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, 10 insertions, 70 deletions

diff --git a/epan/dissectors/packet-mikey.c b/epan/dissectors/packet-mikey.c
index 4a8f524b59..06beba3401 100644
--- a/epan/dissectors/packet-mikey.c
+++ b/epan/dissectors/packet-mikey.c
@@ -646,8 +646,6 @@ add_next_payload(tvbuff_t *tvb, proto_tree *tree, int offset)
 static int
 dissect_payload_cs_id_srtp(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_,  proto_tree *tree)
 {
-	tvb_ensure_bytes_exist(tvb, 0, 9);
-
 	if (tree) {
 		proto_item *id_ti;
 		proto_tree *id_tree;
@@ -750,7 +748,6 @@ dissect_payload_kemac(mikey_t *mikey, tvbuff_t *tvb, packet_info *pinfo, proto_t
 	guint16	mac_length;
 	guint8	mac_alg;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 4);
 	encr_alg    = tvb_get_guint8(tvb, offset+1);
 	encr_length = tvb_get_ntohs(tvb, offset+2);
 	tvb_ensure_bytes_exist(tvb, offset+4, encr_length+1);
@@ -788,10 +785,7 @@ dissect_payload_kemac(mikey_t *mikey, tvbuff_t *tvb, packet_info *pinfo, proto_t
 		return 0;
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+4+encr_length+1, mac_length);
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_KEMAC_MAC], tvb, 4+encr_length+1, mac_length, ENC_NA);
-	}
+	proto_tree_add_item(tree, hf_mikey[POS_KEMAC_MAC], tvb, 4+encr_length+1, mac_length, ENC_NA);
 
 	return 4+encr_length+1+mac_length;
 }
@@ -802,7 +796,6 @@ dissect_payload_pke(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, p
 	int	offset = 0;
 	guint16 length;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 3);
 	length = tvb_get_ntohs(tvb, offset+1) &0x3ff;
 
 	if (tree) {
@@ -811,10 +804,7 @@ dissect_payload_pke(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, p
 		proto_tree_add_item(tree, hf_mikey[POS_PKE_DATA_LEN], tvb, 1, 2, ENC_BIG_ENDIAN);
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+3, length);
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_PKE_DATA], tvb, 3, length, ENC_NA);
-	}
+	proto_tree_add_item(tree, hf_mikey[POS_PKE_DATA], tvb, 3, length, ENC_NA);
 	return 3 + length;
 }
 
@@ -826,7 +816,6 @@ dissect_payload_dh(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pr
 	int    dh_length;
 	guint8 kv;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 2);
 	dh_group = tvb_get_guint8(tvb, offset+1);
 
 	switch (dh_group) {
@@ -843,7 +832,6 @@ dissect_payload_dh(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pr
 		return 0;
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+2, dh_length+1);
 	kv = tvb_get_guint8(tvb, offset+2+dh_length) & 0x0f;
 
 	if (tree) {
@@ -866,7 +854,6 @@ dissect_payload_sign(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_,
 	int	offset = 0;
 	guint16 length;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 2);
 	length = ((tvb_get_guint8(tvb, offset+0) & 0x0f) << 8) + tvb_get_guint8(tvb, offset+1);
 
 	if (tree) {
@@ -874,10 +861,7 @@ dissect_payload_sign(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_,
 		proto_tree_add_uint(tree, hf_mikey[POS_SIGNATURE_LEN], tvb, 0, 2, length);
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+2, length);
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_SIGNATURE], tvb, 2, length, ENC_NA);
-	}
+	proto_tree_add_item(tree, hf_mikey[POS_SIGNATURE], tvb, 2, length, ENC_NA);
 	return 2 + length;
 }
 
@@ -888,7 +872,6 @@ dissect_payload_t(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pro
 	int    offset = 0;
 	int    len    = 0;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 2);
 	ts_type = tvb_get_guint8(tvb, offset+1);
 
 	if (tree) {
@@ -922,7 +905,6 @@ dissect_payload_id(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pr
 	guint8	type;
 	guint16	length;
 
