Commit Graph

29 Commits

Author SHA1 Message Date
Kees Cook eed09ad261 samples/seccomp: Adjust sample to also provide kill option
As a quick way to test SECCOMP_RET_KILL, have a negative errno mean to
kill the process.

While we're in here, also swap the arch and syscall arguments so they're
ordered more like how seccomp filters order them.

Signed-off-by: Kees Cook <keescook@chromium.org>
2022-02-10 19:09:12 -08:00
Ilya Leoshkevich 14e6cac771 samples: seccomp: Use __BYTE_ORDER__
Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined
__BYTE_ORDER for consistency.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211026010831.748682-5-iii@linux.ibm.com
2021-10-25 20:39:42 -07:00
Masahiro Yamada 9009b45581 .gitignore: prefix local generated files with a slash
The pattern prefixed with '/' matches files in the same directory,
but not ones in sub-directories.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Andra Paraschiv <andraprs@amazon.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Gabriel Krisman Bertazi <krisman@collabora.com>
2021-05-02 00:43:35 +09:00
Masahiro Yamada faabed295c kbuild: introduce hostprogs-always-y and userprogs-always-y
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 <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2020-08-10 01:32:59 +09:00
Masahiro Yamada f59e766877 samples: seccomp: build sample programs for target architecture
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 5a79859ae0 ("s390:
remove 31 bit support") killed it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-05-17 18:52:01 +09:00
Masahiro Yamada d198b34f38 .gitignore: add SPDX License Identifier
Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-25 11:50:48 +01:00
Masahiro Yamada 5f2fb52fac kbuild: rename hostprogs-y/always to hostprogs/always-y
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 <masahiroy@kernel.org>
2020-02-04 01:53:07 +09:00
Sargun Dhillon 771b894f2f samples/seccomp: Zero out members based on seccomp_notif_sizes
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 <sargun@sargun.me>
Suggested-by: Tycho Andersen <tycho@tycho.ws>
Link: https://lore.kernel.org/r/20191230203503.4925-1-sargun@sargun.me
Fixes: fec7b66905 ("samples: add an example of seccomp user trap")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-01-02 13:03:39 -08:00
Masahiro Yamada 6944a06d14 samples: guard sub-directories with CONFIG options
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 <yamada.masahiro@socionext.com>
2019-05-18 11:29:01 +09:00
Masahiro Yamada 7206c12474 samples: seccomp: turn CONFIG_SAMPLE_SECCOMP into a bool option
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 <yamada.masahiro@socionext.com>
2019-05-03 23:05:00 +09:00
Tycho Andersen a77d1d196b samples/seccomp: Fix 32-bit build
Both the .o and the actual executable need to be built with -m32 in order
to link correctly.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Tycho Andersen <tycho@tycho.ws>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morris <jmorris@namei.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: fec7b66905 ("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 <mingo@kernel.org>
2019-01-08 07:45:01 +01:00
Tycho Andersen fec7b66905 samples: add an example of seccomp user trap
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 <tycho@tycho.ws>
CC: Kees Cook <keescook@chromium.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: "Serge E. Hallyn" <serge@hallyn.com>
CC: Christian Brauner <christian@brauner.io>
CC: Tyler Hicks <tyhicks@canonical.com>
CC: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-12-11 16:32:11 -08:00
Laura Abbott 8377bd2b9e kbuild: Rename HOST_LOADLIBES to KBUILD_HOSTLDLIBS
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 <labbott@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-18 01:18:05 +09:00
Michal Hocko 6275ecbcd3 samples/seccomp: do not compile when cross compiled
samples/seccomp relies on the host setting which is not suitable for
crosscompilation and it actually fails when crosscompiling s390 and
powerpc all{yes,mod}config on x86_64 with

samples/seccomp/bpf-helper.h:135:2: error: #error __BITS_PER_LONG value unusable.
 #error __BITS_PER_LONG value unusable.
  ^
In file included from samples/seccomp/bpf-fancy.c:13:0:
samples/seccomp/bpf-fancy.c: In function ‘main’:
samples/seccomp/bpf-fancy.c:38:11: error: ‘__NR_exit’ undeclared (first use in this function)
   SYSCALL(__NR_exit, ALLOW),

and many others. I am doing these for compile testing and it's been
quite useful to catch issues. Crosscompiling sample code on the other
hand doesn't seem all that important so it seems like the easiest way to
simply disable samples/seccomp when crosscompiling.

