Date: Wed, 10 Jan 2024 17:50:36 GMT From: Olivier Certner <olce@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: aadb4a1b3fd1 - main - pthread_attr_get_np(): Use malloc(), report ENOMEM, don't tamper on error Message-ID: <202401101750.40AHoalp098271@gitrepo.freebsd.org>
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The branch main has been updated by olce: URL: https://cgit.FreeBSD.org/src/commit/?id=aadb4a1b3fd185d547087f6eafca6ce0b4df3291 commit aadb4a1b3fd185d547087f6eafca6ce0b4df3291 Author: Olivier Certner <olce@FreeBSD.org> AuthorDate: 2024-01-04 17:45:52 +0000 Commit: Olivier Certner <olce@FreeBSD.org> CommitDate: 2024-01-10 17:50:19 +0000 pthread_attr_get_np(): Use malloc(), report ENOMEM, don't tamper on error Similarly as in the previous commit, using calloc() instead of malloc() is useless here in the regular case since the subsequent call to cpuset_getaffinify() is going to completely fill the allocated memory. However, there is an additional complication. This function tries to allocate memory to hold the cpuset if it previously wasn't, and does so before the thread lock is acquired, which can fail on a bad thread ID. In this case, it is necessary to deallocate the memory allocated in this function so that the attributes object appears unmodified to the caller when an error is returned. Without this, a subsequent call to pthread_attr_getaffinity_np() would expose uninitialized memory (not a security problem per se, since it comes from the same process) instead of returning a full mask as it would before the failing call to pthread_attr_get_np(). So the caller would be able to notice a change in the state of the attributes object even if pthread_attr_get_np() reported failure, which would be quite surprising. A similar problem that could occur on failure of cpuset_setaffinity() has been fixed. Finally, we shall always report memory allocation failure. This already goes for pthread_attr_init(), so, if for nothing else, just be consistent. Reviewed by: emaste, kib Approved by: emaste (mentor) MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D43329 --- lib/libthr/thread/thr_attr.c | 45 ++++++++++++++++++++++++----------------- lib/libthr/thread/thr_private.h | 2 -- 2 files changed, 27 insertions(+), 20 deletions(-) diff --git a/lib/libthr/thread/thr_attr.c b/lib/libthr/thread/thr_attr.c index 561037fa5eb4..3c03225c33cb 100644 --- a/lib/libthr/thread/thr_attr.c +++ b/lib/libthr/thread/thr_attr.c @@ -129,8 +129,9 @@ __weak_reference(_thr_attr_get_np, _pthread_attr_get_np); int _thr_attr_get_np(pthread_t pthread, pthread_attr_t *dstattr) { - struct pthread_attr attr, *dst; + struct pthread_attr *dst; struct pthread *curthread; + cpuset_t *cpuset; size_t kern_size; int error; @@ -138,35 +139,43 @@ _thr_attr_get_np(pthread_t pthread, pthread_attr_t *dstattr) return (EINVAL); kern_size = _get_kern_cpuset_size(); - if (dst->cpuset == NULL) { - dst->cpuset = calloc(1, kern_size); - dst->cpusetsize = kern_size; - } + if ((cpuset = malloc(kern_size)) == NULL) + return (ENOMEM); + } else + cpuset = dst->cpuset; curthread = _get_curthread(); /* Arg 0 is to include dead threads. */ if ((error = _thr_find_thread(curthread, pthread, 0)) != 0) - return (error); - - attr = pthread->attr; - if ((pthread->flags & THR_FLAGS_DETACHED) != 0) - attr.flags |= PTHREAD_DETACHED; + goto free_and_exit; error = cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, TID(pthread), - dst->cpusetsize, dst->cpuset); - if (error == -1) + kern_size, cpuset); + if (error == -1) { + THR_THREAD_UNLOCK(curthread, pthread); error = errno; + goto free_and_exit; + } - THR_THREAD_UNLOCK(curthread, pthread); + /* + * From this point on, we can't fail, so we can start modifying 'dst'. + */ - if (error == 0) - memcpy(&dst->pthread_attr_start_copy, - &attr.pthread_attr_start_copy, - offsetof(struct pthread_attr, pthread_attr_end_copy) - - offsetof(struct pthread_attr, pthread_attr_start_copy)); + *dst = pthread->attr; + if ((pthread->flags & THR_FLAGS_DETACHED) != 0) + dst->flags |= PTHREAD_DETACHED; + THR_THREAD_UNLOCK(curthread, pthread); + + dst->cpuset = cpuset; + dst->cpusetsize = kern_size; return (0); + +free_and_exit: + if (dst->cpuset == NULL) + free(cpuset); + return (error); } __weak_reference(_thr_attr_getdetachstate, pthread_attr_getdetachstate); diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h index 3475029f8996..3fc4d02c611e 100644 --- a/lib/libthr/thread/thr_private.h +++ b/lib/libthr/thread/thr_private.h @@ -261,7 +261,6 @@ struct pthread_atfork { }; struct pthread_attr { -#define pthread_attr_start_copy sched_policy int sched_policy; int sched_inherit; int prio; @@ -271,7 +270,6 @@ struct pthread_attr { void *stackaddr_attr; size_t stacksize_attr; size_t guardsize_attr; -#define pthread_attr_end_copy cpuset cpuset_t *cpuset; size_t cpusetsize; };
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