Make bit_offset in _tvb_get_bits64 and related functions unsigned. This

removes a potential buffer overflow and should fix a bunch of Coverity
errors mentioned in bug 6878.

We might want to do the same for no_of_bits.

svn path=/trunk/; revision=41945

6 files changed, 47 insertions, 50 deletions

diff --git a/epan/proto.c b/epan/proto.c
index 452b5fb552..10a1c209a1 100644
--- a/epan/proto.c
+++ b/epan/proto.c
@@ -7311,7 +7311,7 @@ proto_tree_add_bitmask_text(proto_tree *parent_tree, tvbuff_t *tvb,
 
 proto_item *
 proto_tree_add_bits_item(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
-			 const gint bit_offset, const gint no_of_bits,
+			 const guint bit_offset, const gint no_of_bits,
 			 const guint encoding)
 {
 	header_field_info *hfinfo;
@@ -7329,7 +7329,7 @@ proto_tree_add_bits_item(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
 
 static proto_item *
 _proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
-			    const gint bit_offset, const gint no_of_bits,
+			    const guint bit_offset, const gint no_of_bits,
 			    guint64 *return_value, const guint encoding)
 {
 	gint     offset;
@@ -7353,7 +7353,6 @@ _proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb
 						      hf_field->abbrev, hf_field->name));
 	}
 
-	DISSECTOR_ASSERT(bit_offset >= 0);
 	DISSECTOR_ASSERT(no_of_bits >  0);
 
 	/* Byte align offset */
@@ -7449,14 +7448,14 @@ _proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb
 
 proto_item *
 proto_tree_add_split_bits_item_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
-				       const gint bit_offset, const crumb_spec_t *crumb_spec,
+				       const guint bit_offset, const crumb_spec_t *crumb_spec,
 				       guint64 *return_value)
 {
 	proto_item *pi;
 	gint        no_of_bits;
 	gint        octet_offset;
-	gint        mask_initial_bit_offset;
-	gint        mask_greatest_bit_offset;
+	guint       mask_initial_bit_offset;
+	guint       mask_greatest_bit_offset;
 	guint       octet_length;
 	guint8      i;
 	char       *bf_str;
@@ -7609,7 +7608,7 @@ proto_tree_add_split_bits_item_ret_val(proto_tree *tree, const int hf_index, tvb
 }
 
 void
-proto_tree_add_split_bits_crumb(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset,
+proto_tree_add_split_bits_crumb(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset,
 				const crumb_spec_t *crumb_spec, guint16 crumb_index)
 {
 	header_field_info *hf_info;
@@ -7630,7 +7629,7 @@ proto_tree_add_split_bits_crumb(proto_tree *tree, const int hf_index, tvbuff_t *
 
 proto_item *
 proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
-			    const gint bit_offset, const gint no_of_bits,
+			    const guint bit_offset, const gint no_of_bits,
 			    guint64 *return_value, const guint encoding)
 {
 	proto_item *item;
@@ -7646,7 +7645,7 @@ proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
 
 static proto_item *
 _proto_tree_add_bits_format_value(proto_tree *tree, const int hf_index,
-				 tvbuff_t *tvb, const gint bit_offset,
+				 tvbuff_t *tvb, const guint bit_offset,
 				 const gint no_of_bits, void *value_ptr,
 				 gchar *value_str)
 {
@@ -7667,7 +7666,6 @@ _proto_tree_add_bits_format_value(proto_tree *tree, const int hf_index,
 					     hf_field->abbrev, hf_field->name));
 	}
 
-	DISSECTOR_ASSERT(bit_offset >= 0);
 	DISSECTOR_ASSERT(no_of_bits > 0);
 
 	/* Byte align offset */
@@ -7747,7 +7745,7 @@ _proto_tree_add_bits_format_value(proto_tree *tree, const int hf_index,
 
 proto_item *
 proto_tree_add_bits_format_value(proto_tree *tree, const int hf_index,
-				 tvbuff_t *tvb, const gint bit_offset,
+				 tvbuff_t *tvb, const guint bit_offset,
 				 const gint no_of_bits, void *value_ptr,
 				 gchar *value_str)
 {
@@ -7769,7 +7767,7 @@ proto_tree_add_bits_format_value(proto_tree *tree, const int hf_index,
 
 proto_item *
 proto_tree_add_uint_bits_format_value(proto_tree *tree, const int hf_index,
-				      tvbuff_t *tvb, const gint bit_offset,
+				      tvbuff_t *tvb, const guint bit_offset,
 				      const gint no_of_bits, guint32 value,
 				      const char *format, ...)
 {
@@ -7799,7 +7797,7 @@ proto_tree_add_uint_bits_format_value(proto_tree *tree, const int hf_index,
 
