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WIP: Replace dangerous old string functions with less horrible variants, for -fbounds-safety compatibility #24

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e3379f9
Replaced all strcpy(), strcat(), strncpy() with safer variants
seanm Jan 2, 2026
742182f
Add strlcpy and strlcat implementations for non-BSD and old glibc
seanm Jan 2, 2026
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113 changes: 60 additions & 53 deletions nifti2/nifti2_io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1280,13 +1280,13 @@ char *nifti_strdup(const char *str)
{
if( !str ) return NULL; /* allow calls passing NULL */

size_t length = strlen(str);
char *dup = (char *)malloc(length + 1);
size_t length = strlen(str) + 1;
char *dup = (char *)malloc(length);

/* check for failure */
if( dup ) strcpy(dup, str);
if( dup ) strlcpy(dup, str, length);
else fprintf(stderr,"** nifti_strdup: failed to alloc %zu bytes\n",
length+1);
length);

return dup;
}
Expand Down Expand Up @@ -3524,7 +3524,7 @@ const char * nifti_find_file_extension( const char * name )
ext = name + len - 4;

/* make manipulation copy, and possibly convert to lowercase */
strcpy(extcopy, ext);
strlcpy(extcopy, ext, sizeof(extcopy));
if( g_opts.allow_upper_fext ) make_lowercase(extcopy);

/* if it look like a basic extension, fail or return it */
Expand All @@ -3543,11 +3543,13 @@ const char * nifti_find_file_extension( const char * name )
ext = name + len - 7;

/* make manipulation copy, and possibly convert to lowercase */
strcpy(extcopy, ext);
strlcpy(extcopy, ext, sizeof(extcopy));
if( g_opts.allow_upper_fext ) make_lowercase(extcopy);

/* go after .gz extensions using the modifiable strings */
strcat(elist[0], extgz); strcat(elist[1], extgz); strcat(elist[2], extgz);
strlcat(elist[0], extgz, 8);
strlcat(elist[1], extgz, 8);
strlcat(elist[2], extgz, 8);

if( compare_strlist(extcopy, elist, 3) >= 0 ) {
if( is_mixedcase(ext) ) {
Expand Down Expand Up @@ -3730,21 +3732,23 @@ char * nifti_findhdrname(const char* fname)
make_uppercase(extzip);
}

hdrname = (char *)calloc(sizeof(char),strlen(basename)+8);
size_t hdrnamelength = strlen(basename)+8;
hdrname = (char *)calloc(sizeof(char),hdrnamelength);
if( !hdrname ){
fprintf(stderr,"** nifti_findhdrname: failed to alloc hdrname\n");
free(basename);
return NULL;
}

strcpy(hdrname,basename);
strcat(hdrname,elist[efirst]);
strlcpy(hdrname, basename, hdrnamelength);
strlcat(hdrname, elist[efirst], hdrnamelength);
#ifdef FSLSTYLE
if (nifti_fileexists(hdrname)) {
free(basename);
char *gzname = (char *)calloc(sizeof(char),strlen(hdrname)+8);
strcpy(gzname, hdrname);
strcat(gzname,extzip);
size_t gznamelength = strlen(hdrname)+8;
char *gzname = (char *)calloc(sizeof(char), gznamelength);
strlcpy(gzname, hdrname, gznamelength);
strlcat(gzname, extzip, gznamelength);
if (nifti_fileexists(gzname)) {
fprintf(stderr,"Image Exception : Multiple possible filenames detected for basename (*.nii, *.nii.gz): %s\n", basename);
free(gzname);
Expand All @@ -3757,19 +3761,19 @@ char * nifti_findhdrname(const char* fname)
if (nifti_fileexists(hdrname)) { free(basename); return hdrname; }
#endif
#ifdef HAVE_ZLIB
strcat(hdrname,extzip);
strlcat(hdrname, extzip, hdrnamelength);
if (nifti_fileexists(hdrname)) { free(basename); return hdrname; }
#endif

