I found a large or infinite loop in ngiflib

[firefoxxpyang]

I used the command line gif2tga --outbase /dev/null path_to_file to run gif2tga and got a timeout.
The program didn't return or repsond.
The system is ubuntu 16.04.6 amd-64, source commit id is: 0245fd4
compiled by gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.12)

debug informations is:
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Reading symbols from gif2tga...done.
(gdb) r --outbase /dev/null /home/yang/test.gif
Starting program: /home/yang/MyProject/remote_test/target_src/ngiflib/gif2tga --outbase /dev/null /home/yang/test.gif
^C
Program received signal SIGINT, Interrupt.
0x00007ffff7b04320 in __read_nocancel () at ../sysdeps/unix/syscall-template.S:84
84 ../sysdeps/unix/syscall-template.S: No such file or directory.
(gdb) step
_IO_new_file_underflow (fp=0x605070) at fileops.c:594
594 fileops.c: No such file or directory.
(gdb) step
597 in fileops.c
(gdb)
596 in fileops.c
(gdb)
597 in fileops.c
(gdb)
607 in fileops.c
(gdb)
613 in fileops.c
(gdb)
608 in fileops.c
(gdb)
613 in fileops.c
(gdb)
__GI__IO_default_uflow (fp=0x605070) at genops.c:414
414 genops.c: No such file or directory.
(gdb)
417 in genops.c
(gdb)
_IO_getc (fp=0x605070) at getc.c:37
37 getc.c: No such file or directory.
(gdb)
_IO_acquire_lock_fct (p=) at libioP.h:866
866 libioP.h: No such file or directory.
(gdb)
_IO_getc (fp=0x605070) at getc.c:37
37 getc.c: No such file or directory.
(gdb)
_IO_acquire_lock_fct (p=) at libioP.h:867
867 libioP.h: No such file or directory.
(gdb)

The poc is attached below.

Thank you.

[miniupnp]

I do not reproduce

$ ./gif2tga --outbase /dev/null invalid_gif/issue_17.gif 
LoadGif() returned -1
* ngiflib_gif @ 0x607000000020 GIF89a
  344x300, 8 bits, 256 couleurs
  palette = 0x617000000080, backgroundcolorindex 0
  pixelaspectratio = 0
  frbuff = 0x800928800
  cur_img = 0x0
  0 images :

[miniupnp]

no feedback => closing