Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 157 insertions, 0 deletions

diff --git a/epan/tvbuff_lz77.c b/epan/tvbuff_lz77.c
new file mode 100644
index 00000000..08e711ca
--- /dev/null
+++ b/epan/tvbuff_lz77.c
@@ -0,0 +1,157 @@
+/*
+ * Decompression code for Plain LZ77. This encoding is used by
+ * Microsoft in various file formats and protocols including SMB3.
+ *
+ * See MS-XCA.
+ *
+ * Copyright (C) 2019  Aurélien Aptel
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <glib.h>
+#include <epan/exceptions.h>
+#include <epan/tvbuff.h>
+#include <epan/wmem_scopes.h>
+
+#define MAX_INPUT_SIZE (16*1024*1024) /* 16MB */
+
+static gboolean do_uncompress(tvbuff_t *tvb, int offset, int in_size,
+			      wmem_array_t *obuf)
+{
+	guint buf_flags = 0, buf_flag_count = 0;
+	int in_off = 0;
+	int last_length_half_byte = 0;
+	guint match_bytes, match_len, match_off;
+	guint i;
+
+	if (!tvb)
+		return FALSE;
+
+	if (!in_size || in_size > MAX_INPUT_SIZE)
+		return FALSE;
+
+	while (1) {
+		if (buf_flag_count == 0) {
+			buf_flags = tvb_get_letohl(tvb, offset+in_off);
+			in_off += 4;
+			buf_flag_count = 32;
+		}
+		buf_flag_count--;
+		if ((buf_flags & (1u << buf_flag_count)) == 0) {
+			guint8 v = tvb_get_guint8(tvb, offset+in_off);
+			wmem_array_append_one(obuf, v);
+			in_off++;
+		} else {
+			if (in_off == in_size)
+				return TRUE;
+			match_bytes = tvb_get_letohs(tvb, offset+in_off);
+			in_off += 2;
+			match_len = match_bytes % 8;
+			match_off = (match_bytes/8) + 1;
+			if (match_len == 7) {
+				if (last_length_half_byte == 0) {
+					match_len = tvb_get_guint8(tvb, offset+in_off);
+					match_len = match_len % 16;
+					last_length_half_byte = in_off;
+					in_off++;
+				} else {
+					match_len = tvb_get_guint8(tvb, offset+last_length_half_byte);
+					match_len = match_len / 16;
+					last_length_half_byte = 0;
+				}
+				if (match_len == 15) {
+					match_len = tvb_get_guint8(tvb, offset+in_off);
+					in_off++;
+					if (match_len == 255) {
+						match_len = tvb_get_letohs(tvb, offset+in_off);
+						in_off += 2;
+						if (match_len == 0) {
+							/* This case isn't documented */
+							match_len = tvb_get_letohs(tvb, offset+in_off);
+							in_off += 4;
+						}
+						if (match_len < 15+7)
+							return FALSE;
+						match_len -= (15 + 7);
+					}
+					match_len += 15;
+				}
+				match_len += 7;
+			}
+			match_len += 3;
+			for (i = 0; i < match_len; i++) {
+				guint8 byte;
+				if (match_off > wmem_array_get_count(obuf))
+					return FALSE;
+				if (wmem_array_try_index(obuf, wmem_array_get_count(obuf)-match_off, &byte))
+					return FALSE;
+				wmem_array_append_one(obuf, byte);
+			}
+		}
+	}
+
+	return TRUE;
+}
+
+tvbuff_t *
+tvb_uncompress_lz77(tvbuff_t *tvb, const int offset, int in_size)
+{
+	volatile gboolean ok = FALSE;
+	wmem_allocator_t *pool;
+	wmem_array_t *obuf;
+	tvbuff_t *out;
+
+	pool = wmem_allocator_new(WMEM_ALLOCATOR_SIMPLE);
+	obuf = wmem_array_sized_new(pool, 1, in_size*2);
+
+	TRY {
+                ok = do_uncompress(tvb, offset, in_size, obuf);
+	} CATCH_ALL {
+		ok = FALSE;
+	}
+	ENDTRY;
+
+	if (ok) {
+		/*
+		 * Cannot pass a tvb free callback that frees the wmem
+		 * pool, so we make an extra copy that uses bare
+		 * pointers. This could be optimized if tvb API had a
+		 * free pool callback of some sort.
+		 */
+		guint size = wmem_array_get_count(obuf);
+		guint8 *p = (guint8 *)g_malloc(size);
+		memcpy(p, wmem_array_get_raw(obuf), size);
+		out = tvb_new_real_data(p, size, size);
+		tvb_set_free_cb(out, g_free);
+	} else {
+		out = NULL;
+	}
+
+	wmem_destroy_allocator(pool);
+
+	return out;
+}
+
+tvbuff_t *
+tvb_child_uncompress_lz77(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int in_size)
+{
+	tvbuff_t *new_tvb = tvb_uncompress_lz77(tvb, offset, in_size);
+	if (new_tvb)
+		tvb_set_child_real_data_tvbuff(parent, new_tvb);
+	return new_tvb;
+}
+
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */