From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hall.aurel32.net (hall.aurel32.net [IPv6:2001:bc8:30d7:100::1]) by sourceware.org (Postfix) with ESMTPS id 9FF093858D35 for ; Wed, 29 Jul 2020 23:45:17 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 9FF093858D35 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=aurel32.net Authentication-Results: sourceware.org; spf=none smtp.mailfrom=aurelien@aurel32.net DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=aurel32.net ; s=202004.hall; h=Content-Transfer-Encoding:MIME-Version:Message-Id:Date: Subject:Cc:To:From:Content-Type:From:Reply-To:Subject:Content-ID: Content-Description:In-Reply-To:References:X-Debbugs-Cc; bh=koM/vwECcYqZbPyIVCxI/YYnA6RouML3LTKCdSW1Px0=; b=U2t7Yc9ldcacOX1FId5oeA/KsA XgqdEWlIz+ooCzm+ZC/ptYvwBj/UrOSun2R18yFLp6avlbjowUjNIaRWetCuz4s9DmM5DGn+xPBRN +9Tr+5QmBTeEK9uNXe/Eb+9u97VARRRj4VCu68MPh3lSxwIKfs6feKx6nlK5hoDiqKBGLtT3rul4v /Zgom8riTVGZIBEr4nEDL/pUcxHGmXu5h9Aq1YO5SUrfBAsnsA6LSnD6bfS6M9EtAH7qaMQW5sth4 wpEqioNmSHuduxMp8Y81oPc6IcxT/eliI5moNFvEMwTROHbws3qn7PybdAa3N4C+BH2ibxr9lQdM3 ZinxoIpw==; Received: from ohm.aurel32.net ([2001:bc8:30d7:111::1000]) by hall.aurel32.net with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k0vl6-0004hv-CM; Thu, 30 Jul 2020 01:45:16 +0200 Received: from aurel32 by ohm.aurel32.net with local (Exim 4.94) (envelope-from ) id 1k0vl4-007OSZ-Ba; Thu, 30 Jul 2020 01:45:14 +0200 From: Aurelien Jarno To: libc-stable@sourceware.org Subject: [2.31 COMMITTED] nptl: Zero-extend arguments to SETXID syscalls [BZ #26248] Date: Thu, 30 Jul 2020 01:44:39 +0200 Message-Id: <20200729234439.1760925-1-aurelien@aurel32.net> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-10.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, SPF_HELO_PASS, SPF_NONE, 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-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Jul 2020 23:45:19 -0000 From: "H.J. Lu" 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. The kernel XID arguments are unsigned and do not require sign extension. 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 are zero-extended. A testcase is added for x32 and setgroups returned with EFAULT when running as root without the fix. (cherry picked from commit 0ad926f34937f7b4843a8b49e5d93199601fe324) --- NEWS | 1 + nptl/Makefile | 2 +- nptl/descr.h | 8 ++++- nptl/tst-setgroups.c | 79 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 88 insertions(+), 2 deletions(-) create mode 100644 nptl/tst-setgroups.c diff --git a/NEWS b/NEWS index daf4b727cd7..8a857061e11 100644 --- a/NEWS +++ b/NEWS @@ -24,6 +24,7 @@ The following bugs are resolved with this release: [25933] Off by one error in __strncmp_avx2 [25966] Incorrect access of __x86_shared_non_temporal_threshold for x32 [25976] nss_compat: internal_end*ent may clobber errno, hiding ERANGE + [26248] Incorrect argument types for INLINE_SETXID_SYSCALL Security related changes: diff --git a/nptl/Makefile b/nptl/Makefile index 584e0ffd96e..2df4c9098c7 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -332,7 +332,7 @@ tests-internal := tst-rwlock19 tst-rwlock20 \ tst-mutexpi8 tst-mutexpi8-static tst-cancel25 xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \ - tst-mutexpp1 tst-mutexpp6 tst-mutexpp10 + tst-mutexpp1 tst-mutexpp6 tst-mutexpp10 tst-setgroups # This test can run into task limits because of a linux kernel bug # and then cause the make process to fail too, see bug 24537. diff --git a/nptl/descr.h b/nptl/descr.h index 9dcf480bdfc..5f1f35e9a4a 100644 --- a/nptl/descr.h +++ b/nptl/descr.h @@ -94,7 +94,13 @@ 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); + + The kernel XID arguments are unsigned and do not require sign + extension. */ + unsigned long int id[3]; volatile int cntr; volatile int error; /* -1: no call yet, 0: success seen, >0: error seen. */ }; diff --git a/nptl/tst-setgroups.c b/nptl/tst-setgroups.c new file mode 100644 index 00000000000..ae3c1b1ba0d --- /dev/null +++ b/nptl/tst-setgroups.c @@ -0,0 +1,79 @@ +/* Test setgroups as root and in the presence of threads (Bug 26248) + 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 + +/* The purpose of this test is to test the setgroups API as root and in + the presence of threads. Once we create a thread the setgroups + implementation must ensure that all threads are set to the same + group and this operation should not fail. Lastly we test setgroups + with a zero sized group and a bad address and verify we get EPERM. */ + +static void * +start_routine (void *args) +{ + return NULL; +} + +static int +do_test (void) +{ + int size; + /* NB: Stack address can be at 0xfffXXXXX on 32-bit OSes. */ + 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"); + } + } + + if (status == EXIT_SUCCESS && setgroups (0, list) < 0) + { + status = EXIT_FAILURE; + error (0, errno, "setgroups failed"); + } + + xpthread_join (thread); + + return status; +} + +#include -- 2.27.0