diff --git a/lib/doh.c b/lib/doh.c index 26d34b9ffe..6b37727c38 100644 --- a/lib/doh.c +++ b/lib/doh.c @@ -1088,6 +1088,7 @@ static CURLcode doh_resp_decode_httpsrr(struct Curl_easy *data, struct Curl_https_rrinfo **hrr) { uint16_t pcode = 0, plen = 0; + uint32_t expected_min_pcode = 0; struct Curl_https_rrinfo *lhrr = NULL; char *dnsname = NULL; CURLcode result = CURLE_OUT_OF_MEMORY; @@ -1114,13 +1115,16 @@ static CURLcode doh_resp_decode_httpsrr(struct Curl_easy *data, plen = doh_get16bit(cp, 2); cp += 4; len -= 4; + if(pcode < expected_min_pcode || plen > len) { + result = CURLE_WEIRD_SERVER_REPLY; + goto err; + } result = Curl_httpsrr_set(data, lhrr, pcode, cp, plen); if(result) goto err; - if(plen > 0 && plen <= len) { - cp += plen; - len -= plen; - } + cp += plen; + len -= plen; + expected_min_pcode = pcode + 1; } DEBUGASSERT(!len); *hrr = lhrr;