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Linux kernel for uConsole
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Daniel Axtens 3d14b83e71 powerpc/pseries/hvconsole: Fix stack overread via udbg 
[ Upstream commit 934bda59f2 ]

While developing KASAN for 64-bit book3s, I hit the following stack
over-read.

It occurs because the hypercall to put characters onto the terminal
takes 2 longs (128 bits/16 bytes) of characters at a time, and so
hvc_put_chars() would unconditionally copy 16 bytes from the argument
buffer, regardless of supplied length. However, udbg_hvc_putc() can
call hvc_put_chars() with a single-byte buffer, leading to the error.

  ==================================================================
  BUG: KASAN: stack-out-of-bounds in hvc_put_chars+0xdc/0x110
  Read of size 8 at addr c0000000023e7a90 by task swapper/0

  CPU: 0 PID: 0 Comm: swapper Not tainted 5.2.0-rc2-next-20190528-02824-g048a6ab4835b #113
  Call Trace:
    dump_stack+0x104/0x154 (unreliable)
    print_address_description+0xa0/0x30c
    __kasan_report+0x20c/0x224
    kasan_report+0x18/0x30
    __asan_report_load8_noabort+0x24/0x40
    hvc_put_chars+0xdc/0x110
    hvterm_raw_put_chars+0x9c/0x110
    udbg_hvc_putc+0x154/0x200
    udbg_write+0xf0/0x240
    console_unlock+0x868/0xd30
    register_console+0x970/0xe90
    register_early_udbg_console+0xf8/0x114
    setup_arch+0x108/0x790
    start_kernel+0x104/0x784
    start_here_common+0x1c/0x534

  Memory state around the buggy address:
   c0000000023e7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   c0000000023e7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1
  >c0000000023e7a80: f1 f1 01 f2 f2 f2 00 00 00 00 00 00 00 00 00 00
                           ^
   c0000000023e7b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   c0000000023e7b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ==================================================================

Document that a 16-byte buffer is requred, and provide it in udbg.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-09 10:19:08 +01:00
arch powerpc/pseries/hvconsole: Fix stack overread via udbg 2020-01-09 10:19:08 +01:00
block compat_ioctl: block: handle BLKREPORTZONE/BLKRESETZONE 2020-01-09 10:19:01 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: user - fix memory leak in crypto_report 2019-12-13 08:52:48 +01:00
Documentation dt-bindings: clock: renesas: rcar-usb2-clock-sel: Fix typo in example 2020-01-09 10:19:06 +01:00
drivers powerpc/pseries/hvconsole: Fix stack overread via udbg 2020-01-09 10:19:08 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs bdev: Refresh bdev size for disks without partitioning 2020-01-09 10:19:07 +01:00
include regulator: ab8500: Remove AB8505 USB regulator 2020-01-09 10:19:05 +01:00
init fork: fix some -Wmissing-prototypes warnings 2019-12-05 09:21:04 +01:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:06:52 +02:00
kernel ftrace: Avoid potential division by zero in function profiler 2020-01-09 10:19:03 +01:00
lib idr: Fix idr_get_next_ul race with idr_remove 2019-12-17 20:36:02 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm arm64: Revert support for execute-only user mappings 2020-01-09 10:19:03 +01:00
net Bluetooth: Fix memory leak in hci_connect_le_scan 2020-01-09 10:19:04 +01:00
samples samples: pktgen: fix proc_cmd command result check logic 2019-12-31 16:34:59 +01:00
scripts scripts/kallsyms: fix definitely-lost memory leak 2020-01-04 19:13:09 +01:00
security apparmor: fix aa_xattrs_match() may sleep while holding a RCU lock 2020-01-09 10:19:02 +01:00
sound ALSA: firewire-motu: Correct a typo in the clock proc string 2020-01-09 10:19:02 +01:00
tools rseq/selftests: Fix: Namespace gettid() for compatibility with glibc 2.30 2020-01-09 10:19:02 +01:00
usr kbuild: clean compressed initramfs image 2019-10-07 18:57:16 +02:00
virt KVM: arm/arm64: vgic: Don't rely on the wrong pending table 2019-12-13 08:52:45 +01:00
.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 USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
Makefile Linux 4.19.93 2020-01-04 19:13:46 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
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.