Remove unnecessary tvb_ensure_bytes_exist calls.

All of the calls removed are followed by proto_tree_add_xxx calls of the same offset/length of the tvb_ensure_bytes_exist call.  The proto_tree_add_xxx calls should throw the exception, so we don't need the "double check".
There are probably more calls that can be removed, these were just obvious as first glance, spurred mostly by noticing the (ab)use in packet-wsp.c

Change-Id: I37cee347c8cf8ab0559e21562c802d3b37f4871e
Reviewed-on: https://code.wireshark.org/review/4833
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

1 files changed, 1 insertions, 21 deletions

diff --git a/epan/dissectors/packet-dcerpc.c b/epan/dissectors/packet-dcerpc.c
index 6bf658b058..941725cb49 100644
--- a/epan/dissectors/packet-dcerpc.c
+++ b/epan/dissectors/packet-dcerpc.c
@@ -1183,7 +1183,6 @@ static void dissect_auth_verf(tvbuff_t *auth_tvb, packet_info *pinfo,
     if (fn)
         fn(auth_tvb, 0, pinfo, tree, &di, hdr->drep);
     else {
-        tvb_ensure_bytes_exist(auth_tvb, 0, hdr->auth_len);
         proto_tree_add_text(tree, auth_tvb, 0, hdr->auth_len,
                             "%s Verifier",
                             val_to_str(auth_info->auth_type,
@@ -1923,8 +1922,7 @@ dissect_ndr_byte_array(tvbuff_t *tvb, int offset, packet_info *pinfo,
                                   hf_dcerpc_array_actual_count, &len);
 
     DISSECTOR_ASSERT(len <= G_MAXUINT32);
-    if (tree && len) {
-        tvb_ensure_bytes_exist(tvb, offset, (guint32)len);
+    if (len) {
         proto_tree_add_item(tree, di->hf_index, tvb, offset, (guint32)len,
                             ENC_NA);
     }
@@ -2515,7 +2513,6 @@ dissect_ndr_pointer_cb(tvbuff_t *tvb, gint offset, packet_info *pinfo,
         /* get the referent id */
         offset = dissect_ndr_uint3264(tvb, offset, pinfo, NULL, di, drep, -1, &id);
 
-        tvb_ensure_bytes_exist(tvb, offset-pointer_size, pointer_size);
         /* we got a NULL pointer */
         if (id == 0) {
             proto_tree_add_text(tree, tvb, offset-pointer_size,
@@ -2560,7 +2557,6 @@ dissect_ndr_pointer_cb(tvbuff_t *tvb, gint offset, packet_info *pinfo,
         /* get the referent id */
         offset = dissect_ndr_uint3264(tvb, offset, pinfo, NULL, di, drep, -1, &id);
 
-        tvb_ensure_bytes_exist(tvb, offset-pointer_size, pointer_size);
         /* we got a NULL pointer */
         if (id == 0) {
             proto_tree_add_text(tree, tvb, offset-pointer_size,
@@ -2594,7 +2590,6 @@ dissect_ndr_pointer_cb(tvbuff_t *tvb, gint offset, packet_info *pinfo,
         /* get the referent id */
         offset = dissect_ndr_uint3264(tvb, offset, pinfo, NULL, di, drep, -1, &id);
 
-        tvb_ensure_bytes_exist(tvb, offset-pointer_size, pointer_size);
         /* new pointer */
         tr = proto_tree_add_subtree(tree, tvb, offset-pointer_size,
                                  pointer_size,
@@ -2620,7 +2615,6 @@ dissect_ndr_pointer_cb(tvbuff_t *tvb, gint offset, packet_info *pinfo,
         /* get the referent id */
         offset = dissect_ndr_uint3264(tvb, offset, pinfo, NULL, di, drep, -1, &id);
 
-        tvb_ensure_bytes_exist(tvb, offset-pointer_size, pointer_size);
         /* we got a NULL pointer */
         if (id == 0) {
             proto_tree_add_text(tree, tvb, offset-pointer_size,
@@ -2655,7 +2649,6 @@ dissect_ndr_pointer_cb(tvbuff_t *tvb, gint offset, packet_info *pinfo,
         /* get the referent id */
         offset = dissect_ndr_uint3264(tvb, offset, pinfo, NULL, di, drep, -1, &id);
 
-        tvb_ensure_bytes_exist(tvb, offset-pointer_size, pointer_size);
         /* we got a NULL pointer */
         if (id == 0) {
             proto_tree_add_text(tree, tvb, offset-pointer_size,
@@ -2775,27 +2768,23 @@ show_stub_data(tvbuff_t *tvb, gint offset, proto_tree *dcerpc_tree,
         if ((auth_info != NULL) &&
             (auth_info->auth_level == DCE_C_AUTHN_LEVEL_PKT_PRIVACY)) {
             if (is_encrypted) {
-                tvb_ensure_bytes_exist(tvb, offset, length);
                 proto_tree_add_text(dcerpc_tree, tvb, offset, length,
                                     "Encrypted stub data (%d byte%s)",
                                     length, plurality(length, "", "s"));
                 /* is the padding is still inside the encrypted blob, don't display it explicit */
                 auth_pad_len = 0;
             } else {
-                tvb_ensure_bytes_exist(tvb, offset, plain_length);
                 proto_tree_add_text(dcerpc_tree, tvb, offset, plain_length,
                                     "Decrypted stub data (%d byte%s)",
                                     plain_length, plurality(plain_length, "", "s"));
             }
         } else {
-            tvb_ensure_bytes_exist(tvb, offset, plain_length);
             proto_tree_add_text(dcerpc_tree, tvb, offset, plain_length,
                                 "Stub data (%d byte%s)", plain_length,
                                 plurality(plain_length, "", "s"));
         }
         /* If there is auth padding at the end of the stub, display it */
         if (auth_pad_len != 0) {
-            tvb_ensure_bytes_exist(tvb, auth_pad_offset, auth_pad_len);
             proto_tree_add_text(dcerpc_tree, tvb, auth_pad_offset,
                                 auth_pad_len,
                                 "Auth Padding (%u byte%s)",
@@ -3025,7 +3014,6 @@ dcerpc_try_handoff(packet_info *pinfo, proto_tree *tree,
 
