Subject: CVE-2021-47196: RDMA/core: Set send and receive CQ before forwarding to the driver

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

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

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

RDMA/core: Set send and receive CQ before forwarding to the driver

Preset both receive and send CQ pointers prior to call to the drivers and
overwrite it later again till the mlx4 is going to be changed do not
overwrite ibqp properties.

This change is needed for mlx5, because in case of QP creation failure, it
will go to the path of QP destroy which relies on proper CQ pointers.

 BUG: KASAN: use-after-free in create_qp.cold+0x164/0x16e [mlx5_ib]
 Write of size 8 at addr ffff8880064c55c0 by task a.out/246

 CPU: 0 PID: 246 Comm: a.out Not tainted 5.15.0+ #291
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 Call Trace:
  dump_stack_lvl+0x45/0x59
  print_address_description.constprop.0+0x1f/0x140
  kasan_report.cold+0x83/0xdf
  create_qp.cold+0x164/0x16e [mlx5_ib]
  mlx5_ib_create_qp+0x358/0x28a0 [mlx5_ib]
  create_qp.part.0+0x45b/0x6a0 [ib_core]
  ib_create_qp_user+0x97/0x150 [ib_core]
  ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs]
  ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs]
  ib_uverbs_ioctl+0x169/0x260 [ib_uverbs]
  __x64_sys_ioctl+0x866/0x14d0
  do_syscall_64+0x3d/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

 Allocated by task 246:
  kasan_save_stack+0x1b/0x40
  __kasan_kmalloc+0xa4/0xd0
  create_qp.part.0+0x92/0x6a0 [ib_core]
  ib_create_qp_user+0x97/0x150 [ib_core]
  ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs]
  ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs]
  ib_uverbs_ioctl+0x169/0x260 [ib_uverbs]
  __x64_sys_ioctl+0x866/0x14d0
  do_syscall_64+0x3d/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

 Freed by task 246:
  kasan_save_stack+0x1b/0x40
  kasan_set_track+0x1c/0x30
  kasan_set_free_info+0x20/0x30
  __kasan_slab_free+0x10c/0x150
  slab_free_freelist_hook+0xb4/0x1b0
  kfree+0xe7/0x2a0
  create_qp.part.0+0x52b/0x6a0 [ib_core]
  ib_create_qp_user+0x97/0x150 [ib_core]
  ib_uverbs_handler_UVERBS_METHOD_QP_CREATE+0x92c/0x1250 [ib_uverbs]
  ib_uverbs_cmd_verbs+0x1c38/0x3150 [ib_uverbs]
  ib_uverbs_ioctl+0x169/0x260 [ib_uverbs]
  __x64_sys_ioctl+0x866/0x14d0
  do_syscall_64+0x3d/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

The Linux kernel CVE team has assigned CVE-2021-47196 to this issue.

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

	Issue introduced in 5.15 with commit 514aee660df4 and fixed in 5.15.5 with commit b70e072feffa
	Issue introduced in 5.15 with commit 514aee660df4 and fixed in 5.16 with commit 6cd7397d01c4

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-2021-47196
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/core/verbs.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/b70e072feffa0ba5c41a99b9524b9878dee7748e
	https://git.kernel.org/stable/c/6cd7397d01c4a3e09757840299e4f114f0aa5fa0