Bug #79336 [Com]: ext/exif/tests/bug79046.phpt fails on Big endian arch

Edit report at https://bugs.php.net/bug.php?id=79336&edit=1 ID: 79336 Comment by: vibhutisawant18 at gmail dot com Reported by: vibhutisawant18 at gmail dot com Summary: ext/exif/tests/bug79046.phpt fails on Big endian arch Status: Open Type: Bug Package: EXIF related Operating System: Ubuntu 16.04 PHP Version: master-Git-2020-03-03 (Git) Block user comment: N Private report: N New Comment: @nikic following observations were made wrt the TC behaviour on Big endian System(s390x) char data type is signed(-128 to 127) by default on x86 arch whereas char is treated as unsigned(0 to 255) on s390x. In function static float php_ifd_get_float(char *data) of php-src/ext/exif/exif.c ,the 3rd byte (data[2]) is referring to -8(Hex: fffffff8 ),where as its referred to 248 (Hex: f8) on s390x as char is treated as unsigned char. Hence byte swap won't solve the issue, could you please guide us on what could possibly help to tackle the above scenario? Previous Comments: ------------------------------------------------------------------------ [2020-03-09 05:57:40] vibhutisawant18 at gmail dot com I added a byte swap in php_ifd_get_float() and php_ifd_get_double(), however same behavior continues to persist. Could you please provide with some more insights. ------------------------------------------------------------------------ [2020-03-03 10:45:48] nikic@php.net You likely need to introduce a byte-swap into php_ifd_get_float() and php_ifd_get_double() on big-endian architectures. ------------------------------------------------------------------------ [2020-03-03 10:40:51] vibhutisawant18 at gmail dot com Description: ------------ NaN to int cast undefined behavior in exif [ext/exif/tests/bug79046.phpt] Above TC fails on big endian architecture, the expected value for StripOffsets is NAN whereas that returned on Big endian is float(8.9143601808023E-41) Could you please guide us on how to go about it. PFA test case logs on Little and Big endian Architecture. Little Endian: test@a2a9ec71b826:~/php/php-src$ ./sapi/cli/php -f "ext/exif/tests/bug79046.phpt" --TEST-- Bug #79046: NaN to int cast undefined behavior in exif --FILE-- array(8) { ["FileDateTime"]=> int(0) ["FileSize"]=> int(33) ["FileType"]=> int(8) ["MimeType"]=> string(10) "image/tiff" ["SectionsFound"]=> string(24) "ANY_TAG, IFD0, THUMBNAIL" ["COMPUTED"]=> array(2) { ["IsColor"]=> int(0) ["ByteOrderMotorola"]=> int(1) } ["StripOffsets"]=> float(NAN) ["THUMBNAIL"]=> array(1) { ["StripOffsets"]=> float(NAN) } } Big endian: --TEST-- Bug #79046: NaN to int cast undefined behavior in exif --FILE-- array(8) { ["FileDateTime"]=> int(0) ["FileSize"]=> int(33) ["FileType"]=> int(8) ["MimeType"]=> string(10) "image/tiff" ["SectionsFound"]=> string(24) "ANY_TAG, IFD0, THUMBNAIL" ["COMPUTED"]=> array(2) { ["IsColor"]=> int(0) ["ByteOrderMotorola"]=> int(1) } ["StripOffsets"]=> float(8.9143601808023E-41) ["THUMBNAIL"]=> array(1) { ["StripOffsets"]=> float(8.9143601808023E-41) } } ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=79336&edit=1