This release includes a few fixes for MkdirAll when dealing with S_ISUID and S_ISGID, to solve a regression runc hit when switching to MkdirAll.

• Passing the S_ISUID or S_ISGID modes to MkdirAllInRoot will now return an explicit error saying that those bits are ignored by mkdirat(2). In the past a different error was returned, but since the silent ignoring behaviour is codified in the man pages a more explicit error seems apt. While silently ignoring these bits would be the most compatible option, it could lead to users thinking their code sets these bits when it doesn't. Programs that need to deal with compatibility can mask the bits themselves. (#23, #25)

• If a directory has S_ISGID set, then all child directories will have S_ISGID set when created and a different gid will be used for any inode created under the directory. Previously, the "expected owner and mode" validation in securejoin.MkdirAll did not correctly handle this. We now correctly handle this case. (#24, #25)

Signed-off-by: Aleksa Sarai cyphar@cyphar.com