socket_bind_to_ifindex() uses the the SO_BINDTOIFINDEX sockopt of kernel
5.0, with a fallback to SO_BINDTODEVICE on older kernels.
socket_bind_to_ifname() is a trivial wrapper around SO_BINDTODEVICE, the
only benefit of using it instead of SO_BINDTODEVICE directly is that it
determines the size of the interface name properly so that it also works
for unbinding. Moreover, it's an attempt to unify our invocations of the
sockopt with a size of strlen(ifname) rather than strlen(ifname)+1...
I had a test machine with ulimit -n set to 1073741816 through pam
("session required pam_limits.so set_all", which copies the limits from PID 1,
left over from testing of #10921).
test-execute would "hang" and then fail with a timeout when running
exec-inaccessiblepaths-proc.service. It turns out that the problem was in
close_all_fds(), which would go to the fallback path of doing close()
1073741813 times. Let's just fail if we hit this case. This only matters
for cases where both /proc is inaccessible, and the *soft* limit has been
raised.
(gdb) bt
#0 0x00007f7e2e73fdc8 in close () from target:/lib64/libc.so.6
#1 0x00007f7e2e42cdfd in close_nointr ()
from target:/home/zbyszek/src/systemd-work3/build-rawhide/src/shared/libsystemd-shared-241.so
#2 0x00007f7e2e42d525 in close_all_fds ()
from target:/home/zbyszek/src/systemd-work3/build-rawhide/src/shared/libsystemd-shared-241.so
#3 0x0000000000426e53 in exec_child ()
#4 0x0000000000429578 in exec_spawn ()
#5 0x00000000004ce1ab in service_spawn ()
#6 0x00000000004cff77 in service_enter_start ()
#7 0x00000000004d028f in service_enter_start_pre ()
#8 0x00000000004d16f2 in service_start ()
#9 0x00000000004568f4 in unit_start ()
#10 0x0000000000416987 in test ()
#11 0x0000000000417632 in test_exec_inaccessiblepaths ()
#12 0x0000000000419362 in run_tests ()
#13 0x0000000000419632 in main ()
Everyone will be in trouble then (as quite widely caps are store in
64bit fields). But let's protect ourselves at least to the point that we
ignore all higher caps for now.
The kernel only allows dropping bounding caps as long as we have
CAP_SETPCAP. Hence, let's keep that before dropping the bounding caps,
and afterwards drop them too.
The subvol snapshot logic doesn't cover sub-mounts either, and it really
shouldn't in the general case, hence let's simply stop at submounts in
all cases, both in the main and in the fall-back codepath.
As discussed here:
https://github.com/systemd/systemd/pull/11243#pullrequestreview-209477230
Previously, when we'd copy an individual file we'd synthesize a
user.crtime_usec xattr with the source's creation time if we can
determine it. As the creation/birth time was until recently not
queriable form userspace this effectively just propagated the same xattr
on the source to the same xattr on the destination. However, current
kernels now allow to query the birthtime using statx() and we do make
use of that now. Which means that suddenly we started synthesizing these
xattrs much more regularly.
Doing this actually does make sense, but only in very few cases:
not for the typical regular files we copy, but certainly when dealing
with disk images. Hence, let's keep this kind of propagation, but let's
make it a flag and default to off. Then turn it on whenever we deal with
disk images, and leave it off otherwise.
This is particularly relevant as overlayfs combining a real fs, and a
tmpfs on top will result in EOPNOTSUPP when it is attempted to open a
file with xattrs for writing, as tmpfs does not support xattrs, and
hence the copy-up cannot work. Hence, let's avoid synthesizing this
needlessly, to increase compat with overlayfs.
When chase_symlinks is given a root path, it is assumed that all
processed symlinks are restricted under that path. It should not
be necessary to verify components of that prefix path since they
are not relevant to the symlinks.
This change skips unsafe UID transitions in this root prefix, i.e.
it now ignores when an unprivileged user's directory contains a
root-owned directory above the symlink root.
When systemd retrieve the time zone it read what is in the file
/usr/share/zoneinfo/zone.tab provided by the Time Zone Database.
According to the comments in zone.tab its content is for backward-
compatibility aid for older programs. New programs should use
zone1970.tab. This patch replaces zone.tab with zone1970.tab.
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Balint Reczey
Yu Watanabe
David Michael
Ross Burton
Christopher Wong