 proto_item *
 proto_tree_add_float_bits_format_value(proto_tree *tree, const int hf_index,
-				       tvbuff_t *tvb, const gint bit_offset,
+				       tvbuff_t *tvb, const guint bit_offset,
 				       const gint no_of_bits, float value,
 				       const char *format, ...)
 {
@@ -7818,7 +7816,7 @@ proto_tree_add_float_bits_format_value(proto_tree *tree, const int hf_index,
 
 proto_item *
 proto_tree_add_int_bits_format_value(proto_tree *tree, const int hf_index,
-				     tvbuff_t *tvb, const gint bit_offset,
+				     tvbuff_t *tvb, const guint bit_offset,
 				     const gint no_of_bits, gint32 value,
 				     const char *format, ...)
 {
@@ -7848,7 +7846,7 @@ proto_tree_add_int_bits_format_value(proto_tree *tree, const int hf_index,
 
 proto_item *
 proto_tree_add_boolean_bits_format_value(proto_tree *tree, const int hf_index,
-					 tvbuff_t *tvb, const gint bit_offset,
+					 tvbuff_t *tvb, const guint bit_offset,
 					 const gint no_of_bits, guint32 value,
 					 const char *format, ...)
 {
diff --git a/epan/proto.h b/epan/proto.h
index 7eaf6a374b..7b9801106c 100644
--- a/epan/proto.h
+++ b/epan/proto.h
@@ -385,7 +385,7 @@ typedef struct field_info {
 
 /*
  * This structure describes one segment of a split-bits item
- * crumb_bit_offset is the bit offset in the input tvb of the first (most significant) bit of this crumb 
+ * crumb_bit_offset is the bit offset in the input tvb of the first (most significant) bit of this crumb
  * crumb_bit_length is the number of contiguous bits of this crumb.
  * The first element of an array of bits_specs describes the most significant crumb of the output value.
  * The second element of an array of bits_specs describes the next-most significant crumb of the output value, etc.
@@ -1899,7 +1899,7 @@ proto_tree_add_bitmask_text(proto_tree *tree, tvbuff_t *tvb, const guint offset,
  @param encoding data encoding
  @return the newly created item */
 extern proto_item *
-proto_tree_add_bits_item(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits, const guint encoding);
+proto_tree_add_bits_item(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits, const guint encoding);
 
 /** Add bits to a proto_tree, using the text label registered to that item.
 *  The item is extracted from the tvbuff handed to it as a set
@@ -1912,13 +1912,13 @@ proto_tree_add_bits_item(proto_tree *tree, const int hf_index, tvbuff_t *tvb, co
  @param tree the tree to append this item to
  @param hf_index field index. Fields for use with this function should have bitmask==0.
  @param tvb the tv buffer of the current data
- @param bit_offset of the first crumb in tvb expressed in bits 
+ @param bit_offset of the first crumb in tvb expressed in bits
  @param pointer to crumb_spec array
  @param return_value if a pointer is passed here the value is returned.
  @return the newly created item */
 extern proto_item *
 proto_tree_add_split_bits_item_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
-			    const gint bit_offset, const crumb_spec_t *crumb_spec,
+			    const guint bit_offset, const crumb_spec_t *crumb_spec,
 			    guint64 *return_value);
 
 
@@ -1932,11 +1932,11 @@ proto_tree_add_split_bits_item_ret_val(proto_tree *tree, const int hf_index, tvb
  @param tree the tree to append this item to
  @param hf_index field index. Fields for use with this function should have bitmask==0.
  @param tvb the tv buffer of the current data
- @param bit_offset of the first crumb in tvb expressed in bits 
+ @param bit_offset of the first crumb in tvb expressed in bits
  @param pointer to crumb_spec array
  @param index into the crumb_spec array for this crumb */
-void 
-proto_tree_add_split_bits_crumb(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, 
+void
+proto_tree_add_split_bits_crumb(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset,
                                 const crumb_spec_t *crumb_spec, guint16 crumb_index);
 
 /** Add bits to a proto_tree, using the text label registered to that item.
@@ -1950,7 +1950,7 @@ proto_tree_add_split_bits_crumb(proto_tree *tree, const int hf_index, tvbuff_t *
  @param encoding data encoding
  @return the newly created item */
 extern proto_item *
-proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits, guint64 *return_value, const guint encoding);
+proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits, guint64 *return_value, const guint encoding);
 
 /** Add bits for a FT_UINT8, FT_UINT16, FT_UINT24 or FT_UINT32
     header field to a proto_tree, with the format generating the
@@ -1964,7 +1964,7 @@ proto_tree_add_bits_ret_val(proto_tree *tree, const int hf_index, tvbuff_t *tvb,
  @param format printf like format string
  @return the newly created item */
 extern proto_item *
-proto_tree_add_uint_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits,
+proto_tree_add_uint_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits,
 	guint32 value, const char *format, ...) G_GNUC_PRINTF(7,8);
 
