Report the storage shortage in the env-var path instead of resetting silently

src/httpnenv.c

@@ -14,9 +14,17 @@ httpnenv(const UCHAR *name, const UCHAR *value)
     size_t      total   = offsetof(HTTPV, name) + namelen + 1 + vallen + 1;
     HTTPV       *v;
 
-    if (namelen + vallen > 8192) return NULL; /* sanity limit */
+    /* Both rejects return NULL, so set errno to tell the caller which one it
+       was: httpsenv() reports an oversized variable differently from a storage
+       shortage, and since libc370#82 the shortage is a real outcome rather
+       than an S878 (issue #162). */
+    if (namelen + vallen > 8192) {              /* sanity limit */
+        errno = E2BIG;
+        return NULL;
+    }
 
     v = calloc(1, total);
+    if (!v) errno = ENOMEM;
 
     if (v) {
         strcpy(v->eye, HTTPV_EYE);

src/httppc.c

@@ -104,7 +104,14 @@ httppc(HTTPC *httpc)
                 char scriptfile[384];
                 snprintf(scriptfile, sizeof(scriptfile), "%s%s",
                          httpd->docroot, path);
-                http_set_env(httpc, "SCRIPT_FILENAME", scriptfile);
+                /* every other http_set_env() caller checks; dispatching the
+                   CGI without SCRIPT_FILENAME would run it against no file at
+                   all, so fail the request instead of guessing (#162) */
+                if (http_set_env(httpc, "SCRIPT_FILENAME", scriptfile)) {
+                    http_resp_internal_error(httpc);
+                    httpc->state = CSTATE_DONE;
+                    goto check_done;
+                }
             }
 
             /* path needs to be processed by external program */

src/httpsenv.c

@@ -12,6 +12,19 @@ httpsenv(HTTPC *httpc, const UCHAR *name, const UCHAR *value)
     /* allocate a new environment variable */
     v = http_new_env(name, value);
     if (!v) {
+        /* Say so.  Before libc370#82 a storage shortage here abended S878 and
+           try(serve_client) logged HTTPD062E; now it is a quiet -1 that every
+           caller turns into CSTATE_RESET, i.e. a connection reset with no
+           response and no log line -- indistinguishable from a malformed
+           request (issue #162).  This is the one choke point every env-var
+           caller passes through, and it still knows which variable failed,
+           which the reset sites no longer do. */
+        if (errno == E2BIG)
+            wtof("HTTPD905E Environment variable %.32s too large "
+                 "client(%08X)", name, httpc);
+        else
+            wtof("HTTPD904E No storage for environment variable %.32s "
+                 "client(%08X)", name, httpc);
         rc = -1;
         goto quit;
     }
@@ -26,6 +39,8 @@ httpsenv(HTTPC *httpc, const UCHAR *name, const UCHAR *value)
        the new HTTPV would be an unreachable orphan -- free it and report. */
     if (array_add(&httpc->env, v)) {
         free(v);
+        wtof("HTTPD904E No storage for environment variable %.32s "
+             "client(%08X)", name, httpc);
         rc = -1;
     }
 

src/httpshen.c

@@ -28,10 +28,11 @@ parse_cookies(HTTPC *httpc, const UCHAR *in)
 	UCHAR	*value;
 
 	if (!buf) {
-		wtof("%s: out of memory", __func__);
-		return ENOMEM;
+		wtof("HTTPD904E No storage for environment variable HTTP_Cookie "
+		     "client(%08X)", httpc);
+		return -1;      /* -1, like every other setter in this path */
 	}
-	
+
 	for (name = buf; name && *name; ) {
 		/* skip leading delimiters */
 		while (*name == ';' || *name == ' ') name++;
@@ -49,10 +50,16 @@ parse_cookies(HTTPC *httpc, const UCHAR *in)
 		else {
 			value = "";
 		}
-		set_cookie(httpc, name, value);
+		/* stop at the first failure: the caller resets the connection
+		   anyway, and carrying on would emit one HTTPD904E per remaining
+		   cookie instead of one per request */
+		if (set_cookie(httpc, name, value)) {
+			free(buf);
+			return -1;
+		}
 		name = end;
 	}
-	
+
 	free(buf);
 	return 0;
 }

test/tstnenv.c

@@ -52,5 +52,37 @@ int main(void)
         free(v);
     }
 
+    /* Both rejects return NULL, and httpsenv() tells them apart by errno to
+       decide whether to report a storage shortage (HTTPD904E) or an oversized
+       variable (HTTPD905E) -- issue #162.  The sanity limit is the half that
+       needs no storage shortage to reach, so it is the half a test can pin. */
+    {
+        UCHAR *big = malloc(9000);
+
+        CHECK(big != NULL, "oversize probe buffer allocated");
+        if (big) {
+            memset(big, 'X', 8999);
+            big[8999] = 0;
+
+            errno = 0;
+            v = http_new_env((const UCHAR *)"BIG", big);
+            CHECK(v == NULL, "name+value over the sanity limit is rejected");
+            CHECK(errno == E2BIG, "oversize reject reports E2BIG, not ENOMEM");
+            if (v) free(v);
+
+            /* just under the limit still succeeds -- guards the boundary
+               against the reject swallowing legitimate variables */
+            big[8000] = 0;
+            v = http_new_env((const UCHAR *)"BIG", big);
+            CHECK(v != NULL, "name+value under the sanity limit is accepted");
+            if (v) {
+                CHECK(v->value && strlen(v->value) == 8000,
+                      "under-limit value stored at full length");
+                free(v);
+            }
+            free(big);
+        }
+    }
+
     return mbt_test_summary("TSTNENV");
 }