-	tvb_ensure_bytes_exist(tvb,  offset+0, 4);
 	type   = tvb_get_guint8(tvb, offset+1);
 	length = tvb_get_ntohs(tvb,  offset+2);
 	if (tree) {
@@ -930,7 +912,6 @@ dissect_payload_id(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pr
 		proto_tree_add_item(tree, hf_mikey[POS_ID_LEN], tvb, 2, 2, ENC_BIG_ENDIAN);
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+4, length);
 	if (tree) {
 		proto_item* parent;
 		proto_tree_add_item(tree, hf_mikey[POS_ID], tvb, 4, length, ENC_ASCII|ENC_NA);
@@ -951,7 +932,6 @@ dissect_payload_idr(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, p
 	guint8	type;
 	guint16	length;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 5);
 	type = tvb_get_guint8(tvb, offset+2);
 	length = tvb_get_ntohs(tvb, offset+3);
 	if (tree) {
@@ -960,7 +940,6 @@ dissect_payload_idr(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, p
 		proto_tree_add_item(tree, hf_mikey[POS_ID_LEN],  tvb, 3, 2, ENC_BIG_ENDIAN);
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+5, length);
 	if (tree) {
 		proto_item *parent;
 		proto_tree_add_item(tree, hf_mikey[POS_ID], tvb, 5, length, ENC_ASCII|ENC_NA);
@@ -985,7 +964,6 @@ dissect_payload_cert(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo, prot
 
 	asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 4);
 	type   = tvb_get_guint8(tvb, offset+1);
 	length = tvb_get_ntohs(tvb, offset+2);
 
@@ -1013,12 +991,9 @@ dissect_payload_v(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pro
 	guint16 length;
 	guint8	alg;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 2);
 	alg = tvb_get_guint8(tvb, offset+1);
 
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_V_AUTH_ALG], tvb, 1, 1, ENC_BIG_ENDIAN);
-	}
+	proto_tree_add_item(tree, hf_mikey[POS_V_AUTH_ALG], tvb, 1, 1, ENC_BIG_ENDIAN);
 
 	switch (alg) {
 	case MAC_NULL:
@@ -1031,10 +1006,7 @@ dissect_payload_v(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pro
 		return 0;
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+2, length);
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_V_DATA], tvb, 2, length, ENC_NA);
-	}
+	proto_tree_add_item(tree, hf_mikey[POS_V_DATA], tvb, 2, length, ENC_NA);
 
 	return 2 + length;
 }
@@ -1047,10 +1019,8 @@ dissect_payload_sp_param(enum sp_prot_t proto, tvbuff_t *tvb, proto_tree *tree)
 	guint8 length;
 	int    hfindex;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 2);
 	type = tvb_get_guint8(tvb, offset+0);
 	length = tvb_get_guint8(tvb, offset+1);
-	tvb_ensure_bytes_exist(tvb, offset+2, length);
 
 	/* Default */
 	hfindex = hf_mikey[POS_SP_PARAM_F];
@@ -1092,7 +1062,6 @@ dissect_payload_sp(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, pr
 	guint8	       no;
 	enum sp_prot_t type;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 5);
 	length = tvb_get_ntohs(tvb, offset+3);
 	no     = tvb_get_guint8(tvb, offset+1);
 	type   = (enum sp_prot_t)tvb_get_guint8(tvb, offset+2);
@@ -1136,26 +1105,17 @@ dissect_payload_rand(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_,
 	int	offset = 0;
 	guint16 length;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 2);
 	length = tvb_get_guint8(tvb, offset+1);
 
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_RAND_LEN], tvb, 1, 1, ENC_BIG_ENDIAN);
-	}
-
-	tvb_ensure_bytes_exist(tvb, offset+2, length);
+	proto_tree_add_item(tree, hf_mikey[POS_RAND_LEN], tvb, 1, 1, ENC_BIG_ENDIAN);
+	proto_tree_add_item(tree, hf_mikey[POS_RAND], tvb, 2, length, ENC_NA);
 
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_RAND], tvb, 2, length, ENC_NA);
-	}
 	return 2 + length;
 }
 
 static int
 dissect_payload_err(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 {
-	tvb_ensure_bytes_exist(tvb, 0, 4);
-
 	if (tree) {
 		proto_item *parent;
 		guint8 err_no;
@@ -1178,12 +1138,10 @@ dissect_payload_keydata(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U
 	guint8	kv_type;
 
 	offset = 0;
-	tvb_ensure_bytes_exist(tvb, 0, 4);
 	key_type = tvb_get_guint8(tvb, 1) >> 4;
 	kv_type  = tvb_get_guint8(tvb, 1) & 0x0f;
 	data_len = tvb_get_ntohs(tvb, 2);
 
