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tlv_dcbx: bounds-check nested TLVs in legacy DCBX decoders #136

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tlv_dcbx: bounds-check nested TLVs in legacy DCBX decoders #136

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39 changes: 39 additions & 0 deletions tlv_dcbx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -833,6 +833,8 @@ bool unpack_dcbx1_tlvs(struct port *port, struct lldp_agent *agent,

if (agent == NULL)
return false;
if (tlv->length < DCB_OUI_LEN + OUI_SUBTYPE_LEN)
return false;

/* store highest dcbx subtype received */
if (agent->rx.dcbx_st < tlv->info[DCB_OUI_LEN]) {
Expand All @@ -850,6 +852,11 @@ bool unpack_dcbx1_tlvs(struct port *port, struct lldp_agent *agent,
"DCB TLV. \n");
return false;
}
if (current + sizeof(tl) > end) {
LLDPAD_DBG("ERROR: truncated DCB TLV header \n");
free_unpkd_tlv(dcbtlv);
return false;
}
memcpy(&tl, offset, sizeof(tl));
offset += sizeof(tl);
dcbtlv->length = ntohs(tl) & 0x01FF;
Expand All @@ -858,6 +865,11 @@ bool unpack_dcbx1_tlvs(struct port *port, struct lldp_agent *agent,
free_unpkd_tlv(dcbtlv);
return false;
}
if (current + sizeof(tl) + dcbtlv->length > end) {
LLDPAD_DBG("ERROR: truncated DCB TLV info \n");
free_unpkd_tlv(dcbtlv);
return false;
}
dcbtlv->type = (u8)(ntohs(tl) >> 9);
dcbtlv->info = (u8 *)malloc(dcbtlv->length);
if (dcbtlv->info) {
Expand Down Expand Up @@ -913,6 +925,11 @@ bool unpack_dcbx1_tlvs(struct port *port, struct lldp_agent *agent,
}
break;
case DCB_APPLICATION_TLV:
if (dcbtlv->length <= DCBX_HDR_SUB_TYPE_OFFSET) {
LLDPAD_DBG("ERROR: truncated DCB APP TLV \n");
free_unpkd_tlv(dcbtlv);
return false;
}
/* store if subtype 2 is not present */
if ((agent->rx.dcbx_st == DCBX_SUBTYPE1) &&
(dcbtlv->info[DCBX_HDR_SUB_TYPE_OFFSET]
Expand All @@ -930,6 +947,11 @@ bool unpack_dcbx1_tlvs(struct port *port, struct lldp_agent *agent,
}
break;
case DCB_LLINK_TLV:
if (dcbtlv->length <= DCBX_HDR_SUB_TYPE_OFFSET) {
LLDPAD_DBG("ERROR: truncated DCB LLINK TLV \n");
free_unpkd_tlv(dcbtlv);
return false;
}
if (dcbtlv->info[DCBX_HDR_SUB_TYPE_OFFSET]
== LLINK_FCOE_STYPE) {
if (tlvs->manifest->dcbx_llink == NULL) {
Expand Down Expand Up @@ -969,6 +991,8 @@ bool unpack_dcbx2_tlvs(struct port *port, struct lldp_agent *agent,

if (agent == NULL)
return false;
if (tlv->length < DCB_OUI_LEN + OUI_SUBTYPE_LEN)
return false;

/* store highest dcbx subtype received */
if (agent->rx.dcbx_st < tlv->info[DCB_OUI_LEN]) {
Expand All @@ -986,6 +1010,11 @@ bool unpack_dcbx2_tlvs(struct port *port, struct lldp_agent *agent,
"DCB TLV. \n");
return false;
}
if (current + sizeof(tl) > end) {
LLDPAD_DBG("ERROR: truncated DCB TLV header \n");
free_unpkd_tlv(dcbtlv);
return false;
}
memcpy(&tl, offset, sizeof(tl));
offset += sizeof(tl);
dcbtlv->length = ntohs(tl) & 0x01FF;
Expand All @@ -994,6 +1023,11 @@ bool unpack_dcbx2_tlvs(struct port *port, struct lldp_agent *agent,
free_unpkd_tlv(dcbtlv);
return false;
}
if (current + sizeof(tl) + dcbtlv->length > end) {
LLDPAD_DBG("ERROR: truncated DCB TLV info \n");
free_unpkd_tlv(dcbtlv);
return false;
}
dcbtlv->type = (u8)(ntohs(tl) >> 9);
dcbtlv->info = (u8 *)malloc(dcbtlv->length);
if (dcbtlv->info) {
Expand Down Expand Up @@ -1043,6 +1077,11 @@ bool unpack_dcbx2_tlvs(struct port *port, struct lldp_agent *agent,
}
break;
case DCB_APPLICATION_TLV2:
if (dcbtlv->length <= DCBX_HDR_SUB_TYPE_OFFSET) {
LLDPAD_DBG("ERROR: truncated DCB APP TLV \n");
free_unpkd_tlv(dcbtlv);
return false;
}
subtype = dcbtlv->info[DCBX_HDR_SUB_TYPE_OFFSET];
if (subtype == 0) {
if (tlvs->manifest->dcbx_app == NULL) {
Expand Down