Base: Clarify and extend unveil(2) man page

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Max Wipfli 2021-06-06 23:29:17 +02:00 committed by Andreas Kling
parent 573664758a
commit 73084835da

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@ -32,15 +32,23 @@ include the following characters:
A single `unveil()` call may specify multiple permission characters at once.
Subsequent `unveil()` calls may take away permissions from the ones allowed
earlier for the same file. Note that unveiling a path with any set of
permissions does not turn off the regular permission checks: access to a file
which the process has unveiled for itself, but has otherwise no appropriate
permissions for, will still be rejected. Unveiling a directory allows the
process to access any files inside the directory.
earlier for the same file or directory. Note that it remains possible to unveil
subdirectories with any permissions.
Note that unveiling a path with any set of permissions does not turn off the
regular permission checks: access to a file which the process has unveiled for
itself, but has otherwise no appropriate permissions for, will still be rejected.
Unveiling a directory allows the process to access any files inside the
directory.
Calling `unveil()` with both `path` and `permissions` set to null locks the
veil; no further `unveil()` calls are allowed after that.
veil; no further `unveil()` calls are allowed after that. Although `unveil()`
calls start to take effect the moment they are made, until the veil is locked,
it remains possible to sometimes circumvent the restrictions set by unveiling
files and directories contained inside a restricted directory with different
permissions.
When a process calls `fork()`, the unveil state is copied to the new process.
The veil state is reset after the program successfully performs an `execve()`
call.