[ovs-dev] [PATCH 14/22] ofp-util: Allow out-of-range indexes in ofputil_decode_geneve_table_reply().

[Ben Pfaff]

Otherwise, if some future version of OVS supports more Geneve options than
the current version, and any of these extras are in use, then one would be
unable to dump them with "ovs-ofctl dump-geneve-map", and any other
OVS-based software that wants to dump the Geneve map to work with the
existing options (i.e. ovn-controller) would fail entirely, instead of
being able to work with at least a subset.

Signed-off-by: Ben Pfaff <b...@nicira.com>
---
 lib/ofp-util.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/lib/ofp-util.c b/lib/ofp-util.c
index 7e2ee4b..cdb8553 100644
--- a/lib/ofp-util.c
+++ b/lib/ofp-util.c
@@ -9178,7 +9178,8 @@ ofputil_encode_geneve_table_mod(enum ofp_version 
ofp_version,
 }
 
 static enum ofperr
-decode_geneve_table_mappings(struct ofpbuf *msg, struct ovs_list *mappings)
+decode_geneve_table_mappings(struct ofpbuf *msg, unsigned int max_fields,
+                             struct ovs_list *mappings)
 {
     list_init(mappings);
 
@@ -9204,10 +9205,10 @@ decode_geneve_table_mappings(struct ofpbuf *msg, struct 
ovs_list *mappings)
         }
 
         map->index = ntohs(nx_map->index);
-        if (map->index >= TUN_METADATA_NUM_OPTS) {
+        if (map->index >= max_fields) {
             VLOG_WARN_RL(&bad_ofmsg_rl,
                          "geneve table field index (%u) is too large (max %u)",
-                         map->index, TUN_METADATA_NUM_OPTS - 1);
+                         map->index, max_fields - 1);
             ofputil_uninit_geneve_table(mappings);
             return OFPERR_NXGTMFC_BAD_FIELD_IDX;
         }
@@ -9235,7 +9236,8 @@ ofputil_decode_geneve_table_mod(const struct ofp_header 
*oh,
         return OFPERR_NXGTMFC_BAD_COMMAND;
     }
 
-    return decode_geneve_table_mappings(&msg, &gtm->mappings);
+    return decode_geneve_table_mappings(&msg, TUN_METADATA_NUM_OPTS,
+                                        &gtm->mappings);
 }
 
 struct ofpbuf *
@@ -9255,6 +9257,12 @@ ofputil_encode_geneve_table_reply(const struct 
ofp_header *oh,
     return b;
 }
 
+/* Decodes the NXT_GENEVE_TABLE_REPLY message in 'oh' into '*gtr'.  Returns 0
+ * if successful, otherwise an ofperr.
+ *
+ * The decoder verifies that the indexes in 'gtr->mappings' are less than
+ * 'gtr->max_fields', but the caller must ensure, if necessary, that they are
+ * less than TUN_METADATA_NUM_OPTS. */
 enum ofperr
 ofputil_decode_geneve_table_reply(const struct ofp_header *oh,
                                   struct ofputil_geneve_table_reply *gtr)
@@ -9269,7 +9277,7 @@ ofputil_decode_geneve_table_reply(const struct ofp_header 
*oh,
     gtr->max_option_space = ntohl(nx_gtr->max_option_space);
     gtr->max_fields = ntohs(nx_gtr->max_fields);
 
-    return decode_geneve_table_mappings(&msg, &gtr->mappings);
+    return decode_geneve_table_mappings(&msg, gtr->max_fields, &gtr->mappings);
 }
 
 void
-- 
2.1.3

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