Add a new "tvb_strsize()" routine, which finds the size of a

NUL-terminated string, starting at a given offset.  The size includes
the terminating NUL.  If it doesn't find the terminating NUL, it throws
the appropriate exception, as either there's no terminating NUL in the
packet or there is but it's past the end of the captured data in the
packet.

Use that routine in the TFTP dissector.  As it throws an exception if
the string isn't NUL-terminated, we can just use "%s" to print option
strings; we don't need to use "%.*s" with a string length.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@2783 f5534014-38df-0310-8fa8-9805f1628bb7

diff --git a/epan/tvbuff.c b/epan/tvbuff.c
index f2a3566f475b35b663d5abea7d92de114eea18d9..e6ee24fba29ceb0e750d0652ced5cc5fb9886a8d 100644 (file)
--- a/epan/tvbuff.c
+++ b/epan/tvbuff.c
@@ -9,7 +9,7 @@
  *             the data of a backing tvbuff, or can be a composite of
  *             other tvbuffs.
  *
- * $Id: tvbuff.c,v 1.12 2000/11/30 06:11:32 guy Exp $
+ * $Id: tvbuff.c,v 1.13 2000/12/25 23:48:15 guy Exp $
  *
  * Copyright (c) 2000 by Gilbert Ramirez <gram@xiexie.org>
  *
@@ -1136,6 +1136,39 @@ tvb_pbrk_guint8(tvbuff_t *tvb, gint offset, guint maxlength, guint8 *needles)
        return -1;
 }
 
+/* Find size of stringz (NUL-terminated string) by looking for terminating
+ * NUL.  The size of the string includes the terminating NUL.
+ *
+ * If the NUL isn't found, it throws the appropriate exception.
+ */
+guint
+tvb_strsize(tvbuff_t *tvb, gint offset)
+{
+       guint   abs_offset, junk_length;
+       gint    nul_offset;
+
+       check_offset_length(tvb, offset, 0, &abs_offset, &junk_length);
+       nul_offset = tvb_find_guint8(tvb, abs_offset, -1, 0);
+       if (nul_offset == -1) {
+               /*
+                * OK, we hit the end of the tvbuff, so we should throw
+                * an exception.
+                *
+                * Did we hit the end of the captured data, or the end
+                * of the actual data?  If there's less captured data
+                * than actual data, we presumably hit the end of the
+                * captured data, otherwise we hit the end of the actual
+                * data.
+                */
+               if (tvb_length(tvb) < tvb_reported_length(tvb)) {
+                       THROW(BoundsError);
+               } else {
+                       THROW(ReportedBoundsError);
+               }
+       }
+       return (nul_offset - abs_offset) + 1;
+}
+
 /* Find length of string by looking for end of string ('\0'), up to
  * 'maxlength' characters'; if 'maxlength' is -1, searches to end
  * of tvbuff.

diff --git a/epan/tvbuff.h b/epan/tvbuff.h
index ca24ee4bf4ab234be901c6e4606329164b753874..021d074c3f3c244d3162a866c5c69c65e53695df 100644 (file)
--- a/epan/tvbuff.h
+++ b/epan/tvbuff.h
@@ -9,7 +9,7 @@
  *             the data of a backing tvbuff, or can be a composite of
  *             other tvbuffs.
  *
- * $Id: tvbuff.h,v 1.8 2000/11/18 10:38:33 guy Exp $
+ * $Id: tvbuff.h,v 1.9 2000/12/25 23:48:16 guy Exp $
  *
  * Copyright (c) 2000 by Gilbert Ramirez <gram@xiexie.org>
  *
@@ -280,6 +280,13 @@ gint tvb_find_guint8(tvbuff_t*, gint offset, guint maxlength, guint8 needle);
  * the boundary is reached before finding needle. */
 gint tvb_pbrk_guint8(tvbuff_t *, gint offset, guint maxlength, guint8 *needles);
 
+/* Find size of stringz (NUL-terminated string) by looking for terminating
+ * NUL.  The size of the string includes the terminating NUL.
+ *
+ * If the NUL isn't found, it throws the appropriate exception.
+ */
+guint tvb_strsize(tvbuff_t *tvb, gint offset);
+
 /* Find length of string by looking for end of string ('\0'), up to
  * 'maxlength' characters'; if 'maxlength' is -1, searches to end
  * of tvbuff.