             /* If there is auth padding at the end of the stub, display it */
             if (auth_pad_len != 0) {
-                tvb_ensure_bytes_exist(tvb, auth_pad_offset, auth_pad_len);
                 proto_tree_add_text(sub_tree, decrypted_tvb, auth_pad_offset,
                                     auth_pad_len,
                                     "Auth Padding (%u byte%s)",
@@ -3083,7 +3071,6 @@ dissect_dcerpc_verifier(tvbuff_t *tvb, packet_info *pinfo,
                 show_exception(auth_tvb, pinfo, dcerpc_tree, EXCEPT_CODE, GET_MESSAGE);
             } ENDTRY;
         } else {
-            tvb_ensure_bytes_exist(tvb, 0, hdr->auth_len);
             proto_tree_add_text(dcerpc_tree, auth_tvb, 0, hdr->auth_len,
                                 "Auth Verifier");
         }
@@ -3444,7 +3431,6 @@ dissect_dcerpc_cn_bind_ack(tvbuff_t *tvb, gint offset, packet_info *pinfo,
     offset = dissect_dcerpc_uint16(tvb, offset, pinfo, dcerpc_tree, hdr->drep,
                                    hf_dcerpc_cn_sec_addr_len, &sec_addr_len);
     if (sec_addr_len != 0) {
-        tvb_ensure_bytes_exist(tvb, offset, sec_addr_len);
         proto_tree_add_item(dcerpc_tree, hf_dcerpc_cn_sec_addr, tvb, offset,
                             sec_addr_len, ENC_ASCII|ENC_NA);
         offset += sec_addr_len;
@@ -4267,7 +4253,6 @@ dissect_dcerpc_cn_fault(tvbuff_t *tvb, gint offset, packet_info *pinfo,
                      */
                     if (dcerpc_tree) {
                         if (stub_length > 0) {
-                            tvb_ensure_bytes_exist(tvb, offset, stub_length);
                             proto_tree_add_text(dcerpc_tree, tvb, offset, stub_length,
                                                 "Fault stub data (%d byte%s)",
                                                 stub_length,
@@ -4278,7 +4263,6 @@ dissect_dcerpc_cn_fault(tvbuff_t *tvb, gint offset, packet_info *pinfo,
                     /* PDU is fragmented and this isn't the first fragment */
                     if (dcerpc_tree) {
                         if (stub_length > 0) {
-                            tvb_ensure_bytes_exist(tvb, offset, stub_length);
                             proto_tree_add_text(dcerpc_tree, tvb, offset, stub_length,
                                                 "Fragment data (%d byte%s)",
                                                 stub_length,
@@ -4293,7 +4277,6 @@ dissect_dcerpc_cn_fault(tvbuff_t *tvb, gint offset, packet_info *pinfo,
                    third means we can attempt reassembly. */
                 if (dcerpc_tree) {
                     if (length > 0) {
-                        tvb_ensure_bytes_exist(tvb, offset, stub_length);
                         proto_tree_add_text(dcerpc_tree, tvb, offset, stub_length,
                                             "Fragment data (%d byte%s)",
                                             stub_length,
@@ -4340,7 +4323,6 @@ dissect_dcerpc_cn_fault(tvbuff_t *tvb, gint offset, packet_info *pinfo,
                              */
                             if (dcerpc_tree) {
                                 if (length > 0) {
-                                    tvb_ensure_bytes_exist(tvb, offset, stub_length);
                                     proto_tree_add_text(dcerpc_tree, tvb, offset, stub_length,
                                                         "Fault stub data (%d byte%s)",
                                                         stub_length,
@@ -5315,7 +5297,6 @@ dissect_dcerpc_dg_stub(tvbuff_t *tvb, int offset, packet_info *pinfo,
             /* PDU is fragmented and this isn't the first fragment */
             if (dcerpc_tree) {
                 if (length > 0) {
-                    tvb_ensure_bytes_exist(tvb, offset, stub_length);
                     proto_tree_add_text(dcerpc_tree, tvb, offset, stub_length,
                                         "Fragment data (%d byte%s)",
                                         stub_length,
@@ -5330,7 +5311,6 @@ dissect_dcerpc_dg_stub(tvbuff_t *tvb, int offset, packet_info *pinfo,
            third means we can attempt reassembly. */
         if (dcerpc_tree) {
             if (length > 0) {
-                tvb_ensure_bytes_exist(tvb, offset, stub_length);
                 proto_tree_add_text(dcerpc_tree, tvb, offset, stub_length,
                                     "Fragment data (%d byte%s)", stub_length,
                                     plurality(stub_length, "", "s"));