Subject: CVE-2021-47078: RDMA/rxe: Clear all QP fields if creation failed

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

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

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

RDMA/rxe: Clear all QP fields if creation failed

rxe_qp_do_cleanup() relies on valid pointer values in QP for the properly
created ones, but in case rxe_qp_from_init() failed it was filled with
garbage and caused tot the following error.

  refcount_t: underflow; use-after-free.
  WARNING: CPU: 1 PID: 12560 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
  Modules linked in:
  CPU: 1 PID: 12560 Comm: syz-executor.4 Not tainted 5.12.0-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
  Code: e9 db fe ff ff 48 89 df e8 2c c2 ea fd e9 8a fe ff ff e8 72 6a a7 fd 48 c7 c7 e0 b2 c1 89 c6 05 dc 3a e6 09 01 e8 ee 74 fb 04 <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55
  RSP: 0018:ffffc900097ceba8 EFLAGS: 00010286
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
  RDX: 0000000000040000 RSI: ffffffff815bb075 RDI: fffff520012f9d67
  RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
  R10: ffffffff815b4eae R11: 0000000000000000 R12: ffff8880322a4800
  R13: ffff8880322a4940 R14: ffff888033044e00 R15: 0000000000000000
  FS:  00007f6eb2be3700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fdbe5d41000 CR3: 000000001d181000 CR4: 00000000001506e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   __refcount_sub_and_test include/linux/refcount.h:283 [inline]
   __refcount_dec_and_test include/linux/refcount.h:315 [inline]
   refcount_dec_and_test include/linux/refcount.h:333 [inline]
   kref_put include/linux/kref.h:64 [inline]
   rxe_qp_do_cleanup+0x96f/0xaf0 drivers/infiniband/sw/rxe/rxe_qp.c:805
   execute_in_process_context+0x37/0x150 kernel/workqueue.c:3327
   rxe_elem_release+0x9f/0x180 drivers/infiniband/sw/rxe/rxe_pool.c:391
   kref_put include/linux/kref.h:65 [inline]
   rxe_create_qp+0x2cd/0x310 drivers/infiniband/sw/rxe/rxe_verbs.c:425
   _ib_create_qp drivers/infiniband/core/core_priv.h:331 [inline]
   ib_create_named_qp+0x2ad/0x1370 drivers/infiniband/core/verbs.c:1231
   ib_create_qp include/rdma/ib_verbs.h:3644 [inline]
   create_mad_qp+0x177/0x2d0 drivers/infiniband/core/mad.c:2920
   ib_mad_port_open drivers/infiniband/core/mad.c:3001 [inline]
   ib_mad_init_device+0xd6f/0x1400 drivers/infiniband/core/mad.c:3092
   add_client_context+0x405/0x5e0 drivers/infiniband/core/device.c:717
   enable_device_and_get+0x1cd/0x3b0 drivers/infiniband/core/device.c:1331
   ib_register_device drivers/infiniband/core/device.c:1413 [inline]
   ib_register_device+0x7c7/0xa50 drivers/infiniband/core/device.c:1365
   rxe_register_device+0x3d5/0x4a0 drivers/infiniband/sw/rxe/rxe_verbs.c:1147
   rxe_add+0x12fe/0x16d0 drivers/infiniband/sw/rxe/rxe.c:247
   rxe_net_add+0x8c/0xe0 drivers/infiniband/sw/rxe/rxe_net.c:503
   rxe_newlink drivers/infiniband/sw/rxe/rxe.c:269 [inline]
   rxe_newlink+0xb7/0xe0 drivers/infiniband/sw/rxe/rxe.c:250
   nldev_newlink+0x30e/0x550 drivers/infiniband/core/nldev.c:1555
   rdma_nl_rcv_msg+0x36d/0x690 drivers/infiniband/core/netlink.c:195
   rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
   rdma_nl_rcv+0x2ee/0x430 drivers/infiniband/core/netlink.c:259
   netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
   netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
   netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
   sock_sendmsg_nosec net/socket.c:654 [inline]
   sock_sendmsg+0xcf/0x120 net/socket.c:674
   ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
   ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
   __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433
   do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
   entry_SYSCALL_64_after_hwframe+0x44/0xae

The Linux kernel CVE team has assigned CVE-2021-47078 to this issue.

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

	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 4.9.270 with commit c65391dd9f0a
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 4.14.234 with commit 6a8086a42dfb
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 4.19.192 with commit f3783c415bf6
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 5.4.122 with commit a62225d951d7
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 5.10.40 with commit 2ee4d79c3649
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 5.12.7 with commit 03344e843ab6
	Issue introduced in 4.8 with commit 8700e3e7c485 and fixed in 5.13 with commit 67f29896fdc8

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-2021-47078
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_qp.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/c65391dd9f0a47617e96e38bd27e277cbe1c40b0
	https://git.kernel.org/stable/c/6a8086a42dfbf548a42bf2ae4faa291645c72c66
	https://git.kernel.org/stable/c/f3783c415bf6d2ead3d7aa2c38802bbe10723646
	https://git.kernel.org/stable/c/a62225d951d77eb20208fed8fc199e0c9b1df08b
	https://git.kernel.org/stable/c/2ee4d79c364914989c80de382c0b1a7259a7e4b3
	https://git.kernel.org/stable/c/03344e843ab6dd3b3f2cadfb65ed910590856c70
	https://git.kernel.org/stable/c/67f29896fdc83298eed5a6576ff8f9873f709228