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Add new function: validate_offset() which checks if offset is within bounds of tvb. 

svn path=/trunk/; revision=50556
This commit is contained in:
Jakub Zawadzki 2013-07-13 14:51:25 +00:00
parent 611eaf8069
commit af61f188e0
1 changed files with 33 additions and 52 deletions
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85
epan/tvbuff.c
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@ -227,47 +227,43 @@ tvb_new_child_real_data(tvbuff_t *parent, const guint8* data, const guint length
return tvb;
}
static int
compute_offset(const tvbuff_t *tvb, const gint offset, guint *offset_ptr)
/*
* Check whether that offset goes more than one byte past the
* end of the buffer.
*
* If not, return 0; otherwise, return exception
*/
static inline int
validate_offset(const tvbuff_t *tvb, const guint abs_offset)
{
int exception;
if (offset >= 0) {
/* Positive offset - relative to the beginning of the packet. */
if ((guint) offset > tvb->reported_length) {
if (tvb->flags & TVBUFF_FRAGMENT) {
exception = FragmentBoundsError;
} else {
exception = ReportedBoundsError;
}
return exception;
}
else if ((guint) offset > tvb->length) {
return BoundsError;
}
else {
*offset_ptr = offset;
}
}
if (G_LIKELY(abs_offset <= tvb->length))
exception = 0;
else if (abs_offset <= tvb->reported_length)
exception = BoundsError;
else {
/* Negative offset - relative to the end of the packet. */
if ((guint) -offset > tvb->reported_length) {
if (tvb->flags & TVBUFF_FRAGMENT) {
exception = FragmentBoundsError;
} else {
exception = ReportedBoundsError;
}
return exception;
}
else if ((guint) -offset > tvb->length) {
return BoundsError;
}
else {
*offset_ptr = tvb->length + offset;
}
if (tvb->flags & TVBUFF_FRAGMENT)
exception = FragmentBoundsError;
else
exception = ReportedBoundsError;
}
return 0;
return exception;
}
static int
compute_offset(const tvbuff_t *tvb, const gint offset, guint *offset_ptr)
{
if (offset >= 0) {
/* Positive offset - relative to the beginning of the packet. */
*offset_ptr = offset;
} else {
/* Negative offset - relative to the end of the packet. */
*offset_ptr = tvb->length + offset;
}
return validate_offset(tvb, *offset_ptr);
}
static int
@ -332,23 +328,8 @@ check_offset_length_no_exception(const tvbuff_t *tvb,
*/
if (end_offset < *offset_ptr)
exception = BoundsError;
/*
* Check whether that offset goes more than one byte past the
* end of the buffer.
*
* If not, return 0; otherwise, return exception
*/
else if (end_offset <= tvb->length)
exception = 0;
else if (end_offset <= tvb->reported_length)
exception = BoundsError;
else {
if (tvb->flags & TVBUFF_FRAGMENT)
exception = FragmentBoundsError;
else
exception = ReportedBoundsError;
}
else
exception = validate_offset(tvb, end_offset);
return exception;
}