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Sven Eckelmann 7afe374cc7 batman-adv: Reduce tt_global hash refcnt only for removed entry
[ Upstream commit f131a56880 ]

The batadv_hash_remove is a function which searches the hashtable for an
entry using a needle, a hashtable bucket selection function and a compare
function. It will lock the bucket list and delete an entry when the compare
function matches it with the needle. It returns the pointer to the
hlist_node which matches or NULL when no entry matches the needle.

The batadv_tt_global_free is not itself protected in anyway to avoid that
any other function is modifying the hashtable between the search for the
entry and the call to batadv_hash_remove. It can therefore happen that the
entry either doesn't exist anymore or an entry was deleted which is not the
same object as the needle. In such an situation, the reference counter (for
the reference stored in the hashtable) must not be reduced for the needle.
Instead the reference counter of the actually removed entry has to be
reduced.

Otherwise the reference counter will underflow and the object might be
freed before all its references were dropped. The kref helpers reported
this problem as:

  refcount_t: underflow; use-after-free.

Fixes: 7683fdc1e8 ("batman-adv: protect the local and the global trans-tables with rcu")
Reported-by: Martin Weinelt <martin@linuxlounge.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-08 07:21:46 +02:00
arch arm64: dts: rockchip: fix rk3328-roc-cc gmac2io tx/rx_delay 2019-05-08 07:21:45 +02:00
block blk-iolatency: #include "blk.h" 2019-04-20 09:15:58 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: x86/poly1305 - fix overflow during partial reduction 2019-04-27 09:36:37 +02:00
Documentation USB: core: Fix bug caused by duplicate interface PM usage counter 2019-05-08 07:21:44 +02:00
drivers rtc: sh: Fix invalid alarm warning for non-enabled alarm 2019-05-08 07:21:46 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs ceph: fix use-after-free on symlink traversal 2019-05-04 09:20:21 +02:00
include USB: core: Fix bug caused by duplicate interface PM usage counter 2019-05-08 07:21:44 +02:00
init Revert "mm: use early_pfn_to_nid in page_ext_init" 2019-03-23 20:09:46 +01:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK 2019-05-04 09:20:22 +02:00
lib lib/Kconfig.debug: fix build error without CONFIG_BLOCK 2019-05-02 09:58:53 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm: prevent get_user_pages() from overflowing page refcount 2019-05-04 09:20:11 +02:00
net batman-adv: Reduce tt_global hash refcnt only for removed entry 2019-05-08 07:21:46 +02:00
samples samples: mei: use /dev/mei0 instead of /dev/mei 2019-02-15 08:10:11 +01:00
scripts kconfig/[mn]conf: handle backspace (^H) key 2019-05-04 09:20:22 +02:00
security selinux: use kernel linux/socket.h for genheaders and mdp 2019-05-04 09:20:10 +02:00
sound ALSA: hda/realtek - Apply the fixup for ASUS Q325UAR 2019-05-08 07:21:43 +02:00
tools selftests: fib_rule_tests: print the result and return 1 if any tests failed 2019-05-05 14:42:39 +02:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm/arm64: vgic-its: Take the srcu lock when parsing the memslots 2019-05-04 09:20:14 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS platform/x86: Add Intel AtomISP2 dummy / power-management driver 2019-04-20 09:16:02 +02:00
Makefile Linux 4.19.40 2019-05-05 14:42:41 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.