For some syscalls the kernel ABI uses 32 bit signed integers. Whether
these 32 bit integer values are sign extended or zero extended to the
native 64 bit register sizes is undefined and dependent on the {arch,
compiler, libc} being used. Instead of trying to detect which cases
zero-extend and which cases sign-extend, this commit uses a masked
equality check on the lower 32 bits of the value.
The chown/chmod/rename syscalls have never existed on AArch64, and libc
implements the POSIX functions via the fchownat/fchmodat/renameat
syscalls instead.
Add new filter functions for fchownat/fchmodat/renameat, not made
architecture specific since the syscalls exists everywhere else too.
However, in order to limit seccomp filter space usage, we only insert
rules for one of {chown, chown32, fchownat} depending on the
architecture (resp. {chmod, fchmodat}, {rename, renameat}).
New glibc versions not sign-extending 32 bit negative constants seems to
not be a thing on AArch64. I suspect that this might not be the only
architecture where the sign-extensions is happening, and the correct fix
might be instead to use a proper 32 bit comparison for the first openat
parameter. For now, band-aid fix this so the sandbox can work again on
AArch64.
Not revalidating keys on every fork speeds up make test from about 45 seconds
to 10 seconds with OpenSSL 1.1.1n and from 6 minutes to 10 seconds with OpenSSL
3.0.2.
It came as a surprise that Serge, the bridge authority, omits the Running
flag for all bridges in its first 30 minutes after a restart:
https://bugs.torproject.org/tpo/anti-censorship/rdsys/102
The fix we're doing for now is to accept it as correct behavior in
Tor, and change all the supporting tools to be able to handle bridge
networkstatus docs that have no Running bridges.
I'm documenting it here inside Tor too so the next person might not
be so surprised.
This code was heavily reused from the previous DNS timeout work done in
ticket #40491 that was removed afterall from our code.
Closes#40560
Signed-off-by: David Goulet <dgoulet@torproject.org>
cat will always print "cat: test_network_log: Is a directory". change it to
head -n -0, which is arguably not the perfect format but is at least somewhat
useful.
