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From 66570ec9c465e3c6c5d6dbd7dd42e45041a39288 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 19 Sep 2016 11:15:51 -0400
Subject: [PATCH 11/11] fix undefined behavior in sched.h cpu_set_t usage
since cpu sets can be dynamically allocated and have variable size,
accessing their contents via ->__bits is not valid; performing pointer
arithmetic outside the range of the size of the declared __bits array
results in undefined beahavior. instead, only use cpu_set_t for
fixed-size cpu set objects (instantiated by the caller) and as an
abstract pointer type for dynamically allocated ones. perform all
accesses simply by casting the abstract pointer type cpuset_t * back
to unsigned long *.
---
include/sched.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/sched.h b/include/sched.h
index af82d6c..d1cccb7 100644
--- a/include/sched.h
+++ b/include/sched.h
@@ -82,7 +82,7 @@ int sched_getaffinity(pid_t, size_t, cpu_set_t *);
int sched_setaffinity(pid_t, size_t, const cpu_set_t *);
#define __CPU_op_S(i, size, set, op) ( (i)/8U >= (size) ? 0 : \
- ((set)->__bits[(i)/8/sizeof(long)] op (1UL<<((i)%(8*sizeof(long))))) )
+ (((unsigned long *)(set))[(i)/8/sizeof(long)] op (1UL<<((i)%(8*sizeof(long))))) )
#define CPU_SET_S(i, size, set) __CPU_op_S(i, size, set, |=)
#define CPU_CLR_S(i, size, set) __CPU_op_S(i, size, set, &=~)
@@ -94,8 +94,8 @@ static __inline void __CPU_##func##_S(size_t __size, cpu_set_t *__dest, \
{ \
size_t __i; \
for (__i=0; __i<__size/sizeof(long); __i++) \
- __dest->__bits[__i] = __src1->__bits[__i] \
- op __src2->__bits[__i] ; \
+ ((unsigned long *)__dest)[__i] = ((unsigned long *)__src1)[__i] \
+ op ((unsigned long *)__src2)[__i] ; \
}
__CPU_op_func_S(AND, &)
--
2.10.1
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