1 files changed, 659 insertions, 0 deletions

diff --git a/src/plugins/acl/acl-backend-vfile.c b/src/plugins/acl/acl-backend-vfile.c
new file mode 100644
index 0000000..3ee0af9
--- /dev/null
+++ b/src/plugins/acl/acl-backend-vfile.c
@@ -0,0 +1,659 @@
+/* Copyright (c) 2006-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "ioloop.h"
+#include "array.h"
+#include "istream.h"
+#include "nfs-workarounds.h"
+#include "mail-storage-private.h"
+#include "acl-global-file.h"
+#include "acl-cache.h"
+#include "acl-backend-vfile.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#define ACL_ESTALE_RETRY_COUNT NFS_ESTALE_RETRY_COUNT
+#define ACL_VFILE_DEFAULT_CACHE_SECS 30
+
+static struct acl_backend *acl_backend_vfile_alloc(void)
+{
+	struct acl_backend_vfile *backend;
+	pool_t pool;
+
+	pool = pool_alloconly_create("ACL backend", 512);
+	backend = p_new(pool, struct acl_backend_vfile, 1);
+	backend->backend.pool = pool;
+	return &backend->backend;
+}
+
+static int
+acl_backend_vfile_init(struct acl_backend *_backend, const char *data)
+{
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)_backend;
+	struct stat st;
+	const char *const *tmp;
+
+	tmp = t_strsplit(data, ":");
+	backend->global_path = p_strdup_empty(_backend->pool, *tmp);
+	backend->cache_secs = ACL_VFILE_DEFAULT_CACHE_SECS;
+
+	if (*tmp != NULL)
+		tmp++;
+	for (; *tmp != NULL; tmp++) {
+		if (str_begins(*tmp, "cache_secs=")) {
+			if (str_to_uint(*tmp + 11, &backend->cache_secs) < 0) {
+				i_error("acl vfile: Invalid cache_secs value: %s",
+					*tmp + 11);
+				return -1;
+			}
+		} else {
+			i_error("acl vfile: Unknown parameter: %s", *tmp);
+			return -1;
+		}
+	}
+	if (backend->global_path != NULL) {
+		if (stat(backend->global_path, &st) < 0) {
+			if (errno != ENOENT) {
+				i_error("acl vfile: stat(%s) failed: %m",
+					backend->global_path);
+				return -1;
+			}
+		} else if (!S_ISDIR(st.st_mode)) {
+			_backend->global_file =
+				acl_global_file_init(backend->global_path, backend->cache_secs,
+						     _backend->debug);
+		}
+	}
+	if (_backend->debug) {
+		if (backend->global_path == NULL)
+			i_debug("acl vfile: Global ACLs disabled");
+		else if (_backend->global_file != NULL) {
+			i_debug("acl vfile: Global ACL file: %s",
+				backend->global_path);
+		} else {
+			i_debug("acl vfile: Global ACL legacy directory: %s",
+				backend->global_path);
+		}
+	}
+
+	_backend->cache =
+		acl_cache_init(_backend,
+			       sizeof(struct acl_backend_vfile_validity));
+	return 0;
+}
+
+static void acl_backend_vfile_deinit(struct acl_backend *_backend)
+{
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)_backend;
+
+	if (backend->acllist_pool != NULL) {
+		array_free(&backend->acllist);
+		pool_unref(&backend->acllist_pool);
+	}
+	if (_backend->global_file != NULL)
+		acl_global_file_deinit(&_backend->global_file);
+	pool_unref(&backend->backend.pool);
+}
+
+static const char *
+acl_backend_vfile_get_local_dir(struct acl_backend *backend,
+				const char *name, const char *vname)
+{
+	struct mail_namespace *ns = mailbox_list_get_namespace(backend->list);
+	struct mailbox_list *list = ns->list;
+	struct mail_storage *storage;
+	enum mailbox_list_path_type type;
+	const char *dir, *inbox;
+
+	if (*name == '\0')
+		name = NULL;
+
+	if (backend->globals_only)
+		return NULL;
+
+	/* ACL files are very important. try to keep them among the main
+	   mail files. that's not possible though with a) if the mailbox is
+	   a file or b) if the mailbox path doesn't point to filesystem. */
+	if (mailbox_list_get_storage(&list, vname, &storage) < 0)
+		return NULL;
+	i_assert(list == ns->list);
+
+	type = mail_storage_get_acl_list_path_type(storage);
+	if (name == NULL) {
+		if (!mailbox_list_get_root_path(list, type, &dir))
+			return NULL;
+	} else {
+		if (mailbox_list_get_path(list, name, type, &dir) <= 0)
+			return NULL;
+	}
+
+	/* verify that the directory isn't same as INBOX's directory.
