From ee6d97ea88ddc5f387db3f77d5f04cd8d6217ace Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Sun, 27 Feb 2011 02:22:05 +0100
Subject: [PATCH] tlsproxy.c: Add read_http_request().

---
 tlsproxy.c | 71 ++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 50 insertions(+), 21 deletions(-)

diff --git a/tlsproxy.c b/tlsproxy.c
index b417a98..a7b4157 100644
--- a/tlsproxy.c
+++ b/tlsproxy.c
@@ -34,7 +34,14 @@
 #include <poll.h>
 
 
+/* Maximum line of the request line. Longer request lines are aborted with an
+ * error. The standard doesn't specify a maximum line length but this should
+ * be a good limit to make processing simpler. */
+#define MAX_REQUEST_LINE 4096
+
+
 static void handle_connection(int socket);
+static int read_http_request(FILE *client_fd, char *request, size_t length);
 static void send_close_bad_request(FILE *client_fd);
 static void send_close_forwarding_failure(FILE *client_fd);
 
@@ -114,11 +121,12 @@ static void handle_connection(int client_socket) {
     int server_socket;
     FILE *client_fd, *server_fd;
 
-    char buffer[4096];
-    char host[4096];
+    char buffer[MAX_REQUEST_LINE];
+    char host[MAX_REQUEST_LINE];
     char port[5 + 1];
 
     int version_minor;
+    int result;
 
     client_fd = fdopen(client_socket, "a+");
     if (NULL == client_fd) {
@@ -131,13 +139,13 @@ static void handle_connection(int client_socket) {
     printf("New connection:\n");
 #endif
 
-    if (NULL == fgets(buffer, sizeof(buffer), client_fd)) {
-        if (ferror(client_fd)) {
-            perror("fgets(), request");
-            fclose(client_fd);
-            return;
-        }
-
+    /* Read request line (CONNECT ..) and headers (they are discarded). */
+    result = read_http_request(client_fd, buffer, sizeof(buffer));
+    if (result == -1) {
+        /* Read error. */
+        return;
+    } else if (result == -2) {
+        /* EOF */
         send_close_bad_request(client_fd);
         return;
     }
@@ -154,18 +162,6 @@ static void handle_connection(int client_socket) {
         return;
     }
 
-    while (NULL != fgets(buffer, sizeof(buffer), client_fd)) {
-        /* End of header. */
-        if (0 == strcmp(buffer, "\n") || 0 == strcmp(buffer, "\r\n")) {
-            break;
-        }
-    }
-    if (ferror(client_fd)) {
-        perror("fgets(), header");
-        fclose(client_fd);
-        return;
-    }
-
 #ifdef DEBUG
     printf("  %s:%s (HTTP 1.%d)\n", host, port, version_minor);
 #endif
@@ -193,6 +189,39 @@ static void handle_connection(int client_socket) {
     fclose(server_fd);
 }
 
+/* Read HTTP request line and headers (ignored).
+ *
+ * On success 0 is returned, -1 on client error (we close client descriptor in
+ * this case), -2 on unexpected EOF.
+ */
+static int read_http_request(FILE *client_fd, char *request, size_t length) {
+    char buffer[MAX_REQUEST_LINE];
+
+    if (NULL == fgets(request, (int)length, client_fd)) {
+        if (ferror(client_fd)) {
+            perror("fgets(), request");
+            fclose(client_fd);
+            return -1;
+        }
+
+        return -2;
+    }
+
+    while (NULL != fgets(buffer, MAX_REQUEST_LINE, client_fd)) {
+        /* End of header. */
+        if (0 == strcmp(buffer, "\n") || 0 == strcmp(buffer, "\r\n")) {
+            break;
+        }
+    }
+    if (ferror(client_fd)) {
+        perror("fgets(), header");
+        fclose(client_fd);
+        return -1;
+    }
+
+    return 0;
+}
+
 static void send_close_bad_request(FILE *client_fd) {
     fprintf(client_fd, "HTTP/1.0 400 Bad Request\r\n");
     fprintf(client_fd, "\r\n");
-- 
2.43.2