oscore: Small bug fixes.

- Rename Key ID Context header field.
- Account for ID Context in max info length calculation.

Change-Id: I6f61055dba74294ace275eb852e34ea6caa32627
Reviewed-on: https://code.wireshark.org/review/37642
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/epan/dissectors/packet-oscore.c b/epan/dissectors/packet-oscore.c
index 019fc34448..892694ab1b 100644
--- a/epan/dissectors/packet-oscore.c
+++ b/epan/dissectors/packet-oscore.c
@@ -93,11 +93,13 @@ UAT_VS_DEF(oscore_context_uat, algorithm, oscore_context_t, cose_aead_alg_t, COS
 #define OSCORE_PIV_MAX_LEN              5 /* upper bound specified in the draft */
 #define OSCORE_KID_MAX_LEN_CCM_STAR     7 /* upper bound on KID for AES-CCM-16-64-128 (CCM*) */
 #define OSCORE_KID_MAX_LEN              OSCORE_KID_MAX_LEN_CCM_STAR /* upper bound on KID coming from the default algorithm implemented */
+#define OSCORE_KID_CONTEXT_MAX_LEN      64
 
 /* Helper macros to correctly size the statically allocated buffers and verify if an overflow occured */
 
 #define OSCORE_INFO_MAX_LEN             (1 + /* max return of cborencoder_put_array() */             \
                                         2 + OSCORE_KID_MAX_LEN + /* max 2 to encode length, KID following */ \
+                                        2 + OSCORE_KID_CONTEXT_MAX_LEN + /* length + KID CONTEXT */ \
                                         2 + /* max return of cborencoder_put_unsigned() */          \
                                         2 + 3 + /* max 2 to encode length, "Key" following */       \
                                         2 /* max return of cborencoder_put_unsigned() */            )
@@ -217,14 +219,18 @@ static gboolean oscore_context_update_cb(void *r, char **err) {
         return FALSE;
     }
 
-    /* No max length check on ID Context. We use GByteArray to allocate memory
-     * and pass it to the context derivation routine */
     if (hex_str_to_bytes(rec->id_context_prefs, bytes, FALSE) == FALSE) {
         *err = g_strdup("ID Context is invalid.");
         g_byte_array_free(bytes, TRUE);
         return FALSE;
     }
 
+    if (bytes->len > OSCORE_KID_CONTEXT_MAX_LEN) {
+        *err = g_strdup_printf("Should be %u bytes or less.", OSCORE_KID_CONTEXT_MAX_LEN);
+        g_byte_array_free(bytes, TRUE);
+        return FALSE;
+    }
+
     if (hex_str_to_bytes(rec->master_secret_prefs, bytes, FALSE) == FALSE) {
         *err = g_strdup("Master Secret is invalid.");
         g_byte_array_free(bytes, TRUE);