Memory leaks in nifti_image_from_ascii

[zer1t0]

There is (at least) two memory leaks in nifti_image_from_ascii. The nim->iname member will be overwritten, with a new allocated string, as many times as the image_filename attribute is repeated in the file. Thus, the previous iname reference will be lost. Same happens with fname and header_filename.

Here are the affected lines:

nifti_clib/niftilib/nifti1_io.c

Line 6556 in 3146cac

nim->fname = nifti_strdup(rhs) ;

nifti_clib/niftilib/nifti1_io.c

Line 6559 in 3146cac

nim->iname = nifti_strdup(rhs) ;

Here is the test with the included nifti1_test and the backtrace produced by ASAN:

$ ./nifti1_test /tmp/test-many-image-filename.nii 
** ERROR (nifti_read_ascii_image): failed nifti_image_from_ascii() '/tmp/test-many-image-filename.nii'

=================================================================
==21838==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 22 byte(s) in 1 object(s) allocated from:
    #0 0x493b2d in malloc (/home/user/investigations/nifti/build-nifti_clib-libfuzzer/niftilib/nifti1_test+0x493b2d)
    #1 0x4d2161 in nifti_strdup /home/user/nifti/nifti_clib/niftilib/nifti1_io.c:1174:17
    #2 0x4faf7d in nifti_image_from_ascii /home/user/nifti/nifti_clib/niftilib/nifti1_io.c:6568:21
    #3 0x4f7359 in nifti_read_ascii_image /home/user/nifti/nifti_clib/niftilib/nifti1_io.c:4348:10
    #4 0x4c51f0 in nifti_image_read /home/user/nifti/nifti_clib/niftilib/nifti1_io.c:4223:13
    #5 0x4c3969 in main /home/user/nifti/nifti_clib/niftilib/nifti1_test.c:72:10
    #6 0x7fa416a2f082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: 22 byte(s) leaked in 1 allocation(s).

Here are the samples to reproduce the behaviour:
tests.zip