CVE-2023-52636: libceph: just wait for more data to be available on the socket

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

libceph: just wait for more data to be available on the socket

A short read may occur while reading the message footer from the
socket.  Later, when the socket is ready for another read, the
messenger invokes all read_partial_*() handlers, including
read_partial_sparse_msg_data().  The expectation is that
read_partial_sparse_msg_data() would bail, allowing the messenger to
invoke read_partial() for the footer and pick up where it left off.

However read_partial_sparse_msg_data() violates that and ends up
calling into the state machine in the OSD client.  The sparse-read
state machine assumes that it's a new op and interprets some piece of
the footer as the sparse-read header and returns bogus extents/data
length, etc.

To determine whether read_partial_sparse_msg_data() should bail, let's
reuse cursor->total_resid.  Because once it reaches to zero that means
all the extents and data have been successfully received in last read,
else it could break out when partially reading any of the extents and
data.  And then osd_sparse_read() could continue where it left off.

[ idryomov: changelog ]

The Linux kernel CVE team has assigned CVE-2023-52636 to this issue.


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

	Issue introduced in 6.6 with commit d396f89db39a and fixed in 6.6.17 with commit da9c33a70f09
	Issue introduced in 6.6 with commit d396f89db39a and fixed in 6.7.5 with commit bd9442e553ab
	Issue introduced in 6.6 with commit d396f89db39a and fixed in 6.8 with commit 8e46a2d068c9

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-2023-52636
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:
	include/linux/ceph/messenger.h
	net/ceph/messenger_v1.c
	net/ceph/messenger_v2.c
	net/ceph/osd_client.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/da9c33a70f095d5d55c36d0bfeba969e31de08ae
	https://git.kernel.org/stable/c/bd9442e553ab8bf74b8be3b3c0a43bf4af4dc9b8
	https://git.kernel.org/stable/c/8e46a2d068c92a905d01cbb018b00d66991585ab