/* okay, try the other possibility */

efirst = 1 - efirst;

strcpy(hdrname,basename);
strcat(hdrname,elist[efirst]);
strlcpy(hdrname, basename, hdrnamelength);
strlcat(hdrname, elist[efirst], hdrnamelength);
if (nifti_fileexists(hdrname)) { free(basename); return hdrname; }
#ifdef HAVE_ZLIB
strcat(hdrname,extzip);
strlcat(hdrname, extzip, hdrnamelength);
if (nifti_fileexists(hdrname)) { free(basename); return hdrname; }
#endif

Expand Down Expand Up @@ -3808,8 +3812,9 @@ char * nifti_findimgname(const char* fname , int nifti_type)
/* check input file(s) for sanity */
if( !nifti_validfilename(fname) ) return NULL;

basename = nifti_makebasename(fname);
imgname = (char *)calloc(sizeof(char),strlen(basename)+8);
basename = nifti_makebasename(fname);
size_t imgnamelength = strlen(basename)+8;
imgname = (char *)calloc(sizeof(char),imgnamelength);
if( !imgname ){
fprintf(stderr,"** nifti_findimgname: failed to alloc imgname\n");
free(basename);
Expand All @@ -3827,8 +3832,8 @@ char * nifti_findimgname(const char* fname , int nifti_type)

/* only valid extension for ASCII type is .nia, handle first */
if( nifti_type == NIFTI_FTYPE_ASCII ){
strcpy(imgname,basename);
strcat(imgname,extnia);
strlcpy(imgname, basename, imgnamelength);
strlcat(imgname, extnia, imgnamelength);
if (nifti_fileexists(imgname)) { free(basename); return imgname; }

} else {
Expand All @@ -3842,21 +3847,21 @@ char * nifti_findimgname(const char* fname , int nifti_type)
else if (nifti_type == NIFTI_FTYPE_NIFTI2_1) first = 0;
else first = 1; /* should match .img */

strcpy(imgname,basename);
strcat(imgname,elist[first]);
strlcpy(imgname, basename, imgnamelength);
strlcat(imgname, elist[first], imgnamelength);
if (nifti_fileexists(imgname)) { free(basename); return imgname; }
#ifdef HAVE_ZLIB /* then also check for .gz */
strcat(imgname,extzip);
strlcat(imgname, extzip, imgnamelength);
if (nifti_fileexists(imgname)) { free(basename); return imgname; }
#endif

/* failed to find image file with expected extension, try the other */

strcpy(imgname,basename);
strcat(imgname,elist[1-first]); /* can do this with only 2 choices */
strlcpy(imgname, basename, imgnamelength);
strlcat(imgname, elist[1-first], imgnamelength); /* can do this with only 2 choices */
if (nifti_fileexists(imgname)) { free(basename); return imgname; }
#ifdef HAVE_ZLIB /* then also check for .gz */
strcat(imgname,extzip);
strlcat(imgname, extzip, imgnamelength);
if (nifti_fileexists(imgname)) { free(basename); return imgname; }
#endif
}
Expand Down Expand Up @@ -3896,12 +3901,13 @@ char * nifti_makehdrname(const char * prefix, int nifti_type, int check,
if( !nifti_validfilename(prefix) ) return NULL;

/* add space for extension, optional ".gz", and null char */
iname = (char *)calloc(sizeof(char),strlen(prefix)+8);
size_t inamelength = strlen(prefix)+8;
iname = (char *)calloc(sizeof(char),inamelength);
if( !iname ){
fprintf(stderr,"** NIFTI small malloc failure!\n");
return NULL;
}
strcpy(iname, prefix);
strlcpy(iname, prefix, inamelength);