+	   this is mainly for Maildir. */
+	if (name == NULL &&
+	    mailbox_list_get_path(list, "INBOX",
+				  MAILBOX_LIST_PATH_TYPE_MAILBOX, &inbox) > 0 &&
+	    strcmp(inbox, dir) == 0) {
+		/* can't have default ACLs with this setup */
+		return NULL;
+	}
+	return dir;
+}
+
+static struct acl_object *
+acl_backend_vfile_object_init(struct acl_backend *_backend,
+			      const char *name)
+{
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)_backend;
+	struct acl_object_vfile *aclobj;
+	const char *dir, *vname, *error;
+
+	aclobj = i_new(struct acl_object_vfile, 1);
+	aclobj->aclobj.backend = _backend;
+	aclobj->aclobj.name = i_strdup(name);
+
+	T_BEGIN {
+		if (*name == '\0' ||
+		    mailbox_list_is_valid_name(_backend->list, name, &error)) {
+			vname = *name == '\0' ? "" :
+				mailbox_list_get_vname(_backend->list, name);
+
+			dir = acl_backend_vfile_get_local_dir(_backend, name, vname);
+			aclobj->local_path = dir == NULL ? NULL :
+				i_strconcat(dir, "/"ACL_FILENAME, NULL);
+			if (backend->global_path != NULL &&
+			    _backend->global_file == NULL) {
+				aclobj->global_path =
+					i_strconcat(backend->global_path, "/", vname, NULL);
+			}
+		} else {
+			/* Invalid mailbox name, just use the default
+			   global ACL files */
+		}
+	} T_END;
+	return &aclobj->aclobj;
+}
+
+static const char *
+get_parent_mailbox(struct acl_backend *backend, const char *name)
+{
+	const char *p;
+
+	p = strrchr(name, mailbox_list_get_hierarchy_sep(backend->list));
+	return p == NULL ? NULL : t_strdup_until(name, p);
+}
+
+static int
+acl_backend_vfile_exists(struct acl_backend_vfile *backend, const char *path,
+			 struct acl_vfile_validity *validity)
+{
+	struct stat st;
+
+	if (validity->last_check + (time_t)backend->cache_secs > ioloop_time) {
+		/* use the cached value */
+		return validity->last_mtime != ACL_VFILE_VALIDITY_MTIME_NOTFOUND ? 1 : 0;
+	}
+
+	validity->last_check = ioloop_time;
+	if (stat(path, &st) < 0) {
+		if (errno == ENOENT || errno == ENOTDIR) {
+			validity->last_mtime = ACL_VFILE_VALIDITY_MTIME_NOTFOUND;
+			return 0;
+		}
+		if (errno == EACCES) {
+			validity->last_mtime = ACL_VFILE_VALIDITY_MTIME_NOACCESS;
+			return 1;
+		}
+		i_error("stat(%s) failed: %m", path);
+		return -1;
+	}
+	validity->last_mtime = st.st_mtime;
+	validity->last_size = st.st_size;
+	return 1;
+}
+
+static bool
+acl_backend_vfile_has_acl(struct acl_backend *_backend, const char *name)
+{
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)_backend;
+	struct acl_backend_vfile_validity *old_validity, new_validity;
+	const char *global_path, *vname;
+	int ret;
+
+	old_validity = acl_cache_get_validity(_backend->cache, name);
+	if (old_validity != NULL)
+		new_validity = *old_validity;
+	else
+		i_zero(&new_validity);
+
+	/* The caller wants to stop whenever a parent mailbox exists, even if
+	   it has no ACL file. Also, if a mailbox doesn't exist then it can't
+	   have a local ACL file. First check if there's a matching global ACL.
+	   If not, check if the mailbox exists. */
+	vname = *name == '\0' ? "" :
+		mailbox_list_get_vname(_backend->list, name);
+	struct mailbox *box =
+		mailbox_alloc(_backend->list, vname,
+			      MAILBOX_FLAG_READONLY | MAILBOX_FLAG_IGNORE_ACLS);
+	if (backend->global_path == NULL) {
+		/* global ACLs disabled */
+		ret = 0;
+	} else if (_backend->global_file != NULL) {
+		/* check global ACL file */
+		ret = acl_global_file_refresh(_backend->global_file);
+		if (ret == 0 && acl_global_file_have_any(_backend->global_file, box->vname))
+			ret = 1;
+	} else {
+		/* check global ACL directory */
+		global_path = t_strconcat(backend->global_path, "/", name, NULL);
+		ret = acl_backend_vfile_exists(backend, global_path,
+					       &new_validity.global_validity);
+	}
+
+	if (ret != 0) {
+		/* error / global ACL found */
+	} else if (mailbox_open(box) == 0) {
+		/* mailbox exists */
+		ret = 1;
+	} else {
+		enum mail_error error;
+		const char *errstr =
+			mailbox_get_last_internal_error(box, &error);
+		if (error == MAIL_ERROR_NOTFOUND)
+			ret = 0;
+		else {
+			e_error(box->event, "acl: Failed to open mailbox: %s",
+				errstr);
+			ret = -1;
+		}
+	}
+
+	acl_cache_set_validity(_backend->cache, name, &new_validity);
+	mailbox_free(&box);
+	return ret > 0;
+}
+
+static struct acl_object *
+acl_backend_vfile_object_init_parent(struct acl_backend *backend,
+				     const char *child_name)
+{
+	const char *parent;
+
+	/* stop at the first parent that
+	   a) has global ACL file
+	   b) has local ACL file
+	   c) exists */
+	while ((parent = get_parent_mailbox(backend, child_name)) != NULL) {
+		if (acl_backend_vfile_has_acl(backend, parent))
+			break;
+		child_name = parent;
+	}
+	if (parent == NULL) {
+		/* use the root */
+		parent = acl_backend_get_default_object(backend)->name;
+	}
+	return acl_backend_vfile_object_init(backend, parent);
+}
+
+static void acl_backend_vfile_object_deinit(struct acl_object *_aclobj)
+{
+	struct acl_object_vfile *aclobj = (struct acl_object_vfile *)_aclobj;
+
+	i_free(aclobj->local_path);
+	i_free(aclobj->global_path);
+
+	if (array_is_created(&aclobj->aclobj.rights))
+		array_free(&aclobj->aclobj.rights);
+	pool_unref(&aclobj->aclobj.rights_pool);
+	i_free(aclobj->aclobj.name);
+	i_free(aclobj);
+}
+
+static int
+acl_backend_vfile_read(struct acl_object *aclobj, bool global, const char *path,
+		       struct acl_vfile_validity *validity, bool try_retry,
+		       bool *is_dir_r)
+{
+	struct istream *input;
+	struct stat st;
+	struct acl_rights rights;
+	const char *line, *error;
+	unsigned int linenum;
+	int fd, ret = 0;
+
+	*is_dir_r = FALSE;
+
+	fd = nfs_safe_open(path, O_RDONLY);
+	if (fd == -1) {
+		if (errno == ENOENT || errno == ENOTDIR) {
+			if (aclobj->backend->debug)
+				i_debug("acl vfile: file %s not found", path);
+			validity->last_mtime = ACL_VFILE_VALIDITY_MTIME_NOTFOUND;
+		} else if (errno == EACCES) {
+			if (aclobj->backend->debug)
+				i_debug("acl vfile: no access to file %s",
+					path);
+
+			acl_object_remove_all_access(aclobj);
+			validity->last_mtime = ACL_VFILE_VALIDITY_MTIME_NOACCESS;
+		} else {
+			i_error("open(%s) failed: %m", path);
+			return -1;
+		}
+
+		validity->last_size = 0;
+		validity->last_read_time = ioloop_time;
+		return 1;
+	}
+
+	if (fstat(fd, &st) < 0) {
+		if (errno == ESTALE && try_retry) {
+			i_close_fd(&fd);
+			return 0;
+		}
+
+		i_error("fstat(%s) failed: %m", path);
+		i_close_fd(&fd);
+		return -1;
+	}
+	if (S_ISDIR(st.st_mode)) {
+		/* we opened a directory. */
+		*is_dir_r = TRUE;
+		i_close_fd(&fd);
+		return 0;
+	}
+
+	if (aclobj->backend->debug)
+		i_debug("acl vfile: reading file %s", path);
+
+	input = i_stream_create_fd(fd, SIZE_MAX);
+	i_stream_set_return_partial_line(input, TRUE);
+	linenum = 0;
+	while ((line = i_stream_read_next_line(input)) != NULL) {
+		linenum++;
+		if (line[0] == '\0' || line[0] == '#')
+			continue;
+		T_BEGIN {
+			ret = acl_rights_parse_line(line, aclobj->rights_pool,
+						    &rights, &error);
+			rights.global = global;
+			if (ret < 0) {
+				i_error("ACL file %s line %u: %s",
+					path, linenum, error);
+			} else {
+				array_push_back(&aclobj->rights, &rights);
+			}
+		} T_END;
+		if (ret < 0)
+			break;
+	}
+
+	if (ret < 0) {
+		/* parsing failure */
+	} else if (input->stream_errno != 0) {
+		if (input->stream_errno == ESTALE && try_retry)
+			ret = 0;
+		else {
+			ret = -1;
+			i_error("read(%s) failed: %s", path,
+				i_stream_get_error(input));
+		}
+	} else {
+		if (fstat(fd, &st) < 0) {
+			if (errno == ESTALE && try_retry)
+				ret = 0;
+			else {
+				ret = -1;
+				i_error("fstat(%s) failed: %m", path);
+			}
+		} else {
+			ret = 1;
+			validity->last_read_time = ioloop_time;
+			validity->last_mtime = st.st_mtime;
+			validity->last_size = st.st_size;
+		}
+	}
+
+	i_stream_unref(&input);
+	if (close(fd) < 0) {
+		if (errno == ESTALE && try_retry)
+			return 0;
+
+		i_error("close(%s) failed: %m", path);
+		return -1;
+	}
+	return ret;
+}
+
+static int
+acl_backend_vfile_read_with_retry(struct acl_object *aclobj,
+				  bool global, const char *path,
+				  struct acl_vfile_validity *validity)
+{
+	unsigned int i;
+	int ret;
+	bool is_dir;
+
+	if (path == NULL)
+		return 0;
+
+	for (i = 0;; i++) {
+		ret = acl_backend_vfile_read(aclobj, global, path, validity,
+					     i < ACL_ESTALE_RETRY_COUNT,
+					     &is_dir);
+		if (ret != 0)
+			break;
+
+		if (is_dir) {
+			/* opened a directory. use dir/.DEFAULT instead */
+			path = t_strconcat(path, "/.DEFAULT", NULL);
+		} else {
+			/* ESTALE - try again */
+		}
+	}
+
+	return ret <= 0 ? -1 : 0;
+}
+
+static bool
+acl_vfile_validity_has_changed(struct acl_backend_vfile *backend,
+			       const struct acl_vfile_validity *validity,
+			       const struct stat *st)
+{
+	if (st->st_mtime == validity->last_mtime &&
+	    st->st_size == validity->last_size) {
+		/* same timestamp, but if it was modified within the
+		   same second we want to refresh it again later (but
+		   do it only after a couple of seconds so we don't
+		   keep re-reading it all the time within those
+		   seconds) */
+		time_t cache_secs = backend->cache_secs;
+
+		if (validity->last_read_time != 0 &&
+		    (st->st_mtime < validity->last_read_time - cache_secs ||
+		     ioloop_time - validity->last_read_time <= cache_secs))
+			return FALSE;
+	}
+	return TRUE;
+}
+
+static int
+acl_backend_vfile_refresh(struct acl_object *aclobj, const char *path,
+			  struct acl_vfile_validity *validity)
+{
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)aclobj->backend;
+	struct stat st;
+	int ret;
+
+	if (validity == NULL)
+		return 1;
+	if (path == NULL ||
+	    validity->last_check + (time_t)backend->cache_secs > ioloop_time)
+		return 0;
+
+	validity->last_check = ioloop_time;
+	ret = stat(path, &st);
+	if (ret == 0 && S_ISDIR(st.st_mode)) {
+		/* it's a directory. use dir/.DEFAULT instead */
+		path = t_strconcat(path, "/.DEFAULT", NULL);
+		ret = stat(path, &st);
+	}
+
+	if (ret < 0) {
+		if (errno == ENOENT || errno == ENOTDIR) {
+			/* if the file used to exist, we have to re-read it */
+			return validity->last_mtime != ACL_VFILE_VALIDITY_MTIME_NOTFOUND ? 1 : 0;
+		} 
+		if (errno == EACCES)
+			return validity->last_mtime != ACL_VFILE_VALIDITY_MTIME_NOACCESS ? 1 : 0;
+		i_error("stat(%s) failed: %m", path);
+		return -1;
+	}
+	return acl_vfile_validity_has_changed(backend, validity, &st) ? 1 : 0;
+}
+
+int acl_backend_vfile_object_get_mtime(struct acl_object *aclobj,
+				       time_t *mtime_r)
+{
+	struct acl_backend_vfile_validity *validity;
+
+	validity = acl_cache_get_validity(aclobj->backend->cache, aclobj->name);
+	if (validity == NULL)
+		return -1;
+
+	if (validity->local_validity.last_mtime != 0)
+		*mtime_r = validity->local_validity.last_mtime;
+	else if (validity->global_validity.last_mtime != 0)
+		*mtime_r = validity->global_validity.last_mtime;
+	else
+		*mtime_r = 0;
+	return 0;
+}
+
+static int
+acl_backend_global_file_refresh(struct acl_object *_aclobj,
+				struct acl_vfile_validity *validity)
+{
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)_aclobj->backend;
+	struct stat st;
+
+	if (acl_global_file_refresh(_aclobj->backend->global_file) < 0)
+		return -1;
+
+	acl_global_file_last_stat(_aclobj->backend->global_file, &st);
+	if (validity == NULL)
+		return 1;
+	return acl_vfile_validity_has_changed(backend, validity, &st) ? 1 : 0;
+}
+
+static int acl_backend_vfile_object_refresh_cache(struct acl_object *_aclobj)
+{
+	struct acl_object_vfile *aclobj = (struct acl_object_vfile *)_aclobj;
+	struct acl_backend_vfile *backend =
+		(struct acl_backend_vfile *)_aclobj->backend;
+	struct acl_backend_vfile_validity *old_validity;
+	struct acl_backend_vfile_validity validity;
+	time_t mtime;
+	int ret;
+
+	old_validity = acl_cache_get_validity(_aclobj->backend->cache,
+					      _aclobj->name);
+	ret = _aclobj->backend->global_file != NULL ?
