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Kees Cook f4d0227ff1 pstore/ram: Run without kernel crash dump region
commit 8880fa32c5 upstream.

The ram pstore backend has always had the crash dumper frontend enabled
unconditionally. However, it was possible to effectively disable it
by setting a record_size=0. All the machinery would run (storing dumps
to the temporary crash buffer), but 0 bytes would ultimately get stored
due to there being no przs allocated for dumps. Commit 89d328f637
("pstore/ram: Correctly calculate usable PRZ bytes"), however, assumed
that there would always be at least one allocated dprz for calculating
the size of the temporary crash buffer. This was, of course, not the
case when record_size=0, and would lead to a NULL deref trying to find
the dprz buffer size:

BUG: unable to handle kernel NULL pointer dereference at (null)
...
IP: ramoops_probe+0x285/0x37e (fs/pstore/ram.c:808)

        cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;

Instead, we need to only enable the frontends based on the success of the
prz initialization and only take the needed actions when those zones are
available. (This also fixes a possible error in detecting if the ftrace
frontend should be enabled.)

Reported-and-tested-by: Yaro Slav <yaro330@gmail.com>
Fixes: 89d328f637 ("pstore/ram: Correctly calculate usable PRZ bytes")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-11 12:20:52 +02:00
arch pstore: Convert buf_lock to semaphore 2019-06-11 12:20:52 +02:00
block block: sed-opal: fix IOC_OPAL_ENABLE_DISABLE_MBR 2019-05-31 06:46:24 -07:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: ccm - fix incompatibility between "ccm" and "ccm_base" 2019-05-22 07:37:43 +02:00
Documentation doc: Cope with Sphinx logging deprecations 2019-06-09 09:17:21 +02:00
drivers pstore: Convert buf_lock to semaphore 2019-06-11 12:20:52 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs pstore/ram: Run without kernel crash dump region 2019-06-11 12:20:52 +02:00
include pstore: Convert buf_lock to semaphore 2019-06-11 12:20:52 +02:00
init jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel kernel/signal.c: trace_signal_deliver when signal_group_exit 2019-06-09 09:17:20 +02:00
lib jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm memcg: make it work on sparse non-0-node systems 2019-06-09 09:17:19 +02:00
net ipv6: fix EFAULT on sendto with icmpv6 and hdrincl 2019-06-11 12:20:50 +02:00
samples samples: mei: use /dev/mei0 instead of /dev/mei 2019-02-15 08:10:11 +01:00
scripts gcc-plugins: Fix build failures under Darwin host 2019-06-09 09:17:22 +02:00
security evm: check hash algorithm passed to init_desc() 2019-06-09 09:17:21 +02:00
sound ALSA: hda/realtek - Improve the headset mic for Acer Aspire laptops 2019-06-09 09:17:17 +02:00
tools jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID 2019-06-09 09:17:18 +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 4.19.49 2019-06-09 09:17:25 +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.