/* use any valid extension */
if( (ext = nifti_find_file_extension(iname)) != NULL ){
Expand All @@ -3920,13 +3926,13 @@ char * nifti_makehdrname(const char * prefix, int nifti_type, int check,
}
}
/* otherwise, make one up */
else if( nifti_type == NIFTI_FTYPE_NIFTI1_1 ) strcat(iname, extnii);
else if( nifti_type == NIFTI_FTYPE_NIFTI2_1 ) strcat(iname, extnii);
else if( nifti_type == NIFTI_FTYPE_ASCII ) strcat(iname, extnia);
else strcat(iname, exthdr);
else if( nifti_type == NIFTI_FTYPE_NIFTI1_1 ) strlcat(iname, extnii, inamelength);
else if( nifti_type == NIFTI_FTYPE_NIFTI2_1 ) strlcat(iname, extnii, inamelength);
else if( nifti_type == NIFTI_FTYPE_ASCII ) strlcat(iname, extnia, inamelength);
else strlcat(iname, exthdr, inamelength);

#ifdef HAVE_ZLIB /* if compression is requested, make sure of suffix */
if( comp && (!ext || !strstr(iname,extgz)) ) strcat(iname,extgz);
if( comp && (!ext || !strstr(iname,extgz)) ) strlcat(iname, extgz, inamelength);
#endif

/* check for existence failure */
Expand Down Expand Up @@ -3971,12 +3977,13 @@ char * nifti_makeimgname(const char * prefix, int nifti_type, int check,
if( !nifti_validfilename(prefix) ) return NULL;

/* add space for extension, optional ".gz", and null char */
iname = (char *)calloc(sizeof(char),strlen(prefix)+8);
size_t inamelength = strlen(prefix)+8;
iname = (char *)calloc(sizeof(char),inamelength);
if( !iname ){
fprintf(stderr,"** NIFTI: small malloc failure!\n");
return NULL;
}
strcpy(iname, prefix);
strlcpy(iname, prefix, inamelength);

/* use any valid extension */
if( (ext = nifti_find_file_extension(iname)) != NULL ){
Expand All @@ -3995,13 +4002,13 @@ char * nifti_makeimgname(const char * prefix, int nifti_type, int check,
}
}
/* otherwise, make one up */
else if( nifti_type == NIFTI_FTYPE_NIFTI1_1 ) strcat(iname, extnii);
else if( nifti_type == NIFTI_FTYPE_NIFTI2_1 ) strcat(iname, extnii);
else if( nifti_type == NIFTI_FTYPE_ASCII ) strcat(iname, extnia);
else strcat(iname, extimg);
else if( nifti_type == NIFTI_FTYPE_NIFTI1_1 ) strlcat(iname, extnii, inamelength);
else if( nifti_type == NIFTI_FTYPE_NIFTI2_1 ) strlcat(iname, extnii, inamelength);
else if( nifti_type == NIFTI_FTYPE_ASCII ) strlcat(iname, extnia, inamelength);
else strlcat(iname, extimg, inamelength);

#ifdef HAVE_ZLIB /* if compression is requested, make sure of suffix */
if( comp && (!ext || !strstr(iname,extgz)) ) strcat(iname,extgz);
if( comp && (!ext || !strstr(iname,extgz)) ) strlcat(iname, extgz, inamelength);
#endif

/* check for existence failure */
Expand Down Expand Up @@ -7325,7 +7332,7 @@ nifti_1_header * nifti_make_new_n1_header(const int64_t arg_dims[8],
nifti_datatype_sizes( nhdr->datatype , &nbyper, &swapsize );
nhdr->bitpix = 8 * nbyper ;

strcpy(nhdr->magic, "n+1"); /* init to single file */
strlcpy(nhdr->magic, "n+1", sizeof(nhdr->magic)); /* init to single file */

return nhdr;
}
Expand Down Expand Up @@ -7457,8 +7464,8 @@ int nifti_convert_nim2n1hdr(const nifti_image * nim, nifti_1_header * hdr)

if( nim->nifti_type > NIFTI_FTYPE_ANALYZE ){ /* then not ANALYZE */

if( nim->nifti_type == NIFTI_FTYPE_NIFTI1_1 ) strcpy(nhdr.magic,"n+1") ;
else strcpy(nhdr.magic,"ni1") ;
if( nim->nifti_type == NIFTI_FTYPE_NIFTI1_1 ) strlcpy(nhdr.magic, "n+1", sizeof(nhdr.magic)) ;
else strlcpy(nhdr.magic, "ni1", sizeof(nhdr.magic)) ;

