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samba-mirror/source3/lib/sharesec.c
2010-08-26 00:25:55 +02:00

535 lines
14 KiB
C

/*
* Unix SMB/Netbios implementation.
* SEC_DESC handling functions
* Copyright (C) Jeremy R. Allison 1995-2003.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "../librpc/gen_ndr/ndr_security.h"
#include "dbwrap.h"
/*******************************************************************
Create the share security tdb.
********************************************************************/
static struct db_context *share_db; /* used for share security descriptors */
#define SHARE_DATABASE_VERSION_V1 1
#define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
#define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */
#define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"
/* Map generic permissions to file object specific permissions */
extern const struct generic_mapping file_generic_mapping;
static int delete_fn(struct db_record *rec, void *priv)
{
rec->delete_rec(rec);
return 0;
}
/*****************************************************
Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".
If we find one re-write it into a canonical case form.
*****************************************************/
static int upgrade_v2_to_v3(struct db_record *rec, void *priv)
{
size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);
const char *servicename = NULL;
char *c_servicename = NULL;
char *newkey = NULL;
bool *p_upgrade_ok = (bool *)priv;
NTSTATUS status;
/* Is there space for a one character sharename ? */
if (rec->key.dsize <= prefix_len+2) {
return 0;
}
/* Does it start with the share key prefix ? */
if (memcmp(rec->key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,
prefix_len) != 0) {
return 0;
}
/* Is it a null terminated string as a key ? */
if (rec->key.dptr[rec->key.dsize-1] != '\0') {
return 0;
}
/* Bytes after the prefix are the sharename string. */
servicename = (char *)&rec->key.dptr[prefix_len];
c_servicename = canonicalize_servicename(talloc_tos(), servicename);
if (!c_servicename) {
smb_panic("out of memory upgrading share security db from v2 -> v3");
}
if (strcmp(servicename, c_servicename) == 0) {
/* Old and new names match. No canonicalization needed. */
TALLOC_FREE(c_servicename);
return 0;
}
/* Oops. Need to canonicalize name, delete old then store new. */
status = rec->delete_rec(rec);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "
"%s: %s\n", rec->key.dptr, nt_errstr(status)));
TALLOC_FREE(c_servicename);
*p_upgrade_ok = false;
return -1;
} else {
DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "
"%s\n", rec->key.dptr ));
}
if (!(newkey = talloc_asprintf(talloc_tos(),
SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
c_servicename))) {
smb_panic("out of memory upgrading share security db from v2 -> v3");
}
status = dbwrap_store(share_db,
string_term_tdb_data(newkey),
rec->value,
TDB_REPLACE);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "
"%s: %s\n", c_servicename, nt_errstr(status)));
TALLOC_FREE(c_servicename);
TALLOC_FREE(newkey);
*p_upgrade_ok = false;
return -1;
} else {
DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "
"%s\n", newkey ));
}
TALLOC_FREE(newkey);
TALLOC_FREE(c_servicename);
return 0;
}
bool share_info_db_init(void)
{
const char *vstring = "INFO/version";
int32 vers_id;
int ret;
bool upgrade_ok = true;
if (share_db != NULL) {
return True;
}
share_db = db_open(NULL, state_path("share_info.tdb"), 0,
TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
if (share_db == NULL) {
DEBUG(0,("Failed to open share info database %s (%s)\n",
state_path("share_info.tdb"), strerror(errno) ));
return False;
}
vers_id = dbwrap_fetch_int32(share_db, vstring);
