Subject: CVE-2024-47742: firmware_loader: Block path traversal

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

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

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

firmware_loader: Block path traversal

Most firmware names are hardcoded strings, or are constructed from fairly
constrained format strings where the dynamic parts are just some hex
numbers or such.

However, there are a couple codepaths in the kernel where firmware file
names contain string components that are passed through from a device or
semi-privileged userspace; the ones I could find (not counting interfaces
that require root privileges) are:

 - lpfc_sli4_request_firmware_update() seems to construct the firmware
   filename from "ModelName", a string that was previously parsed out of
   some descriptor ("Vital Product Data") in lpfc_fill_vpd()
 - nfp_net_fw_find() seems to construct a firmware filename from a model
   name coming from nfp_hwinfo_lookup(pf->hwinfo, "nffw.partno"), which I
   think parses some descriptor that was read from the device.
   (But this case likely isn't exploitable because the format string looks
   like "netronome/nic_%s", and there shouldn't be any *folders* starting
   with "netronome/nic_". The previous case was different because there,
   the "%s" is *at the start* of the format string.)
 - module_flash_fw_schedule() is reachable from the
   ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command, which is marked as
   GENL_UNS_ADMIN_PERM (meaning CAP_NET_ADMIN inside a user namespace is
   enough to pass the privilege check), and takes a userspace-provided
   firmware name.
   (But I think to reach this case, you need to have CAP_NET_ADMIN over a
   network namespace that a special kind of ethernet device is mapped into,
   so I think this is not a viable attack path in practice.)

Fix it by rejecting any firmware names containing ".." path components.

For what it's worth, I went looking and haven't found any USB device
drivers that use the firmware loader dangerously.

The Linux kernel CVE team has assigned CVE-2024-47742 to this issue.

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

	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 5.10.227 with commit c30558e6c5c9
	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 5.15.168 with commit a77fc4acfd49
	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 6.1.113 with commit 3d2411f4edcb
	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 6.6.54 with commit 7420c1bf7fc7
	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 6.10.13 with commit 28f1cd94d3f1
	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 6.11.2 with commit 6c4e13fdfcab
	Issue introduced in 3.7 with commit abb139e75c2c and fixed in 6.12-rc1 with commit f0e5311aa802

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-2024-47742
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/base/firmware_loader/main.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/c30558e6c5c9ad6c86459d9acce1520ceeab9ea6
	https://git.kernel.org/stable/c/a77fc4acfd49fc6076e565445b2bc5fdc3244da4
	https://git.kernel.org/stable/c/3d2411f4edcb649eaf232160db459bb4770b5251
	https://git.kernel.org/stable/c/7420c1bf7fc784e587b87329cc6dfa3dca537aa4
	https://git.kernel.org/stable/c/28f1cd94d3f1092728fb775a0fe26c5f1ac2ebeb
	https://git.kernel.org/stable/c/6c4e13fdfcab34811c3143a0a03c05fec4e870ec
	https://git.kernel.org/stable/c/f0e5311aa8022107d63c54e2f03684ec097d1394