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- From 66570ec9c465e3c6c5d6dbd7dd42e45041a39288 Mon Sep 17 00:00:00 2001
- From: Rich Felker <[email protected]>
- Date: Mon, 19 Sep 2016 11:15:51 -0400
- Subject: 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, &)
- --
- cgit v0.11.2
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