[haiku-bugs] Re: [Haiku] #6750: chmod is broken for non-superuser
- From: "bonefish" <trac@xxxxxxxxxxxx>
- Date: Wed, 10 Nov 2010 16:44:22 -0000
#6750: chmod is broken for non-superuser
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Reporter: grahamh | Owner: axeld
Type: bug | Status: closed
Priority: normal | Milestone: R1
Component: File Systems/BFS | Version: R1/Development
Resolution: fixed | Keywords: chmod, write_stat
Blocked By: | Has a Patch: 1
Platform: All | Blocking:
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Comment (by bonefish):
Replying to [comment:17 axeld]:
> Applied in r39378, and r39379, thanks a lot Rohit Yadav!
>
> To Ingo: the check_access() a.k.a. CheckPermissions() function could
easily be a VFS delivered utility function.
Sure.
> BTW there is at least one functional difference between the previous
version in BFS: before, root could always enter a directory, no matter if
any X was set. In your version, that is no longer possible; I would assume
the former version is the correct one, though.
Possibly. At least it's what one might expect and what e.g. Linux does.
But
[http://www.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_04
POSIX says]:
"If a process has appropriate privileges: [...] If execute permission is
requested, access shall be granted if execute permission is granted to at
least one user by the file permission bits or by an alternate access
control mechanism; otherwise, access shall be denied."
At least if one ties directory entry resolution to the execute permission,
it would be correct to also deny root the access when none of the X bits
is set.
Anyway, I only claimed that I got the permission handling in
`write_stat()` right, not everywhere. :-) E.g. `access()` is wrong for
sure as the standard requires to use the real user and group IDs for the
check. If we want to support the `faccessat()` `AT_EACCESS` flag, we have
to change the hook signature anyway, though (e.g. pass the user and group
IDs).
--
Ticket URL: <http://dev.haiku-os.org/ticket/6750#comment:19>
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