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iSCSI: Handle invalid opcodes inside Reject message 

Allow dissect_iscsi_pdu to handle iSCSI messages with invalid
opcodes, so that it does not crash when receiving them in Reject
messages.

Fix #18796
master
John Thacker 2023-01-15 18:57:46 -05:00
parent 3bde296404
commit 1e1e733d8c
1 changed files with 18 additions and 15 deletions
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33
epan/dissectors/packet-iscsi.c
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@ -193,6 +193,7 @@ static gint ett_iscsi_ISID = -1;
/* #endif */
static expert_field ei_iscsi_keyvalue_invalid = EI_INIT;
static expert_field ei_iscsi_opcode_invalid = EI_INIT;
enum iscsi_digest {
ISCSI_DIGEST_AUTO,
@ -710,10 +711,10 @@ handleDataSegmentAsTextKeys(iscsi_session_t *iscsi_session, packet_info *pinfo,
/* Code to actually dissect the packets */
static void
dissect_iscsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint offset, guint8 opcode, const char *opcode_str, guint32 data_segment_len, iscsi_session_t *iscsi_session, conversation_t *conversation) {
dissect_iscsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint offset, guint8 opcode, guint32 data_segment_len, iscsi_session_t *iscsi_session, conversation_t *conversation) {
guint original_offset = offset;
proto_tree *ti = NULL;
proto_tree *ti = NULL, *opcode_item = NULL;
guint8 scsi_status = 0;
gboolean S_bit=FALSE;
gboolean A_bit=FALSE;
@ -730,6 +731,7 @@ dissect_iscsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint off
guint32 data_offset=0;
wmem_tree_key_t key[3];
guint32 itt;
const char* opcode_str = val_to_str_const(opcode, iscsi_opcodes, "Unknown");
if(paddedDataSegmentLength & 3)
paddedDataSegmentLength += 4 - (paddedDataSegmentLength & 3);
@ -921,8 +923,11 @@ dissect_iscsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint off
opcode_str);
ti = proto_item_add_subtree(tp, ett_iscsi);
}
proto_tree_add_uint(ti, hf_iscsi_Opcode, tvb,
offset + 0, 1, opcode);
opcode_item = proto_tree_add_item(ti, hf_iscsi_Opcode, tvb,
offset + 0, 1, ENC_NA);
if (!try_val_to_str(opcode, iscsi_opcodes)) {
expert_add_info(pinfo, opcode_item, &ei_iscsi_opcode_invalid);
}
if((opcode & TARGET_OPCODE_BIT) == 0) {
/* initiator -> target */
gint b = tvb_get_guint8(tvb, offset + 0);
@ -1535,8 +1540,7 @@ dissect_iscsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint off
offset=end_offset;
} else if(opcode == ISCSI_OPCODE_REJECT) {
proto_tree *tt;
int next_opcode;
const char *next_opcode_str;
guint8 next_opcode;
/* Reject */
proto_tree_add_item(ti, hf_iscsi_Reject_Reason, tvb, offset + 2, 1, ENC_BIG_ENDIAN);
@ -1550,12 +1554,11 @@ dissect_iscsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint off
proto_tree_add_item(ti, hf_iscsi_DataSN, tvb, offset + 36, 4, ENC_BIG_ENDIAN);
offset = handleHeaderDigest(iscsi_session, ti, tvb, offset, 48);
next_opcode = tvb_get_guint8(tvb, offset) & 0x3f;
next_opcode_str = try_val_to_str(next_opcode, iscsi_opcodes);
next_opcode = tvb_get_guint8(tvb, offset) & OPCODE_MASK;
tt = proto_tree_add_subtree(ti, tvb, offset, -1, ett_iscsi_RejectHeader, NULL, "Rejected Header");
dissect_iscsi_pdu(tvb, pinfo, tt, offset, next_opcode, next_opcode_str, 0, iscsi_session, conversation);
dissect_iscsi_pdu(tvb, pinfo, tt, offset, next_opcode, 0, iscsi_session, conversation);
} else if(opcode == ISCSI_OPCODE_VENDOR_SPECIFIC_I0 ||
opcode == ISCSI_OPCODE_VENDOR_SPECIFIC_I1 ||
opcode == ISCSI_OPCODE_VENDOR_SPECIFIC_I2 ||
@ -2277,7 +2280,6 @@ dissect_iscsi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean chec
/* process multiple iSCSI PDUs per packet */
while(available_bytes >= 48 || (iscsi_desegment && available_bytes >= 8)) {
const char *opcode_str = NULL;
guint32 data_segment_len;
guint32 pduLen = 48;
guint8 secondPduByte = tvb_get_guint8(tvb, offset + 1);
@ -2289,7 +2291,6 @@ dissect_iscsi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean chec
opcode = tvb_get_guint8(tvb, offset + 0);
opcode &= OPCODE_MASK;
opcode_str = try_val_to_str(opcode, iscsi_opcodes);
if(opcode == ISCSI_OPCODE_TASK_MANAGEMENT_FUNCTION ||
opcode == ISCSI_OPCODE_TASK_MANAGEMENT_FUNCTION_RESPONSE ||
opcode == ISCSI_OPCODE_R2T ||
@ -2300,7 +2301,7 @@ dissect_iscsi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean chec
else
data_segment_len = tvb_get_ntohl(tvb, offset + 4) & 0x00ffffff;
if(opcode_str == NULL) {
if (!try_val_to_str(opcode, iscsi_opcodes)) {
badPdu = TRUE;
}
@ -2500,7 +2501,7 @@ dissect_iscsi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean chec
else
col_append_str(pinfo->cinfo, COL_INFO, ", ");
dissect_iscsi_pdu(tvb, pinfo, tree, offset, opcode, opcode_str, data_segment_len, iscsi_session, conversation);
dissect_iscsi_pdu(tvb, pinfo, tree, offset, opcode, data_segment_len, iscsi_session, conversation);
if(pduLen > available_bytes)
pduLen = available_bytes;
offset += pduLen;
@ -2642,7 +2643,7 @@ proto_register_iscsi(void)
},
{ &hf_iscsi_Opcode,
{ "Opcode", "iscsi.opcode",
FT_UINT8, BASE_HEX, VALS(iscsi_opcodes), 0,
FT_UINT8, BASE_HEX, VALS(iscsi_opcodes), OPCODE_MASK,
NULL, HFILL }
},
/* #ifdef DRAFT08 */
@ -3072,7 +3073,9 @@ proto_register_iscsi(void)
static ei_register_info ei[] = {
{ &ei_iscsi_keyvalue_invalid, { "iscsi.keyvalue.invalid", PI_MALFORMED, PI_ERROR,
"Invalid key/value pair", EXPFILL }}
"Invalid key/value pair", EXPFILL }},
{ &ei_iscsi_opcode_invalid, { "iscsi.opcode.invalid", PI_MALFORMED, PI_ERROR,
"Invalid opcode", EXPFILL }},
};
/* Register the protocol name and description */