Subject: CVE-2024-26587: net: netdevsim: don't try to destroy PHC on VFs

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

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

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

net: netdevsim: don't try to destroy PHC on VFs

PHC gets initialized in nsim_init_netdevsim(), which
is only called if (nsim_dev_port_is_pf()).

Create a counterpart of nsim_init_netdevsim() and
move the mock_phc_destroy() there.

This fixes a crash trying to destroy netdevsim with
VFs instantiated, as caught by running the devlink.sh test:

    BUG: kernel NULL pointer dereference, address: 00000000000000b8
    RIP: 0010:mock_phc_destroy+0xd/0x30
    Call Trace:
     <TASK>
     nsim_destroy+0x4a/0x70 [netdevsim]
     __nsim_dev_port_del+0x47/0x70 [netdevsim]
     nsim_dev_reload_destroy+0x105/0x120 [netdevsim]
     nsim_drv_remove+0x2f/0xb0 [netdevsim]
     device_release_driver_internal+0x1a1/0x210
     bus_remove_device+0xd5/0x120
     device_del+0x159/0x490
     device_unregister+0x12/0x30
     del_device_store+0x11a/0x1a0 [netdevsim]
     kernfs_fop_write_iter+0x130/0x1d0
     vfs_write+0x30b/0x4b0
     ksys_write+0x69/0xf0
     do_syscall_64+0xcc/0x1e0
     entry_SYSCALL_64_after_hwframe+0x6f/0x77

The Linux kernel CVE team has assigned CVE-2024-26587 to this issue.

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

	Issue introduced in 6.6 with commit b63e78fca889 and fixed in 6.6.14 with commit 08aca65997fb
	Issue introduced in 6.6 with commit b63e78fca889 and fixed in 6.7.2 with commit c5068e442eed
	Issue introduced in 6.6 with commit b63e78fca889 and fixed in 6.8 with commit ea937f772083

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-2024-26587
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/net/netdevsim/netdev.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/08aca65997fb6f233066883b1f1e653bcb1f26ca
	https://git.kernel.org/stable/c/c5068e442eed063d2f1658e6b6d3c1c6fcf1e588
	https://git.kernel.org/stable/c/ea937f77208323d35ffe2f8d8fc81b00118bfcda