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am deb1ec4a: am 47150dca: am 1a57de71: Merge "Fix overflow testing in sbrk."

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* commit 'deb1ec4aaa0e7f74746c97ccbc22a367640c301f':
  Fix overflow testing in sbrk.
This commit is contained in:
Christopher Ferris
2014-05-29 21:09:29 +00:00
committed by Android Git Automerger
parent dd4489bfbe deb1ec4aaa
commit ea1004b6b3
2 changed files with 71 additions and 10 deletions
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8
libc/bionic/brk.cpp
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@@ -56,19 +56,19 @@ void* sbrk(ptrdiff_t increment) {
}
// Avoid overflow.
intptr_t old_brk = reinterpret_cast<intptr_t>(__bionic_brk);
if ((increment > 0 && INTPTR_MAX - increment > old_brk) ||
(increment < 0 && (increment == PTRDIFF_MIN || old_brk < -increment))) {
uintptr_t old_brk = reinterpret_cast<uintptr_t>(__bionic_brk);
if ((increment > 0 && static_cast<uintptr_t>(increment) > (UINTPTR_MAX - old_brk)) ||
(increment < 0 && static_cast<uintptr_t>(-increment) > old_brk)) {
errno = ENOMEM;
return reinterpret_cast<void*>(-1);
}
void* desired_brk = reinterpret_cast<void*>(old_brk + increment);
__bionic_brk = __brk(desired_brk);
if (__bionic_brk < desired_brk) {
errno = ENOMEM;
return reinterpret_cast<void*>(-1);
}
return reinterpret_cast<void*>(old_brk);
}