From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Drysdale Subject: [PATCH man-pages 3/3] open.2: describe O_BENEATH flag Date: Mon, 3 Nov 2014 11:48:25 +0000 Message-ID: <1415015305-15494-4-git-send-email-drysdale@google.com> References: <1415015305-15494-1-git-send-email-drysdale@google.com> Return-path: In-Reply-To: <1415015305-15494-1-git-send-email-drysdale-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Alexander Viro , Kees Cook Cc: Greg Kroah-Hartman , Meredydd Luff , Will Drewry , Jorge Lucangeli Obes , Ricky Zhou , Lee Campbell , Julien Tinnes , Mike Depinet , James Morris , Andy Lutomirski , Paolo Bonzini , Paul Moore , Christoph Hellwig , "Eric W. Biederman" , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Drysdale List-Id: linux-api@vger.kernel.org Signed-off-by: David Drysdale --- man2/open.2 | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/man2/open.2 b/man2/open.2 index abc3c35b8b3a..495c7f1e81a4 100644 --- a/man2/open.2 +++ b/man2/open.2 @@ -716,6 +716,31 @@ XFS support was added .\" commit ab29743117f9f4c22ac44c13c1647fb24fb2bafe in Linux 3.15. .TP +.B O_BENEATH " (since Linux 3.??)" +Ensure that the +.I pathname +is beneath the current working directory (for +.BR open (2)) +or the +.I dirfd +(for +.BR openat (2)). +If the +.I pathname +is absolute or contains a path component of "..", the +.BR open () +fails with the error +.BR EACCES. +This occurs even if ".." path component would not actually +escape the original directory; for example, a +.I pathname +of "subdir/../filename" would be rejected. +Path components that are symbolic links to absolute paths, or that are +relative paths containing a ".." component, will also cause the +.BR open () +operation to fail with the error +.BR EACCES. +.TP .B O_TRUNC If the file already exists and is a regular file and the access mode allows writing (i.e., is @@ -792,7 +817,11 @@ The requested access to the file is not allowed, or search permission is denied for one of the directories in the path prefix of .IR pathname , or the file did not exist yet and write access to the parent directory -is not allowed. +is not allowed, or the +.B O_BENEATH +flag was specified and the +.I pathname +was not beneath the relevant directory. (See also .BR path_resolution (7).) .TP -- 2.1.0.rc2.206.gedb03e5