seccomp: allow personality with UNAME26 bit set

From personality(2):

    Have uname(2) report a 2.6.40+ version number rather than a 3.x version
    number.  Added as a stopgap measure to support broken applications that
    could not handle the  kernel  version-numbering  switch  from 2.6.x to 3.x.

This allows both "UNAME26|PER_LINUX" and "UNAME26|PER_LINUX32".

Fixes: "setarch broken in docker packages from Debian stretch"

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

contrib/seccomp/seccomp_default.go

@@ -412,6 +412,28 @@ func DefaultProfile(sp *specs.Spec) *specs.LinuxSeccomp {
 				},
 			},
 		},
+		{
+			Names:  []string{"personality"},
+			Action: specs.ActAllow,
+			Args: []specs.LinuxSeccompArg{
+				{
+					Index: 0,
+					Value: 0x20000,
+					Op:    specs.OpEqualTo,
+				},
+			},
+		},
+		{
+			Names:  []string{"personality"},
+			Action: specs.ActAllow,
+			Args: []specs.LinuxSeccompArg{
+				{
+					Index: 0,
+					Value: 0x20008,
+					Op:    specs.OpEqualTo,
+				},
+			},
+		},
 		{
 			Names:  []string{"personality"},
 			Action: specs.ActAllow,