From patchwork Fri Sep 4 16:05:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 11758053 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2327392C for ; Fri, 4 Sep 2020 16:06:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CC2920772 for ; Fri, 4 Sep 2020 16:06:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599235611; bh=QzbxtHS3+Lm/aqHBZG+er39st6vN5vnrx+888HiKRxg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=P332sYOhv8JILUlA/z/bqOyQj/FqnkU0JyPuphWYKAiySoD5esgDjiX1l0b6I3ym6 HY72o1da3cnexpnbFXY2VVWU/2UuPiJR/3JvhQbl+zyP7tQUle8NX/QdmrEW2YINn6 6eKFKyHNWnKJc2EvhGCTDwjlMyd2ofvyboR+my/w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728001AbgIDQGa (ORCPT ); Fri, 4 Sep 2020 12:06:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:51326 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727969AbgIDQFx (ORCPT ); Fri, 4 Sep 2020 12:05:53 -0400 Received: from tleilax.com (68-20-15-154.lightspeed.rlghnc.sbcglobal.net [68.20.15.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E57E420829; Fri, 4 Sep 2020 16:05:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599235553; bh=QzbxtHS3+Lm/aqHBZG+er39st6vN5vnrx+888HiKRxg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U+eTGRggMxd2NI4ma7gSyXv25V00uWF+UiPSAq5xiIUIXoD+514cQBNZhVoBDhCPd YeM68XQcr3XP3tJfR1w7XZqpyxC86SLd234IdS3hHJWN7KE9e5XVFCCD/XvetwuLH6 f2vJUXfv1Gan5v4y9dTFuMZMqeW3do5x7Y5cjZHY= From: Jeff Layton To: ceph-devel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org, ebiggers@kernel.org Subject: [RFC PATCH v2 18/18] ceph: create symlinks with encrypted and base64-encoded targets Date: Fri, 4 Sep 2020 12:05:37 -0400 Message-Id: <20200904160537.76663-19-jlayton@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200904160537.76663-1-jlayton@kernel.org> References: <20200904160537.76663-1-jlayton@kernel.org> MIME-Version: 1.0 Sender: linux-fscrypt-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org When creating symlinks in encrypted directories, encrypt and base64-encode the target with the new inode's key before sending to the MDS. When filling a symlinked inode, base64-decode it into a buffer that we'll keep in ci->i_symlink. When get_link is called, decrypt the buffer into a new one that will hang off i_link. Signed-off-by: Jeff Layton --- fs/ceph/dir.c | 32 ++++++++++++++++--- fs/ceph/inode.c | 82 +++++++++++++++++++++++++++++++++++++++---------- fs/ceph/super.h | 3 ++ 3 files changed, 96 insertions(+), 21 deletions(-) diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 0ba17c592fe1..7ff8921dd3a7 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -948,6 +948,7 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry, struct ceph_mds_client *mdsc = fsc->mdsc; struct ceph_mds_request *req; struct ceph_acl_sec_ctx as_ctx = {}; + struct fscrypt_str osd_link = FSTR_INIT(NULL, 0); umode_t mode = S_IFLNK | 0777; int err; @@ -973,11 +974,33 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry, goto out_req; } - req->r_path2 = kstrdup(dest, GFP_KERNEL); - if (!req->r_path2) { - err = -ENOMEM; - goto out_req; + if (IS_ENCRYPTED(req->r_new_inode)) { + int len = strlen(dest); + + err = fscrypt_prepare_symlink(dir, dest, len, PATH_MAX, &osd_link); + if (err) + goto out_req; + + err = fscrypt_encrypt_symlink(req->r_new_inode, dest, len, &osd_link); + if (err) + goto out_req; + + req->r_path2 = kmalloc(BASE64_CHARS(osd_link.len) + 1, GFP_KERNEL); + if (!req->r_path2) { + err = -ENOMEM; + goto out_req; + } + + len = base64_encode_fname(osd_link.name, osd_link.len, req->r_path2); + req->r_path2[len] = '\0'; + } else { + req->r_path2 = kstrdup(dest, GFP_KERNEL); + if (!req->r_path2) { + err = -ENOMEM; + goto out_req; + } } + req->r_parent = dir; set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags); req->r_dentry = dget(dentry); @@ -997,6 +1020,7 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry, if (err) d_drop(dentry); ceph_release_acl_sec_ctx(&as_ctx); + fscrypt_fname_free_buffer(&osd_link); return err; } diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index e578e4cdcf30..dd39f886b03c 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "super.h" #include "mds_client.h" @@ -33,8 +34,6 @@ * (typically because they are in the message handler path). */ -static const struct inode_operations ceph_symlink_iops; - static void ceph_inode_work(struct work_struct *work); /* @@ -503,6 +502,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb) atomic64_set(&ci->i_complete_seq[0], 0); atomic64_set(&ci->i_complete_seq[1], 0); ci->i_symlink = NULL; + ci->i_symlink_len = 0; ci->i_max_bytes = 0; ci->i_max_files = 0; @@ -590,6 +590,7 @@ void ceph_free_inode(struct inode *inode) struct ceph_inode_info *ci = ceph_inode(inode); kfree(ci->i_symlink); + fscrypt_free_inode(inode); kmem_cache_free(ceph_inode_cachep, ci); } @@ -991,34 +992,60 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page, inode->i_fop = &ceph_file_fops; break; case S_IFLNK: - inode->i_op = &ceph_symlink_iops; if (!ci->i_symlink) { u32 symlen = iinfo->symlink_len; char *sym; spin_unlock(&ci->i_ceph_lock); - if (symlen != i_size_read(inode)) { - pr_err("%s %llx.%llx BAD symlink " - "size %lld\n", __func__, - ceph_vinop(inode), - i_size_read(inode)); + if (IS_ENCRYPTED(inode)) { + /* Do base64 decode so that we get the right size (maybe?) */ + err = -ENOMEM; + sym = kmalloc(symlen + 1, GFP_NOFS); + if (!sym) + goto out; + + symlen = base64_decode_fname(iinfo->symlink, symlen, sym); + /* + * i_size as reported by the MDS may be wrong, due to base64 + * inflation and padding. Fix it up here. + */ i_size_write(inode, symlen); inode->i_blocks = calc_inode_blocks(symlen); - } + } else { + if (symlen != i_size_read(inode)) { + pr_err("%s %llx.%llx BAD symlink size %lld\n", + __func__, ceph_vinop(inode), i_size_read(inode)); + i_size_write(inode, symlen); + inode->i_blocks = calc_inode_blocks(symlen); + } - err = -ENOMEM; - sym = kstrndup(iinfo->symlink, symlen, GFP_NOFS); - if (!sym) - goto out; + err = -ENOMEM; + sym = kstrndup(iinfo->symlink, symlen, GFP_NOFS); + if (!sym) + goto out; + } spin_lock(&ci->i_ceph_lock); - if (!ci->i_symlink) + if (!ci->i_symlink) { ci->i_symlink = sym; - else + ci->i_symlink_len = symlen; + } else { kfree(sym); /* lost a race */ + } + } + + if (IS_ENCRYPTED(inode)) { + /* + * Encrypted symlinks need to be decrypted before we can + * cache their targets in i_link. Leave it blank for now. + */ + inode->i_link = NULL; + inode->i_op = &ceph_encrypted_symlink_iops; + } else { + inode->i_link = ci->i_symlink; + inode->i_op = &ceph_symlink_iops; } - inode->i_link = ci->i_symlink; break; case S_IFDIR: inode->i_op = &ceph_dir_iops; @@ -2123,16 +2150,37 @@ static void ceph_inode_work(struct work_struct *work) iput(inode); } +static const char *ceph_encrypted_get_link(struct dentry *dentry, struct inode *inode, + struct delayed_call *done) +{ + struct ceph_inode_info *ci = ceph_inode(inode); + + if (inode->i_link) + return inode->i_link; + + if (!dentry) + return ERR_PTR(-ECHILD); + + return fscrypt_get_symlink(inode, ci->i_symlink, ci->i_symlink_len, done); +} + /* * symlinks */ -static const struct inode_operations ceph_symlink_iops = { +const struct inode_operations ceph_symlink_iops = { .get_link = simple_get_link, .setattr = ceph_setattr, .getattr = ceph_getattr, .listxattr = ceph_listxattr, }; +const struct inode_operations ceph_encrypted_symlink_iops = { + .get_link = ceph_encrypted_get_link, + .setattr = ceph_setattr, + .getattr = ceph_getattr, + .listxattr = ceph_listxattr, +}; + int __ceph_setattr(struct inode *inode, struct iattr *attr) { struct ceph_inode_info *ci = ceph_inode(inode); diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 7c859824f64c..eea0ee17b747 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -344,6 +344,7 @@ struct ceph_inode_info { u64 i_max_bytes, i_max_files; s32 i_dir_pin; + u32 i_symlink_len; struct rb_root i_fragtree; int i_fragtree_nsplits; @@ -932,6 +933,8 @@ struct ceph_mds_reply_dirfrag; struct ceph_acl_sec_ctx; extern const struct inode_operations ceph_file_iops; +extern const struct inode_operations ceph_symlink_iops; +extern const struct inode_operations ceph_encrypted_symlink_iops; extern struct inode *ceph_alloc_inode(struct super_block *sb); extern void ceph_evict_inode(struct inode *inode);