/infiniband/sw/rxe/rxe_mr.c | 3 +-
>>>   tools/testing/selftests/rdma/Makefile | 8 +-
>>>   tools/testing/selftests/rdma/config | 2 +
>>>   .../testing/selftests/rdma/rxe_mr_overflow.c | 187 ++++++++++++++++++
>>>   .../testing/selftests/rdma/rxe_mr_overflow.sh | 132 +++++++++++++
>>>   5 files changed, 330 insertions(+), 2 deletions(-)
>>>   create mode 100644 tools/testing/selftests/rdma/rxe_mr_overflow.c
>>>   create mode 100644 tools/testing/selftests/rdma/rxe_mr_overflow.sh
>>>
>> -- Best Regards,
>> Yanjun.Zhu
>>