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Filename Latest commit message Latest commit date
Will Deacon 9002b21465 kernel/sysctl.c: fix out-of-bounds access when setting file-max
Commit 32a5ad9c22 ("sysctl: handle overflow for file-max") hooked up
min/max values for the file-max sysctl parameter via the .extra1 and
.extra2 fields in the corresponding struct ctl_table entry.

Unfortunately, the minimum value points at the global 'zero' variable,
which is an int.  This results in a KASAN splat when accessed as a long
by proc_doulongvec_minmax on 64-bit architectures:

  | BUG: KASAN: global-out-of-bounds in __do_proc_doulongvec_minmax+0x5d8/0x6a0
  | Read of size 8 at addr ffff2000133d1c20 by task systemd/1
  |
  | CPU: 0 PID: 1 Comm: systemd Not tainted 5.1.0-rc3-00012-g40b114779944 #2
  | Hardware name: linux,dummy-virt (DT)
  | Call trace:
  |  dump_backtrace+0x0/0x228
  |  show_stack+0x14/0x20
  |  dump_stack+0xe8/0x124
  |  print_address_description+0x60/0x258
  |  kasan_report+0x140/0x1a0
  |  __asan_report_load8_noabort+0x18/0x20
  |  __do_proc_doulongvec_minmax+0x5d8/0x6a0
  |  proc_doulongvec_minmax+0x4c/0x78
  |  proc_sys_call_handler.isra.19+0x144/0x1d8
  |  proc_sys_write+0x34/0x58
  |  __vfs_write+0x54/0xe8
  |  vfs_write+0x124/0x3c0
  |  ksys_write+0xbc/0x168
  |  __arm64_sys_write+0x68/0x98
  |  el0_svc_common+0x100/0x258
  |  el0_svc_handler+0x48/0xc0
  |  el0_svc+0x8/0xc
  |
  | The buggy address belongs to the variable:
  |  zero+0x0/0x40
  |
  | Memory state around the buggy address:
  |  ffff2000133d1b00: 00 00 00 00 00 00 00 00 fa fa fa fa 04 fa fa fa
  |  ffff2000133d1b80: fa fa fa fa 04 fa fa fa fa fa fa fa 04 fa fa fa
  | >ffff2000133d1c00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00
  |                                ^
  |  ffff2000133d1c80: fa fa fa fa 00 fa fa fa fa fa fa fa 00 00 00 00
  |  ffff2000133d1d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Fix the splat by introducing a unsigned long 'zero_ul' and using that
instead.

Link: http://lkml.kernel.org/r/20190403153409.17307-1-will.deacon@arm.com
Fixes: 32a5ad9c22 ("sysctl: handle overflow for file-max")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Christian Brauner <christian@brauner.io>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-05 16:02:31 -10:00
arch sh: fix multiple function definition build errors 2019-04-05 16:02:31 -10:00
block
certs
crypto
Documentation psi: clarify the units used in pressure files 2019-04-05 16:02:31 -10:00
drivers
fs hugetlbfs: fix memory leak for resv_map 2019-04-05 16:02:31 -10:00
include mm: writeback: use exact memcg dirty counts 2019-04-05 16:02:31 -10:00
init
ipc
kernel kernel/sysctl.c: fix out-of-bounds access when setting file-max 2019-04-05 16:02:31 -10:00
lib lib/lzo: fix bugs for very short or empty input 2019-04-05 16:02:30 -10:00
LICENSES
mm mm/util.c: fix strndup_user() comment 2019-04-05 16:02:31 -10:00
net
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MAINTAINERS MAINTAINERS: add maintainer and replacing reviewer ARM/NUVOTON NPCM 2019-04-05 16:02:31 -10:00
Makefile
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.