From c0c872653431a6ae3c7958495d937f0fbb5d4b11 Mon Sep 17 00:00:00 2001
From: Ben Kibbey <bjk@luxsci.net>
Date: Wed, 10 Jan 2007 21:05:03 -0500
Subject: [PATCH] Added libXML memory handlers: xmlfree(), xmlmalloc(),
 xmlrealloc() and xmlstrdup(). xmlfree() and xmlrealloc() will clear the
 contents of memory before free()'ing.

---
 TODO           |   3 +-
 src/commands.c |  26 ++++++-------
 src/common.h   |   7 ++++
 src/pwmd.c     | 117 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 137 insertions(+), 16 deletions(-)

diff --git a/TODO b/TODO
index e04a6361..b65d36c7 100644
--- a/TODO
+++ b/TODO
@@ -1,5 +1,4 @@
-More secure memory allocation in libxml, libgcrypt and everywhere else. Both
-of these API's have the ability to specify custom memory allocators.
+More secure memory allocation in libgcrypt and everywhere else.
 
 Let the LIST command take an element path as an argument.
 
diff --git a/src/commands.c b/src/commands.c
index 8f48c02f..cff393df 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -246,24 +246,22 @@ gboolean open_command(struct client_s *client, gchar **req)
 		    strerror(errno));
 	    return FALSE;
 	}
-	else {
 new_doc:
-	    if ((client->xml = new_document()) == NULL) {
-		send_to_client(client, "ERR %03i malloc(): %s\n", EPWMD_ERROR,
-			strerror(errno));
-		return FALSE;
-	    }
-
-	    client->len = strlen(client->xml);
+	if ((client->xml = new_document()) == NULL) {
+	    send_to_client(client, "ERR %03i malloc(): %s\n", EPWMD_ERROR,
+		    strerror(errno));
+	    return FALSE;
+	}
 
-	    if (cache_add_file(client->md5file, NULL) == FALSE) {
-		send_error(client, EPWMD_MAX_SLOTS);
-		return FALSE;
-	    }
+	client->len = strlen(client->xml);
 
-	    client->filename = g_strdup(filename);
-	    return parse_xml(client);
+	if (cache_add_file(client->md5file, NULL) == FALSE) {
+	    send_error(client, EPWMD_MAX_SLOTS);
+	    return FALSE;
 	}
+
+	client->filename = g_strdup(filename);
+	return parse_xml(client);
     }
 
     if (cache_get_key(client->md5file, shakey) == TRUE) 
diff --git a/src/common.h b/src/common.h
index 0cea103b..7440e757 100644
--- a/src/common.h
+++ b/src/common.h
@@ -20,6 +20,13 @@
 #define COMMON_H
 
 typedef struct {
+    void *data;
+    size_t size;
+} mem_t;
+
+GSList *memlist;
+
+typedef struct {
     guchar filename[16];	// MD5
     guchar key[32];		// SHA256
     gboolean used;
diff --git a/src/pwmd.c b/src/pwmd.c
index c7c415e1..27f3011c 100644
--- a/src/pwmd.c
+++ b/src/pwmd.c
@@ -36,6 +36,7 @@
 #include <gcrypt.h>
 #include <sys/mman.h>
 #include <termios.h>
+#include <assert.h>
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
@@ -414,6 +415,9 @@ quit:
 	    if (cl->filename)
 		g_free(cl->filename);
 
+	    if (memlist)
+		g_slist_free(memlist);
+
 	    g_main_loop_unref(gloop);
 	    g_main_loop_quit(gloop);
 	    return FALSE;
@@ -426,6 +430,117 @@ quit:
     return TRUE;
 }
 
+static void xmlfree(void *ptr)
+{
+    gpointer p;
+    int n;
+    mem_t *data;
+
+    if (!ptr)
+	return;
+
+    for (n = 0; ; n++) {
+	if ((p = g_slist_nth_data(memlist, n)) == NULL)
+	    break;
+
+	data = p;
+
+	if (data->data == ptr) {
+	    memset(data->data, 0, data->size);
+	    free(data->data);
+	    memlist = g_slist_remove(memlist, p);
+	    return;
+	}
+    }
+
+#ifdef DEBUG
+    warnx("xmlfree(): %p not found", ptr);
+    assert(0);
+#endif
+}
+
+static void *xmlmalloc(size_t size)
+{
+    void *p;
+    mem_t *new;
+
+    if (size <= 0)
+	return NULL;
+
+    if ((new = malloc(sizeof(mem_t))) == NULL)
+	return NULL;
+
+    if ((p = malloc(size)) == NULL) {
+	free(new);
+	return NULL;
+    }
+
+    new->data = p;
+    new->size = size;
+    memlist = g_slist_append(memlist, new);
+    return new->data;
+}
+
+static void *xmlrealloc(void *ptr, size_t size)
+{
+    void *p, *new;
+    int n;
+    mem_t *data;
+
+    if (!ptr)
+	return xmlmalloc(size);
+
+    if (size <= 0)
+	return ptr;
+
+    for (n = 0; ; n++) {
+	if ((p = g_slist_nth_data(memlist, n)) == NULL)
+	    break;
+
+	data = p;
+
+	if (data->data == ptr) {
+	    if ((new = malloc(size)) == NULL)
+		return NULL;
+
+	    memcpy(new, data->data, (size < data->size) ? size : data->size);
+	    memset(data->data, 0, data->size);
+	    free(data->data);
+	    data->data = new;
+	    data->size = size;
+	    return data->data;
+	}
+    }
+
+#ifdef DEBUG
+    warnx("xmlrealloc(): %p not found", ptr);
+    assert(0);
+#endif
+    return NULL;
+}
+
+static char *xmlstrdup(const char *str)
+{
+    char *new;
+    size_t len;
+    const char *p;
+    char *np;
+
+    if (!str)
+	return NULL;
+
+    len = strlen(str) + 1;
+
+    if ((new = xmlmalloc(len * sizeof(char))) == NULL)
+	return NULL;
+
+    for (p = str, np = new; *p; p++)
+	*np++ = *p;
+
+    *np = 0;
+    return new;
+}
+
 /* 
  * Called every time a connection is made.
  */
@@ -465,6 +580,8 @@ static void doit(int fd)
 	// FIXME 100% CPU if removed (poll()).
 	send_to_client(cl, "OK \n");
 
+    xmlMemSetup(xmlfree, xmlmalloc, xmlrealloc, xmlstrdup);
+    xmlInitMemory();
     g_main_loop_run(gloop);
     g_io_channel_unref(cl->ioc);
     g_free(cl);
-- 
2.11.4.GIT