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Tycho Andersen a566a9012a seccomp: don't leak memory when filter install races
In seccomp_set_mode_filter() with TSYNC | NEW_LISTENER, we first initialize
the listener fd, then check to see if we can actually use it later in
seccomp_may_assign_mode(), which can fail if anyone else in our thread
group has installed a filter and caused some divergence. If we can't, we
partially clean up the newly allocated file: we put the fd, put the file,
but don't actually clean up the *memory* that was allocated at
filter->notif. Let's clean that up too.

To accomplish this, let's hoist the actual "detach a notifier from a
filter" code to its own helper out of seccomp_notify_release(), so that in
case anyone adds stuff to init_listener(), they only have to add the
cleanup code in one spot. This does a bit of extra locking and such on the
failure path when the filter is not attached, but it's a slow failure path
anyway.

Fixes: 51891498f2 ("seccomp: allow TSYNC and USER_NOTIF together")
Reported-by: syzbot+3ad9614a12f80994c32e@syzkaller.appspotmail.com
Signed-off-by: Tycho Andersen <tycho@tycho.pizza>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20200902014017.934315-1-tycho@tycho.pizza
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-09-08 11:19:50 -07:00
Documentation powerpc fixes for 5.9 #3 2020-08-23 11:37:23 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch powerpc fixes for 5.9 #3 2020-08-23 11:37:23 -07:00
block block-5.9-2020-08-14 2020-08-15 20:36:42 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-14 13:09:15 -07:00
drivers A set of EFI fixes: 2020-08-23 11:08:32 -07:00
fs Merge branch 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-22 17:11:38 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-23 10:52:33 -07:00
init OpenRISC updates for 5.9 2020-08-14 14:04:53 -07:00
ipc ipc/shm.c: remove the superfluous break 2020-08-12 10:58:02 -07:00
kernel seccomp: don't leak memory when filter install races 2020-09-08 11:19:50 -07:00
lib lib/string.c: Use freestanding environment 2020-08-19 11:23:45 -07:00
mm mm, page_alloc: fix core hung in free_pcppages_bulk() 2020-08-21 09:52:53 -07:00
net net: nexthop: don't allow empty NHA_GROUP 2020-08-22 12:39:55 -07:00
samples Kbuild updates for v5.9 2020-08-09 14:10:26 -07:00
scripts kconfig: qconf: replace deprecated QString::sprintf() with QTextStream 2020-08-21 10:23:38 +09:00
security Merge branch 'akpm' (patches from Andrew) 2020-08-12 11:24:12 -07:00
sound sound fixes for 5.9-rc2 2020-08-21 10:07:54 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-23 10:52:33 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Update Mellanox and Cumulus Network addresses to new domain 2020-08-21 10:48:48 -03:00
Makefile Linux 5.9-rc2 2020-08-23 14:08:43 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.