diff --git a/ChangeLog b/ChangeLog
index a252fb6b5a..35ef951ffc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jan 25 17:16:53 CET 2008 (acab)
+-----------------------------------
+  * libclamunrar: same behaviour on 32bit and 64bit systems - bb#474
+
 Fri Jan 25 18:15:21 EET 2008 (edwin)
 ------------------------------------
   * libclamav/htmlnorm.[ch]: handle NULL characters in HTML files. (bb #539).
diff --git a/libclamunrar/unrarppm.c b/libclamunrar/unrarppm.c
index 343fcad63b..1679e53987 100644
--- a/libclamunrar/unrarppm.c
+++ b/libclamunrar/unrarppm.c
@@ -104,12 +104,16 @@ static int sub_allocator_start_sub_allocator(sub_allocator_t *sub_alloc, int sa_
 		return TRUE;
 	}
 	sub_allocator_stop_sub_allocator(sub_alloc);
+	if (t>138412020) {
+		rar_dbgmsg("too much memory needed for uncompressing this file\n");
+		return FALSE;
+	}
 	alloc_size = t/FIXED_UNIT_SIZE*UNIT_SIZE+UNIT_SIZE;
 #if defined(__sparc) || defined(sparc) || defined(__sparcv9)
 	/* Allow for aligned access requirements */
 	alloc_size += UNIT_SIZE;
 #endif
-	if ((sub_alloc->heap_start = (uint8_t *) rar_malloc(alloc_size)) == NULL) {
+	if ((sub_alloc->heap_start = (uint8_t *) malloc(alloc_size)) == NULL) {
 		rar_dbgmsg("sub_alloc start failed\n");
 		return FALSE;
 	}
diff --git a/libclamunrar/unrarppm.h b/libclamunrar/unrarppm.h
index 4a51463e97..a588a19e59 100644
--- a/libclamunrar/unrarppm.h
+++ b/libclamunrar/unrarppm.h
@@ -59,18 +59,27 @@ struct see2_context_tag
 	uint8_t shift, count;
 };
 
+#ifndef HAVE_ATTRIB_PACKED
+#define __attribute__(x)
+#endif
+#ifdef HAVE_PRAGMA_PACK
+#pragma pack(1)
+#endif
+#ifdef HAVE_PRAGMA_PACK_HPPA
+#pragma pack 1
+#endif
 struct state_tag
 {
 	struct ppm_context *successor;
 	uint8_t symbol;
 	uint8_t freq;
-};
+} __attribute__((packed));
 
 struct freq_data_tag
 {
 	struct state_tag *stats;
 	uint16_t summ_freq;
-};
+} __attribute__((packed));
 
 struct ppm_context {
 	struct ppm_context *suffix;
@@ -79,7 +88,13 @@ struct ppm_context {
 		struct state_tag one_state;
 	} con_ut;
 	uint16_t num_stats;
-};
+} __attribute__((packed));
+#ifdef HAVE_PRAGMA_PACK
+#pragma pack()
+#endif
+#ifdef HAVE_PRAGMA_PACK_HPPA
+#pragma pack
+#endif
 
 typedef struct ppm_data_tag
 {