Adding upstream version 4.2.2.upstream/4.2.2

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

1 files changed, 381 insertions, 0 deletions

diff --git a/epan/dissectors/packet-git.c b/epan/dissectors/packet-git.c
new file mode 100644
index 00000000..a9644ac1
--- /dev/null
+++ b/epan/dissectors/packet-git.c
@@ -0,0 +1,381 @@
+/* packet-git.c
+ * Routines for git packet dissection
+ * Copyright 2010, Jelmer Vernooij <jelmer@samba.org>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * Copied from packet-pop.c
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Current testing suite 'case_dissect_git' can be found at
+ * test/suite_dissection.py
+ */
+
+#include "config.h"
+
+#include <stdio.h>    /* for sscanf() */
+
+#include <epan/packet.h>
+#include <epan/expert.h>
+#include <epan/prefs.h>
+#include "packet-tcp.h"
+
+void proto_register_git(void);
+void proto_reg_handoff_git(void);
+
+static dissector_handle_t git_handle;
+
+static int proto_git = -1;
+static expert_field ei_git_bad_pkt_len = EI_INIT;
+static expert_field ei_git_malformed = EI_INIT;
+
+static gint ett_git = -1;
+
+static gint hf_git_protocol_version = -1;
+static gint hf_git_packet_type = -1;
+static gint hf_git_packet_len = -1;
+static gint hf_git_packet_data = -1;
+static gint hf_git_sideband_control_code = -1;
+static gint hf_git_upload_pack_adv = -1;
+static gint hf_git_upload_pack_req = -1;
+static gint hf_git_upload_pack_res = -1;
+
+#define PNAME  "Git Smart Protocol"
+#define PSNAME "Git"
+#define PFNAME "git"
+
+#define TCP_PORT_GIT    9418
+
+static const value_string packet_type_vals[] = {
+  { 0, "Flush" },
+  { 1, "Delimiter" },
+  { 2, "Response end" },
+  { 0, NULL }
+};
+
+static const value_string version_vals[] = {
+  { '1', "Git protocol version 1" },
+  { '2', "Git protocol version 2" },
+  { 0, NULL }
+};
+
+#define SIDEBAND_PACKFILE_DATA 0x01
+#define SIDEBAND_PROGRESS_INFO 0x02
+#define SIDEBAND_ERROR_INFO 0x03
+static const value_string sideband_vals[] = {
+  { SIDEBAND_PACKFILE_DATA, "Git packfile data" },
+  { SIDEBAND_PROGRESS_INFO, "Git progress data" },
+  { SIDEBAND_ERROR_INFO, "Git error data" },
+  { 0, NULL }
+};
+
+/* desegmentation of Git over TCP */
+static gboolean git_desegment = TRUE;
+
+static gboolean get_packet_length(tvbuff_t *tvb, int offset,
+                                  guint16 *length)
+{
+  guint8 *lenstr;
+
+  lenstr = tvb_get_string_enc(wmem_packet_scope(), tvb, offset, 4, ENC_ASCII);
+
+  return (sscanf(lenstr, "%hx", length) == 1);
+}
+
+static guint
+get_git_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
+{
+  guint16 plen;
+
+  if (!get_packet_length(tvb, offset, &plen))
+    return 0; /* No idea what this is */
+
+  return plen < 4
+      ? 4   // Special packet (e.g., flush-pkt)
+      : plen;
+}
+
+/* Parse pkt-lines one-by-one
+ *
+ * @param  tvb       The buffer to dissect.
+ * @param  pinfo     Packet info associated to this buffer.
+ * @param  git_tree  The git protocol subtree.
+ * @param  offset    The offset at which to start the dissection.
+ * @return bool      After successful/unsuccessful parsing.
+ *
+ * This new helper takes the contents of the tvbuffer, updates the
+ * offset, and returns to the caller for subsequent processing of the
+ * remainder of the data.
+*/
+static gboolean
+dissect_pkt_line(tvbuff_t *tvb, packet_info *pinfo, proto_tree *git_tree,
+                 int *offset)
+{
+  guint16 plen;
+
+  // what type of pkt-line is it?
