From patchwork Thu Jul 16 12:46:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 40116 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 3149A383E835; Thu, 16 Jul 2020 12:47:09 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3149A383E835 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1594903629; bh=4kXrGCo/7oPpPgLKGAFuRg13RQKynMWSWYnIJScLUNM=; h=References:In-Reply-To:Date:Subject:To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=Uvgkd00qv7laLhiimU1KRVs9OEQLf4l+9SO/dK+QAlXBGktm7qXKwbLIAM4liGd4r CL3BCTIq8i/+MUrWv8TVfvjeg43N+7Mkt1Np2bGi0IIoe7dbXBeq9bb2xrUP58QY/u HC2UThYZDMmv9n/rrPnh29aOGMm8C/YTJLymuyTI= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-il1-x142.google.com (mail-il1-x142.google.com [IPv6:2607:f8b0:4864:20::142]) by sourceware.org (Postfix) with ESMTPS id 6800C383E835 for ; Thu, 16 Jul 2020 12:47:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 6800C383E835 Received: by mail-il1-x142.google.com with SMTP id e18so4908597ilr.7 for ; Thu, 16 Jul 2020 05:47:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4kXrGCo/7oPpPgLKGAFuRg13RQKynMWSWYnIJScLUNM=; b=lJoTcnh41n61cXXxFRh+xircrlm+mztVU0eZGXwuHx/ZSXAge9Sy3er17ZjgdksL2S FsB8BpD+cjgVjrk1ogvVUrIePSN1Cj49QoTljVFNDuXHbw/uVvQPd4Sp3bNVR6Qp34aK /ek6l1fXYTr8R130K2ZKsJuAW0ZcdBpsOerkhVN9a+LQdnDpmgbw1CPW4ozjwwHfathB UVr/s9RltklRNt93xkfAwyLozDHwZKDcuSSlh1knMajmFirQBWYOHyywDjes3sJh/kN3 uIsocNLZuvzGhW+i/e4hN1hj+ofBqaGuBO/bvoEKVbDDb9uoe91F+kVpNAme/2481AqB wvvw== X-Gm-Message-State: AOAM533DUvXGIEWbXJBw1rGGViuCOYfYswMuILMwfq1FcXEup3+qfE3N d7uSRXHdr2L21gP3yxSolCirFnMa1hcBsTqrvB0= X-Google-Smtp-Source: ABdhPJxfLNrD3Lntt5Q7+BPg/LNNbCMrGiV9N1GQ18egL6uyOWEUa6qHHpNdt+XSBSNSoI6JOUcGd2X7B8O/dP3aCro= X-Received: by 2002:a92:874a:: with SMTP id d10mr4479229ilm.273.1594903625873; Thu, 16 Jul 2020 05:47:05 -0700 (PDT) MIME-Version: 1.0 References: <20200716112651.2257283-1-hjl.tools@gmail.com> <87o8ofy8e7.fsf@oldenburg2.str.redhat.com> In-Reply-To: <87o8ofy8e7.fsf@oldenburg2.str.redhat.com> Date: Thu, 16 Jul 2020 05:46:30 -0700 Message-ID: Subject: [PATCH] nptl: Zero-extend arguments to SETXID syscalls [BZ #26248] To: Florian Weimer X-Spam-Status: No, score=-9.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: "H.J. Lu via Libc-alpha" From: "H.J. Lu" Reply-To: "H.J. Lu" Cc: "H.J. Lu via Libc-alpha" Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" On Thu, Jul 16, 2020 at 5:03 AM Florian Weimer wrote: > > * H. J. Lu via Libc-alpha: > > > nptl has > > > > /* Opcodes and data types for communication with the signal handler to > > change user/group IDs. */ > > struct xid_command > > { > > int syscall_no; > > long int id[3]; > > volatile int cntr; > > volatile int error; > > }; > > > > /* This must be last, otherwise the current thread might not have > > permissions to send SIGSETXID syscall to the other threads. */ > > result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, 3, > > cmdp->id[0], cmdp->id[1], cmdp->id[2]); > > > > But the second argument of setgroups syscal is a pointer: > > > > int setgroups(size_t size, const gid_t *list); > > > > But on x32, pointers passed to syscall must have pointer type so that they > > will be zero-extended. > > > > Add to define INTERNAL_SETXID_SYSCALL_NCS and use it, > > instead of INTERNAL_SYSCALL_NCS, for SETXID syscalls. X32 override it > > with pointer type for setgroups. A testcase is added and setgroups > > returned with EFAULT when running as root without the fix. > > Isn't it sufficient to change the type of id to unsigned long int[3]? > The UID arguments are unsigned on the kernel side, so no sign extension > is required. > It