From patchwork Mon Nov 20 08:26:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wenchao Hao X-Patchwork-Id: 13460900 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C3B1126; Mon, 20 Nov 2023 00:27:24 -0800 (PST) Received: from kwepemm000012.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4SYgbH62HvzWhcs; Mon, 20 Nov 2023 16:26:51 +0800 (CST) Received: from build.huawei.com (10.175.101.6) by kwepemm000012.china.huawei.com (7.193.23.142) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Mon, 20 Nov 2023 16:27:21 +0800 From: Wenchao Hao To: Xiubo Li , Ilya Dryomov , Jeff Layton , Luis Henriques , CC: , Wenchao Hao Subject: [PATCH v2] ceph: quota: Fix invalid pointer access if get_quota_realm return ERR_PTR Date: Mon, 20 Nov 2023 16:26:37 +0800 Message-ID: <20231120082637.2717550-1-haowenchao2@huawei.com> X-Mailer: git-send-email 2.32.0 Precedence: bulk X-Mailing-List: ceph-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm000012.china.huawei.com (7.193.23.142) X-CFilter-Loop: Reflected This issue is reported by smatch that get_quota_realm() might return ERR_PTR but we did not handle it. It's not a immediate bug, while we still should address it to avoid potential bugs if get_quota_realm() is changed to return other ERR_PTR in future. Set ceph_snap_realm's pointer in get_quota_realm()'s to address this issue, the pointer would be set to NULL if get_quota_realm() failed to get struct ceph_snap_realm, so no ERR_PTR would happen any more. Signed-off-by: Wenchao Hao --- V2: - Fix all potential invalid pointer access caused by get_quota_realm - Update commit comment and point it's not a immediate bug fs/ceph/quota.c | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c index 9d36c3532de1..e85a85b34a83 100644 --- a/fs/ceph/quota.c +++ b/fs/ceph/quota.c @@ -197,10 +197,10 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc) } /* - * This function walks through the snaprealm for an inode and returns the - * ceph_snap_realm for the first snaprealm that has quotas set (max_files, + * This function walks through the snaprealm for an inode and set the + * realmp with the first snaprealm that has quotas set (max_files, * max_bytes, or any, depending on the 'which_quota' argument). If the root is - * reached, return the root ceph_snap_realm instead. + * reached, set the realmp with the root ceph_snap_realm instead. * * Note that the caller is responsible for calling ceph_put_snap_realm() on the * returned realm. @@ -211,10 +211,9 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc) * this function will return -EAGAIN; otherwise, the snaprealms walk-through * will be restarted. */ -static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc, - struct inode *inode, - enum quota_get_realm which_quota, - bool retry) +static int get_quota_realm(struct ceph_mds_client *mdsc, struct inode *inode, + enum quota_get_realm which_quota, + struct ceph_snap_realm **realmp, bool retry) { struct ceph_client *cl = mdsc->fsc->client; struct ceph_inode_info *ci = NULL; @@ -222,8 +221,10 @@ static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc, struct inode *in; bool has_quota; + if (realmp) + *realmp = NULL; if (ceph_snap(inode) != CEPH_NOSNAP) - return NULL; + return 0; restart: realm = ceph_inode(inode)->i_snap_realm; @@ -250,7 +251,7 @@ static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc, break; ceph_put_snap_realm(mdsc, realm); if (!retry) - return ERR_PTR(-EAGAIN); + return -EAGAIN; goto restart; } @@ -259,8 +260,11 @@ static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc, iput(in); next = realm->parent; - if (has_quota || !next) - return realm; + if (has_quota || !next) { + if (realmp) + *realmp = realm; + return 0; + } ceph_get_snap_realm(mdsc, next); ceph_put_snap_realm(mdsc, realm); @@ -269,14 +273,15 @@ static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc, if (realm) ceph_put_snap_realm(mdsc, realm); - return NULL; + return 0; } bool ceph_quota_is_same_realm(struct inode *old, struct inode *new) { struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(old->i_sb); - struct ceph_snap_realm *old_realm, *new_realm; + struct ceph_snap_realm *old_realm = NULL, *new_realm = NULL; bool is_same; + int ret; restart: /* @@ -286,9 +291,9 @@ bool ceph_quota_is_same_realm(struct inode *old, struct inode *new) * dropped and we can then restart the whole operation. */ down_read(&mdsc->snap_rwsem); - old_realm = get_quota_realm(mdsc, old, QUOTA_GET_ANY, true); - new_realm = get_quota_realm(mdsc, new, QUOTA_GET_ANY, false); - if (PTR_ERR(new_realm) == -EAGAIN) { + get_quota_realm(mdsc, old, QUOTA_GET_ANY, &old_realm, true); + ret = get_quota_realm(mdsc, new, QUOTA_GET_ANY, &new_realm, false); + if (ret == -EAGAIN) { up_read(&mdsc->snap_rwsem); if (old_realm) ceph_put_snap_realm(mdsc, old_realm); @@ -492,8 +497,8 @@ bool ceph_quota_update_statfs(struct ceph_fs_client *fsc, struct kstatfs *buf) bool is_updated = false; down_read(&mdsc->snap_rwsem); - realm = get_quota_realm(mdsc, d_inode(fsc->sb->s_root), - QUOTA_GET_MAX_BYTES, true); + get_quota_realm(mdsc, d_inode(fsc->sb->s_root), + QUOTA_GET_MAX_BYTES, &realm, true); up_read(&mdsc->snap_rwsem); if (!realm) return false;