Allow the macOS sandbox to write in the /var/folders/ and /var/db/mds/ directories#4797
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kit-ty-kate merged 1 commit intoocaml:masterfrom Nov 4, 2025
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AltGr
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What's up with the macOS test? |
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I've sent a bug report to Apple about it btw. |
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Found it! |
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So sandbox check is failing, and it is removed from config file. |
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From tests, seems that this changes disable sandbox. |
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…mds/` directories It is required by some of macOS core tools such as security(1) and previous TMPDIR stored in /var/folders/*/*/T/ have been seen accessed by xcode in the wild on occasion. While the /var/folders/*/*/C/ directory contain things that are kept indefinitely, these files are in theory understood by applications to be writeable by anyone and thus not trusted. The mds subdirectory is a cache used to search for files in the system. Both of these are part of other tools that use sandbox-exec such as MacPorts. See for example: https://github.com/macports/macports-base/blob/2c6fc24ddd1d6961afa83c5b35be12224b6850f6/src/port1.0/portsandbox.tcl#L92
/var/folders/ and /var/db/mds/ directories
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Coping the new commit description: |
rjbou
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Discussed on dev meeting: The PR is good to go.
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ocaml-benchmarks is failing with no log, it's out of the scope of this PR. |
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The ocaml-benchmark failure comes from ocaml/infrastructure#179. Ignoring. |
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This is an attempt at fixing #4389
Fixes discuss.ocaml.org#17407
I've used
dtraceon/usr/bin/securitybut I still can't find the exact point where something is written in that directory.It looks related to something in
/private/var/db/mds, probably a symlink to/private/var/folders.In any case i've looked around and realized that macports had similar things so maybe it makes sense(?). They also have other things but I'm not sure we should allow even more: https://github.com/macports/macports-base/blob/2c6fc24ddd1d6961afa83c5b35be12224b6850f6/src/port1.0/portsandbox.tcl#L92
All in all I have no idea what this directory is supposed to be in the context of
/usr/bin/security. Their commit adding it doesn't say anything either: macports/macports-base@e3eceeaSeveral blog posts in the wild are also trying to understand what's up with this directory:
hier(7)says it's "per-user temporary files and caches", so allowing writes like macports does doesn't seem right to me.However, I found out (late into writing this PR even ^^") that if we forbid reads into that directory,
/usr/bin/securitywon't try to write in it and still succeeds.This is most likely a bug in macOS itself but there we are!
cc @hannesm
Backported to the 2.5 branch in #6775