Subject: CVE-2023-52474: IB/hfi1: Fix bugs with non-PAGE_SIZE-end multi-iovec user SDMA requests

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

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

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

IB/hfi1: Fix bugs with non-PAGE_SIZE-end multi-iovec user SDMA requests

hfi1 user SDMA request processing has two bugs that can cause data
corruption for user SDMA requests that have multiple payload iovecs
where an iovec other than the tail iovec does not run up to the page
boundary for the buffer pointed to by that iovec.a

Here are the specific bugs:
1. user_sdma_txadd() does not use struct user_sdma_iovec->iov.iov_len.
   Rather, user_sdma_txadd() will add up to PAGE_SIZE bytes from iovec
   to the packet, even if some of those bytes are past
   iovec->iov.iov_len and are thus not intended to be in the packet.
2. user_sdma_txadd() and user_sdma_send_pkts() fail to advance to the
   next iovec in user_sdma_request->iovs when the current iovec
   is not PAGE_SIZE and does not contain enough data to complete the
   packet. The transmitted packet will contain the wrong data from the
   iovec pages.

This has not been an issue with SDMA packets from hfi1 Verbs or PSM2
because they only produce iovecs that end short of PAGE_SIZE as the tail
iovec of an SDMA request.

Fixing these bugs exposes other bugs with the SDMA pin cache
(struct mmu_rb_handler) that get in way of supporting user SDMA requests
with multiple payload iovecs whose buffers do not end at PAGE_SIZE. So
this commit fixes those issues as well.

Here are the mmu_rb_handler bugs that non-PAGE_SIZE-end multi-iovec
payload user SDMA requests can hit:
1. Overlapping memory ranges in mmu_rb_handler will result in duplicate
   pinnings.
2. When extending an existing mmu_rb_handler entry (struct mmu_rb_node),
   the mmu_rb code (1) removes the existing entry under a lock, (2)
   releases that lock, pins the new pages, (3) then reacquires the lock
   to insert the extended mmu_rb_node.

   If someone else comes in and inserts an overlapping entry between (2)
   and (3), insert in (3) will fail.

   The failure path code in this case unpins _all_ pages in either the
   original mmu_rb_node or the new mmu_rb_node that was inserted between
   (2) and (3).
3. In hfi1_mmu_rb_remove_unless_exact(), mmu_rb_node->refcount is
   incremented outside of mmu_rb_handler->lock. As a result, mmu_rb_node
   could be evicted by another thread that gets mmu_rb_handler->lock and
   checks mmu_rb_node->refcount before mmu_rb_node->refcount is
   incremented.
4. Related to #2 above, SDMA request submission failure path does not
   check mmu_rb_node->refcount before freeing mmu_rb_node object.

   If there are other SDMA requests in progress whose iovecs have
   pointers to the now-freed mmu_rb_node(s), those pointers to the
   now-freed mmu_rb nodes will be dereferenced when those SDMA requests
   complete.

The Linux kernel CVE team has assigned CVE-2023-52474 to this issue.

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

	Issue introduced in 4.3 with commit 7724105686e7 and fixed in 5.10.180 with commit 9c4c6512d733
	Issue introduced in 4.3 with commit 7724105686e7 and fixed in 5.15.111 with commit a2bd706ab635
	Issue introduced in 4.3 with commit 7724105686e7 and fixed in 6.1.28 with commit dce59b544370
	Issue introduced in 4.3 with commit 7724105686e7 and fixed in 6.2.15 with commit c76cb8f4bdf2
	Issue introduced in 4.3 with commit 7724105686e7 and fixed in 6.3.2 with commit 7e6010f79b58
	Issue introduced in 4.3 with commit 7724105686e7 and fixed in 6.4 with commit 00cbce5cbf88

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-2023-52474
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/hw/hfi1/ipoib_tx.c
	drivers/infiniband/hw/hfi1/mmu_rb.c
	drivers/infiniband/hw/hfi1/mmu_rb.h
	drivers/infiniband/hw/hfi1/sdma.c
	drivers/infiniband/hw/hfi1/sdma.h
	drivers/infiniband/hw/hfi1/sdma_txreq.h
	drivers/infiniband/hw/hfi1/trace_mmu.h
	drivers/infiniband/hw/hfi1/user_sdma.c
	drivers/infiniband/hw/hfi1/user_sdma.h
	drivers/infiniband/hw/hfi1/verbs.c
	drivers/infiniband/hw/hfi1/vnic_sdma.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/9c4c6512d7330b743c4ffd18bd999a86ca26db0d
	https://git.kernel.org/stable/c/a2bd706ab63509793b5cd5065e685b7ef5cba678
	https://git.kernel.org/stable/c/dce59b5443700fbd0d2433ec6e4d4cf063448844
	https://git.kernel.org/stable/c/c76cb8f4bdf26d04cfa5485a93ce297dba5e6a80
	https://git.kernel.org/stable/c/7e6010f79b58f45b204cf18aa58f4b73c3f30adc
	https://git.kernel.org/stable/c/00cbce5cbf88459cd1aa1d60d0f1df15477df127