Fixing this properly is not that easy as Kees explains:
: IIRC, one of the problems is with build ordering problems: the kernel
: headers used by the samples aren't available when cross compiling.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-02-22 09:31:43 -08:00
Masahiro Yamada bf070bb0e6 kbuild: remove all dummy assignments to obj-
Now kbuild core scripts create empty built-in.o where necessary.
Remove "obj- := dummy.o" tricks.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-11-18 11:46:06 +09:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Mathias Svensson 916cafdc95 samples/seccomp: fix 64-bit comparison macros
There were some bugs in the JNE64 and JLT64 comparision macros. This fixes
them, improves comments, and cleans up the file while we are at it.

Reported-by: Stephen Röttger <sroettger@google.com>
Signed-off-by: Mathias Svensson <idolf@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-01-09 17:22:03 +11:00
Ricky Zhou d881d25cf5 samples/seccomp: Support programs with >256 instructions
Previously, the program size was incorrectly truncated to 8 bits,
resulting in broken labels in large programs. Also changes the jump
resolution loop to not rely on undefined behavior (making a pointer
point before the filter array).

Signed-off-by: Ricky Zhou <rickyz@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-11-01 08:58:17 -07:00
Ricky Zhou 1ff120504f samples/seccomp: Enable PR_SET_NO_NEW_PRIVS in dropper
Either CAP_SYS_ADMIN or PR_SET_NO_NEW_PRIVS is required to enable
seccomp. This allows samples/seccomp/dropper to be run without
CAP_SYS_ADMIN.

Signed-off-by: Ricky Zhou <rickyz@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-11-01 08:58:10 -07:00
Ricky Zhou 0af04ba564 samples/seccomp: Fix hostprogs variable
In f6041c1d, a separate SAMPLES_SECCOMP option was added. This changed
hostprogs-y to hostprogs-m, so adjust it.

Signed-off-by: Ricky Zhou <rickyz@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-11-01 08:57:42 -07:00
Olof Johansson f6041c1d8a samples/seccomp: Add standalone config option
Add a separate Kconfig option for SAMPLES_SECCOMP.

Main reason for this is that, just like other samples, it's forced to
be a module.

Without this, since the sample is a target only controlled by
CONFIG_SECCOMP_FILTER, the samples will be built before include files are
put in place properly. For example, from an arm64 allmodconfig built with
"make -sk -j 32" (without specific target), the following happens:

  samples/seccomp/bpf-fancy.c:13:27: fatal error: linux/seccomp.h: No such file or directory
  samples/seccomp/bpf-helper.h:20:50: fatal error: linux/seccomp.h: No such file or directory
  samples/seccomp/dropper.c:20:27: fatal error: linux/seccomp.h: No such file or directory
  samples/seccomp/bpf-direct.c:21:27: fatal error: linux/seccomp.h: No such file or directory

So, just stick to the same format as other samples.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-07 10:58:03 -07:00
Kees Cook 3a9af0bd34 samples/seccomp: improve label helper
Fixes a potential corruption with uninitialized stack memory in the
seccomp BPF sample program.

[akpm@linux-foundation.org: coding-style fixlet]
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Robert Swiecki <swiecki@google.com>
Tested-by: Robert Swiecki <swiecki@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-17 14:34:55 -08:00
Markos Chandras e9107f88c9 samples/seccomp/Makefile: do not build tests if cross-compiling for MIPS
The Makefile is designed to use the host toolchain so it may be unsafe
to build the tests if the kernel has been configured and built for
another architecture.  This fixes a build problem when the kernel has
been configured and built for the MIPS architecture but the host is not
MIPS (cross-compiled).  The MIPS syscalls are only defined if one of the
following is true:

 1) _MIPS_SIM == _MIPS_SIM_ABI64
 2) _MIPS_SIM == _MIPS_SIM_ABI32
 3) _MIPS_SIM == _MIPS_SIM_NABI32

Of course, none of these make sense on a non-MIPS toolchain and the
following build problem occurs when building on a non-MIPS host.

  linux/usr/include/linux/kexec.h:50: userspace cannot reference function or variable defined in the kernel
  samples/seccomp/bpf-direct.c: In function `emulator':
  samples/seccomp/bpf-direct.c:76:17: error: `__NR_write' undeclared (first use in this function)

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:06 -07:00
Arnd Bergmann 275aaa6833 samples/seccomp: be less stupid about cross compiling
The seccomp filters are currently built for the build host, not for the
machine that they are going to run on, but they are also built for with
the -m32 flag if the kernel is built for a 32 bit machine, both of which
seems rather odd.

