BTLE: check connection_info presence before trying to perform reassembly

Bug: 13379
Change-Id: Idafa780f24bf9f181c0913cbe16a0cfa9bce382e
Reviewed-on: https://code.wireshark.org/review/19927
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
Petri-Dish: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 52 insertions, 48 deletions

diff --git a/epan/dissectors/packet-btle.c b/epan/dissectors/packet-btle.c
index 103fe45ec9..53e9f8e4a9 100644
--- a/epan/dissectors/packet-btle.c
+++ b/epan/dissectors/packet-btle.c
@@ -872,36 +872,38 @@ dissect_btle(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
         case 0x01: /* Continuation fragment of an L2CAP message, or an Empty PDU */
 /* TODO: Try reassemble cases 0x01 and 0x02 */
             if (length > 0) {
-                tvbuff_t *new_tvb;
+                tvbuff_t *new_tvb = NULL;
 
-                if ((!pinfo->fd->flags.visited) && (connection_info)) {
-                    if (connection_info->segmentation_started == 1) {
-                        connection_info->segment_len_rem = connection_info->segment_len_rem - length;
-                        if(connection_info->segment_len_rem > 0){
-                            btle_frame_info->more_fragments = 1;
-                        }
-                        else {
-                            btle_frame_info->more_fragments = 0;
-                            connection_info->segmentation_started = 0;
-                            connection_info->segment_len_rem = 0;
+                pinfo->fragmented = TRUE;
+                if (connection_info) {
+                    if (!pinfo->fd->flags.visited) {
+                        if (connection_info->segmentation_started == 1) {
+                            connection_info->segment_len_rem = connection_info->segment_len_rem - length;
+                            if(connection_info->segment_len_rem > 0){
+                                btle_frame_info->more_fragments = 1;
+                            }
+                            else {
+                                btle_frame_info->more_fragments = 0;
+                                connection_info->segmentation_started = 0;
+                                connection_info->segment_len_rem = 0;
+                            }
                         }
                     }
+                    frag_btl2cap_msg = fragment_add_seq_next(&btle_l2cap_msg_reassembly_table,
+                        tvb, offset,
+                        pinfo,
+                        connection_info->access_address,   /* guint32 ID for fragments belonging together */
+                        NULL,                              /* data* */
+                        length,                            /* Fragment length */
+                        btle_frame_info->more_fragments);  /* More fragments */
+
+                    new_tvb = process_reassembled_data(tvb, offset, pinfo,
+                        "Reassembled L2CAP",
+                        frag_btl2cap_msg,
+                        &btle_l2cap_msg_frag_items,
+                        NULL,
+                        btle_tree);
                 }
-                pinfo->fragmented = TRUE;
-                frag_btl2cap_msg = fragment_add_seq_next(&btle_l2cap_msg_reassembly_table,
-                    tvb, offset,
-                    pinfo,
-                    connection_info->access_address,   /* guint32 ID for fragments belonging together */
-                    NULL,                              /* data* */
-                    length,                            /* Fragment length */
-                    btle_frame_info->more_fragments);  /* More fragments */
-
-                new_tvb = process_reassembled_data(tvb, offset, pinfo,
-                    "Reassembled L2CAP",
-                    frag_btl2cap_msg,
-                    &btle_l2cap_msg_frag_items,
-                    NULL,
-                    btle_tree);
 
                 if (new_tvb) {
                     bthci_acl_data_t  *acl_data;
@@ -939,30 +941,32 @@ dissect_btle(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
                 gint le_frame_len = tvb_get_letohs(tvb, offset);
                 if (le_frame_len > length) {
 /* TODO: Try reassemble cases 0x01 and 0x02 */
-                    if ((!pinfo->fd->flags.visited) && (connection_info )){
-                        connection_info->segmentation_started = 1;
-                        /* The first two octets in the L2CAP PDU contain the length of the entire
-                         * L2CAP PDU in octets, excluding the Length and CID fields(4 octets).
-                         */
-                        connection_info->segment_len_rem = le_frame_len + 4 - length;
-                        btle_frame_info->more_fragments = 1;
-                    }
                     pinfo->fragmented = TRUE;
+                    if (connection_info) {
+                        if (!pinfo->fd->flags.visited) {
+                            connection_info->segmentation_started = 1;
+                            /* The first two octets in the L2CAP PDU contain the length of the entire
+                            * L2CAP PDU in octets, excluding the Length and CID fields(4 octets).
+                            */
+                            connection_info->segment_len_rem = le_frame_len + 4 - length;
+                            btle_frame_info->more_fragments = 1;
+                        }
 
-                    frag_btl2cap_msg = fragment_add_seq_next(&btle_l2cap_msg_reassembly_table,
-                        tvb, offset,
-                        pinfo,
-                        connection_info->access_address, /* guint32 ID for fragments belonging together */
-                        NULL,
-                        length, /* Fragment length */
-                        TRUE);  /* More fragments */
-
-                    process_reassembled_data(tvb, offset, pinfo,
-                        "Reassembled L2CAP",
-                        frag_btl2cap_msg,
-                        &btle_l2cap_msg_frag_items,
-                        NULL,
-                        btle_tree);
+                        frag_btl2cap_msg = fragment_add_seq_next(&btle_l2cap_msg_reassembly_table,
+                            tvb, offset,
+                            pinfo,
+                            connection_info->access_address, /* guint32 ID for fragments belonging together */
+                            NULL,
+                            length, /* Fragment length */
+                            TRUE);  /* More fragments */
+
+                        process_reassembled_data(tvb, offset, pinfo,
+                            "Reassembled L2CAP",
+                            frag_btl2cap_msg,
+                            &btle_l2cap_msg_frag_items,
+                            NULL,
+                            btle_tree);
+                    }
 
                     col_set_str(pinfo->cinfo, COL_INFO, "L2CAP Fragment Start");
                     proto_tree_add_item(btle_tree, hf_l2cap_fragment, tvb, offset, length, ENC_NA);