diff options
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c')
| -rw-r--r-- | nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c b/nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c index 714ad49428..92a188a2f3 100644 --- a/nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c +++ b/nptl/sysdeps/unix/sysv/linux/libc_pthread_init.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2002, 2003, 2005, 2006 Free Software Foundation, Inc. +/* Copyright (C) 2002, 2003, 2005, 2006, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -25,6 +25,7 @@ #include <string.h> #include <pthreadP.h> #include <bits/libc-lock.h> +#include <sysdep.h> #ifdef TLS_MULTIPLE_THREADS_IN_TCB @@ -46,11 +47,29 @@ __libc_pthread_init (ptr, reclaim, functions) __register_atfork (NULL, NULL, reclaim, NULL); #ifdef SHARED - /* We copy the content of the variable pointed to by the FUNCTIONS - parameter to one in libc.so since this means access to the array - can be done with one memory access instead of two. */ - memcpy (&__libc_pthread_functions, functions, - sizeof (__libc_pthread_functions)); + /* Copy the function pointers into an array in libc. This enables + access with just one memory reference but moreso, it prevents + hijacking the function pointers with just one pointer change. We + "encrypt" the function pointers since we cannot write-protect the + array easily enough. */ + union ptrhack + { + struct pthread_functions pf; + void *parr[1]; + } const *src; + union ptrhack *dest; +# define NPTRS (sizeof (struct pthread_functions) / sizeof (void *)) + + src = (const void *) functions; + dest = (void *) &__libc_pthread_functions; + + for (size_t cnt = 0; cnt < NPTRS; ++cnt) + { + void *p = src->parr[cnt]; + PTR_MANGLE (p); + dest->parr[cnt] = p; + } + __libc_pthread_functions_init = 1; #endif #ifndef TLS_MULTIPLE_THREADS_IN_TCB @@ -61,7 +80,7 @@ __libc_pthread_init (ptr, reclaim, functions) #ifdef SHARED libc_freeres_fn (freeres_libptread) { - if (__libc_pthread_functions.ptr_freeres != NULL) - __libc_pthread_functions.ptr_freeres (); + if (__libc_pthread_functions_init) + PTHFCT_CALL (ptr_freeres, ()); } #endif |