From b5b02f2a9b8772d8814096f86c60a32889d61f2c Mon Sep 17 00:00:00 2001 From: Jaap Keuter Date: Mon, 24 Dec 2018 23:15:26 +0100 Subject: [PATCH] ISAKMP: Fix a crash when no decryption data block is there Don't try to (re)set parameters in a struct when its pointer points to NULL. Bug: 15374 Change-Id: I953e82795990fde5fce2ad6d955781b372a9e405 Signed-off-by: Jaap Keuter Reviewed-on: https://code.wireshark.org/review/31189 Tested-by: Petri Dish Buildbot Reviewed-by: Michael Mann (cherry picked from commit c9cfae7fecd4bc21b8b4f48328d08e104d47dd52) Reviewed-on: https://code.wireshark.org/review/31220 Petri-Dish: Michael Mann --- epan/dissectors/packet-isakmp.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/epan/dissectors/packet-isakmp.c b/epan/dissectors/packet-isakmp.c index 8b9ba85db5..e134ca8632 100644 --- a/epan/dissectors/packet-isakmp.c +++ b/epan/dissectors/packet-isakmp.c @@ -3741,8 +3741,7 @@ dissect_resp_lifetime_ipsec_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_t /* Returns the number of bytes consumed by this attribute. */ static int -dissect_ike_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, decrypt_data_t *decr -) +dissect_ike_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, decrypt_data_t *decr) { guint headerlen, value_len, attr_type; proto_item *attr_item; @@ -3765,22 +3764,22 @@ dissect_ike_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int o case IKE_ATTR_ENCRYPTION_ALGORITHM: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_encryption_algorithm, tvb, offset, value_len, ENC_BIG_ENDIAN); proto_item_append_text(attr_item, ": %s", val_to_str(tvb_get_ntohs(tvb, offset), ike_attr_enc_algo, "Unknown %d")); - decr->ike_encr_alg = tvb_get_ntohs(tvb, offset); + if (decr) decr->ike_encr_alg = tvb_get_ntohs(tvb, offset); break; case IKE_ATTR_HASH_ALGORITHM: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_hash_algorithm, tvb, offset, value_len, ENC_BIG_ENDIAN); proto_item_append_text(attr_item, ": %s", val_to_str(tvb_get_ntohs(tvb, offset), ike_attr_hash_algo, "Unknown %d")); - decr->ike_hash_alg = tvb_get_ntohs(tvb, offset); + if (decr) decr->ike_hash_alg = tvb_get_ntohs(tvb, offset); break; case IKE_ATTR_AUTHENTICATION_METHOD: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_authentication_method, tvb, offset, value_len, ENC_BIG_ENDIAN); proto_item_append_text(attr_item, ": %s", val_to_str(tvb_get_ntohs(tvb, offset), ike_attr_authmeth, "Unknown %d")); - decr->is_psk = tvb_get_ntohs(tvb, offset) == 0x01 ? TRUE : FALSE; + if (decr) decr->is_psk = tvb_get_ntohs(tvb, offset) == 0x01 ? TRUE : FALSE; break; case IKE_ATTR_GROUP_DESCRIPTION: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_group_description, tvb, offset, value_len, ENC_BIG_ENDIAN); proto_item_append_text(attr_item, ": %s", val_to_str(tvb_get_ntohs(tvb, offset), dh_group, "Unknown %d")); - decr->group = tvb_get_ntohs(tvb, offset); + if (decr) decr->group = tvb_get_ntohs(tvb, offset); break; case IKE_ATTR_GROUP_TYPE: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_group_type, tvb, offset, value_len, ENC_BIG_ENDIAN); @@ -3814,7 +3813,7 @@ dissect_ike_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int o case IKE_ATTR_KEY_LENGTH: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_key_length, tvb, offset, value_len, ENC_BIG_ENDIAN); proto_item_append_text(attr_item, ": %d", tvb_get_ntohs(tvb, offset)); - decr->ike_encr_keylen = tvb_get_ntohs(tvb, offset); + if (decr) decr->ike_encr_keylen = tvb_get_ntohs(tvb, offset); break; case IKE_ATTR_FIELD_SIZE: proto_tree_add_item(attr_tree, hf_isakmp_ike_attr_field_size, tvb, offset, value_len, ENC_NA); @@ -3950,12 +3949,14 @@ dissect_transform(tvbuff_t *tvb, packet_info *pinfo, int offset, int length, pro offset += 2; if (protocol_id == 1 && transform_id == 1) { - /* Allow detection of missing IKE transform attributes: - * Make sure their values are not carried over from another transform - * dissected previously. */ - decr->ike_encr_alg = 0; - decr->ike_encr_keylen = 0; - decr->ike_hash_alg = 0; + if (decr) { + /* Allow detection of missing IKE transform attributes: + * Make sure their values are not carried over from another transform + * dissected previously. */ + decr->ike_encr_alg = 0; + decr->ike_encr_keylen = 0; + decr->ike_hash_alg = 0; + } while (offset < offset_end) { offset += dissect_ike_attribute(tvb, pinfo, tree, offset, decr); }