linux-toradex.git/kernel/debug, branch v5.19-rc1 Linux kernel for Apalis and Colibri modules Merge tag 'modules-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux 2022-05-27T00:13:43+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-05-27T00:13:43+00:00 ef98f9cfe20d8ca063365d46d4ab2b85eeeb324f Pull modules updates from Luis Chamberlain: - It was time to tidy up kernel/module.c and one way of starting with that effort was to split it up into files. At my request Aaron Tomlin spearheaded that effort with the goal to not introduce any functional at all during that endeavour. The penalty for the split is +1322 bytes total, +112 bytes in data, +1210 bytes in text while bss is unchanged. One of the benefits of this other than helping make the code easier to read and review is summoning more help on review for changes with livepatching so kernel/module/livepatch.c is now pegged as maintained by the live patching folks. The before and after with just the move on a defconfig on x86-64: $ size kernel/module.o text data bss dec hex filename 38434 4540 104 43078 a846 kernel/module.o $ size -t kernel/module/*.o text data bss dec hex filename 4785 120 0 4905 1329 kernel/module/kallsyms.o 28577 4416 104 33097 8149 kernel/module/main.o 1158 8 0 1166 48e kernel/module/procfs.o 902 108 0 1010 3f2 kernel/module/strict_rwx.o 3390 0 0 3390 d3e kernel/module/sysfs.o 832 0 0 832 340 kernel/module/tree_lookup.o 39644 4652 104 44400 ad70 (TOTALS) - Aaron added module unload taint tracking (MODULE_UNLOAD_TAINT_TRACKING), to enable tracking unloaded modules which did taint the kernel. - Christophe Leroy added CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC which lets architectures to request having modules data in vmalloc area instead of module area. There are three reasons why an architecture might want this: a) On some architectures (like book3s/32) it is not possible to protect against execution on a page basis. The exec stuff can be mapped by different arch segment sizes (on book3s/32 that is 256M segments). By default the module area is in an Exec segment while vmalloc area is in a NoExec segment. Using vmalloc lets you muck with module data as NoExec on those architectures whereas before you could not. b) By pushing more module data to vmalloc you also increase the probability of module text to remain within a closer distance from kernel core text and this reduces trampolines, this has been reported on arm first and powerpc folks are following that lead. c) Free'ing module_alloc() (Exec by default) area leaves this exposed as Exec by default, some architectures have some security enhancements to set this as NoExec on free, and splitting module data with text let's future generic special allocators be added to the kernel without having developers try to grok the tribal knowledge per arch. Work like Rick Edgecombe's permission vmalloc interface [0] becomes easier to address over time. [0] https://lore.kernel.org/lkml/20201120202426.18009-1-rick.p.edgecombe@intel.com/#r - Masahiro Yamada's symbol search enhancements * tag 'modules-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (33 commits) module: merge check_exported_symbol() into find_exported_symbol_in_section() module: do not binary-search in __ksymtab_gpl if fsa->gplok is false module: do not pass opaque pointer for symbol search module: show disallowed symbol name for inherit_taint() module: fix [e_shstrndx].sh_size=0 OOB access module: Introduce module unload taint tracking module: Move module_assert_mutex_or_preempt() to internal.h module: Make module_flags_taint() accept a module's taints bitmap and usable outside core code module.h: simplify MODULE_IMPORT_NS powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx module: Remove module_addr_min and module_addr_max module: Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC module: Introduce data_layout module: Prepare for handling several RB trees module: Always have struct mod_tree_root module: Rename debug_align() as strict_align() module: Rework layout alignment to avoid BUG_ON()s module: Move module_enable_x() and frob_text() in strict_rwx.c module: Make module_enable_x() independent of CONFIG_ARCH_HAS_STRICT_MODULE_RWX module: Move version support into a separate file ... 
Pull modules updates from  Luis Chamberlain:

 - It was time to tidy up kernel/module.c and one way of starting with
   that effort was to split it up into files. At my request Aaron Tomlin
   spearheaded that effort with the goal to not introduce any functional
   at all during that endeavour. The penalty for the split is +1322
   bytes total, +112 bytes in data, +1210 bytes in text while bss is
   unchanged. One of the benefits of this other than helping make the
   code easier to read and review is summoning more help on review for
   changes with livepatching so kernel/module/livepatch.c is now pegged
   as maintained by the live patching folks.

   The before and after with just the move on a defconfig on x86-64:

     $ size kernel/module.o
        text    data     bss     dec     hex filename
       38434    4540     104   43078    a846 kernel/module.o

     $ size -t kernel/module/*.o
        text    data     bss     dec     hex filename
       4785     120       0    4905    1329 kernel/module/kallsyms.o
      28577    4416     104   33097    8149 kernel/module/main.o
       1158       8       0    1166     48e kernel/module/procfs.o
        902     108       0    1010     3f2 kernel/module/strict_rwx.o
       3390       0       0    3390     d3e kernel/module/sysfs.o
        832       0       0     832     340 kernel/module/tree_lookup.o
      39644    4652     104   44400    ad70 (TOTALS)

 - Aaron added module unload taint tracking (MODULE_UNLOAD_TAINT_TRACKING),
   to enable tracking unloaded modules which did taint the kernel.

 - Christophe Leroy added CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
   which lets architectures to request having modules data in vmalloc
   area instead of module area. There are three reasons why an
   architecture might want this:

    a) On some architectures (like book3s/32) it is not possible to
       protect against execution on a page basis. The exec stuff can be
       mapped by different arch segment sizes (on book3s/32 that is 256M
       segments). By default the module area is in an Exec segment while
       vmalloc area is in a NoExec segment. Using vmalloc lets you muck
       with module data as NoExec on those architectures whereas before
       you could not.

    b) By pushing more module data to vmalloc you also increase the
       probability of module text to remain within a closer distance
       from kernel core text and this reduces trampolines, this has been
       reported on arm first and powerpc folks are following that lead.

    c) Free'ing module_alloc() (Exec by default) area leaves this
       exposed as Exec by default, some architectures have some security
       enhancements to set this as NoExec on free, and splitting module
       data with text let's future generic special allocators be added
       to the kernel without having developers try to grok the tribal
       knowledge per arch. Work like Rick Edgecombe's permission vmalloc
       interface [0] becomes easier to address over time.

       [0] https://lore.kernel.org/lkml/20201120202426.18009-1-rick.p.edgecombe@intel.com/#r

 - Masahiro Yamada's symbol search enhancements

* tag 'modules-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (33 commits)
  module: merge check_exported_symbol() into find_exported_symbol_in_section()
  module: do not binary-search in __ksymtab_gpl if fsa->gplok is false
  module: do not pass opaque pointer for symbol search
  module: show disallowed symbol name for inherit_taint()
  module: fix [e_shstrndx].sh_size=0 OOB access
  module: Introduce module unload taint tracking
  module: Move module_assert_mutex_or_preempt() to internal.h
  module: Make module_flags_taint() accept a module's taints bitmap and usable outside core code
  module.h: simplify MODULE_IMPORT_NS
  powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx
  module: Remove module_addr_min and module_addr_max
  module: Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
  module: Introduce data_layout
  module: Prepare for handling several RB trees
  module: Always have struct mod_tree_root
  module: Rename debug_align() as strict_align()
  module: Rework layout alignment to avoid BUG_ON()s
  module: Move module_enable_x() and frob_text() in strict_rwx.c
  module: Make module_enable_x() independent of CONFIG_ARCH_HAS_STRICT_MODULE_RWX
  module: Move version support into a separate file
  ...
lockdown: also lock down previous kgdb use 2022-05-24T18:29:34+00:00 Daniel Thompson daniel.thompson@linaro.org 2022-05-23T18:11:02+00:00 eadb2f47a3ced5c64b23b90fd2a3463f63726066 KGDB and KDB allow read and write access to kernel memory, and thus should be restricted during lockdown. An attacker with access to a serial port (for example, via a hypervisor console, which some cloud vendors provide over the network) could trigger the debugger so it is important that the debugger respect the lockdown mode when/if it is triggered. Fix this by integrating lockdown into kdb's existing permissions mechanism. Unfortunately kgdb does not have any permissions mechanism (although it certainly could be added later) so, for now, kgdb is simply and brutally disabled by immediately exiting the gdb stub without taking any action. For lockdowns established early in the boot (e.g. the normal case) then this should be fine but on systems where kgdb has set breakpoints before the lockdown is enacted than "bad things" will happen. CVE: CVE-2022-21499 Co-developed-by: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
KGDB and KDB allow read and write access to kernel memory, and thus
should be restricted during lockdown.  An attacker with access to a
serial port (for example, via a hypervisor console, which some cloud
vendors provide over the network) could trigger the debugger so it is
important that the debugger respect the lockdown mode when/if it is
triggered.

