From ef605e86821253d16d47a02ce1f766a461614fef Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Fri, 3 Jun 2022 16:13:02 -0300 Subject: [PATCH] cifs: skip trailing separators of prefix paths During DFS failover, prefix paths may change, so make sure to not leave trailing separators when parsing thew in dfs_cache_get_tgt_share(). The separators of prefix paths are already handled by build_path_from_dentry_optional_prefix(). Consider the following DFS link: //dom/dfs/link: [\srv1\share\dir1, \srv2\share\dir1] Before commit: mount.cifs //dom/dfs/link tree connect to \\srv1\share; prefix_path=dir1 disconnect srv1; failover to srv2 tree connect to \\srv2\share; prefix_path=dir1\ mv foo bar ... SMB2 430 Create Request File: dir1\\foo;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request SMB2 582 Create Response File: dir1\\foo;GetInfo Response;Close Response SMB2 430 Create Request File: dir1\\bar;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request SMB2 286 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;GetInfo Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;Close Response, Error: STATUS_OBJECT_NAME_NOT_FOUND SMB2 462 Create Request File: dir1\\foo;SetInfo Request FILE_INFO/SMB2_FILE_RENAME_INFO NewName:dir1\\bar;Close Request SMB2 478 Create Response File: dir1\\foo;SetInfo Response, Error: STATUS_OBJECT_NAME_INVALID;Close Response After commit: mount.cifs //dom/dfs/link tree connect to \\srv1\share; prefix_path=dir1 disconnect srv1; failover to srv2 tree connect to \\srv2\share; prefix_path=dir1 mv foo bar ... SMB2 430 Create Request File: dir1\foo;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request SMB2 582 Create Response File: dir1\foo;GetInfo Response;Close Response SMB2 430 Create Request File: dir1\bar;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request SMB2 286 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;GetInfo Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;Close Response, Error: STATUS_OBJECT_NAME_NOT_FOUND SMB2 462 Create Request File: dir1\foo;SetInfo Request FILE_INFO/SMB2_FILE_RENAME_INFO NewName:dir1\bar;Close Request SMB2 478 Create Response File: dir1\foo;SetInfo Response;Close Response Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French --- fs/cifs/dfs_cache.c | 85 ++++++++++++++++++++++++++------------------- 1 file changed, 49 insertions(+), 36 deletions(-) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index aa7d00b5b3e7..7b978a126268 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -1229,6 +1229,30 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id) kref_put(&mg->refcount, mount_group_release); } +/* Extract share from DFS target and return a pointer to prefix path or NULL */ +static const char *parse_target_share(const char *target, char **share) +{ + const char *s, *seps = "/\\"; + size_t len; + + s = strpbrk(target + 1, seps); + if (!s) + return ERR_PTR(-EINVAL); + + len = strcspn(s + 1, seps); + if (!len) + return ERR_PTR(-EINVAL); + s += len; + + len = s - target + 1; + *share = kstrndup(target, len, GFP_KERNEL); + if (!*share) + return ERR_PTR(-ENOMEM); + + s = target + len; + return s + strspn(s, seps); +} + /** * dfs_cache_get_tgt_share - parse a DFS target * @@ -1242,56 +1266,45 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id) int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share, char **prefix) { - char *s, sep, *p; - size_t len; - size_t plen1, plen2; + char sep; + char *target_share, *ppath; + const char *target_ppath, *dfsref_ppath; + size_t target_pplen, dfsref_pplen; + size_t len, c; if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed) return -EINVAL; - *share = NULL; - *prefix = NULL; - sep = it->it_name[0]; if (sep != '\\' && sep != '/') return -EINVAL; - s = strchr(it->it_name + 1, sep); - if (!s) - return -EINVAL; + target_ppath = parse_target_share(it->it_name, &target_share); + if (IS_ERR(target_ppath)) + return PTR_ERR(target_ppath); - /* point to prefix in target node */ - s = strchrnul(s + 1, sep); + /* point to prefix in DFS referral path */ + dfsref_ppath = path + it->it_path_consumed; + dfsref_ppath += strspn(dfsref_ppath, "/\\"); - /* extract target share */ - *share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL); - if (!*share) - return -ENOMEM; + target_pplen = strlen(target_ppath); + dfsref_pplen = strlen(dfsref_ppath); - /* skip separator */ - if (*s) - s++; - /* point to prefix in DFS path */ - p = path + it->it_path_consumed; - if (*p == sep) - p++; - - /* merge prefix paths from DFS path and target node */ - plen1 = it->it_name + strlen(it->it_name) - s; - plen2 = path + strlen(path) - p; - if (plen1 || plen2) { - len = plen1 + plen2 + 2; - *prefix = kmalloc(len, GFP_KERNEL); - if (!*prefix) { - kfree(*share); - *share = NULL; + /* merge prefix paths from DFS referral path and target node */ + if (target_pplen || dfsref_pplen) { + len = target_pplen + dfsref_pplen + 2; + ppath = kzalloc(len, GFP_KERNEL); + if (!ppath) { + kfree(target_share); return -ENOMEM; } - if (plen1) - scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p); - else - strscpy(*prefix, p, len); + c = strscpy(ppath, target_ppath, len); + if (c && dfsref_pplen) + ppath[c] = sep; + strlcat(ppath, dfsref_ppath, len); } + *share = target_share; + *prefix = ppath; return 0; } -- 2.34.1