nextcloud
Opt-in to Arm MTE / MIE
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Feature request
Opt in to Arm MTE aka Memory Integrity Enforcement (MIE.
MTE is an easy security improvement (at least for users with iPhone 17, which have the hardware for MTE). To do so, you need to set the appropriate entitlement: https://developer.apple.com/documentation/xcode/enabling-enhanced-security-for-your-app
Nextcloud parses potentially attacker controlled data, so enabling MTE/MIE is an easy defense-in-depth.
Important: before enabling MIE in production, you need to thoroughly test on an iPhone 17 that there are no crashes! If there are crashes "caused" by MTE, these need to be fixed. Note that these crashes are present even without MTE, MTE just makes them visible. So MTE is also a useful bug finding tool.
For background on MTE/MIE, see:
- Apple announcement: security.apple.com/blog/memory-integrity-enforcement/
- iOS docs: https://developer.apple.com/documentation/xcode/enabling-enhanced-security-for-your-app
- My blog post :innocent: : https://thore.io/posts/2025/09/introduction-to-arm-memory-tagging-extensions/
For Nextcloud Files for Android I made a PR: https://github.com/nextcloud/android/pull/15661
