CVE-2024-26800: tls: fix use-after-free on failed backlog decryption

CVE-2024-26800: tls: fix use-after-free on failed backlog decryption

[Greg Kroah-Hartman]

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

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

tls: fix use-after-free on failed backlog decryption

When the decrypt request goes to the backlog and crypto_aead_decrypt
returns -EBUSY, tls_do_decryption will wait until all async
decryptions have completed. If one of them fails, tls_do_decryption
will return -EBADMSG and tls_decrypt_sg jumps to the error path,
releasing all the pages. But the pages have been passed to the async
callback, and have already been released by tls_decrypt_done.

The only true async case is when crypto_aead_decrypt returns
 -EINPROGRESS. With -EBUSY, we already waited so we can tell
tls_sw_recvmsg that the data is available for immediate copy, but we
need to notify tls_decrypt_sg (via the new ->async_done flag) that the
memory has already been released.

The Linux kernel CVE team has assigned CVE-2024-26800 to this issue.


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

	Issue introduced in 6.6.18 with commit 13eca403876b and fixed in 6.6.21 with commit 81be85353b0f
	Issue introduced in 6.7.6 with commit ab6397f072e5 and fixed in 6.7.9 with commit 1ac9fb84bc7e

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-2024-26800
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:
	net/tls/tls_sw.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/f2b85a4cc763841843de693bbd7308fe9a2c4c89
	https://git.kernel.org/stable/c/81be85353b0f5a7b660635634b655329b429eefe
	https://git.kernel.org/stable/c/1ac9fb84bc7ecd4bc6428118301d9d864d2a58d1
	https://git.kernel.org/stable/c/13114dc5543069f7b97991e3b79937b6da05f5b0