+  if (!get_packet_length(tvb, *offset, &plen))
+    return FALSE;
+  if (plen < 4) {   // a special packet (e.g., flush-pkt)
+    proto_item *ti =
+        proto_tree_add_uint(git_tree, hf_git_packet_type, tvb,
+                            *offset, 4, plen);
+    *offset += 4;
+
+    if (!try_val_to_str(plen, packet_type_vals))
+      expert_add_info(pinfo, ti, &ei_git_bad_pkt_len);
+    return TRUE;
+  }
+
+  proto_tree_add_uint(git_tree, hf_git_packet_len, tvb, *offset, 4, plen);
+  *offset += 4;
+  plen -= 4;
+
+  /*
+   * Parse out the version of the Git Protocol
+   *
+   * The initial server response contains the version of the Git Protocol in use;
+   * 1 or 2. Parsing out this information helps identify the capabilities and
+   * information that can be used with the protocol.
+  */
+  if (plen >= 9 && !tvb_strneql(tvb, *offset, "version ", 8)) {
+    proto_tree_add_item(git_tree, hf_git_protocol_version, tvb, *offset + 8,
+                        1, ENC_NA);
+  }
+
+  /*
+   * Parse out the sideband control code.
+   *
+   * Not all pkt-lines have a sideband control code. With more context from the rest of
+   * the request or response, we would be able to tell whether sideband is expected here;
+   * lacking that, let's assume for now that all pkt-lines starting with \1, \2, or \3
+   * are using sideband.
+   */
+  int sideband_code = tvb_get_guint8(tvb, *offset);
+
+  if (1 <= sideband_code && sideband_code <= 3) {
+    proto_tree_add_uint(git_tree, hf_git_sideband_control_code, tvb, *offset, 1,
+                        sideband_code);
+    (*offset)++;
+    plen--;
+  }
+
+  proto_tree_add_item(git_tree, hf_git_packet_data, tvb, *offset, plen, ENC_NA);
+  *offset += plen;
+  return TRUE;
+}
+
+static int
+dissect_git_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+  proto_tree             *git_tree;
+  proto_item             *ti;
+  int offset = 0;
+
+  col_set_str(pinfo->cinfo, COL_PROTOCOL, PSNAME);
+
+  col_set_str(pinfo->cinfo, COL_INFO, PNAME);
+
+  ti = proto_tree_add_item(tree, proto_git, tvb, offset, -1, ENC_NA);
+  git_tree = proto_item_add_subtree(ti, ett_git);
+
+  if (!dissect_pkt_line(tvb, pinfo, git_tree, &offset))
+    return 0;
+
+  return tvb_captured_length(tvb);
+}
+
+/* Parse http packs
+ *
+ * @param  tvb        The buffer to dissect.
+ * @param  pinfo      The Packet Info.
+ * @param  tree       The protocol tree.
+ * @param  hfindex    The type of http pack.
+ * @return tvb_length The amount of captured data in the buffer,
+ *                    returns 0 if parsing failed.
+ *
+ * This new helper takes the contents of the tvbuffer sent by http
+ * dissectors, adds the packs to the git subtree and returns the amount
+ * of consumed bytes in the tvb buffer.
+*/
+static int
+dissect_http_pkt_lines(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int hfindex)
+{
+  proto_tree             *git_tree;
+  proto_item             *ti;
+  int offset = 0;
+  int total_len = 0;
+
+  col_set_str(pinfo->cinfo, COL_PROTOCOL, PSNAME);
+
+  col_set_str(pinfo->cinfo, COL_INFO, PNAME);
+
+  ti = proto_tree_add_item(tree, proto_git, tvb, offset, -1, ENC_NA);
+  git_tree = proto_item_add_subtree(ti, ett_git);
+
+  proto_tree_add_item(git_tree, hfindex, tvb, offset,
+                      tvb_captured_length(tvb), ENC_NA);
+
+  total_len = tvb_reported_length(tvb);
+  while (offset < total_len) {
+    /* Add expert info if there is trouble parsing part-way through */
+    if (!dissect_pkt_line(tvb, pinfo, git_tree, &offset)) {
+      proto_tree_add_expert(git_tree, pinfo, &ei_git_malformed, tvb, offset, -1);
+      break;
+    }
+  }
+
+  return tvb_captured_length(tvb);
+}
+
+static int
+dissect_git_upload_pack_adv(tvbuff_t *tvb, packet_info *pinfo,
+                            proto_tree *tree, void *data _U_)
+{
+  return dissect_http_pkt_lines(tvb, pinfo, tree, hf_git_upload_pack_adv);
+}
+
+static int
+dissect_git_upload_pack_req(tvbuff_t *tvb, packet_info *pinfo,
+                            proto_tree *tree, void *data _U_)
+{
+  return dissect_http_pkt_lines(tvb, pinfo, tree, hf_git_upload_pack_req);
+}
+
+static int
+dissect_git_upload_pack_res(tvbuff_t *tvb, packet_info *pinfo,
+                            proto_tree *tree, void *data _U_)