Fix this by integrating lockdown into kdb's existing permissions
mechanism.  Unfortunately kgdb does not have any permissions mechanism
(although it certainly could be added later) so, for now, kgdb is simply
and brutally disabled by immediately exiting the gdb stub without taking
any action.

For lockdowns established early in the boot (e.g. the normal case) then
this should be fine but on systems where kgdb has set breakpoints before
the lockdown is enacted than "bad things" will happen.

CVE: CVE-2022-21499
Co-developed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
module: Move kdb module related code out of main kdb code 2022-04-05T15:43:04+00:00 Aaron Tomlin atomlin@redhat.com 2022-03-22T14:03:43+00:00 f64205a42046d3802c423fa2059e7fca39af127c No functional change. This patch migrates the kdb 'lsmod' command support out of main kdb code into its own file under kernel/module. In addition to the above, a minor style warning i.e. missing a blank line after declarations, was resolved too. The new file was added to MAINTAINERS. Finally we remove linux/module.h as it is entirely redundant. Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> 
No functional change.

This patch migrates the kdb 'lsmod' command support out of main
kdb code into its own file under kernel/module. In addition to
the above, a minor style warning i.e. missing a blank line after
declarations, was resolved too. The new file was added to
MAINTAINERS. Finally we remove linux/module.h as it is entirely
redundant.

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
kdb: Fix the putarea helper function 2022-03-24T16:39:47+00:00 Daniel Thompson daniel.thompson@linaro.org 2022-01-28T14:40:55+00:00 c1cb81429df462eca1b6ba615cddd21dd3103c46 Currently kdb_putarea_size() uses copy_from_kernel_nofault() to write *to* arbitrary kernel memory. This is obviously wrong and means the memory modify ('mm') command is a serious risk to debugger stability: if we poke to a bad address we'll double-fault and lose our debug session. Fix this the (very) obvious way. Note that there are two Fixes: tags because the API was renamed and this patch will only trivially backport as far as the rename (and this is probably enough). Nevertheless Christoph's rename did not introduce this problem so I wanted to record that! Fixes: fe557319aa06 ("maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault") Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20220128144055.207267-1-daniel.thompson@linaro.org 
Currently kdb_putarea_size() uses copy_from_kernel_nofault() to write *to*
arbitrary kernel memory. This is obviously wrong and means the memory
modify ('mm') command is a serious risk to debugger stability: if we poke
to a bad address we'll double-fault and lose our debug session.

Fix this the (very) obvious way.

Note that there are two Fixes: tags because the API was renamed and this
patch will only trivially backport as far as the rename (and this is
probably enough). Nevertheless Christoph's rename did not introduce this
problem so I wanted to record that!

Fixes: fe557319aa06 ("maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault")
Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20220128144055.207267-1-daniel.thompson@linaro.org
kdb: Adopt scheduler's task classification 2021-11-03T17:21:37+00:00 Daniel Thompson daniel.thompson@linaro.org 2021-11-02T17:31:58+00:00 b77dbc86d60459b42ab375e4e23172e7245f2854 Currently kdb contains some open-coded routines to generate a summary character for each task. This code currently issues warnings, is almost certainly broken and won't make sense to any kernel dev who has ever used /proc to examine task states. Fix both the warning and the potential for confusion by adopting the scheduler's task classification. Whilst doing this we also simplify the filtering by using mask strings directly (which means we don't have to guess all the characters the scheduler might give us). Unfortunately we can't quite match the scheduler classification completely. We add four extra states: - for idle loops and i, m and s for sleeping system daemons (which means kthreads in one of the I, M and S states). These extra states are used to manage the filters for tools to make the output of ps and bta less noisy. Note: The Fixes below is the last point the original dubious code was moved; it was not introduced by that patch. However it gives us the last point to which this patch can be easily backported. Happily that should be enough to cover the introduction of CONFIG_WERROR! Fixes: 2f064a59a11f ("sched: Change task_struct::state") Link: https://lore.kernel.org/r/20211102173158.3315227-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> 
Currently kdb contains some open-coded routines to generate a summary
character for each task. This code currently issues warnings, is
almost certainly broken and won't make sense to any kernel dev who
has ever used /proc to examine task states.

Fix both the warning and the potential for confusion by adopting the
scheduler's task classification. Whilst doing this we also simplify the
filtering by using mask strings directly (which means we don't have to
guess all the characters the scheduler might give us).

Unfortunately we can't quite match the scheduler classification completely.
We add four extra states: - for idle loops and i, m and s for sleeping
system daemons (which means kthreads in one of the I, M and S states).
These extra states are used to manage the filters for tools to make the
output of ps and bta less noisy.

Note: The Fixes below is the last point the original dubious code was
      moved; it was not introduced by that patch. However it gives us
      the last point to which this patch can be easily backported.
      Happily that should be enough to cover the introduction of
      CONFIG_WERROR!

Fixes: 2f064a59a11f ("sched: Change task_struct::state")
Link: https://lore.kernel.org/r/20211102173158.3315227-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Merge tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux 2021-09-07T19:08:04+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-09-07T19:08:04+00:00 996fe06160998a38ff07189feb3ec8ab8f68fd4e Pull kgdb updates from Daniel Thompson: "Changes for kgdb/kdb this cycle are dominated by a change from Sumit that removes as small (256K) private heap from kdb. This is change I've hoped for ever since I discovered how few users of this heap remained in the kernel, so many thanks to Sumit for hunting these down. The other change is an incremental step towards SPDX headers" * tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux: kernel: debug: Convert to SPDX identifier kdb: Rename members of struct kdbtab_t kdb: Simplify kdb_defcmd macro logic kdb: Get rid of redundant kdb_register_flags() kdb: Rename struct defcmd_set to struct kdb_macro kdb: Get rid of custom debug heap allocator 
Pull kgdb updates from Daniel Thompson:
 "Changes for kgdb/kdb this cycle are dominated by a change from Sumit
  that removes as small (256K) private heap from kdb. This is change
  I've hoped for ever since I discovered how few users of this heap
  remained in the kernel, so many thanks to Sumit for hunting these
  down.

  The other change is an incremental step towards SPDX headers"

* tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  kernel: debug: Convert to SPDX identifier
  kdb: Rename members of struct kdbtab_t
  kdb: Simplify kdb_defcmd macro logic
  kdb: Get rid of redundant kdb_register_flags()
  kdb: Rename struct defcmd_set to struct kdb_macro
  kdb: Get rid of custom debug heap allocator
kernel: debug: Convert to SPDX identifier 2021-09-06T13:31:11+00:00 Cai Huoqing caihuoqing@baidu.com 2021-09-06T11:23:02+00:00 f8416aa29185468e0d914ba4b2a330fd53ee263f use SPDX-License-Identifier instead of a verbose license text Signed-off-by: Cai Huoqing <caihuoqing@baidu.com> Link: https://lore.kernel.org/r/20210906112302.937-1-caihuoqing@baidu.com Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> 
use SPDX-License-Identifier instead of a verbose license text

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20210906112302.937-1-caihuoqing@baidu.com
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
isystem: trim/fixup stdarg.h and other headers 2021-08-19T00:02:55+00:00 Alexey Dobriyan adobriyan@gmail.com 2021-08-02T20:40:31+00:00 39f75da7bcc829ddc4d40bb60d0e95520de7898b Delete/fixup few includes in anticipation of global -isystem compile option removal. Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition of uintptr_t error (one definition comes from <stddef.h>, another from <linux/types.h>). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> 
Delete/fixup few includes in anticipation of global -isystem compile
option removal.

Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
kdb: Rename members of struct kdbtab_t 2021-07-27T16:05:06+00:00 Sumit Garg sumit.garg@linaro.org 2021-07-12T13:46:20+00:00 e868f0a3c4b9c1d7721f08b703142a876814a3f8 Remove redundant prefix "cmd_" from name of members in struct kdbtab_t for better readibility. Suggested-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210712134620.276667-5-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> 
Remove redundant prefix "cmd_" from name of members in struct kdbtab_t
for better readibility.

Suggested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210712134620.276667-5-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
kdb: Simplify kdb_defcmd macro logic 2021-07-27T16:04:50+00:00 Sumit Garg sumit.garg@linaro.org 2021-07-12T13:46:19+00:00 9a5db530aa7d98b10c4f5104027565c98cca49e6 Switch to use a linked list instead of dynamic array which makes allocation of kdb macro and traversing the kdb macro commands list simpler. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210712134620.276667-4-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> 
Switch to use a linked list instead of dynamic array which makes
allocation of kdb macro and traversing the kdb macro commands list
simpler.

Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210712134620.276667-4-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>