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MacOS Catalina: Slow by Design?

(sigpipe.macromates.com)
2031 points jrk | 3 comments | | HN request time: 0s | source
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usmannk ◴[] No.23275922[source]
It seems like there is a lot of confusion here as to whether this is real or not. I've been able to confirm the behavior in the post by:

- Using a new, random executable. Even echo $rand_int will work. Edit: What I mean here is generate your rand int beforehand and statically include it in your script.

- Using a fresh filename too. Just throw a rand int at the end there. e.g. /tmp/test4329.sh

I MITMd myself while recording the network traffic and, sure enough, there is a request to ocsp.apple.com with a hash in the URL path and a bunch of binary data in the response body. Unsure what it is yet but the URL suggests it is generating a cert for the binary and checking it. See: https://en.wikipedia.org/wiki/Online_Certificate_Status_Prot...

Here's the URL I saw:

http://ocsp.apple.com/ocsp-devid01/ME4wTKADAgEAMEUwQzBBMAkGB...

Edit2: Anyone know what this hash format is? It's not quite base64, nor is it multiple base64 strings separated with '+'s but it seems similar...

Edit3: Here is the exact filename and file I used: https://gist.github.com/UsmannK/abb4b239c98ee45bdfcc5b284bf0...

Edit4 (final one probably...): On subsequent attempts I'm only seeing a request to https://api.apple-cloudkit.com and not the OCSP one anymore. Curiously, there's no headers at all. It is just checking for connectivity.

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varenc ◴[] No.23278258[source]
Here's some shell script to use a random file name and have friendlier output.

  RAND_FILE="/tmp/test-$RANDOM.sh";
  time_helper() { /usr/bin/time $RAND_FILE 2>&1 | tail -1 | awk '{print $1}'; }  # this just returns the real run time
  echo $'#!/bin/sh\necho Hello' $RANDOM > $RAND_FILE && chmod a+x  $RAND_FILE;
  echo "Testing $RAND_FILE";
  echo "execution time #1: $(time_helper) seconds";
  echo "execution time #2: $(time_helper) seconds";
Introducing a network delay makes the effect much more obvious. Normally I see a delay of about 0.1 seconds, but after using the XCode network link conditioner (pf rules) to add 500ms latency to everything the delay shoots way up to ~2 seconds.

example output:

  Testing /tmp/test-24411.sh
  execution time #1: 2.32 seconds
  execution time #2: 0.00 seconds
with developer tools checked both executions report "0.0 seconds".
replies(2): >>23279897 #>>23281106 #
varenc ◴[] No.23281106[source]
I tried just blocking "api.apple-cloudkit.com" with /etc/hosts. This reduces the delay but doesn't eliminate it. A connection attempt is still made every time. (I don't recommend making this change permanent. Just give your terminal app the "Developers Tools" permission instead)

After blocking that domain I can see that tccd and syspolicyd are logging some error messages to the console related to the failed connection. I don't recommend blocking because my guess is that'll put syspolicyd/tccd in some unexpected state and they'll repeatedly keep trying to make requests.

Try this for watching security related console log messages:

  sudo log stream --debug --info --predicate "processImagePath contains 'tccd' OR processImagePath contains 'syspolicyd' OR processImagePath Contains[c] 'taskgated' OR processImagePath contains 'trustd' OR eventMessage Contains[c] 'malware' OR senderImagePath Contains[c] 'security' "
syspolicyd explicitly logs when it makes the network request.

   syspolicyd: cloudkit record fetch: https://api.apple-cloudkit.com/database/1/com.apple.gk.ticket-delivery/production/public/records/lookup, 2/2/23de35......
(you need to enable private logging to see that url)
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1. saagarjha ◴[] No.23281380{3}[source]
Enabling private logging is fairly annoying these days, unfortunately. (Interestingly, if macOS thinks you're AppleInternal, it will make it just as annoying to disable private logging…)
replies(1): >>23281632 #
2. varenc ◴[] No.23281632[source]
wait a sec...I recognize that name. I only know how to enable private logging thanks to your detailed and informative blog post! Seriously, it's one of the favorite macOS things I've read in a while. I loved the step by step walk through using gdb you showed.

Though just today I saw that apparently an enterprise policy config can enable private logging in 10.15.3+ without having to disable SIP. https://georgegarside.com/blog/macos/sierra-console-private/

For reference for others: this is the blog post by OP on enabling private logging in Catalina. check it out! https://saagarjha.com/blog/2019/09/29/making-os-log-public-o...

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3. saagarjha ◴[] No.23289953[source]
I’m glad you appreciated it, but I think it also happened to be some of the fastest-to-deteriorate advice I’ve given :) I should go back and revisit this, as on my system I have it currently stuck in a state where it unconditionally enables private data logging at boot (which mean my crash logs have personal information in them unless I remember to turn it off with the workaround I’ve been using until now…)