if (vers_id == SHARE_DATABASE_VERSION_V3) {
return true;
}
if (share_db->transaction_start(share_db) != 0) {
DEBUG(0, ("transaction_start failed\n"));
TALLOC_FREE(share_db);
return false;
}
vers_id = dbwrap_fetch_int32(share_db, vstring);
if (vers_id == SHARE_DATABASE_VERSION_V3) {
/*
* Race condition
*/
if (share_db->transaction_cancel(share_db)) {
smb_panic("transaction_cancel failed");
}
return true;
}
/* Move to at least V2. */
/* Cope with byte-reversed older versions of the db. */
if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
/* Written on a bigendian machine with old fetch_int code. Save as le. */
if (dbwrap_store_int32(share_db, vstring,
SHARE_DATABASE_VERSION_V2) != 0) {
DEBUG(0, ("dbwrap_store_int32 failed\n"));
goto cancel;
}
vers_id = SHARE_DATABASE_VERSION_V2;
}
if (vers_id != SHARE_DATABASE_VERSION_V2) {
ret = share_db->traverse(share_db, delete_fn, NULL);
if (ret < 0) {
DEBUG(0, ("traverse failed\n"));
goto cancel;
}
if (dbwrap_store_int32(share_db, vstring,
SHARE_DATABASE_VERSION_V2) != 0) {
DEBUG(0, ("dbwrap_store_int32 failed\n"));
goto cancel;
}
}
/* Finally upgrade to version 3, with canonicalized sharenames. */
ret = share_db->traverse(share_db, upgrade_v2_to_v3, &upgrade_ok);
if (ret < 0 || upgrade_ok == false) {
DEBUG(0, ("traverse failed\n"));
goto cancel;
}
if (dbwrap_store_int32(share_db, vstring,
SHARE_DATABASE_VERSION_V3) != 0) {
DEBUG(0, ("dbwrap_store_int32 failed\n"));
goto cancel;
}
if (share_db->transaction_commit(share_db) != 0) {
DEBUG(0, ("transaction_commit failed\n"));
return false;
}
return true;
cancel:
if (share_db->transaction_cancel(share_db)) {
smb_panic("transaction_cancel failed");
}
return false;
}
/*******************************************************************
Fake up a Everyone, default access as a default.
def_access is a GENERIC_XXX access mode.
********************************************************************/
struct security_descriptor *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
{
uint32_t sa;
struct security_ace ace;
struct security_acl *psa = NULL;
struct security_descriptor *psd = NULL;
uint32 spec_access = def_access;
se_map_generic(&spec_access, &file_generic_mapping);
sa = (def_access | spec_access );
init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
psa, psize);
}
if (!psd) {
DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
return NULL;
}
return psd;
}
/*******************************************************************
Pull a security descriptor from the share tdb.
********************************************************************/
struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,
size_t *psize)
{
char *key;
struct security_descriptor *psd = NULL;
TDB_DATA data;
char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
NTSTATUS status;
if (!c_servicename) {
return NULL;
}
if (!share_info_db_init()) {
TALLOC_FREE(c_servicename);
return NULL;
}
if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
TALLOC_FREE(c_servicename);
DEBUG(0, ("talloc_asprintf failed\n"));
return NULL;
}
TALLOC_FREE(c_servicename);
data = dbwrap_fetch_bystring(share_db, talloc_tos(), key);
TALLOC_FREE(key);
if (data.dptr == NULL) {
return get_share_security_default(ctx, psize,
GENERIC_ALL_ACCESS);
}
status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
TALLOC_FREE(data.dptr);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
nt_errstr(status)));
return get_share_security_default(ctx, psize,
GENERIC_ALL_ACCESS);
}
if (psd) {
*psize = ndr_size_security_descriptor(psd, 0);
} else {
return get_share_security_default(ctx, psize,
GENERIC_ALL_ACCESS);
}
return psd;
}
/*******************************************************************
Store a security descriptor in the share db.
