fix(win32): use file handles for checking/modifying DACLs #9109
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/backport to stable-4.0 |
mgallien
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Nov 20, 2025
`GetFileSecurityW`/`SetFileSecurityW` can not deal with long paths, even with the special `\\?\` prefix. Since `CreateFileW` can deal with those paths just fine, refactor the handling of DACLs to make use of `GetSecurityInfo`/`SetSecurityInfo`. This change also resolves an issue seen in #8860 where the access denied ACE would be present more than once. Signed-off-by: Jyrki Gadinger <nilsding@nilsding.org>
…Win32 buffers Apparently std::unique_ptr can be made to work with `HANDLE`s and whatever buffers allocated from the Win32 API need to be freed. This allows for much cleaner and safer code. Some related articles on that topic from "The Old New Thing" blog: - "Confusing gotcha: PSECURITY_DESCRIPTOR is not a pointer to a SECURITY_DESCRIPTOR" (23rd of December 2015) https://devblogs.microsoft.com/oldnewthing/20151223-00/?p=92701 - "Why are HANDLE return values so inconsistent?" (2nd of March 2004) https://devblogs.microsoft.com/oldnewthing/20040302-00/?p=40443 Signed-off-by: Jyrki Gadinger <nilsding@nilsding.org>
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Artifact containing the AppImage: nextcloud-appimage-pr-9109.zip Digest: To test this change/fix you can download the above artifact file, unzip it, and run it. Please make sure to quit your existing Nextcloud app and backup your data. |
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mgallien
approved these changes
Nov 21, 2025
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GetFileSecurityW/SetFileSecurityWcan not deal with long paths, even with the special\\?\prefix.Since
CreateFileWcan deal with those paths just fine, refactor the handling of DACLs to make use of a file handle returned by it withGetSecurityInfo/SetSecurityInfo.This change also resolves an issue seen in #8860 where the access denied ACE would be present more than once.