From patchwork Mon Dec 11 15:14:20 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thiago Becker X-Patchwork-Id: 10105413 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3B74260360 for ; Mon, 11 Dec 2017 15:14:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 143322950B for ; Mon, 11 Dec 2017 15:14:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 08DA429725; Mon, 11 Dec 2017 15:14:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7CE322950B for ; Mon, 11 Dec 2017 15:14:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750707AbdLKPOz (ORCPT ); Mon, 11 Dec 2017 10:14:55 -0500 Received: from mail-qt0-f195.google.com ([209.85.216.195]:42918 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751628AbdLKPOx (ORCPT ); Mon, 11 Dec 2017 10:14:53 -0500 Received: by mail-qt0-f195.google.com with SMTP id g9so39236285qth.9; Mon, 11 Dec 2017 07:14:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=o7Mc/raLlEjUfD7QDbnfuZXTvi5ZerdfmWAFJ2STytM=; b=P+spsdcCdFuiElZfPLLHf4ZtaaDxFIC3ovXujuUbjKCBtTafVjJPE0u+5liYu99fGT plo8f5YMfM4cS7w+3mIVEhdkKkYmkhNF+VLjEyBl9rh+Gn469bmzLP1X4LzE9m4a6wjX wie4uuakgk+Nz2Pjn+oWEdFma26nUNMyiNrorayFtwxcatkjpoHOy3QS3OeQ7752at6T qzAYtkShTHVZvX9QUcjBy/TRfynLPHtYiHiqXqVHUQY8jEVTmITpOvU7RgqNUPFkdQ11 3ieT/FHSUjZYMGEXWixRTxJTY78PIzsq9+gYbuy1oNAXhdJ08egn1gjmiLubQCyzuC2Q pOwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=o7Mc/raLlEjUfD7QDbnfuZXTvi5ZerdfmWAFJ2STytM=; b=OSRX+XsAe0BPYudFFvgbgKi4y/RKRZz86WxbeuTy5Lwq+E6pQa85T0HuDtcU2sgnpN ebiNSJKIYf4TU0mZEYi4fOv4xAtleCmwQBsVOMQKRO9bDX1IAU4B0z1s4eKz0atc7eyr cX3LjWRf4wdmU5IzWGNq9V9VMJrlXpLWBsChAnG1KPv4aknnpx92LlIdutkNmRQ4u4LF RbQSl5E16Kfzzw6gYZOAc8s+qoPy3/OTkTI21Znrs16Cu/QPzEIPi5zouNvpx2CRDDbr amIbYh96QrypyMsYuUaSQP343QqA1PeU4dp2AkpGgziOHwN52KeRuUG5uclTdvKJA+DL nBuw== X-Gm-Message-State: AKGB3mKIdJcXYuStQJszPAJTJgxBnhP9zJaDeqjo48Xu8yLXNttueKlt 7QFJvfyrvfToMHhHy392cA== X-Google-Smtp-Source: ACJfBospftlddXIK7j7L/Fg2+fIoqBUxzVMjE3HF0hk9FaZCzp5iQQEcia9S2y12XCRJVTjHWJZmLw== X-Received: by 10.55.163.12 with SMTP id m12mr1022513qke.60.1513005292845; Mon, 11 Dec 2017 07:14:52 -0800 (PST) Received: from tbecker-rhat.redhat.com ([201.37.68.249]) by smtp.googlemail.com with ESMTPSA id p8sm4370783qtj.70.2017.12.11.07.14.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 Dec 2017 07:14:52 -0800 (PST) From: Thiago Rafael Becker To: viro@zeniv.linux.org.uk, schwidefsky@de.ibm.com, willy@infradead.org, bfields@fieldses.org, neilb@suse.com Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Thiago Rafael Becker Subject: [PATCH v5] kernel: make groups_sort calling a responsibility group_info allocators Date: Mon, 11 Dec 2017 13:14:20 -0200 Message-Id: <20171211151420.18655-1-thiago.becker@gmail.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20171211142708.GA23284@bombadil.infradead.org> References: <20171211142708.GA23284@bombadil.infradead.org> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In testing, we found that nfsd threads may call set_groups in parallel for the same entry cached in auth.unix.gid, racing in the call of groups_sort, corrupting the groups for that entry and leading to permission denials for the client. This patch: - Make groups_sort globally visible. - Move the call to groups_sort to the modifiers of group_info - Remove the call to groups_sort from set_groups Signed-off-by: Thiago Rafael Becker Reviewed-by: Matthew Wilcox Reviewed-by: NeilBrown --- arch/s390/kernel/compat_linux.c | 1 + fs/nfsd/auth.c | 3 +++ include/linux/cred.h | 1 + kernel/groups.c | 5 +++-- kernel/uid16.c | 1 + net/sunrpc/auth_gss/gss_rpc_xdr.c | 1 + net/sunrpc/auth_gss/svcauth_gss.c | 1 + net/sunrpc/svcauth_unix.c | 2 ++ 8 files changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c index f04db37..59eea9c 100644 --- a/arch/s390/kernel/compat_linux.c +++ b/arch/s390/kernel/compat_linux.c @@ -263,6 +263,7 @@ COMPAT_SYSCALL_DEFINE2(s390_setgroups16, int, gidsetsize, u16 __user *, grouplis return retval; } + groups_sort(group_info); retval = set_current_groups(group_info); put_group_info(group_info); diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c index 697f8ae..f650e47 100644 --- a/fs/nfsd/auth.c +++ b/fs/nfsd/auth.c @@ -60,6 +60,9 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp) gi->gid[i] = exp->ex_anon_gid; else gi->gid[i] = rqgi->gid[i]; + + /* Each thread allocates its own gi, no race */ + groups_sort(gi); } } else { gi = get_group_info(rqgi); diff --git a/include/linux/cred.h b/include/linux/cred.h index 099058e..6312865 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -83,6 +83,7 @@ extern int set_current_groups(struct group_info *); extern void set_groups(struct cred *, struct group_info *); extern int groups_search(const struct group_info *, kgid_t); extern bool may_setgroups(void); +extern void groups_sort(struct group_info *); /* * The security context of a task diff --git a/kernel/groups.c b/kernel/groups.c index e357bc8..daae2f2 100644 --- a/kernel/groups.c +++ b/kernel/groups.c @@ -86,11 +86,12 @@ static int gid_cmp(const void *_a, const void *_b) return gid_gt(a, b) - gid_lt(a, b); } -static void groups_sort(struct group_info *group_info) +void groups_sort(struct group_info *group_info) { sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid), gid_cmp, NULL); } +EXPORT_SYMBOL(groups_sort); /* a simple bsearch */ int groups_search(const struct group_info *group_info, kgid_t grp) @@ -122,7 +123,6 @@ int groups_search(const struct group_info *group_info, kgid_t grp) void set_groups(struct cred *new, struct group_info *group_info) { put_group_info(new->group_info); - groups_sort(group_info); get_group_info(group_info); new->group_info = group_info; } @@ -206,6 +206,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist) return retval; } + groups_sort(group_info); retval = set_current_groups(group_info); put_group_info(group_info); diff --git a/kernel/uid16.c b/kernel/uid16.c index ce74a49..ef1da2a 100644 --- a/kernel/uid16.c +++ b/kernel/uid16.c @@ -192,6 +192,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist) return retval; } + groups_sort(group_info); retval = set_current_groups(group_info); put_group_info(group_info); diff --git a/net/sunrpc/auth_gss/gss_rpc_xdr.c b/net/sunrpc/auth_gss/gss_rpc_xdr.c index c4778ca..444380f 100644 --- a/net/sunrpc/auth_gss/gss_rpc_xdr.c +++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c @@ -231,6 +231,7 @@ static int gssx_dec_linux_creds(struct xdr_stream *xdr, goto out_free_groups; creds->cr_group_info->gid[i] = kgid; } + groups_sort(creds->cr_group_info); return 0; out_free_groups: diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 5dd4e6c..2653119 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -481,6 +481,7 @@ static int rsc_parse(struct cache_detail *cd, goto out; rsci.cred.cr_group_info->gid[i] = kgid; } + groups_sort(rsci.cred.cr_group_info); /* mech name */ len = qword_get(&mesg, buf, mlen); diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index 740b67d..af7f28f 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -520,6 +520,7 @@ static int unix_gid_parse(struct cache_detail *cd, ug.gi->gid[i] = kgid; } + groups_sort(ug.gi); ugp = unix_gid_lookup(cd, uid); if (ugp) { struct cache_head *ch; @@ -819,6 +820,7 @@ svcauth_unix_accept(struct svc_rqst *rqstp, __be32 *authp) kgid_t kgid = make_kgid(&init_user_ns, svc_getnl(argv)); cred->cr_group_info->gid[i] = kgid; } + groups_sort(cred->cr_group_info); if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) { *authp = rpc_autherr_badverf; return SVC_DENIED;