********************************************************************/
bool set_share_security(const char *share_name, struct security_descriptor *psd)
{
TALLOC_CTX *frame = talloc_stackframe();
char *key;
bool ret = False;
TDB_DATA blob;
NTSTATUS status;
char *c_share_name = canonicalize_servicename(frame, share_name);
if (!c_share_name) {
goto out;
}
if (!share_info_db_init()) {
goto out;
}
status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0, ("marshall_sec_desc failed: %s\n",
nt_errstr(status)));
goto out;
}
if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
DEBUG(0, ("talloc_asprintf failed\n"));
goto out;
}
status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
TDB_REPLACE);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("set_share_security: Failed to store secdesc for "
"%s: %s\n", share_name, nt_errstr(status)));
goto out;
}
DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
ret = True;
out:
TALLOC_FREE(frame);
return ret;
}
/*******************************************************************
Delete a security descriptor.
********************************************************************/
bool delete_share_security(const char *servicename)
{
TDB_DATA kbuf;
char *key;
NTSTATUS status;
char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
if (!c_servicename) {
return NULL;
}
if (!share_info_db_init()) {
TALLOC_FREE(c_servicename);
return False;
}
if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
c_servicename))) {
TALLOC_FREE(c_servicename);
return False;
}
kbuf = string_term_tdb_data(key);
status = dbwrap_trans_delete(share_db, kbuf);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0, ("delete_share_security: Failed to delete entry for "
"share %s: %s\n", c_servicename, nt_errstr(status)));
TALLOC_FREE(c_servicename);
return False;
}
TALLOC_FREE(c_servicename);
return True;
}
/*******************************************************************
Can this user access with share with the required permissions ?
********************************************************************/
bool share_access_check(const NT_USER_TOKEN *token, const char *sharename,
uint32 desired_access)
{
uint32 granted;
NTSTATUS status;
struct security_descriptor *psd = NULL;
size_t sd_size;
psd = get_share_security(talloc_tos(), sharename, &sd_size);
if (!psd) {
return True;
}
status = se_access_check(psd, token, desired_access, &granted);
TALLOC_FREE(psd);
return NT_STATUS_IS_OK(status);
}
/***************************************************************************
Parse the contents of an acl string from a usershare file.
***************************************************************************/
bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)
{
size_t s_size = 0;
const char *pacl = acl_str;
int num_aces = 0;
struct security_ace *ace_list = NULL;
struct security_acl *psa = NULL;
struct security_descriptor *psd = NULL;
size_t sd_size = 0;
int i;
*ppsd = NULL;
/* If the acl string is blank return "Everyone:R" */
if (!*acl_str) {
struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
if (!default_psd) {
return False;
}
*ppsd = default_psd;
return True;
}
num_aces = 1;
/* Add the number of ',' characters to get the number of aces. */
num_aces += count_chars(pacl,',');
ace_list = TALLOC_ARRAY(ctx, struct security_ace, num_aces);
if (!ace_list) {
return False;
}
for (i = 0; i < num_aces; i++) {
uint32_t sa;
uint32 g_access;
uint32 s_access;
struct dom_sid sid;
char *sidstr;
enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
"for ':' in string '%s'\n", pacl));
return False;
}
if (!string_to_sid(&sid, sidstr)) {
DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
sidstr ));
return False;
}
switch (*pacl) {
case 'F': /* Full Control, ie. R+W */
case 'f': /* Full Control, ie. R+W */
s_access = g_access = GENERIC_ALL_ACCESS;
break;
case 'R': /* Read only. */
case 'r': /* Read only. */
s_access = g_access = GENERIC_READ_ACCESS;
break;
case 'D': /* Deny all to this SID. */
case 'd': /* Deny all to this SID. */
type = SEC_ACE_TYPE_ACCESS_DENIED;
s_access = g_access = GENERIC_ALL_ACCESS;
break;
default:
DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
pacl ));
return False;
}
pacl++;
if (*pacl && *pacl != ',') {
DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
pacl ));
return False;
}
pacl++; /* Go past any ',' */
se_map_generic(&s_access, &file_generic_mapping);
sa = (g_access | s_access);
init_sec_ace(&ace_list[i], &sid, type, sa, 0);
}
if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
psa, &sd_size);
}
if (!psd) {
DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
return False;
}
*ppsd = psd;
return True;
}