www-cgi/: Decentralize the whitelist of environment variables.

[userv-utils.git] / www-cgi / ucgi.c

diff --git a/www-cgi/ucgi.c b/www-cgi/ucgi.c
index 0e11624a357ed216da0c33bc8555b6173f9b0f84..006f8ae4cd93223986d15c146967d032908eeefa 100644 (file)
--- a/www-cgi/ucgi.c
+++ b/www-cgi/ucgi.c
@@ -2,7 +2,7 @@
  * Usage: as CGI script
  */
 /*
- * Copyright (C) 1998-1999 Ian Jackson
+ * Copyright (C) 1998-1999,2003 Ian Jackson
  *
  * This is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by
@@ -30,14 +30,54 @@
 
 #include "ucgi.h"
 
+static const char *const envok[] = {
+  "AUTH_TYPE",
+  "CONTENT_TYPE",
+  "CONTENT_LENGTH",
+  "DOCUMENT_ROOT",
+  "GATEWAY_INTERFACE",
+  "HTTP_*",
+  "HTTPS",
+  "PATH_INFO",
+  "PATH_TRANSLATED",
+  "QUERY_STRING",
+  "REMOTE_*",
+  "REQUEST_METHOD",
+  "REQUEST_URI",
+  "SCRIPT_*",
+  "SERVER_*",
+  0
+};
+
+struct buildargs {
+  const char **v;
+  int n, max;
+};
+
+static void addarg(struct buildargs *args, const char *a) {
+  if (args->n > args->max) error("too many arguments");
+  args->v[args->n++]= a;
+}
+
+static void add_userv_var(const char *fulln,
+                         const char *en, const char *ev, void *p) {
+  struct buildargs *args= p;
+  size_t l;
+  char *a;
+
+  l= strlen(ev); if (l > MAX_ENVVAR_VALUE) error("environment variable too long");
+  a= xmalloc(strlen(en)+l+6);
+  sprintf(a,"-DE_%s=%s",en,ev);
+  addarg(args, a);
+}
+
 int main(int argc, const char **argv) {
-  char *defarg, *username;
-  const char *slash2, *pathi, *ev, *en, *av;
-  const char *const *ep;
-  const char **arguments;
+  char *username;
+  const char *slash2, *pathi, *av;
   size_t usernamelen, l;
+  struct buildargs args;
   pid_t child, rchild;
-  int nargs, status;
+  int status;
 
   l= strlen(argv[0]);
   if (l>6 && !strcmp(argv[0]+l-6,"-debug")) debugmode= 1;
@@ -46,41 +86,44 @@ int main(int argc, const char **argv) {
     if (fputs("Content-Type: text/plain\n\n",stdout)==EOF || fflush(stdout))
       syserror("write stdout");
     if (dup2(1,2)<0) { perror("dup stdout to stderr"); exit(-1); }
+    D( printf(";;; UCGI\n"); )
   }
   
   if (argc > MAX_ARGS) error("too many arguments");
 
   pathi= getenv("PATH_INFO");
   if (!pathi) error("PATH_INFO not found");
+  D( if (debugmode) {
+       printf(";; find user name...\n"
+             ";;   initial PATH_INFO = `%s'\n",
+             pathi);
+  } )
   if (pathi[0] != '/' || pathi[1] != '~') error("PATH_INFO must start with /~");
   slash2= strchr(pathi+2,'/'); if (!slash2) error("PATH_INFO must have more than one /");
   usernamelen= slash2-(pathi+2);
   if (usernamelen > MAX_USERNAME_LEN) error("PATH_INFO username too long");
   username= xmalloc(usernamelen+1);
   memcpy(username,pathi+2,usernamelen); username[usernamelen]= 0;
+  D( if (debugmode)
+       printf(";;   user = `%s'; tail = `%s'\n", username, slash2); )
   if (!isalpha(username[0])) error("username 1st character is not alphabetic");
   xsetenv("PATH_INFO",slash2,1);
+
+  args.n= 0; args.max= argc + MAX_ENVVARS + 10;
+  args.v= xmalloc(args.max * sizeof(*args.v));
   
-  arguments= xmalloc(sizeof(const char*)*(nenvok+argc+10));
-  nargs= 0;
-  
-  arguments[nargs++]= "userv";
-  if (debugmode) arguments[nargs++]= "-DDEBUG=1";
-  
-  for (ep= envok; (en= *ep); ep++) {
-    ev= getenv(en); if (!ev) continue;
-    l= strlen(ev); if (l > MAX_ENVVAR_VALUE) error("environment variable too long");
-    defarg= xmalloc(strlen(en)+l+6);
-    sprintf(defarg,"-DE_%s=%s",en,ev);
-    arguments[nargs++]= defarg;
-  }
+  addarg(&args, "userv");
+  if (debugmode) addarg(&args, "-DDEBUG=1");
 
-  arguments[nargs++]= username;
-  arguments[nargs++]= "www-cgi";
-  while ((av= (*++argv))) arguments[nargs++]= av;
-  arguments[nargs++]= 0;
+  filter_environment(FILTF_WILDCARD, "", envok, add_userv_var, &args);
+
+  addarg(&args, username);
+  addarg(&args, "www-cgi");
+  while ((av= (*++argv))) addarg(&args, av);
+  addarg(&args, 0);
 
   if (debugmode) {
+    D( fflush(stdout); )
     child= fork(); if (child==-1) syserror("fork");
     if (child) {
       rchild= waitpid(child,&status,0);
@@ -90,7 +133,16 @@ int main(int argc, const char **argv) {
     }
   }
       
-  execvp("userv",(char*const*)arguments);
+  D( if (debugmode) {
+       int i;
+
+       printf(";; final command line...\n");
+       for (i = 0; args.v[i]; i++)
+        printf(";;   %s\n", args.v[i]);
+       fflush(stdout);
+  } )
+
+  execvp("userv",(char*const*)args.v);
   syserror("exec userv");
   return -1;
 }