Fix header matches potentially occurring in the record body

warc-dump-responses.c

@@ -31,6 +31,7 @@ int main(int argc, char* argv[]) {
 	char* bufp;
 	char* m0;
 	char* m1;
+	char* eoh;
 	size_t record_bytes_read;
 	size_t record_length;
 	size_t nscan;
@@ -58,8 +59,16 @@ checkstate:
 			}
 			if (memcmp(bufp, "WARC/1.0\r\n", 10) == 0 || memcmp(bufp, "WARC/1.1\r\n", 10) == 0) {
 				// Got some headers; find the record type, content length, and end of headers
+				eoh = memmem(bufp, n, "\r\n\r\n", 4);
+				if (!eoh) {
+					fprintf(stderr, "Error: end of headers not found\n");
+					return 1;
+				}
+				eoh += 4;
+				DEBUG_PRINTF("Record body begins at %p (offset %zu)\n", (void*)eoh, eoh - bufp);
+
 				m0 = memmem(bufp, n, "\r\nContent-Length:", 17);
-				if (!m0) {
+				if (!m0 || m0 >= eoh) {
 					fprintf(stderr, "Error: Content-Length missing\n");
 					return 1;
 				}
@@ -88,7 +97,7 @@ checkstate:
 				DEBUG_PRINTF("Record body length: %zu\n", record_length);
 
 				m0 = memmem(bufp, n, "\r\nWARC-Type:", 12);
-				if (!m0) {
+				if (!m0 || m0 >= eoh) {
 					fprintf(stderr, "Error: WARC-Type missing\n");
 					return 1;
 				}
@@ -110,7 +119,7 @@ checkstate:
 
 				if (meta && state == STATE_RESPONSE_RECORD) {
 					m0 = memmem(bufp, n, "\r\nWARC-Target-URI:", 18);
-					if (!m0) {
+					if (!m0 || m0 >= eoh) {
 						fprintf(stderr, "Error: WARC-Target-URI missing\n");
 						return 1;
 					}
@@ -134,17 +143,9 @@ checkstate:
 					fprintf(stdout, " %zu\n", record_length);
 				}
 
-				m0 = memmem(bufp, n, "\r\n\r\n", 4);
-				if (!m0) {
-					fprintf(stderr, "Error: end of headers not found\n");
-					return 1;
-				}
-				m0 += 4;
-				DEBUG_PRINTF("Record body begins at %p (offset %zu)\n", (void*)m0, m0 - bufp);
-
-				DEBUG_PRINTF("Adjusting buffer pointer and n by %zu\n", m0 - bufp);
-				n = n - (m0 - bufp);
-				bufp = m0;
+				DEBUG_PRINTF("Adjusting buffer pointer and n by %zu\n", eoh - bufp);
+				n = n - (eoh - bufp);
+				bufp = eoh;
 				record_bytes_read = 0;
 				goto checkstate;
 			} else {