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2017-01-09samples/seccomp: fix 64-bit comparison macrosMathias Svensson
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>
2016-11-01samples/seccomp: Support programs with >256 instructionsRicky Zhou
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>
2016-11-01samples/seccomp: Enable PR_SET_NO_NEW_PRIVS in dropperRicky Zhou
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>
2016-11-01samples/seccomp: Fix hostprogs variableRicky Zhou
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>
2016-07-07samples/seccomp: Add standalone config optionOlof Johansson
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>
2015-02-17samples/seccomp: improve label helperKees Cook
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>
2014-04-03samples/seccomp/Makefile: do not build tests if cross-compiling for MIPSMarkos Chandras
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>
2013-02-05samples/seccomp: be less stupid about cross compilingArnd Bergmann
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>
2012-09-12samples/seccomp: fix 31 bit build on s390Heiko Carstens
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>
2012-08-03samples/seccomp: fix endianness bug in LO_ARG defineHeiko Carstens
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>
2012-06-29samples: seccomp: add .gitignore for untracked executablesChad Williamson
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>
2012-04-19samples/seccomp: fix dependencies on arch macrosWill Drewry
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>
2012-04-14Documentation: prctl/seccomp_filterWill Drewry
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 88ebdda6159ffc15699f204c33feb3e431bf9bdc 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>