works. Here is the updated patch. OK for master? Thanks. From 2af9e56c2306dc9d80a4476fa5b154a26a935557 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 16 Jul 2020 03:37:10 -0700 Subject: [PATCH] nptl: Zero-extend arguments to SETXID syscalls [BZ #26248] nptl has /* Opcodes and data types for communication with the signal handler to change user/group IDs. */ struct xid_command { int syscall_no; long int id[3]; volatile int cntr; volatile int error; }; /* This must be last, otherwise the current thread might not have permissions to send SIGSETXID syscall to the other threads. */ result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, 3, cmdp->id[0], cmdp->id[1], cmdp->id[2]); But the second argument of setgroups syscal is a pointer: int setgroups(size_t size, const gid_t *list); But on x32, pointers passed to syscall must have pointer type so that they will be zero-extended. Since the XID arguments are unsigned on the kernel side, so no sign extension is required. Change xid_command to struct xid_command { int syscall_no; unsigned long int id[3]; volatile int cntr; volatile int error; }; so that all arguments zero-extended. A testcase is added for x32 and setgroups returned with EFAULT when running as root without the fix. --- nptl/descr.h | 8 ++- sysdeps/unix/sysv/linux/x86_64/x32/Makefile | 4 ++ .../sysv/linux/x86_64/x32/tst-setgroups.c | 67 +++++++++++++++++++ 3 files changed, 78 insertions(+), 1 deletion(-) create mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/tst-setgroups.c diff --git a/nptl/descr.h b/nptl/descr.h index 6a509b6725..e98fe4084d 100644 --- a/nptl/descr.h +++ b/nptl/descr.h @@ -95,7 +95,13 @@ struct pthread_unwind_buf struct xid_command { int syscall_no; - long int id[3]; + /* Enforce zero-extension for the pointer argument in + + int setgroups(size_t size, const gid_t *list); + + Since the XID arguments are unsigned on the kernel side, so no sign + extension is required. */ + unsigned long int id[3]; volatile int cntr; volatile int error; /* -1: no call yet, 0: success seen, >0: error seen. */ }; diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/Makefile b/sysdeps/unix/sysv/linux/x86_64/x32/Makefile index 16b768d8ba..1a6c984f96 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/Makefile +++ b/sysdeps/unix/sysv/linux/x86_64/x32/Makefile @@ -5,6 +5,10 @@ ifeq ($(subdir),misc) sysdep_routines += arch_prctl endif +ifeq ($(subdir),nptl) +xtests += tst-setgroups +endif + ifeq ($(subdir),conform) # For bugs 16437 and 21279. conformtest-xfail-conds += x86_64-x32-linux diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/tst-setgroups.c b/sysdeps/unix/sysv/linux/x86_64/x32/tst-setgroups.c new file mode 100644 index 0000000000..9895443278 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/x32/tst-setgroups.c @@ -0,0 +1,67 @@ +/* Basic test for setgroups + 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 +#include +#include +#include +#include +#include + +static void * +start_routine (void *args) +{ + return NULL; +} + +static int +do_test (void) +{ + int size; + /* NB: Stack address is at 0xfffXXXXX. */ + gid_t list[NGROUPS_MAX]; + int status = EXIT_SUCCESS; + + pthread_t thread = xpthread_create (NULL, start_routine, NULL); + + size = getgroups (sizeof (list) / sizeof (list[0]), list); + if (size < 0) + { + status = EXIT_FAILURE; + error (0, errno, "getgroups failed"); + } + if (setgroups (size, list) < 0) + { + if (errno == EPERM) + status = EXIT_UNSUPPORTED; + else + { + status = EXIT_FAILURE; + error (0, errno, "setgroups failed"); + } + } + + xpthread_join (thread); + + return status; +} + +#include -- 2.26.2