+{
+  return dissect_http_pkt_lines(tvb, pinfo, tree, hf_git_upload_pack_res);
+}
+
+static int
+dissect_git(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
+{
+  tcp_dissect_pdus(tvb, pinfo, tree, git_desegment, 4, get_git_pdu_len,
+                   dissect_git_pdu, data);
+  return tvb_captured_length(tvb);
+}
+
+void
+proto_register_git(void)
+{
+  static hf_register_info hf[] = {
+    { &hf_git_protocol_version,
+      { "Git Protocol Version", "git.version", FT_UINT8, BASE_NONE, VALS(version_vals),
+      0, NULL, HFILL },
+    },
+    { &hf_git_packet_type,
+      { "Git Packet Type", "git.packet_type", FT_UINT8, BASE_NONE, VALS(packet_type_vals),
+      0, NULL, HFILL },
+    },
+    { &hf_git_packet_len,
+      { "Packet length", "git.length", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL },
+    },
+    { &hf_git_packet_data,
+      { "Packet data", "git.data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL },
+    },
+    { &hf_git_sideband_control_code,
+      { "Sideband control code", "git.sideband_control_code", FT_UINT8,
+      BASE_HEX, VALS(sideband_vals), 0, NULL, HFILL },
+    },
+    { &hf_git_upload_pack_adv,
+      { "Upload Pack Advertisement", "git.upload_pack_advertisement",
+      FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL },
+    },
+    { &hf_git_upload_pack_req,
+      { "Upload Pack Request", "git.upload_pack_request",
+      FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL },
+    },
+    { &hf_git_upload_pack_res,
+      { "Upload Pack Result", "git.upload_pack_result",
+      FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL },
+    },
+  };
+
+  static gint *ett[] = {
+    &ett_git,
+  };
+
+  static ei_register_info ei[] = {
+    { &ei_git_bad_pkt_len,
+      { "git.bad_pkt_len", PI_PROTOCOL, PI_ERROR,
+        "unrecognized special pkt-len value", EXPFILL }
+    },
+    { &ei_git_malformed,
+      { "git.malformed", PI_MALFORMED, PI_ERROR,
+        "malformed packet", EXPFILL }
+    },
+  };
+
+  module_t *git_module;
+  expert_module_t *expert_git;
+
+  proto_git = proto_register_protocol(PNAME, PSNAME, PFNAME);
+  proto_register_field_array(proto_git, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+
+  expert_git = expert_register_protocol(proto_git);
+  expert_register_field_array(expert_git, ei, array_length(ei));
+
+  git_handle = register_dissector(PFNAME, dissect_git, proto_git);
+
+  git_module = prefs_register_protocol(proto_git, NULL);
+
+  prefs_register_bool_preference(git_module, "desegment",
+                                 "Reassemble GIT messages spanning multiple TCP segments",
+                                 "Whether the GIT dissector should reassemble messages spanning multiple TCP segments."
+                                 " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
+                                 &git_desegment);
+}
+
+void
+proto_reg_handoff_git(void)
+{
+  /*
+   * Add the dissectors for GIT over HTTP
+   *
+   * Reference documentation at
+   * https://www.kernel.org/pub/software/scm/git/docs//technical/http-protocol.txt
+   */
+  dissector_handle_t git_upload_pack_adv_handle;
+  dissector_handle_t git_upload_pack_req_handle;
+  dissector_handle_t git_upload_pack_res_handle;
+
+  git_upload_pack_adv_handle = create_dissector_handle(dissect_git_upload_pack_adv,
+                        proto_git);
+
+  git_upload_pack_req_handle = create_dissector_handle(dissect_git_upload_pack_req,
+                        proto_git);
+
+  git_upload_pack_res_handle = create_dissector_handle(dissect_git_upload_pack_res,
+                        proto_git);
+
+  dissector_add_string("media_type",
+                        "application/x-git-upload-pack-advertisement",
+                        git_upload_pack_adv_handle);
+  dissector_add_string("media_type",
+                        "application/x-git-upload-pack-request",
+                        git_upload_pack_req_handle);
+  dissector_add_string("media_type",
+                        "application/x-git-upload-pack-result",
+                        git_upload_pack_res_handle);
+
+  dissector_add_uint_with_preference("tcp.port", TCP_PORT_GIT, git_handle);
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */