Check if flags to mmap and madvise are defined before using them.
Should fix problems building on older Linux systems that don't have
these. bz#3537, with & ok djm@.
Linux mmap(2) and madvise(2) syscalls support quite a number of funky
flags that we don't expect that sshd/libc will ever need. We can
exclude this kernel attack surface by filtering the mmap(2) flags
and the madvise(2) advice arguments.
Similarly, the sandboxed process in sshd is a single-threaded program
that does not use shared memory for synchronisation or communication.
Therefore, there should be no reason for the advanced priority
inheritance futex(2) operations to be necessary. These can also be
excluded.
Motivated by Jann Horn pointing out that there have been kernel bugs
in nearby Linux kernel code, e.g. CVE-2020-29368, CVE-2020-29374 and
CVE-2022-42703.
Feedback Jann Horn, ok dtucker@
Should fix sandbox violations on (some? at least i386 and armhf) 32bit
Linux platforms. Patch from chutzpahu at gentoo.org and cjwatson at
debian.org via bz#3396.
Needed to add ppoll syscall but also to relax the fallback rlimit
sandbox. Linux poll() fails with EINVAL if npfds > RLIMIT_NOFILE,
so we have to allow a single fd in the rlimit.
In some architecture/libc configurations we need to explicitly include
sys/syscall.h for the syscall number (__NR_xxx) definitions. bz#3085,
patch from blowfist at xroutine.net.
As noted in openssh/openssh-portable#149, i386 does not have have
_NR_shmget etc. Instead, it has a single ipc syscall (see man 2 ipc,
https://linux.die.net/man/2/ipc). Add this syscall, if present, to the
list of syscalls that seccomp will deny non-fatally.
The EP11 crypto card needs to make an ioctl call, which receives an
specific argument. This crypto card is for s390 only.
Signed-off-by: Eduardo Barretto <ebarretto@linux.vnet.ibm.com>
Adding another s390 specific ioctl to be able to support ECC hardware
acceleration to the sandbox seccomp filter rules.
Now the ibmca openssl engine provides elliptic curve cryptography
support with the help of libica and CCA crypto cards. This is done via
jet another ioctl call to the zcrypt device driver and so there is a
need to enable this on the openssl sandbox.
Code is s390 specific and has been tested, verified and reviewed.
Please note that I am also the originator of the previous changes in
that area. I posted these changes to Eduardo and he forwarded the
patches to the openssl community.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Joerg Schmidbauer <jschmidb@de.ibm.com>
OpenSSL is using socket() calls (in FIPS mode) when handling ECDSA keys
in privsep child. The socket() syscall is already denied in the seccomp
filter, but in ppc64le kernel, it is implemented using socketcall()
syscall, which is not denied yet (only SYS_SHUTDOWN is allowed) and
therefore fails hard.
Patch from jjelen at redhat.com.
Allow clock_gettime syscall with X32 bit masked off. Apparently
this is required for at least some kernel versions. bz#2142
Patch mostly by Colin Watson. ok dtucker@
This stops the SC_ALLOW(), SC_ALLOW_ARG() and SC_DENY() macros
prepending __NR_ to the syscall number parameter and just makes
them explicit in the macro invocations.
No binary change in stripped object file before/after.
Syscall arguments are passed via an array of 64-bit values in struct
seccomp_data, but we were only inspecting the bottom 32 bits and not
even those correctly for BE systems.
Fortunately, the only case argument inspection was used was in the
socketcall filtering so using this for sandbox escape seems
impossible.
ok dtucker
When doing arg inspection and the syscall doesn't match, skip
past the instruction that reloads the syscall into the accumulator,
since the accumulator hasn't been modified at this point.
[sandbox-null.c sandbox-rlimit.c sandbox-seccomp-filter.c]
[sandbox-systrace.c ssh-sandbox.h sshd.c] Support preauth sandboxing
using the Capsicum API introduced in FreeBSD 10. Patch by Dag-Erling
Smorgrav, updated by Loganaden Velvindron @ AfriNIC; ok dtucker@
Darren Tucker
Damien Miller
Alex James
Luca Weiss
Jeremy Drake
Khem Raj
Eduardo Barretto
Lonnie Abelbeck
Harald Freudenberger
Darren Tucker
djm@openbsd.org