It broke allyesconfig on my machine, which is x86-64, but building for
32 bit ARM, with this error message:

  In file included from /usr/include/stdio.h:28:0,
                   from samples/seccomp/bpf-fancy.c:15:
  /usr/include/features.h:324:26: fatal error: bits/predefs.h: No such file or directory

because there are no 32 bit libc headers installed on this machine.  We
should really be building all the samples for the target machine rather
than the build host, but since the infrastructure for that appears to be
missing right now, let's be a little bit smarter and not pass the '-m32'
flag to the HOSTCC when cross- compiling.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: James Morris <james.l.morris@oracle.com>
Acked-by: Will Drewry <wad@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-05 20:38:49 +11:00
Heiko Carstens b25b09ecf9 samples/seccomp: fix 31 bit build on s390
On s390 the flag to force 31 builds is -m31 instead of -m32 unlike
on all (?) other architectures.

Fixes this compile error:

  HOSTCC  samples/seccomp/bpf-direct.o
cc1: error: unrecognized command line option "-m32"
make[2]: *** [samples/seccomp/bpf-direct.o] Error 1

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-09-12 12:55:31 +10:00
Heiko Carstens de4bb3b9c7 samples/seccomp: fix endianness bug in LO_ARG define
The LO_ARG define needs to consider endianness also for 32 bit builds.

The "bpf_fancy" test case didn't work on s390 in 32 bit and compat mode
because the LO_ARG define resulted in a BPF program which read the upper
halve of the 64 bit system call arguments instead of the lower halves.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-08-03 14:27:40 +10:00
Chad Williamson 8aec836acb samples: seccomp: add .gitignore for untracked executables
git status should be clean following make allmodconfig && make. Add
a .gitignore file to the samples/seccomp directory to ignore binaries
produced there.

Signed-off-by: Chad Williamson <chad@dahc.us>
Reviewed-By: Will Drewry <wad@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-06-29 00:54:17 +10:00
Will Drewry 561381a146 samples/seccomp: fix dependencies on arch macros
This change fixes the compilation error triggered here for
i386 allmodconfig in linux-next:
  http://kisskb.ellerman.id.au/kisskb/buildresult/6123842/

Logic attempting to predict the host architecture has been
removed from the Makefile.  Instead, the bpf-direct sample
should now compile on any architecture, but if the architecture
is not supported, it will compile a minimal main() function.

This change also ensures the samples are not compiled when
there is no seccomp filter support.

(Note, I wasn't able to reproduce the error locally, but
 the existing approach was clearly flawed.  This tweak
 should resolve your issue and avoid other future weirdness.)

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-19 13:44:06 +10:00
Will Drewry 8ac270d1e2 Documentation: prctl/seccomp_filter
Documents how system call filtering using Berkeley Packet
Filter programs works and how it may be used.
Includes an example for x86 and a semi-generic
example using a macro-based code generator.

Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>

v18: - added acked by
     - update no new privs numbers
v17: - remove @compat note and add Pitfalls section for arch checking
       (keescook@chromium.org)
v16: -
v15: -
v14: - rebase/nochanges
v13: - rebase on to 88ebdda615
v12: - comment on the ptrace_event use
     - update arch support comment
     - note the behavior of SECCOMP_RET_DATA when there are multiple filters
       (keescook@chromium.org)
     - lots of samples/ clean up incl 64-bit bpf-direct support
       (markus@chromium.org)
     - rebase to linux-next
v11: - overhaul return value language, updates (keescook@chromium.org)
     - comment on do_exit(SIGSYS)
v10: - update for SIGSYS
     - update for new seccomp_data layout
     - update for ptrace option use
v9: - updated bpf-direct.c for SIGILL
v8: - add PR_SET_NO_NEW_PRIVS to the samples.
v7: - updated for all the new stuff in v7: TRAP, TRACE
    - only talk about PR_SET_SECCOMP now
    - fixed bad JLE32 check (coreyb@linux.vnet.ibm.com)
    - adds dropper.c: a simple system call disabler
v6: - tweak the language to note the requirement of
      PR_SET_NO_NEW_PRIVS being called prior to use. (luto@mit.edu)
v5: - update sample to use system call arguments
    - adds a "fancy" example using a macro-based generator
    - cleaned up bpf in the sample
    - update docs to mention arguments
    - fix prctl value (eparis@redhat.com)
    - language cleanup (rdunlap@xenotime.net)
v4: - update for no_new_privs use
    - minor tweaks
v3: - call out BPF <-> Berkeley Packet Filter (rdunlap@xenotime.net)
    - document use of tentative always-unprivileged
    - guard sample compilation for i386 and x86_64
v2: - move code to samples (corbet@lwn.net)
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-14 11:13:22 +10:00