Fix an off-by-one bug reported by David Ceccanti, as suggested by Guy at

http://www.wireshark.org/lists/wireshark-users/200806/msg00077.html.
Add a comment about the usage of gsm_sms_char_7bit_unpack().

svn path=/trunk/; revision=25462

2 files changed, 17 insertions, 2 deletions

diff --git a/epan/dissectors/packet-gsm_sms.c b/epan/dissectors/packet-gsm_sms.c
index e7d62398d9..204b9e56f6 100644
--- a/epan/dissectors/packet-gsm_sms.c
+++ b/epan/dissectors/packet-gsm_sms.c
@@ -215,6 +215,7 @@ static gint ett_udh_ieis[NUM_UDH_IEIS];
 	oct); \
 }
 
+#define ADDRBUF_MAX_MESSAGE_SIZE 20
 static void
 dis_field_addr(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p, const gchar *title)
 {
@@ -227,7 +228,7 @@ dis_field_addr(tvbuff_t *tvb, proto_tree *tree, guint32 *offset_p, const gchar *
     guint32		numdigocts;
     guint32		length;
     guint32		i, j;
-    char                addrbuf[20];
+    char                addrbuf[ADDRBUF_MAX_MESSAGE_SIZE+1];
 
     offset = *offset_p;
 
@@ -1804,6 +1805,7 @@ dis_field_ud_iei(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint8 length)
 
 /* 9.2.3.24 */
 #define NUM_FILL_BITS_MASKS 6
+#define SMS_MAX_MESSAGE_SIZE 160
 static void
 dis_field_ud(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint32 length, gboolean udhi, guint8 udl,
     gboolean seven_bit, gboolean eight_bit, gboolean ucs2, gboolean compressed)
@@ -1818,7 +1820,7 @@ dis_field_ud(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint32 length, gb
     guint	fill_bits;
     guint32	out_len;
     char	*ustr;
-    char        messagebuf[160];
+    char        messagebuf[SMS_MAX_MESSAGE_SIZE+1];
     proto_item *ucs2_item;
     gchar *utf8_text = NULL;
     GIConv cd;
diff --git a/epan/dissectors/packet-gsm_sms.h b/epan/dissectors/packet-gsm_sms.h
index 2a652b52b9..33c6737215 100644
--- a/epan/dissectors/packet-gsm_sms.h
+++ b/epan/dissectors/packet-gsm_sms.h
@@ -24,6 +24,19 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+/* Convert a 7-bit GSM SMS packed string into an unpacked string.
+ *
+ * @param offset Bit offset of the start of the string.
+ * @param in_length Length of the packed string in bytes.
+ * @param out_length Length of the output string in bytes.
+ * @param input The string to unpack
+ * @param output The buffer for the output string. This buffer must
+ *               be pre-allocated and be at least out_length characters
+ *               long, or out_length + 1 if you're planning on adding a
+ *               terminating '\0'.
+ * @return The number of unpacked characters.
+ */
+
 extern int gsm_sms_char_7bit_unpack(unsigned int offset, unsigned int in_length, unsigned int out_length,
 		     const guint8 *input, unsigned char *output);
 extern void gsm_sms_char_ascii_decode(unsigned char* dest, const unsigned char* src, int len);