UDP doesn't guarantee delivery, so reattempt packet transmission if we don't
get a response and timeout if we still don't have anything after (by
default) 10 seconds.
Look at the device ID and figure out what type of device it is, and provide
appropriate classes for each that only support the functionality available
on that device.
These syscalls are only available in 32bit architectures, but libseccomp
should handle them correctly even if we're on native architectures that
do not have these syscalls.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Commands such as "cp -p" also use fsetxattr() in addition to fchown(),
so we need to make sure these syscalls always return successful as well
in order to avoid nasty "Invalid value" errors.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Right now it only tests whether seccomp correctly forges the return
value of chown, but the long-term goal is to test the full sandboxing
functionality at some point in the future.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
What we basically want is a seccomp mode 2 BPF program like this but for
every architecture:
BPF_STMT(BPF_LD+BPF_W+BPF_ABS, offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_chown, 4, 0),
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_fchown, 3, 0),
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_fchownat, 2, 0),
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_lchown, 1, 0),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ERRNO)
However, on 32 bit architectures we do have chown32, lchown32 and
fchown32, so we'd need to add all the architecture blurb which
libseccomp handles for us.
So we only need to make sure that we add the 32bit seccomp arch while
we're on x86_64 and otherwise we just stay at the native architecture
which was set during seccomp_init(), which more or less replicates
setting 32bit personality during runChild().
The FORCE_SUCCESS() macro here could be a bit less ugly but I think
repeating the seccomp_rule_add() all over the place is way uglier.
Another way would have been to create a vector of syscalls to iterate
over, but that would make error messages uglier because we can either
only print the (libseccomp-internal) syscall number or use
seccomp_syscall_resolve_num_arch() to get the name or even make the
vector a pair number/name, essentially duplicating everything again.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
We're going to use libseccomp instead of creating the raw BPF program,
because we have different syscall numbers on different architectures.
Although our initial seccomp rules will be quite small it really doesn't
make sense to generate the raw BPF program because we need to duplicate
it and/or make branches on every single architecture we want to suuport.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
This reverts commit ff0c0b645c.
We're going to use seccomp to allow "cp -p" and force chown-related
syscalls to always return 0.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
This solves a problem whereby if /gnu/store/.links had enough entries,
ext4's directory index would be full, leading to link(2) returning
ENOSPC.
* nix/libstore/optimise-store.cc (LocalStore::optimisePath_): Upon
ENOSPC from link(2), print a message and return instead of throwing a
'SysError'.
