tools/tiffcrop.c:7175: error: Null Dereference
  pointer `sect_buff` last assigned on line 7173 could be null and is dereferenced by call to `_TIFFmemset()` at line 7175, column 5.

tools/tiffcrop.c:7162:1: start of procedure createImageSection()
7160. 
7161. /* Create a buffer to write one section at a time */
7162. static int
      ^
7163. createImageSection(uint32 sectsize, unsigned char **sect_buff_ptr)
7164.   {

tools/tiffcrop.c:7165:3: 
7163. createImageSection(uint32 sectsize, unsigned char **sect_buff_ptr)
7164.   {
7165.   unsigned  char *sect_buff = NULL;
        ^
7166.   unsigned  char *new_buff  = NULL;
7167.   static    uint32  prev_sectsize = 0;

tools/tiffcrop.c:7166:3: 
7164.   {
7165.   unsigned  char *sect_buff = NULL;
7166.   unsigned  char *new_buff  = NULL;
        ^
7167.   static    uint32  prev_sectsize = 0;
7168.   

tools/tiffcrop.c:7167:3: 
7165.   unsigned  char *sect_buff = NULL;
7166.   unsigned  char *new_buff  = NULL;
7167.   static    uint32  prev_sectsize = 0;
        ^
7168.   
7169.   sect_buff = *sect_buff_ptr;

tools/tiffcrop.c:7169:3: 
7167.   static    uint32  prev_sectsize = 0;
7168.   
7169.   sect_buff = *sect_buff_ptr;
        ^
7170. 
7171.   if (!sect_buff)

tools/tiffcrop.c:7171:8: Taking true branch
7169.   sect_buff = *sect_buff_ptr;
7170. 
7171.   if (!sect_buff)
             ^
7172.     {
7173.     sect_buff = (unsigned char *)_TIFFmalloc(sectsize);

tools/tiffcrop.c:7173:5: 
7171.   if (!sect_buff)
7172.     {
7173.     sect_buff = (unsigned char *)_TIFFmalloc(sectsize);
          ^
7174.     *sect_buff_ptr = sect_buff;
7175.     _TIFFmemset(sect_buff, 0, sectsize);

libtiff/tif_unix.c:253:1: start of procedure _TIFFmalloc()
  251. #endif
  252. 
  253. void*
       ^
  254. _TIFFmalloc(tmsize_t s)
  255. {

libtiff/tif_unix.c:256:2: 
  254. _TIFFmalloc(tmsize_t s)
  255. {
  256. 	return (malloc((size_t) s));
        ^
  257. }
  258. 

libtiff/tif_unix.c:257:1: return from a call to _TIFFmalloc
  255. {
  256. 	return (malloc((size_t) s));
  257. }
       ^
  258. 
  259. void

tools/tiffcrop.c:7174:5: 
7172.     {
7173.     sect_buff = (unsigned char *)_TIFFmalloc(sectsize);
7174.     *sect_buff_ptr = sect_buff;
          ^
7175.     _TIFFmemset(sect_buff, 0, sectsize);
7176.     }

tools/tiffcrop.c:7175:5: 
7173.     sect_buff = (unsigned char *)_TIFFmalloc(sectsize);
7174.     *sect_buff_ptr = sect_buff;
7175.     _TIFFmemset(sect_buff, 0, sectsize);
          ^
7176.     }
7177.   else

libtiff/tif_unix.c:271:1: start of procedure _TIFFmemset()
  269. }
  270. 
  271. void
       ^
  272. _TIFFmemset(void* p, int v, tmsize_t c)
  273. {

libtiff/tif_unix.c:274:2: 
  272. _TIFFmemset(void* p, int v, tmsize_t c)
  273. {
  274. 	memset(p, v, (size_t) c);
        ^
  275. }
  276. 

libtiff/tif_unix.c:275:1: return from a call to _TIFFmemset
  273. {
  274. 	memset(p, v, (size_t) c);
  275. }
       ^
  276. 
  277. void
