move buffer-management code to its own module, with tests; fix memory corruption bug in quote()

pam/.gitignore

 *.in
 aclocal.m4
 autom4te.cache
+compile
 config.guess
 config.sub
 configure
@@ -26,5 +27,7 @@ libtool
 stamp-*
 Makefile
 auth_client_test
+cbuf_test
 test-driver
 test-suite.log
+.dirstamp

pam/Makefile.am

@@ -8,7 +8,8 @@ pam_LTLIBRARIES = pam_authclient.la
 noinst_LIBRARIES = libgtest.a
 
 libauthclient_la_SOURCES = \
-	auth_client.c auth_client.h
+	auth_client.c auth_client.h \
+	cbuf.c cbuf.h
 libauthclient_la_includedir = $(includedir)/authclient
 libauthclient_la_include_HEADERS =  auth_client.h
 
@@ -18,7 +19,8 @@ pam_authclient_la_LDFLAGS = -module
 pam_authclient_la_LIBADD = libauthclient.la
 
 check_PROGRAMS = \
-	auth_client_test
+	auth_client_test \
+	cbuf_test
 
 TESTS = $(check_PROGRAMS)
 
@@ -26,6 +28,9 @@ auth_client_test_CPPFLAGS = $(GTEST_CPPFLAGS)
 auth_client_test_LDADD = libauthclient.la libgtest.a
 auth_client_test_SOURCES = auth_client_test.cc
 
+cbuf_test_CPPFLAGS = $(GTEST_CPPFLAGS)
+cbuf_test_LDADD = libauthclient.la libgtest.a
+cbuf_test_SOURCES = cbuf_test.cc
 
 # GTest sources.
 

pam/auth_client.c

@@ -9,6 +9,7 @@
 #include <sys/stat.h>
 #include <curl/curl.h>
 #include "auth_client.h"
+#include "cbuf.h"
 
 #define CURL_CHECK(x) { \
   int _err = (x); if (_err != CURLE_OK) { return auth_client_err_from_curl(_err); } \
@@ -106,44 +107,6 @@ const char *auth_client_strerror(int err) {
   }
 }
 
-/*
- * A dynamically sized memory buffer that can be appended to, and will
- * grow accordingly. It is optimized to perform well for a specific
- * size (the initial allocation).
- */
-struct cbuf {
-  char *buf;
-  size_t alloc, size;
-};
-
-static void cbuf_init(struct cbuf *cbuf, size_t alloc) {
-  cbuf->buf = (char *)malloc(alloc);
-  cbuf->alloc = alloc;
-  cbuf->size = 0;
-}
-
-static void cbuf_free(struct cbuf *cbuf) {
-  free(cbuf->buf);
-}
-
-static void cbuf_append(struct cbuf *cbuf, void *data, size_t size) {
-  // Resize if necessary.
-  size_t required_alloc = cbuf->size + size + 1;
-  if (required_alloc > cbuf->alloc) {
-    size_t new_alloc = cbuf->alloc;
-    while (new_alloc < required_alloc) {
-      new_alloc *= 2;
-    }
-    cbuf->buf = (char *)realloc(cbuf->buf, new_alloc);
-    cbuf->alloc = new_alloc;
-  }
-
-  // Append data to the buffer.
-  memcpy(cbuf->buf + cbuf->size, data, size);
-  cbuf->size += size;
-  cbuf->buf[cbuf->size] = '\0';
-}
-
 static char *quote(const char *s) {
   char *out = (char *)malloc(strlen(s) * 3 + 1), *optr;
   for (optr = out; *s; s++) {
@@ -165,6 +128,7 @@ static char *quote(const char *s) {
       *optr++ = *s;
     }
   }
+  *optr = '\0';
   return out;
 }
 
@@ -177,14 +141,13 @@ static size_t responsebuf_callback(void *contents, size_t size, size_t nmemb, vo
 }
 
 static void post_field_add(struct cbuf *form_data, const char *key, const char *value) {
-  char *quoted_key = quote(key), *quoted_value = quote(value);
+  char *quoted_value = quote(value);
   if (form_data->size != 0) {
     cbuf_append(form_data, "&", 1);
   }
-  cbuf_append(form_data, quoted_key, strlen(quoted_key));
+  cbuf_append(form_data, key, strlen(key));
   cbuf_append(form_data, "=", 1);
   cbuf_append(form_data, quoted_value, strlen(quoted_value));
-  free(quoted_key);
   free(quoted_value);
 }
 
