Issue 521: Properly check reading from lzss decompression buffer

Prior code could be tricked into trying to copy data
from beyond the end of the internal decompression buffer.

Thanks to Hanno Böck for his ongoing fuzz-testing work with libarchive.

5 files changed, 59 insertions, 4 deletions

diff --git a/Makefile.am b/Makefile.am
index 3e2dc629..b93b921a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -454,6 +454,7 @@ libarchive_test_SOURCES= \
 	libarchive/test/test_read_format_rar_encryption_data.c \
 	libarchive/test/test_read_format_rar_encryption_partially.c \
 	libarchive/test/test_read_format_rar_encryption_header.c \
+	libarchive/test/test_read_foramt_rar_invalid1.c \
 	libarchive/test/test_read_format_raw.c \
 	libarchive/test/test_read_format_tar.c \
 	libarchive/test/test_read_format_tar_concatenated.c \
diff --git a/libarchive/archive_read_support_format_rar.c b/libarchive/archive_read_support_format_rar.c
index 6c49f1a1..f729f173 100644
--- a/libarchive/archive_read_support_format_rar.c
+++ b/libarchive/archive_read_support_format_rar.c
@@ -2890,11 +2890,10 @@ copy_from_lzss_window(struct archive_read *a, const void **buffer,
   }
 
   windowoffs = lzss_offset_for_position(&rar->lzss, startpos);
-  if(windowoffs + length <= lzss_size(&rar->lzss))
+  if(windowoffs + length <= lzss_size(&rar->lzss)) {
     memcpy(&rar->unp_buffer[rar->unp_offset], &rar->lzss.window[windowoffs],
            length);
-  else
-  {
+  } else if (length <= lzss_size(&rar->lzss)) {
     firstpart = lzss_size(&rar->lzss) - windowoffs;
     if (firstpart < 0) {
       archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
@@ -2906,9 +2905,14 @@ copy_from_lzss_window(struct archive_read *a, const void **buffer,
              &rar->lzss.window[windowoffs], firstpart);
       memcpy(&rar->unp_buffer[rar->unp_offset + firstpart],
              &rar->lzss.window[0], length - firstpart);
-    } else
+    } else {
       memcpy(&rar->unp_buffer[rar->unp_offset],
              &rar->lzss.window[windowoffs], length);
+    }
+  } else {
+      archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
+                        "Bad RAR file data");
+      return (ARCHIVE_FATAL);
   }
   rar->unp_offset += length;
   if (rar->unp_offset >= rar->unp_buffer_size)
diff --git a/libarchive/test/CMakeLists.txt b/libarchive/test/CMakeLists.txt
index b70be742..124aa3a8 100644
--- a/libarchive/test/CMakeLists.txt
+++ b/libarchive/test/CMakeLists.txt
@@ -143,6 +143,7 @@ IF(ENABLE_TEST)
     test_read_format_rar_encryption_data.c
     test_read_format_rar_encryption_header.c
     test_read_format_rar_encryption_partially.c
+    test_read_format_rar_invalid1.c
     test_read_format_raw.c
     test_read_format_tar.c
     test_read_format_tar_concatenated.c
diff --git a/libarchive/test/test_read_format_rar_invalid1.c b/libarchive/test/test_read_format_rar_invalid1.c
new file mode 100644
index 00000000..61dea164
--- /dev/null
+++ b/libarchive/test/test_read_format_rar_invalid1.c
@@ -0,0 +1,44 @@
+/*-
+ * Copyright (c) 2003-2016 Tim Kientzle
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "test.h"
+__FBSDID("$FreeBSD$");
+
+DEFINE_TEST(test_read_format_rar_invalid1)
+{
+	const char *refname = "test_read_format_rar_invalid1.rar";
+	struct archive *a;
+	struct archive_entry *ae;
+	char *buff[100];
+
+	extract_reference_file(refname);
+	assert((a = archive_read_new()) != NULL);
+	assertEqualIntA(a, ARCHIVE_OK, archive_read_support_format_all(a));
+	assertEqualIntA(a, ARCHIVE_OK, archive_read_support_filter_all(a));
+	assertEqualIntA(a, ARCHIVE_OK, archive_read_open_filename(a, refname, 10240));
+	assertEqualIntA(a, ARCHIVE_OK, archive_read_next_header(a, &ae));
+	assertEqualIntA(a, ARCHIVE_FATAL, archive_read_data(a, buff, 99));
+	assertEqualIntA(a, ARCHIVE_OK, archive_read_close(a));
+	assertEqualInt(ARCHIVE_OK, archive_read_free(a));
+}
diff --git a/libarchive/test/test_read_format_rar_invalid1.rar.uu b/libarchive/test/test_read_format_rar_invalid1.rar.uu
new file mode 100644
index 00000000..2380399d
--- /dev/null
+++ b/libarchive/test/test_read_format_rar_invalid1.rar.uu
@@ -0,0 +1,5 @@
+begin 644 test_read_format_rar_invalid1.rar
+M4F%R(1H'`,^0<P``#0````````"9SG0@D"8`#`````,````#+7,'\(^>B$4=
+2,P0`I($``'1E<W0`P/\````)
+`
+end