diff --git a/packet-tftp.c b/packet-tftp.c
index 2c51258b90b70fca6835a3d272006cfc26542f3b..8926974bc2685469d769963d837d1b6bcf42cdce 100644 (file)
--- a/packet-tftp.c
+++ b/packet-tftp.c
@@ -5,7 +5,7 @@
  * Craig Newell <CraigN@cheque.uq.edu.au>
  *     RFC2347 TFTP Option Extension
  *
- * $Id: packet-tftp.c,v 1.20 2000/12/24 20:33:04 guy Exp $
+ * $Id: packet-tftp.c,v 1.21 2000/12/25 23:48:14 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -87,7 +87,6 @@ static const value_string tftp_error_code_vals[] = {
 };
 
 static void tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree);
-static gint tftp_strnlen(tvbuff_t *tvb, gint offset);
 
 static void
 dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
@@ -152,12 +151,12 @@ dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
            
          switch (opcode) {
          case RRQ:
-           i1 = tftp_strnlen(tvb, offset);
+           i1 = tvb_strsize(tvb, offset);
            proto_tree_add_item(tftp_tree, hf_tftp_source_file,
                            tvb, offset, i1, FALSE);
            offset += i1;
 
-           i1 = tftp_strnlen(tvb, offset);
+           i1 = tvb_strsize(tvb, offset);
            ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
                            tvb, offset, i1, FALSE);
            offset += i1;
@@ -165,12 +164,12 @@ dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
            tftp_dissect_options(tvb, offset, tftp_tree);
            break;
          case WRQ:
-           i1 = tftp_strnlen(tvb, offset);
+           i1 = tvb_strsize(tvb, offset);
            proto_tree_add_item(tftp_tree, hf_tftp_destination_file,
                            tvb, offset, i1, FALSE);
            offset += i1;
 
-           i1 = tftp_strnlen(tvb, offset);
+           i1 = tvb_strsize(tvb, offset);
            ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
                            tvb, offset, i1, FALSE);
            offset += i1;
@@ -194,7 +193,7 @@ dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
                            FALSE);
            offset += 2;
 
-           i1 = tftp_strnlen(tvb, offset);
+           i1 = tvb_strsize(tvb, offset);
            proto_tree_add_item(tftp_tree, hf_tftp_error_string, tvb, offset,
                i1, FALSE);
            break;
@@ -217,44 +216,17 @@ tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree)
        int value_offset;
 
        while (tvb_offset_exists(tvb, offset)) {
-         option_len = tftp_strnlen(tvb, offset);       /* length of option */
+         option_len = tvb_strsize(tvb, offset);        /* length of option */
          value_offset = offset + option_len;
-         value_len = tftp_strnlen(tvb, value_offset);  /* length of value */
+         value_len = tvb_strsize(tvb, value_offset);   /* length of value */
          proto_tree_add_text(tree, tvb, offset, option_len+value_len,
-                 "Option: %.*s = %.*s",
-                 option_len - 1, tvb_get_ptr(tvb, offset, option_len - 1),
-                 value_len - 1, tvb_get_ptr(tvb, value_offset, value_len - 1));
+                 "Option: %s = %s",
+                 tvb_get_ptr(tvb, offset, option_len),
+                 tvb_get_ptr(tvb, value_offset, value_len));
          offset += option_len + value_len;
        }
 }
 
-/*
- * Find the length of a null-terminated string in a TFTP packet; if we
- * don't find the '\0', throw an exception, as it means that either
- * we didn't capture enough of the frame, or the frame is malformed.
- *
- * XXX - we'd like to know *which* exception to throw....
- *
- * XXX - this should probably be a standard tvbuff accessor.
- *
- * Add 1 to the resulting length, so that it includes the '\0'.
- */
-static gint
-tftp_strnlen(tvbuff_t *tvb, gint offset)
-{
-       gint len;
-
-       len = tvb_strnlen(tvb, offset, -1);
-       if (len == -1) {
-           /*
-            * No '\0' found before the end of the tvbuff; throw an
-            * exception.
-            */
-           THROW(BoundsError);
-       }
-       return len + 1;
-}
-
 void
 proto_register_tftp(void)
 {