linux-toradex.git/samples/seccomp, branch v5.12-rc8

kbuild: introduce hostprogs-always-y and userprogs-always-y

2020-08-09T16:32:59+00:00

To build host programs, you need to add the program names to 'hostprogs'
to use the necessary build rule, but it is not enough to build them
because there is no dependency.

There are two types of host programs: built as the prerequisite of
another (e.g. gen_crc32table in lib/Makefile), or always built when
Kbuild visits the Makefile (e.g. genksyms in scripts/genksyms/Makefile).

The latter is typical in Makefiles under scripts/, which contains host
programs globally used during the kernel build. To build them, you need
to add them to both 'hostprogs' and 'always-y'.

This commit adds hostprogs-always-y as a shorthand.

The same applies to user programs. net/bpfilter/Makefile builds
bpfilter_umh on demand, hence always-y is unneeded. In contrast,
programs under samples/ are added to both 'userprogs' and 'always-y'
so they are always built when Kbuild visits the Makefiles.

userprogs-always-y works as a shorthand.

Signed-off-by: Masahiro Yamada 
Acked-by: Miguel Ojeda

samples: seccomp: build sample programs for target architecture

2020-05-17T09:52:01+00:00

These userspace programs include UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample programs should be built for
the target as well. Kbuild now supports 'userprogs' for that.

I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.

The 'ifndef CROSS_COMPILE' is no longer needed.

BTW, the -m31 for s390 is left-over code. Commit 5a79859ae0f3 ("s390:
remove 31 bit support") killed it.

Signed-off-by: Masahiro Yamada 
Acked-by: Sam Ravnborg

.gitignore: add SPDX License Identifier

2020-03-25T10:50:48+00:00

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman

kbuild: rename hostprogs-y/always to hostprogs/always-y

2020-02-03T16:53:07+00:00

In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.

It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.

This commit renames like follows:

  always       ->  always-y
  hostprogs-y  ->  hostprogs

So, scripts/Makefile will look like this:

  always-$(CONFIG_BUILD_BIN2C) += ...
  always-$(CONFIG_KALLSYMS)    += ...
      ...
  hostprogs := $(always-y) $(always-m)

I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.

The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.

Signed-off-by: Masahiro Yamada

samples/seccomp: Zero out members based on seccomp_notif_sizes

2020-01-02T21:03:39+00:00

The sizes by which seccomp_notif and seccomp_notif_resp are allocated are
based on the SECCOMP_GET_NOTIF_SIZES ioctl. This allows for graceful
extension of these datastructures. If userspace zeroes out the
datastructure based on its version, and it is lagging behind the kernel's
version, it will end up sending trailing garbage. On the other hand,
if it is ahead of the kernel version, it will write extra zero space,
and potentially cause corruption.

Signed-off-by: Sargun Dhillon 
Suggested-by: Tycho Andersen 
Link: https://lore.kernel.org/r/20191230203503.4925-1-sargun@sargun.me
Fixes: fec7b6690541 ("samples: add an example of seccomp user trap")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook

samples: guard sub-directories with CONFIG options

2019-05-18T02:29:01+00:00

Do not descend to sub-directories when unneeded.

I used subdir-$(CONFIG_...) for hidraw, seccomp, and vfs because
they only contain host programs.

While we are here, let's add SPDX License tag, and sort the directories
alphabetically.

Signed-off-by: Masahiro Yamada

samples: seccomp: turn CONFIG_SAMPLE_SECCOMP into a bool option

2019-05-03T14:05:00+00:00

The prompt of CONFIG_SAMPLE_SECCOMP claims this is "loadable module
only", which is invalid.

samples/seccomp/ only contains host programs, so having it tristate
is pointless.

Signed-off-by: Masahiro Yamada

samples/seccomp: Fix 32-bit build

2019-01-08T06:45:01+00:00

Both the .o and the actual executable need to be built with -m32 in order
to link correctly.

Reported-by: Ingo Molnar 
Signed-off-by: Tycho Andersen 
Reviewed-by: Kees Cook 
Cc: Borislav Petkov 
Cc: James Morris 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: fec7b6690541 ("samples: add an example of seccomp user trap")
Link: http://lkml.kernel.org/r/20190107231631.1849-1-tycho@tycho.ws
Signed-off-by: Ingo Molnar

samples: add an example of seccomp user trap

2018-12-12T00:32:11+00:00

The idea here is just to give a demonstration of how one could safely use
the SECCOMP_RET_USER_NOTIF feature to do mount policies. This particular
policy is (as noted in the comment) not very interesting, but it serves to
illustrate how one might apply a policy dodging the various TOCTOU issues.

Signed-off-by: Tycho Andersen 
CC: Kees Cook 
CC: Andy Lutomirski 
CC: Oleg Nesterov 
CC: Eric W. Biederman 
CC: "Serge E. Hallyn" 
CC: Christian Brauner 
CC: Tyler Hicks 
CC: Akihiro Suda 
Signed-off-by: Kees Cook

kbuild: Rename HOST_LOADLIBES to KBUILD_HOSTLDLIBS

2018-07-17T16:18:05+00:00

In preparation for enabling command line LDLIBS, re-name HOST_LOADLIBES
to KBUILD_HOSTLDLIBS as the internal use only flags. Also rename
existing usage to HOSTLDLIBS for consistency. This should not have any
visible effects.

Signed-off-by: Laura Abbott 
Signed-off-by: Masahiro Yamada