Remove bin.lua unpacking from more scripts

scripts/http-exif-spider.nse

@@ -30,7 +30,6 @@ local shortport = require 'shortport'
 local stdnse = require 'stdnse'
 local httpspider = require 'httpspider'
 local string = require 'string'
-local bin = require 'bin'
 local table = require 'table'
 
 -- These definitions are copied/pasted/reformatted from the jhead-2.96 sourcecode
@@ -338,7 +337,7 @@ portrule = shortport.http
 --@return the new position, and the value.
 local function unpack_rational(endian, data, pos)
   local v1, v2
-  pos, v1, v2 = bin.unpack(endian .. "II", data, pos)
+  v1, v2, pos = string.unpack(endian .. "I4I4", data, pos)
   return pos, v1 / v2
 end
 
@@ -347,7 +346,7 @@ local function process_gps(data, pos, endian, result)
   local latitude, latitude_ref, longitude, longitude_ref
 
   -- The first entry in the gps section is a 16-bit size
-  pos, num_entries = bin.unpack(endian .. "S", data, pos)
+  num_entries, pos = string.unpack(endian .. "I2", data, pos)
 
   -- Loop through the entries to find the fun stuff
   for i=1, num_entries do
@@ -403,8 +402,8 @@ local function parse_exif(exif_data)
   result = {}
 
   -- Read the verify the EXIF header
-  local pos, header1, header2, endian = bin.unpack(">ISS", exif_data, 1)
-  if(header1 ~= 0x45786966 or header2 ~= 0x0000) then
+  local header, endian, pos = string.unpack(">c6 I2", exif_data, 1)
+  if(header ~= "Exif\0\0") then
     return false, "Invalid EXIF header"
   end
 
@@ -419,7 +418,7 @@ local function parse_exif(exif_data)
   end
 
   -- Read the first tiff header and the offset to the first data entry (should be 8)
-  pos, tiff_header_1, first_offset = bin.unpack(endian .. "SI", exif_data, pos)
+  tiff_header_1, first_offset, pos = string.unpack(endian .. "I2 I4", exif_data, pos)
   if(tiff_header_1 ~= 0x002A or first_offset ~= 0x00000008) then
     return false, "Invalid tiff header"
   end
@@ -428,12 +427,12 @@ local function parse_exif(exif_data)
   pos = first_offset + 8 - 1
 
   -- The first 16-bit value is the number of entries
-  local pos, num_entries = bin.unpack(endian .. "S", exif_data, pos)
+  local num_entries, pos = string.unpack(endian .. "I2", exif_data, pos)
 
   -- Loop through the entries
   for i=1,num_entries do
     -- Read the entry's header
-    pos, tag, format, components, value = bin.unpack(endian .. "SSII", exif_data, pos)
+    tag, format, components, value, pos = string.unpack(endian .. "I2 I2 I4 I4", exif_data, pos)
 
     -- Look at the tags we care about
     if(tag == TAG_GPSINFO) then
@@ -442,15 +441,15 @@ local function parse_exif(exif_data)
       if(not(status)) then
         return false, result
       end
-    elseif(tag == TAG_MAKE) then
-      dummy, value = bin.unpack("z", exif_data, value + 8 - 1)
-      table.insert(result, string.format("Make: %s", value))
-    elseif(tag == TAG_MODEL) then
-      dummy, value = bin.unpack("z", exif_data, value + 8 - 1)
-      table.insert(result, string.format("Model: %s", value))
-    elseif(tag == TAG_DATETIME) then
-      dummy, value = bin.unpack("z", exif_data, value + 8 - 1)
-      table.insert(result, string.format("Date: %s", value))
+    else
+      value = string.unpack("z", exif_data, value + 8 - 1)
+      if (tag == TAG_MAKE) then
+        table.insert(result, string.format("Make: %s", value))
+      elseif(tag == TAG_MODEL) then
+        table.insert(result, string.format("Model: %s", value))
+      elseif(tag == TAG_DATETIME) then
+        table.insert(result, string.format("Date: %s", value))
+      end
     end
   end
 
@@ -462,14 +461,14 @@ local function parse_jpeg(s)
   local pos, sig, marker, size, exif_data
 
   -- Parse the jpeg header, make sure it's valid (we expect 0xFFD8)
-  pos, sig = bin.unpack(">S", s, pos)
+  sig, pos = string.unpack(">I2", s, pos)
   if(sig ~= 0xFFD8) then
     return false, "Unexpected signature"
   end
 
   -- Parse the sections to find the exif marker (0xffe1)
   while(true) do
-    pos, marker, size = bin.unpack(">SS", s, pos)
+    marker, size, pos = string.unpack(">I2I2", s, pos)
 
     -- Check if we found the exif metadata section, break if we did
     if(marker == 0xffe1) then
@@ -483,7 +482,7 @@ local function parse_jpeg(s)
     pos = pos + size - 2
   end
 
-  pos, exif_data = bin.unpack(string.format(">A%d", size), s, pos)
+  exif_data, pos = string.unpack(string.format(">c%d", size), s, pos)
 
   return parse_exif(exif_data)
 end