Fix overflow testing in sbrk.
Modify the overflow testing for sbrk.
Bug: 15188366
Change-Id: Ia83f85f7c1789454d872279bd41f38f1ce6b8a34
diff --git a/libc/bionic/brk.cpp b/libc/bionic/brk.cpp
index 4d08a61..4e46193 100644
--- a/libc/bionic/brk.cpp
+++ b/libc/bionic/brk.cpp
@@ -56,19 +56,19 @@
}
// 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);
}