From patchwork Mon Jan 15 15:08:39 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 25397 Received: (qmail 104257 invoked by alias); 15 Jan 2018 15:08:44 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 101583 invoked by uid 89); 15 Jan 2018 15:08:43 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, SPF_HELO_PASS, T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy=H*MI:str X-HELO: mx1.redhat.com Date: Mon, 15 Jan 2018 16:08:39 +0100 To: libc-alpha@sourceware.org Subject: [PATCH] [BZ #22637] Fix stack guard size accounting User-Agent: Heirloom mailx 12.5 7/5/10 MIME-Version: 1.0 Message-Id: <20180115150839.4EA504034FFAF@oldenburg.str.redhat.com> From: fweimer@redhat.com (Florian Weimer) From: Szabolcs Nagy Previously if user requested S stack and G guard when creating a thread, the total mapping was S and the actual available stack was S - G - static_tls, which is not what the user requested. This patch fixes the guard size accounting by pretending the user requested S+G stack. This way all later logic works out except when reporting the user requested stack size (pthread_getattr_np) or when computing the minimal stack size (__pthread_get_minstack). Normally this will increase thread stack allocations by one page. TLS accounting is not affected, that will require a separate fix. [BZ #22637] * nptl/descr.h (stackblock, stackblock_size): Update comments. * nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize. * nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from stacksize. * nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise. (cherry picked from commit 630f4cc3aa019ede55976ea561f1a7af2f068639) 2018-01-08 Szabolcs Nagy [BZ #22637] * nptl/descr.h (stackblock, stackblock_size): Update comments. * nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize. * nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from stacksize. * nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise. diff --git a/NEWS b/NEWS index 7f88e9e310..3a719e81e3 100644 --- a/NEWS +++ b/NEWS @@ -101,6 +101,7 @@ The following bugs are resolved with this release: [22325] glibc: Memory leak in glob with GLOB_TILDE (CVE-2017-15671) [22375] malloc returns pointer from tcache instead of NULL (CVE-2017-17426) [22627] $ORIGIN in $LD_LIBRARY_PATH is substituted twice + [22637] nptl: Fix stack guard size accounting [22679] getcwd(3) can succeed without returning an absolute path (CVE-2018-1000001) diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index 1a760e92e5..e351ce9d99 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -533,6 +533,10 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, /* Make sure the size of the stack is enough for the guard and eventually the thread descriptor. */ guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1; + if (guardsize < attr->guardsize || size + guardsize < guardsize) + /* Arithmetic overflow. */ + return EINVAL; + size += guardsize; if (__builtin_expect (size < ((guardsize + __static_tls_size + MINIMAL_REST_STACK + pagesize_m1) & ~pagesize_m1), diff --git a/nptl/descr.h b/nptl/descr.h index c83b17b674..82dab056e2 100644 --- a/nptl/descr.h +++ b/nptl/descr.h @@ -380,9 +380,9 @@ struct pthread /* Machine-specific unwind info. */ struct _Unwind_Exception exc; - /* If nonzero pointer to area allocated for the stack and its - size. */ + /* If nonzero, pointer to the area allocated for the stack and guard. */ void *stackblock; + /* Size of the stackblock area including the guard. */ size_t stackblock_size; /* Size of the included guard area. */ size_t guardsize; diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index 869e926f17..e5c0bdfbeb 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -473,8 +473,5 @@ strong_alias (__pthread_initialize_minimal_internal, size_t __pthread_get_minstack (const pthread_attr_t *attr) { - struct pthread_attr *iattr = (struct pthread_attr *) attr; - - return (GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN - + iattr->guardsize); + return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN; } diff --git a/nptl/pthread_getattr_np.c b/nptl/pthread_getattr_np.c index 06093b3d92..210a3f8a1f 100644 --- a/nptl/pthread_getattr_np.c +++ b/nptl/pthread_getattr_np.c @@ -57,9 +57,12 @@ pthread_getattr_np (pthread_t thread_id, pthread_attr_t *attr) /* The sizes are subject to alignment. */ if (__glibc_likely (thread->stackblock != NULL)) { - iattr->stacksize = thread->stackblock_size; + /* The stack size reported to the user should not include the + guard size. */ + iattr->stacksize = thread->stackblock_size - thread->guardsize; #if _STACK_GROWS_DOWN - iattr->stackaddr = (char *) thread->stackblock + iattr->stacksize; + iattr->stackaddr = (char *) thread->stackblock + + thread->stackblock_size; #else iattr->stackaddr = (char *) thread->stackblock; #endif