Subject: CVE-2021-47076: RDMA/rxe: Return CQE error if invalid lkey was supplied

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rxe: Return CQE error if invalid lkey was supplied

RXE is missing update of WQE status in LOCAL_WRITE failures.  This caused
the following kernel panic if someone sent an atomic operation with an
explicitly wrong lkey.

[leonro@vm ~]$ mkt test
test_atomic_invalid_lkey (tests.test_atomic.AtomicTest) ...
 WARNING: CPU: 5 PID: 263 at drivers/infiniband/sw/rxe/rxe_comp.c:740 rxe_completer+0x1a6d/0x2e30 [rdma_rxe]
 Modules linked in: crc32_generic rdma_rxe ip6_udp_tunnel udp_tunnel rdma_ucm rdma_cm ib_umad ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5_core ptp pps_core
 CPU: 5 PID: 263 Comm: python3 Not tainted 5.13.0-rc1+ #2936
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 RIP: 0010:rxe_completer+0x1a6d/0x2e30 [rdma_rxe]
 Code: 03 0f 8e 65 0e 00 00 3b 93 10 06 00 00 0f 84 82 0a 00 00 4c 89 ff 4c 89 44 24 38 e8 2d 74 a9 e1 4c 8b 44 24 38 e9 1c f5 ff ff <0f> 0b e9 0c e8 ff ff b8 05 00 00 00 41 bf 05 00 00 00 e9 ab e7 ff
 RSP: 0018:ffff8880158af090 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff888016a78000 RCX: ffffffffa0cf1652
 RDX: 1ffff9200004b442 RSI: 0000000000000004 RDI: ffffc9000025a210
 RBP: dffffc0000000000 R08: 00000000ffffffea R09: ffff88801617740b
 R10: ffffed1002c2ee81 R11: 0000000000000007 R12: ffff88800f3b63e8
 R13: ffff888016a78008 R14: ffffc9000025a180 R15: 000000000000000c
 FS:  00007f88b622a740(0000) GS:ffff88806d540000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f88b5a1fa10 CR3: 000000000d848004 CR4: 0000000000370ea0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  rxe_do_task+0x130/0x230 [rdma_rxe]
  rxe_rcv+0xb11/0x1df0 [rdma_rxe]
  rxe_loopback+0x157/0x1e0 [rdma_rxe]
  rxe_responder+0x5532/0x7620 [rdma_rxe]
  rxe_do_task+0x130/0x230 [rdma_rxe]
  rxe_rcv+0x9c8/0x1df0 [rdma_rxe]
  rxe_loopback+0x157/0x1e0 [rdma_rxe]
  rxe_requester+0x1efd/0x58c0 [rdma_rxe]
  rxe_do_task+0x130/0x230 [rdma_rxe]
  rxe_post_send+0x998/0x1860 [rdma_rxe]
  ib_uverbs_post_send+0xd5f/0x1220 [ib_uverbs]
  ib_uverbs_write+0x847/0xc80 [ib_uverbs]
  vfs_write+0x1c5/0x840
  ksys_write+0x176/0x1d0
  do_syscall_64+0x3f/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

The Linux kernel CVE team has assigned CVE-2021-47076 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 5.12.7 with commit abe31d25facd
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 5.13 with commit dc07628bd2bb

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-47076
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/infiniband/sw/rxe/rxe_comp.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/abe31d25facdb9109fe2cf69890748295291570c
	https://git.kernel.org/stable/c/dc07628bd2bbc1da768e265192c28ebd301f509d