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Date: Fri, 28 Oct 2016 19:56:18 +0000
From: "LeMay, Michael" <michael.lemay@...el.com>
To: "musl@...ts.openwall.com" <musl@...ts.openwall.com>
Subject: [RFC PATCH v2 1/4] disable check for buggy brk implementations when
SafeStack is enabled
The check relies on comparing the addresses of stack-allocated objects
to addresses returned by the brk syscall. SafeStack moves the
allocations to the unsafe stack, breaking the check. This patch
disables the check when SafeStack is enabled.
Signed-off-by: Michael LeMay <michael.lemay@...el.com>
---
src/malloc/expand_heap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/src/malloc/expand_heap.c b/src/malloc/expand_heap.c
index d8c0be7..af51451 100644
--- a/src/malloc/expand_heap.c
+++ b/src/malloc/expand_heap.c
@@ -13,6 +13,7 @@
static int traverses_stack_p(uintptr_t old, uintptr_t new)
{
+#if !defined(__has_feature) || !__has_feature(safe_stack)
const uintptr_t len = 8<<20;
uintptr_t a, b;
@@ -23,6 +24,7 @@ static int traverses_stack_p(uintptr_t old, uintptr_t new)
b = (uintptr_t)&b;
a = b > len ? b-len : 0;
if (new>a && old<b) return 1;
+#endif
return 0;
}
--
2.7.4
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