@@ -217,6 +180,7 @@ int auth_client_authenticate(auth_client_t ac,
     post_field_add(&form, "shard", shard);
   }
   curl_easy_setopt(ac->c, CURLOPT_POSTFIELDS, form.buf);
+  curl_easy_setopt(ac->c, CURLOPT_POSTFIELDSIZE, form.size);
 
   // Set request headers.
   curl_slist_append(headers, "Content-Type: application/x-form-www-urlencoded");

pam/auth_client_test.cc

@@ -8,8 +8,8 @@ extern "C" {
 
 static const char *server = NULL;
 
-static const char *ssl_ca = "../authserv/test/testca/ca.pem";
-static const char *ssl_cert = "../authserv/test/testca/certs/client.pem";
+static const char *ssl_ca = "../authserv/test/testca/public/ca.pem";
+static const char *ssl_cert = "../authserv/test/testca/public/certs/client.pem";
 static const char *ssl_key = "../authserv/test/testca/private/client.key";
 static const char *ssl_bad_ca = "../authserv/test/testca-bad/ca.pem";
 static const char *ssl_bad_cert = "../authserv/test/testca-bad/certs/client.pem";
@@ -59,6 +59,21 @@ TEST_F(AuthClientTest, AuthOK) {
                            << ", server=" << server;
 }
 
+TEST_F(AuthClientTest, ManyAuthOK) {
+  int result;
+
+  for (int i = 0; i < 3; i++) {
+
+    result = auth_client_set_certificate(ac, ssl_ca, ssl_cert, ssl_key);
+    EXPECT_EQ(AC_OK, result) << "set_certificate() error: " << auth_client_strerror(result);
+    
+    result = auth_client_authenticate(ac, "user", "pass", NULL, "127.0.0.1", NULL);
+    EXPECT_EQ(AC_OK, result) << "authenticate() error: " << auth_client_strerror(result)
+                             << ", server=" << server;
+  }
+
+}
+
 TEST_F(AuthClientTest, AuthFail) {
   int result;
 

pam/cbuf.c

+
+#include <stdlib.h>
+#include <memory.h>
+#include "cbuf.h"
+
+
+void cbuf_init(struct cbuf *cbuf, size_t alloc) {
+  cbuf->buf = (char *)malloc(1);
+  cbuf->buf[0] = '\0';
+  cbuf->alloc = cbuf->size = 0;
+}
+
+void cbuf_free(struct cbuf *cbuf) {
+  free(cbuf->buf);
+}
+
+void cbuf_append(struct cbuf *cbuf, const char *data, size_t size) {
+  size_t new_alloc = cbuf->alloc + size;
+  cbuf->buf = (char *)realloc(cbuf->buf, new_alloc + 1);
+  memcpy(cbuf->buf + cbuf->size, data, size);
+  cbuf->alloc = cbuf->size = new_alloc;
+  cbuf->buf[cbuf->size] = '\0';
+}

pam/cbuf.h

+#ifndef __libauthclient_cbuf_h
+#define __libauthclient_cbuf_h 1
+
+#include <sys/types.h>
+
+/*
+ * A dynamically sized memory buffer that can be appended to, and will
+ * grow accordingly. It is optimized to perform well for a specific
+ * size (the initial allocation).
+ */
+
+struct cbuf {
+  char *buf;
+  size_t alloc, size;
+};
+
+void cbuf_init(struct cbuf *cbuf, size_t alloc);
+void cbuf_free(struct cbuf *cbuf);
+void cbuf_append(struct cbuf *cbuf, const char *data, size_t size);
+
+#endif

pam/cbuf_test.cc

+// Tests for cbuf.c.
+
+#include <stdlib.h>
+#include <string>
+#include "gtest/gtest.h"
+extern "C" {
+#include "cbuf.h"
+}
+
+TEST(Cbuf, Append) {
+  struct cbuf c;
+  cbuf_init(&c, 0);
+  cbuf_append(&c, "hello, ", 7);
+  cbuf_append(&c, "world", 5);
+  std::string a(c.buf);
+  EXPECT_EQ("hello, world", a);
+  cbuf_free(&c);
+}
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}

pam/configure.ac

@@ -2,7 +2,7 @@ AC_INIT([libauthclient], [0.1], [info@autistici.org])
 AC_CONFIG_SRCDIR([auth_client.h])
 dnl AC_LANG(C)
 
-AM_INIT_AUTOMAKE([foreign])
+AM_INIT_AUTOMAKE([foreign subdir-objects])
 AC_CONFIG_HEADERS(config.h)
 AC_CONFIG_MACRO_DIR([m4])
 AC_DISABLE_STATIC