ioam6: improve checks on user data

This patch improves two checks on user data.

The first one prevents bit 23 from being set, as specified by RFC 9197
(Sec 4.4.1):

  Bit 23    Reserved; MUST be set to zero upon transmission and be
            ignored upon receipt.  This bit is reserved to allow for
            future extensions of the IOAM Trace-Type bit field.

The second one checks that the tunnel destination address !=
IPV6_ADDR_ANY, just like we already do for the tunnel source address.

Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Link: https://patch.msgid.link/20240830191919.51439-1-justin.iurman@uliege.be
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c
index e34e1ff24546d0a9708a8393739ab7f83fc7d18d..beb6b4cfc551cf603f2d9234493b0c00cb26aee1 100644 (file)
--- a/net/ipv6/ioam6_iptunnel.c
+++ b/net/ipv6/ioam6_iptunnel.c
@@ -89,7 +89,7 @@ static bool ioam6_validate_trace_hdr(struct ioam6_trace_hdr *trace)
            trace->type.bit12 | trace->type.bit13 | trace->type.bit14 |
            trace->type.bit15 | trace->type.bit16 | trace->type.bit17 |
            trace->type.bit18 | trace->type.bit19 | trace->type.bit20 |
-           trace->type.bit21)
+           trace->type.bit21 | trace->type.bit23)
                return false;
 
        trace->nodelen = 0;
@@ -199,9 +199,17 @@ static int ioam6_build_state(struct net *net, struct nlattr *nla,
                }
        }
 
-       if (tb[IOAM6_IPTUNNEL_DST])
+       if (tb[IOAM6_IPTUNNEL_DST]) {
                ilwt->tundst = nla_get_in6_addr(tb[IOAM6_IPTUNNEL_DST]);
 
+               if (ipv6_addr_any(&ilwt->tundst)) {
+                       NL_SET_ERR_MSG_ATTR(extack, tb[IOAM6_IPTUNNEL_DST],
+                                           "invalid tunnel dest address");
+                       err = -EINVAL;
+                       goto free_cache;
+               }
+       }
+
        tuninfo = ioam6_lwt_info(lwt);
        tuninfo->eh.hdrlen = ((sizeof(*tuninfo) + len_aligned) >> 3) - 1;
        tuninfo->pad[0] = IPV6_TLV_PADN;