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Check for __builtin_mul_overflow before using it #9573

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Check for __builtin_mul_overflow before using it #9573

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21 changes: 21 additions & 0 deletions build/php.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -2567,6 +2567,27 @@ AC_DEFUN([PHP_CHECK_BUILTIN_CTZLL], [
AC_DEFINE_UNQUOTED([PHP_HAVE_BUILTIN_CTZLL], [$have_builtin_ctzll], [Whether the compiler supports __builtin_ctzll])
])

dnl
dnl PHP_CHECK_BUILTIN_MUL_OVERFLOW
dnl
AC_DEFUN([PHP_CHECK_BUILTIN_MUL_OVERFLOW], [
AC_MSG_CHECKING([for __builtin_mul_overflow])

AC_LINK_IFELSE([AC_LANG_PROGRAM([], [[
long tmpvar;
return __builtin_mul_overflow(3, 7, &tmpvar);
]])], [
have_builtin_mul_overflow=1
AC_MSG_RESULT([yes])
], [
have_builtin_mul_overflow=0
AC_MSG_RESULT([no])
])

AC_DEFINE_UNQUOTED([PHP_HAVE_BUILTIN_MUL_OVERFLOW],
[$have_builtin_mul_overflow], [Whether the compiler supports __builtin_mul_overflow])
])

dnl
dnl PHP_CHECK_BUILTIN_SMULL_OVERFLOW
dnl
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2 changes: 2 additions & 0 deletions configure.ac
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Expand Up @@ -494,6 +494,8 @@ dnl Check __builtin_ctzl
PHP_CHECK_BUILTIN_CTZL
dnl Check __builtin_ctzll
PHP_CHECK_BUILTIN_CTZLL
dnl Check __builtin_mul_overflow
PHP_CHECK_BUILTIN_MUL_OVERFLOW
dnl Check __builtin_smull_overflow
PHP_CHECK_BUILTIN_SMULL_OVERFLOW
dnl Check __builtin_smulll_overflow
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7 changes: 5 additions & 2 deletions main/reallocarray.c
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Expand Up @@ -23,10 +23,13 @@
PHPAPI void* php_reallocarray(void *p, size_t nmb, size_t siz)
{
size_t r;
#ifndef _WIN32
#ifdef _WIN32
if (SizeTMult(nmb, siz, &r) != S_OK) {
#elif PHP_HAVE_BUILTIN_MUL_OVERFLOW
if (__builtin_mul_overflow(nmb, siz, &r)) {
#else
if (SizeTMult(nmb, siz, &r) != S_OK) {
r = siz * nmb;
if (siz != 0 && r / siz != nmb) {
#endif
// EOVERFLOW may have been, arguably, more appropriate
// but this is what other implementations set
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