+		acl_backend_global_file_refresh(_aclobj, old_validity == NULL ? NULL :
+						&old_validity->global_validity) :
+		acl_backend_vfile_refresh(_aclobj, aclobj->global_path,
+					  old_validity == NULL ? NULL :
+					  &old_validity->global_validity);
+	if (ret == 0) {
+		ret = acl_backend_vfile_refresh(_aclobj, aclobj->local_path,
+						old_validity == NULL ? NULL :
+						&old_validity->local_validity);
+	}
+	if (ret <= 0)
+		return ret;
+
+	/* either global or local ACLs changed, need to re-read both */
+	if (!array_is_created(&_aclobj->rights)) {
+		_aclobj->rights_pool =
+			pool_alloconly_create("acl rights", 256);
+		i_array_init(&_aclobj->rights, 16);
+	} else {
+		array_clear(&_aclobj->rights);
+		p_clear(_aclobj->rights_pool);
+	}
+
+	i_zero(&validity);
+	if (_aclobj->backend->global_file != NULL) {
+		struct stat st;
+
+		acl_object_add_global_acls(_aclobj);
+		acl_global_file_last_stat(_aclobj->backend->global_file, &st);
+		validity.global_validity.last_read_time = ioloop_time;
+		validity.global_validity.last_mtime = st.st_mtime;
+		validity.global_validity.last_size = st.st_size;
+	} else {
+		if (acl_backend_vfile_read_with_retry(_aclobj, TRUE, aclobj->global_path,
+						      &validity.global_validity) < 0)
+			return -1;
+	}
+	if (acl_backend_vfile_read_with_retry(_aclobj, FALSE, aclobj->local_path,
+					      &validity.local_validity) < 0)
+		return -1;
+
+	acl_rights_sort(_aclobj);
+	/* update cache only after we've successfully read everything */
+	acl_object_rebuild_cache(_aclobj);
+	acl_cache_set_validity(_aclobj->backend->cache,
+			       _aclobj->name, &validity);
+
+	if (acl_backend_vfile_object_get_mtime(_aclobj, &mtime) == 0)
+		acl_backend_vfile_acllist_verify(backend, _aclobj->name, mtime);
+	return 0;
+}
+
+static int acl_backend_vfile_object_last_changed(struct acl_object *_aclobj,
+						 time_t *last_changed_r)
+{
+	struct acl_backend_vfile_validity *old_validity;
+
+	*last_changed_r = 0;
+
+	old_validity = acl_cache_get_validity(_aclobj->backend->cache,
+					      _aclobj->name);
+	if (old_validity == NULL) {
+		if (acl_backend_vfile_object_refresh_cache(_aclobj) < 0)
+			return -1;
+		old_validity = acl_cache_get_validity(_aclobj->backend->cache,
+						      _aclobj->name);
+		if (old_validity == NULL)
+			return 0;
+	}
+	*last_changed_r = old_validity->local_validity.last_mtime;
+	return 0;
+}
+
+struct acl_backend_vfuncs acl_backend_vfile = {
+	acl_backend_vfile_alloc,
+	acl_backend_vfile_init,
+	acl_backend_vfile_deinit,
+	acl_backend_vfile_nonowner_iter_init,
+	acl_backend_vfile_nonowner_iter_next,
+	acl_backend_vfile_nonowner_iter_deinit,
+	acl_backend_vfile_nonowner_lookups_rebuild,
+	acl_backend_vfile_object_init,
+	acl_backend_vfile_object_init_parent,
+	acl_backend_vfile_object_deinit,
+	acl_backend_vfile_object_refresh_cache,
+	acl_backend_vfile_object_update,
+	acl_backend_vfile_object_last_changed,
+	acl_default_object_list_init,
+	acl_default_object_list_next,
+	acl_default_object_list_deinit
+};