 /** Add bits for a FT_BOOLEAN header field to a proto_tree, with
@@ -1980,7 +1980,7 @@ proto_tree_add_uint_bits_format_value(proto_tree *tree, const int hf_index, tvbu
  @param ... printf like parameters
  @return the newly created item */
 extern proto_item *
-proto_tree_add_boolean_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits,
+proto_tree_add_boolean_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits,
 	guint32 value, const char *format, ...) G_GNUC_PRINTF(7,8);
 
 /** Add bits for a FT_INT8, FT_INT16, FT_INT24 or FT_INT32
@@ -1996,7 +1996,7 @@ proto_tree_add_boolean_bits_format_value(proto_tree *tree, const int hf_index, t
  @param ... printf like parameters
  @return the newly created item */
 extern proto_item *
-proto_tree_add_int_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits,
+proto_tree_add_int_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits,
 	gint32 value, const char *format, ...) G_GNUC_PRINTF(7,8);
 
 /** Add bits for a FT_FLOAT header field to a proto_tree, with
@@ -2012,7 +2012,7 @@ proto_tree_add_int_bits_format_value(proto_tree *tree, const int hf_index, tvbuf
  @param ... printf like parameters
  @return the newly created item */
 extern proto_item *
-proto_tree_add_float_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits,
+proto_tree_add_float_bits_format_value(proto_tree *tree, const int hf_index, tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits,
 	float value, const char *format, ...) G_GNUC_PRINTF(7,8);
 
 /** Check if given string is a valid field name
diff --git a/epan/to_str.c b/epan/to_str.c
index 93d3ad51aa..faab5d6956 100644
--- a/epan/to_str.c
+++ b/epan/to_str.c
@@ -892,7 +892,7 @@ rel_time_to_secs_str(const nstime_t *rel_time)
  */
 
 char *
-decode_bits_in_field(const gint bit_offset, const gint no_of_bits, const guint64 value)
+decode_bits_in_field(const guint bit_offset, const gint no_of_bits, const guint64 value)
 {
 	guint64 mask = 0,tmp;
 	char *str;
@@ -1097,4 +1097,3 @@ gchar* guid_to_str_buf(const e_guid_t *guid, gchar *buf, int buf_len) {
   *tempptr   = '\0';
   return buf;
 }
-
diff --git a/epan/to_str.h b/epan/to_str.h
index fb1cad9982..3093dffa59 100644
--- a/epan/to_str.h
+++ b/epan/to_str.h
@@ -87,7 +87,7 @@ extern gchar*	rel_time_to_secs_str(const nstime_t*);
 extern gchar*	guid_to_str(const e_guid_t*);
 extern gchar*	guid_to_str_buf(const e_guid_t*, gchar*, int);
 
-extern char *decode_bits_in_field(const gint bit_offset, const gint no_of_bits, const guint64 value);
+extern char *decode_bits_in_field(const guint bit_offset, const gint no_of_bits, const guint64 value);
 
 extern char	*other_decode_bitfield_value(char *buf, const guint32 val, const guint32 mask,
     const int width);
diff --git a/epan/tvbuff.c b/epan/tvbuff.c
index ea9d3fe405..aa88539d64 100644
--- a/epan/tvbuff.c
+++ b/epan/tvbuff.c
@@ -62,7 +62,7 @@ ensure_contiguous(tvbuff_t *tvb, const gint offset, const gint length);
 
 
 static guint64
-_tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint total_no_of_bits);
+_tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint total_no_of_bits);
 
 static void
 tvb_init(tvbuff_t *tvb, const tvbuff_type type)
@@ -1648,14 +1648,14 @@ static const guint8 bit_mask8[] = {
 
 /* Get 1 - 8 bits */
 guint8
-tvb_get_bits8(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits)
+tvb_get_bits8(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits)
 {
 	return (guint8)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
 }
 
 /* Get 1 - 16 bits */
 void
-tvb_get_bits_buf(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, guint8 *buf, gboolean lsb0)
+tvb_get_bits_buf(tvbuff_t *tvb, guint bit_offset, gint no_of_bits, guint8 *buf, gboolean lsb0)
 {
 	guint8 bit_mask, bit_shift;
 	/* Byte align offset */
@@ -1726,14 +1726,14 @@ tvb_get_bits_buf(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, guint8 *buf, g
 }
 
 guint8 *
-ep_tvb_get_bits(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, gboolean lsb0)
+ep_tvb_get_bits(tvbuff_t *tvb, guint bit_offset, gint no_of_bits, gboolean lsb0)
 {
 	gint    no_of_bytes;
 	guint8 *buf;
 
