Fix undefined behaviour in string uppercasing and lowercasing #10936
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At least on 32-bit, the address computations overflow in running the test on CI with UBSAN enabled. Fix it by reordering the arithmetic. Since a part of the expression is already used in the code above the computation, this should not negatively affect performance.
iluuu1994
approved these changes
Mar 25, 2023
| @@ -2760,7 +2760,7 @@ ZEND_API zend_string* ZEND_FASTCALL zend_string_tolower_ex(zend_string *str, boo | |||
| if (_mm_movemask_epi8(mingle)) { | |||
| zend_string *res = zend_string_alloc(length, persistent); | |||
| memcpy(ZSTR_VAL(res), ZSTR_VAL(str), p - (unsigned char *) ZSTR_VAL(str)); | |||
| unsigned char *q = p + (ZSTR_VAL(res) - ZSTR_VAL(str)); | |||
| unsigned char *q = p - (unsigned char*) ZSTR_VAL(str) + (unsigned char*) ZSTR_VAL(res); | |||
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Nit:
unsigned char *q = (unsigned char*) ZSTR_VAL(res) + (p - (unsigned char*) ZSTR_VAL(str));would be slightly more intuitive to me. Maybe other brains work differently 🙂
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Sure. I'll wait for CI to finish and then do this in the merge I guess. I'll have to adapt the patch upon merging anyway due to refactors.
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At least on 32-bit, the address computations overflow in running the test on CI with UBSAN enabled. Fix it by reordering the arithmetic. Since a part of the expression is already used in the code above the computation, this should not negatively affect performance.
I'm running the test suite with UBSAN enabled on my fork and noticed this.