1. 02 May, 2019 38 commits
  2. 27 Apr, 2019 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.19.37 · 19bb613a
      Greg Kroah-Hartman authored
      19bb613a
    • Will Deacon's avatar
      kernel/sysctl.c: fix out-of-bounds access when setting file-max · cdd369fe
      Will Deacon authored
      commit 9002b214 upstream.
      
      Commit 32a5ad9c ("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: 32a5ad9c ("sysctl: handle overflow for file-max")
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      Acked-by: default avatarChristian 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      cdd369fe