 	/* XXX, no_of_bits == -1 -> to end of tvb? */
 
-	if (no_of_bits < 0 || bit_offset < 0) {
+	if (no_of_bits < 0) {
 		DISSECTOR_ASSERT_NOT_REACHED();
 	}
 
@@ -1745,7 +1745,7 @@ ep_tvb_get_bits(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, gboolean lsb0)
 
 /* Get 9 - 16 bits */
 guint16
-tvb_get_bits16(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits,const guint encoding _U_)
+tvb_get_bits16(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits,const guint encoding _U_)
 {
 	/* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
 	return (guint16)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
@@ -1753,7 +1753,7 @@ tvb_get_bits16(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits,const guint
 
 /* Get 1 - 32 bits */
 guint32
-tvb_get_bits32(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding _U_)
+tvb_get_bits32(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding _U_)
 {
 	/* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
 	return (guint32)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
@@ -1761,7 +1761,7 @@ tvb_get_bits32(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guin
 
 /* Get 1 - 64 bits */
 guint64
-tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding _U_)
+tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding _U_)
 {
 	/* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
 	return _tvb_get_bits64(tvb, bit_offset, no_of_bits);
@@ -1773,7 +1773,7 @@ tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guin
  * The function tolerates requests for more than 64 bits, but will only return the least significant 64 bits.
  */
 static guint64
-_tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint total_no_of_bits)
+_tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint total_no_of_bits)
 {
 	guint64 value;
 	guint octet_offset = bit_offset >> 3;
@@ -1847,7 +1847,7 @@ _tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint total_no_of_bits)
 }
 /* Get 1 - 32 bits (should be deprecated as same as tvb_get_bits32??) */
 guint32
-tvb_get_bits(tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits, const guint encoding _U_)
+tvb_get_bits(tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits, const guint encoding _U_)
 {
 	/* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
 	return (guint32)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
@@ -3315,12 +3315,12 @@ tvb_uncompress(tvbuff_t *tvb, const int offset, int comprlen)
 #endif
 
 			if (uncompr == NULL) {
-				/* 
+				/*
 				 * This is ugly workaround for bug #6480
 				 * (https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6480)
 				 *
 				 * g_memdup(..., 0) returns NULL (g_malloc(0) also)
-				 * when uncompr is NULL logic below doesn't create tvb 
+				 * when uncompr is NULL logic below doesn't create tvb
 				 * which is later interpreted as decompression failed.
 				 */
 				uncompr = (bytes_pass || err != Z_STREAM_END) ?
diff --git a/epan/tvbuff.h b/epan/tvbuff.h
index 23939aeed1..d535fd0fca 100644
--- a/epan/tvbuff.h
+++ b/epan/tvbuff.h
@@ -301,26 +301,26 @@ extern void tvb_get_letohguid(tvbuff_t *tvb, const gint offset, e_guid_t *guid);
 extern void tvb_get_guid(tvbuff_t *tvb, const gint offset, e_guid_t *guid, const guint representation);
 
 /* Fetch a specified number of bits from bit offset in a tvb.
-   All of these functions are equivalent, except for the type of the retun value. 
+   All of these functions are equivalent, except for the type of the retun value.
    Note that the parameter encoding (where supplied) is meaningless and ignored */
 
 /* get 1 - 8 bits returned in a guint8 */
-extern guint8 tvb_get_bits8(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits);
+extern guint8 tvb_get_bits8(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits);
 /* get 1 - 16 bits returned in a guint16 */
-extern guint16 tvb_get_bits16(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding);
+extern guint16 tvb_get_bits16(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding);
 /* get 1 - 32 bits returned in a guint32 */
-extern guint32 tvb_get_bits32(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding);
+extern guint32 tvb_get_bits32(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding);
 /* get 1 - 64 bits returned in a guint64 */
-extern guint64 tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding);
+extern guint64 tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding);
 
 /**
  *  This function has EXACTLY the same behaviour as
  *  tvb_get_bits32()
  */
-extern guint32 tvb_get_bits(tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits, const guint encoding);
+extern guint32 tvb_get_bits(tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits, const guint encoding);
 
-void tvb_get_bits_buf(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, guint8 *buf, gboolean lsb0);
-guint8 *ep_tvb_get_bits(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, gboolean lsb0);
+void tvb_get_bits_buf(tvbuff_t *tvb, guint bit_offset, gint no_of_bits, guint8 *buf, gboolean lsb0);
+guint8 *ep_tvb_get_bits(tvbuff_t *tvb, guint bit_offset, gint no_of_bits, gboolean lsb0);
 
 /** Returns target for convenience. Does not suffer from possible
  * expense of tvb_get_ptr(), since this routine is smart enough