From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD104C433F5 for ; Thu, 28 Apr 2022 01:38:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235775AbiD1Bl5 (ORCPT ); Wed, 27 Apr 2022 21:41:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229528AbiD1Bl5 (ORCPT ); Wed, 27 Apr 2022 21:41:57 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 321CA7EA12 for ; Wed, 27 Apr 2022 18:38:44 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id D785E1F37F; Thu, 28 Apr 2022 01:38:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1651109922; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SoKCsaGfsTOGC9N/Bhbr+pKiQVsIWfPcP+PixLIaDg8=; b=ZsgnEBLT35NafYPmdsLyXfDIuVb0BnadTEUrkLn25y7CldffmK6A5L8rE8dcl6unqLgoBd 3yhbnmJdaPC4nSYeVjyIyCd5C/qxJ1eoHXRQRZLj+OREOumBK0U8EbippO4ehwp53LY2mw +rwZvPxRON/rE1lpnBwODjqGRY4cug0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1651109922; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SoKCsaGfsTOGC9N/Bhbr+pKiQVsIWfPcP+PixLIaDg8=; b=XcQwMeSOVJcCFfuPptf8QNJjcQbvkB3L6QfEu9Z4oai10A4atADCjmNbeHQPDyRhb0iCKL 3esEt788lwW8dZAQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 6240B13425; Thu, 28 Apr 2022 01:38:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 8rHJByHwaWJMbQAAMHmgww (envelope-from ); Thu, 28 Apr 2022 01:38:41 +0000 Subject: [PATCH 1/2] NFS: change nfs_access_get_cached() to nfs_access_check_cached() From: NeilBrown To: Trond Myklebust , Anna Schumaker Cc: linux-nfs@vger.kernel.org Date: Thu, 28 Apr 2022 11:37:32 +1000 Message-ID: <165110985230.7595.10676160398710495817.stgit@noble.brown> In-Reply-To: <165110909570.7595.8578730126480600782.stgit@noble.brown> References: <165110909570.7595.8578730126480600782.stgit@noble.brown> User-Agent: StGit/1.5 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org nfs_access_get_cached() reports (on success) the access modes known to be permitted. The caller than has to compare this against the wanted modes. This is replaced with nfs_access_check_cached() which is told what modes are wanted and returns -EACCES if they are not available, 0 if they are, or -ECHILD or -ENOENT as before. This new interface will allow more subtlety for choose when to trust the cache to be encoded in nfs_access_check_cached(), which is then available to all callers. nfs_access_calc_mask() is changed to nfs_calc_access_mask(). This new function is given a set of Linux MAY_* flags and returns the corresponding set of NFS_ACCESS_* flags. This is the inverse of nfs_access_calc_mask(). Because of this inversion there is a small change in behaviour. For a non-file, non-directory, the previous code would grant MAY_WRITE if any for NFS_ACCESS_MODIFY, NFS_ACCESS_EXTEND, NFS_ACCESS_DELETE were granted. This new code does not support this "any" approach, and it isn't clear it is the most correct approach. So for non-file, non-directories, MAY_WRITE will only be granted if NFS_ACCESS_MODIFY is granted. The nfs_access_exit trace event now reports the NFS_ACCESS flags, not he Linux MAY flags. Signed-off-by: NeilBrown --- fs/nfs/dir.c | 62 +++++++++++++++++++++++++----------------------- fs/nfs/nfs4proc.c | 24 +++++++------------ include/linux/nfs_fs.h | 4 ++- 3 files changed, 43 insertions(+), 47 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index c6b263b5faf1..b4e2c6a34234 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -2971,19 +2971,22 @@ static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cre return err; } -int nfs_access_get_cached(struct inode *inode, const struct cred *cred, - u32 *mask, bool may_block) +int nfs_access_check_cached(struct inode *inode, const struct cred *cred, + u32 want, bool may_block) { + u32 have; int status; - status = nfs_access_get_cached_rcu(inode, cred, mask); + status = nfs_access_get_cached_rcu(inode, cred, &have); if (status != 0) - status = nfs_access_get_cached_locked(inode, cred, mask, - may_block); + status = nfs_access_get_cached_locked(inode, cred, &have, + may_block); + if (status == 0 && (want & ~have) != 0) + status = -EACCES; return status; } -EXPORT_SYMBOL_GPL(nfs_access_get_cached); +EXPORT_SYMBOL_GPL(nfs_access_check_cached); static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set, @@ -3067,26 +3070,26 @@ EXPORT_SYMBOL_GPL(nfs_access_add_cache); #define NFS_DIR_MAY_WRITE NFS_MAY_WRITE #define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP) #define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE) -static int -nfs_access_calc_mask(u32 access_result, umode_t umode) +static u32 +nfs_calc_access_mask(int may_mask, umode_t umode) { - int mask = 0; + int