Signed-off-by: David Drysdale <redacted>
---
 man2/open.2 | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/man2/open.2 b/man2/open.2
index 3824ab5be1f0..ba0da01c1a4f 100644
--- a/man2/open.2
+++ b/man2/open.2

@@ -713,7 +713,7 @@ in a fully formed state (using
 as described above).
 .RE
 .IP
-.B O_TMPFILE
+.B O_TMPFILE " (since Linux 3.??)"
 requires support by the underlying filesystem;
 only a subset of Linux filesystems provide that support.
 In the initial implementation, support was provided in

@@ -723,6 +723,31 @@ XFS support was added
 .\" commit ab29743117f9f4c22ac44c13c1647fb24fb2bafe
 in Linux 3.15.
 .TP
+.B O_BENEATH_ONLY
+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, are cause the