nhdr.pixdim[1] = (float)fabs(nhdr.pixdim[1]) ;
nhdr.pixdim[2] = (float)fabs(nhdr.pixdim[2]) ;
Expand Down Expand Up @@ -7842,10 +7849,10 @@ znzFile nifti_image_write_hdr_img2(nifti_image *nim, int write_opts,
int doPigz2(nifti_image *nim, struct nifti_2_header nhdr, const nifti_brick_list * NBL) {
FILE *pigzPipe;
char command[768];
strcpy(command, "pigz" );
strcat(command, " -n -f > \"");
strcat(command, nim->fname);
strcat(command, "\"");
strlcpy(command, "pigz", sizeof(command));
strlcat(command, " -n -f > \"", sizeof(command));
strlcat(command, nim->fname, sizeof(command));
strlcat(command, "\"", sizeof(command));
#ifdef _MSC_VER
if (( pigzPipe = _popen(command, "w")) == NULL)
return -1;
Expand Down Expand Up @@ -7874,10 +7881,10 @@ int doPigz2(nifti_image *nim, struct nifti_2_header nhdr, const nifti_brick_list
int doPigz(nifti_image *nim, struct nifti_1_header nhdr, const nifti_brick_list * NBL) {
FILE *pigzPipe;
char command[768];
strcpy(command, "pigz" );
strcat(command, " -n -f > \"");
strcat(command, nim->fname);
strcat(command, "\"");
strlcpy(command, "pigz", sizeof(command));
strlcat(command, " -n -f > \"", sizeof(command));
strlcat(command, nim->fname, sizeof(command));
strlcat(command, "\"", sizeof(command));
#ifdef _MSC_VER
if (( pigzPipe = _popen(command, "w")) == NULL)
return -1;
Expand Down Expand Up @@ -8713,7 +8720,7 @@ int nifti_short_order(void) /* determine this CPU's byte order */
put rhs string into nim->"nam" string, with field size = "sz" */

#define QSTR(nam,sz) if( strcmp(lhs,#nam) == 0 ) \
strncpy(nim->nam,rhs,sz), nim->nam[sz-1]='\0'
memset(nim->nam, 0, sz), strlcpy(nim->nam,rhs,sz)

/*---------------------------------------------------------------------------*/
/*! Take an XML-ish ASCII string and create a NIFTI image header to match.
Expand Down
3 changes: 1 addition & 2 deletions nifti2/nifti_tool.c
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Expand Up @@ -6098,8 +6098,7 @@ int fill_field( field_s * fp, int type, int offset, int num, const char * name )
fp->size = 1; /* init before check */
fp->len = num;

strncpy(fp->name, name, sizeof(fp->name));
fp->name[sizeof(fp->name) - 1] = 0;
strlcpy(fp->name, name, sizeof(fp->name));

switch( type ){
case DT_UNKNOWN:
Expand Down
18 changes: 10 additions & 8 deletions nifticdf/nifticdf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11044,17 +11044,19 @@ char const * const inam[]={ NULL , NULL ,

int nifti_intent_code( const char *name )
{
char *unam , *upt ;
int ii ;

if( name == NULL || *name == '\0' ) return -1 ;
if( name == NULL || *name == '\0' )
return -1 ;

unam = (char *)malloc(strlen(name)+1);
strcpy(unam,name);
for( upt=unam ; *upt != '\0' ; upt++ ) *upt = (char)toupper(*upt) ;
size_t size = strlen(name)+1;
char *unam = (char *)malloc(size);
strlcpy(unam,name,size);
for( char *upt=unam ; *upt != '\0' ; upt++ )
*upt = (char)toupper(*upt) ;

int ii ;
for( ii=NIFTI_FIRST_STATCODE ; ii <= NIFTI_LAST_STATCODE ; ii++ )
if( strcmp(inam[ii],unam) == 0 ) break ;
if( strcmp(inam[ii],unam) == 0 )
break ;

free(unam) ;
return (ii <= NIFTI_LAST_STATCODE) ? ii : -1 ;
Expand Down
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