access_mask = 0; - if (access_result & NFS_MAY_READ) - mask |= MAY_READ; + if (may_mask & MAY_READ) + access_mask |= NFS_MAY_READ; if (S_ISDIR(umode)) { - if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE) - mask |= MAY_WRITE; - if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP) - mask |= MAY_EXEC; + if (may_mask & MAY_WRITE) + access_mask |= NFS_DIR_MAY_WRITE; + if (may_mask & MAY_EXEC) + access_mask |= NFS_MAY_LOOKUP; } else if (S_ISREG(umode)) { - if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE) - mask |= MAY_WRITE; - if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE) - mask |= MAY_EXEC; - } else if (access_result & NFS_MAY_WRITE) - mask |= MAY_WRITE; - return mask; + if (may_mask & MAY_WRITE) + access_mask |= NFS_FILE_MAY_WRITE; + if (may_mask & MAY_EXEC) + access_mask |= NFS_MAY_EXECUTE; + } else if (may_mask & MAY_WRITE) + access_mask |= NFS_ACCESS_MODIFY; + return access_mask; } void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) @@ -3099,14 +3102,15 @@ static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask) { struct nfs_access_entry cache; bool may_block = (mask & MAY_NOT_BLOCK) == 0; - int cache_mask = -1; + u32 want; int status; trace_nfs_access_enter(inode); - status = nfs_access_get_cached(inode, cred, &cache.mask, may_block); - if (status == 0) - goto out_cached; + want = nfs_calc_access_mask(mask, inode->i_mode); + status = nfs_access_check_cached(inode, cred, want, may_block); + if (status == 0 || status == -EACCES) + goto out; status = -ECHILD; if (!may_block) @@ -3132,12 +3136,10 @@ static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask) goto out; } nfs_access_add_cache(inode, &cache, cred); -out_cached: - cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode); - if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) + if ((want & ~cache.mask) != 0) status = -EACCES; out: - trace_nfs_access_exit(inode, mask, cache_mask, status); + trace_nfs_access_exit(inode, want, cache.mask, status); return status; } diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 16106f805ffa..1e80d88df588 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -7719,7 +7719,6 @@ static int nfs4_xattr_set_nfs4_user(const struct xattr_handler *handler, const char *key, const void *buf, size_t buflen, int flags) { - u32 mask; int ret; if (!nfs_server_capable(inode, NFS_CAP_XATTR)) @@ -7734,10 +7733,9 @@ static int nfs4_xattr_set_nfs4_user(const struct xattr_handler *handler, * do a cached access check for the XA* flags to possibly avoid * doing an RPC and getting EACCES back. */ - if (!nfs_access_get_cached(inode, current_cred(), &mask, true)) { - if (!(mask & NFS_ACCESS_XAWRITE)) - return -EACCES; - } + if (nfs_access_check_cached(inode, current_cred(), NFS_ACCESS_XAWRITE, + true) == -EACCES) + return -EACCES; if (buf == NULL) { ret = nfs42_proc_removexattr(inode, key); @@ -7756,16 +7754,14 @@ static int nfs4_xattr_get_nfs4_user(const struct xattr_handler *handler, struct dentry *unused, struct inode *inode, const char *key, void *buf, size_t buflen) { - u32 mask; ssize_t ret; if (!nfs_server_capable(inode, NFS_CAP_XATTR)) return -EOPNOTSUPP; - if (!nfs_access_get_cached(inode, current_cred(), &mask, true)) { - if (!(mask & NFS_ACCESS_XAREAD)) - return -EACCES; - } + if (nfs_access_check_cached(inode, current_cred(), NFS_ACCESS_XAREAD, + true) == -EACCES) + return -EACCES; ret = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE); if (ret) @@ -7788,15 +7784,13 @@ nfs4_listxattr_nfs4_user(struct inode *inode, char *list, size_t list_len) ssize_t ret, size; char *buf; size_t buflen; - u32 mask; if (!nfs_server_capable(inode, NFS_CAP_XATTR)) return 0; - if (!nfs_access_get_cached(inode, current_cred(), &mask, true)) { - if (!(mask & NFS_ACCESS_XALIST)) - return 0; - } + if (nfs_access_check_cached(inode, current_cred(), NFS_ACCESS_XALIST, + true) == -EACCES) + return 0; ret = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE); if (ret) diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index b48b9259e02c..7614f621c42d 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -530,8 +530,8 @@ extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh, struct nfs_fattr *fattr); extern int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags); extern void nfs_access_zap_cache(struct inode *inode); -extern int nfs_access_get_cached(struct inode *inode, const struct cred *cred, - u32 *mask, bool may_block); +extern int nfs_access_check_cached(struct inode *inode, const struct cred *cred, + u32 want, bool may_block); /* * linux/fs/nfs/symlink.c