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Tejun Heo 4665722d36 cgroup: Use open-time credentials for process migraton perm checks
commit 1756d7994ad85c2479af6ae5a9750b92324685af upstream.

cgroup process migration permission checks are performed at write time as
whether a given operation is allowed or not is dependent on the content of
the write - the PID. This currently uses current's credentials which is a
potential security weakness as it may allow scenarios where a less
privileged process tricks a more privileged one into writing into a fd that
it created.

This patch makes both cgroup2 and cgroup1 process migration interfaces to
use the credentials saved at the time of open (file->f_cred) instead of
current's.

Reported-by: "Eric W. Biederman" <ebiederm@xmission.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Fixes: 187fe84067 ("cgroup: require write perm on common ancestor when moving processes on the default hierarchy")
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
[OP: apply original __cgroup_procs_write() changes to cgroup_threads_write()
and cgroup_procs_write(), as the refactoring commit da70862efe006 ("cgroup:
cgroup.{procs,threads} factor out common parts") is not present in 5.10-stable]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-13 21:01:10 +02:00
arch arm64: patch_text: Fixup last cpu should be master 2022-04-13 21:01:08 +02:00
block Revert "Revert "block, bfq: honor already-setup queue merges"" 2022-04-08 14:40:32 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:50:29 +02:00
crypto crypto: authenc - Fix sleep in atomic context in decrypt_tail 2022-04-08 14:39:59 +02:00
Documentation docs: sysctl/kernel: add missing bit to panic_print 2022-04-08 14:40:44 +02:00
drivers dmaengine: Revert "dmaengine: shdma: Fix runtime PM imbalance on error" 2022-04-13 21:01:10 +02:00
fs btrfs: prevent subvol with swapfile from being deleted 2022-04-13 21:01:08 +02:00
include gpio: Restrict usage of GPIO chip irq members before initialization 2022-04-13 21:01:09 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 21:01:01 +02:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:19:10 +01:00
kernel cgroup: Use open-time credentials for process migraton perm checks 2022-04-13 21:01:10 +02:00
lib ubsan: remove CONFIG_UBSAN_OBJECT_SIZE 2022-04-13 21:01:10 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: don't skip swap entry even if zap_details specified 2022-04-13 21:01:10 +02:00
net SUNRPC: svc_tcp_sendmsg() should handle errors from xdr_alloc_bvec() 2022-04-13 21:01:07 +02:00
samples samples/bpf, xdpsock: Fix race when running for fix duration of time 2022-04-08 14:40:21 +02:00
scripts ubsan: remove CONFIG_UBSAN_OBJECT_SIZE 2022-04-13 21:01:10 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-08 14:40:31 +02:00
sound ASoC: topology: Allow TLV control to be either read or write 2022-04-08 14:40:44 +02:00
tools tools build: Use $(shell ) instead of `` to get embedded libperl's ccopts 2022-04-13 21:01:10 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: Prevent module exit until all VMs are freed 2022-04-08 14:40:38 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: adjust GCC PLUGINS after gcc-plugin.sh removal 2021-12-14 11:32:46 +01:00
Makefile Linux 5.10.110 2022-04-08 14:40:45 +02:00
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 Restructured Text 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.