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3a0504d54b
sctp_sf_do_5_2_4_dupcook() currently calls security_sctp_assoc_request()
on new_asoc, but as it turns out, this association is always discarded
and the LSM labels never get into the final association (asoc).
This can be reproduced by having two SCTP endpoints try to initiate an
association with each other at approximately the same time and then peel
off the association into a new socket, which exposes the unitialized
labels and triggers SELinux denials.
Fix it by calling security_sctp_assoc_request() on asoc instead of
new_asoc. Xin Long also suggested limit calling the hook only to cases
A, B, and D, since in cases C and E the COOKIE ECHO chunk is discarded
and the association doesn't enter the ESTABLISHED state, so rectify that
as well.
One related caveat with SELinux and peer labeling: When an SCTP
connection is set up simultaneously in this way, we will end up with an
association that is initialized with security_sctp_assoc_request() on
both sides, so the MLS component of the security context of the
association will get swapped between the peers, instead of just one side
setting it to the other's MLS component. However, at that point
security_sctp_assoc_request() had already been called on both sides in
sctp_sf_do_unexpected_init() (on a temporary association) and thus if
the exchange didn't fail before due to MLS, it won't fail now either
(most likely both endpoints have the same MLS range).
Tested by:
- reproducer from https://src.fedoraproject.org/tests/selinux/pull-request/530
- selinux-testsuite (https://github.com/SELinuxProject/selinux-testsuite/)
- sctp-tests (https://github.com/sctp/sctp-tests) - no tests failed
that wouldn't fail also without the patch applied
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.