-	tvb_ensure_bytes_exist(tvb, 4, data_len);
 	offset += 4;
 
 	if (tree) {
@@ -1202,14 +1160,10 @@ dissect_payload_keydata(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U
 	/* Dissect SALT key */
 	if ((key_type == KD_TGK_SALT) || (key_type == KD_TEK_SALT)) {
 		guint16	salt_len;
-		tvb_ensure_bytes_exist(tvb, offset, 2);
 		salt_len = tvb_get_ntohs(tvb, offset);
 		if (salt_len > 0) {
-			tvb_ensure_bytes_exist(tvb, offset+2, salt_len);
-			if (tree) {
-				proto_tree_add_item(tree, hf_mikey[POS_KEY_SALT_LEN], tvb, offset, 2, ENC_BIG_ENDIAN);
-				proto_tree_add_item(tree, hf_mikey[POS_KEY_SALT], tvb, offset+2, salt_len, ENC_NA);
-			}
+			proto_tree_add_item(tree, hf_mikey[POS_KEY_SALT_LEN], tvb, offset, 2, ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_mikey[POS_KEY_SALT], tvb, offset+2, salt_len, ENC_NA);
 		}
 		offset += 2+salt_len;
 	}
@@ -1219,31 +1173,25 @@ dissect_payload_keydata(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U
 		guint16	kv_from_len;
 		guint16	kv_to_len;
 
-		tvb_ensure_bytes_exist(tvb, offset, 1);
 		kv_from_len = tvb_get_guint8(tvb, offset);
 		proto_tree_add_item(tree, hf_mikey[POS_KEY_KV_FROM_LEN], tvb, offset, 1, ENC_BIG_ENDIAN);
 		if (kv_from_len > 0) {
-			tvb_ensure_bytes_exist(tvb, offset+1, kv_from_len);
 			proto_tree_add_item(tree, hf_mikey[POS_KEY_KV_FROM], tvb, offset+1, kv_from_len, ENC_NA);
 		}
 		offset += 1+kv_from_len;
 
-		tvb_ensure_bytes_exist(tvb, offset, 1);
 		kv_to_len = tvb_get_guint8(tvb, offset);
 		proto_tree_add_item(tree, hf_mikey[POS_KEY_KV_TO_LEN], tvb, offset, 1, ENC_BIG_ENDIAN);
 		if (kv_to_len > 0) {
-			tvb_ensure_bytes_exist(tvb, offset+1, kv_to_len);
 			proto_tree_add_item(tree, hf_mikey[POS_KEY_KV_TO], tvb, offset+1, kv_to_len, ENC_NA);
 		}
 		offset += 1+kv_to_len;
 	} else if (kv_type == KV_SPI) {
 		guint16	kv_spi_len;
 
-		tvb_ensure_bytes_exist(tvb, offset, 1);
 		kv_spi_len = tvb_get_guint8(tvb, offset);
 		proto_tree_add_item(tree, hf_mikey[POS_KEY_KV_SPI_LEN], tvb, offset, 1, ENC_BIG_ENDIAN);
 		if (kv_spi_len > 0) {
-			tvb_ensure_bytes_exist(tvb, offset+1, kv_spi_len);
 			proto_tree_add_item(tree, hf_mikey[POS_KEY_KV_SPI], tvb, offset+1, kv_spi_len, ENC_NA);
 		}
 		offset += 1+kv_spi_len;
@@ -1259,7 +1207,6 @@ dissect_payload_general_ext(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinf
 	guint8	type;
 	guint16	data_len;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 4);
 	type	 = tvb_get_guint8(tvb, offset+1);
 	data_len = tvb_get_ntohs(tvb, offset+2);
 
@@ -1268,8 +1215,6 @@ dissect_payload_general_ext(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinf
 		proto_tree_add_item(tree, hf_mikey[POS_GENERAL_EXT_LEN], tvb, 2, 2, ENC_BIG_ENDIAN);
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+3, data_len);
-
 	if (tree) {
 		proto_item *parent;
 
@@ -1291,7 +1236,6 @@ dissect_payload_sakke(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_,
 	int	offset = 0;
 	guint16 data_len;
 
-	tvb_ensure_bytes_exist(tvb, offset+0, 5);
 	data_len = tvb_get_ntohs(tvb, offset+3);
 
 	if (tree) {
@@ -1300,11 +1244,7 @@ dissect_payload_sakke(mikey_t *mikey _U_, tvbuff_t *tvb, packet_info *pinfo _U_,
 		proto_tree_add_item(tree, hf_mikey[POS_SAKKE_LEN],       tvb, 3, 2, ENC_BIG_ENDIAN);
 	}
 
-	tvb_ensure_bytes_exist(tvb, offset+5, data_len);
-
-	if (tree) {
-		proto_tree_add_item(tree, hf_mikey[POS_SAKKE_DATA], tvb, 5, data_len, ENC_NA);
-	}
+	proto_tree_add_item(tree, hf_mikey[POS_SAKKE_DATA], tvb, 5, data_len, ENC_NA);
 	return 5 + data_len;
 }