From cea81e2b7e441663539d196c18bb2568e3e2fae8 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Fri, 15 May 2020 21:24:59 +0200 Subject: [PATCH] nptl: Use __pthread_attr_copy in pthread_getattr_default_np (bug 25999) pthread_getattr_default_np needs to make a deep copy. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell --- nptl/Makefile | 1 + nptl/pthread_getattr_default_np.c | 12 ++---- nptl/tst-pthread-defaultattr-free.c | 78 +++++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+), 9 deletions(-) create mode 100644 nptl/tst-pthread-defaultattr-free.c diff --git a/nptl/Makefile b/nptl/Makefile index b4aaad0..e5686b2 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -328,6 +328,7 @@ tests = tst-attr2 tst-attr3 tst-default-attr \ tst-thread-affinity-pthread \ tst-thread-affinity-pthread2 \ tst-thread-affinity-sched \ + tst-pthread-defaultattr-free \ tests-container = tst-pthread-getattr diff --git a/nptl/pthread_getattr_default_np.c b/nptl/pthread_getattr_default_np.c index cce20cb..a9665c5 100644 --- a/nptl/pthread_getattr_default_np.c +++ b/nptl/pthread_getattr_default_np.c @@ -16,20 +16,14 @@ License along with the GNU C Library; if not, see . */ -#include -#include #include int pthread_getattr_default_np (pthread_attr_t *out) { - struct pthread_attr *real_out; - - real_out = (struct pthread_attr *) out; - lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); - *real_out = __default_pthread_attr; + int ret = __pthread_attr_copy (out, + (pthread_attr_t *) &__default_pthread_attr); lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); - - return 0; + return ret; } diff --git a/nptl/tst-pthread-defaultattr-free.c b/nptl/tst-pthread-defaultattr-free.c new file mode 100644 index 0000000..5a84302 --- /dev/null +++ b/nptl/tst-pthread-defaultattr-free.c @@ -0,0 +1,78 @@ +/* Test for user-after-free bug in pthread_getattr_default_np (bug 25999). + Copyright (C) 2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include + +static int +do_test (void) +{ + /* This is a typical affinity size. */ + enum { cpu_count = 128 }; + cpu_set_t *set = CPU_ALLOC (cpu_count); + size_t set_size = CPU_ALLOC_SIZE (cpu_count); + CPU_ZERO_S (set_size, set); + CPU_SET (1, set); + CPU_SET (3, set); + + /* Apply the affinity mask to the default attribute. */ + pthread_attr_t attr; + xpthread_attr_init (&attr); + TEST_COMPARE (pthread_attr_setaffinity_np (&attr, set_size, set), 0); + TEST_COMPARE (pthread_setattr_default_np (&attr), 0); + xpthread_attr_destroy (&attr); + + /* Read back the default attribute and check affinity mask. */ + pthread_getattr_default_np (&attr); + CPU_ZERO_S (set_size, set); + TEST_COMPARE (pthread_attr_getaffinity_np (&attr, set_size, set), 0); + for (int i = 0; i < cpu_count; ++i) + TEST_COMPARE (!!CPU_ISSET (i, set), i == 1 || i == 3); + + + /* Apply a larger CPU affinity mask to the default attribute, to + trigger reallocation. */ + { + cpu_set_t *large_set = CPU_ALLOC (4 * cpu_count); + size_t large_set_size = CPU_ALLOC_SIZE (4 * cpu_count); + CPU_ZERO_S (large_set_size, large_set); + pthread_attr_t large_attr; + xpthread_attr_init (&large_attr); + TEST_COMPARE (pthread_attr_setaffinity_np (&large_attr, + large_set_size, large_set), 0); + TEST_COMPARE (pthread_setattr_default_np (&large_attr), 0); + xpthread_attr_destroy (&large_attr); + CPU_FREE (large_set); + } + + /* Read back the default attribute and check affinity mask. */ + CPU_ZERO_S (set_size, set); + TEST_COMPARE (pthread_attr_getaffinity_np (&attr, set_size, set), 0); + for (int i = 0; i < cpu_count; ++i) + TEST_COMPARE (!!CPU_ISSET (i, set), i == 1 || i == 3); + /* Due to bug 25999, the following caused a double-free abort. */ + xpthread_attr_destroy (&attr); + + CPU_FREE (set); + + return 0; +} + +#include -- 2.7.4