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533 lines
14 KiB
533 lines
14 KiB
/*
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* fs/cifs/cifsacl.c
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*
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* Copyright (C) International Business Machines Corp., 2007
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* Author(s): Steve French (sfrench@us.ibm.com)
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*
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* Contains the routines for mapping CIFS/NTFS ACLs
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/fs.h>
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#include "cifspdu.h"
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#include "cifsglob.h"
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#include "cifsacl.h"
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#include "cifsproto.h"
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#include "cifs_debug.h"
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#ifdef CONFIG_CIFS_EXPERIMENTAL
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static struct cifs_wksid wksidarr[NUM_WK_SIDS] = {
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{{1, 0, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0} }, "null user"},
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{{1, 1, {0, 0, 0, 0, 0, 1}, {0, 0, 0, 0, 0} }, "nobody"},
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{{1, 1, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(11), 0, 0, 0, 0} }, "net-users"},
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{{1, 1, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(18), 0, 0, 0, 0} }, "sys"},
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{{1, 2, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(32), cpu_to_le32(544), 0, 0, 0} }, "root"},
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{{1, 2, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(32), cpu_to_le32(545), 0, 0, 0} }, "users"},
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{{1, 2, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(32), cpu_to_le32(546), 0, 0, 0} }, "guest"} }
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;
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/* security id for everyone */
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static const struct cifs_sid sid_everyone = {
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1, 1, {0, 0, 0, 0, 0, 1}, {0} };
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/* group users */
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static const struct cifs_sid sid_user =
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{1, 2 , {0, 0, 0, 0, 0, 5}, {} };
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int match_sid(struct cifs_sid *ctsid)
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{
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int i, j;
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int num_subauth, num_sat, num_saw;
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struct cifs_sid *cwsid;
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if (!ctsid)
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return (-1);
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for (i = 0; i < NUM_WK_SIDS; ++i) {
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cwsid = &(wksidarr[i].cifssid);
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/* compare the revision */
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if (ctsid->revision != cwsid->revision)
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continue;
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/* compare all of the six auth values */
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for (j = 0; j < 6; ++j) {
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if (ctsid->authority[j] != cwsid->authority[j])
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break;
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}
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if (j < 6)
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continue; /* all of the auth values did not match */
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/* compare all of the subauth values if any */
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num_sat = ctsid->num_subauth;
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num_saw = cwsid->num_subauth;
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num_subauth = num_sat < num_saw ? num_sat : num_saw;
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if (num_subauth) {
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for (j = 0; j < num_subauth; ++j) {
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if (ctsid->sub_auth[j] != cwsid->sub_auth[j])
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break;
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}
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if (j < num_subauth)
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continue; /* all sub_auth values do not match */
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}
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cFYI(1, ("matching sid: %s\n", wksidarr[i].sidname));
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return (0); /* sids compare/match */
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}
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cFYI(1, ("No matching sid"));
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return (-1);
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}
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/* if the two SIDs (roughly equivalent to a UUID for a user or group) are
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the same returns 1, if they do not match returns 0 */
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int compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid)
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{
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int i;
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int num_subauth, num_sat, num_saw;
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if ((!ctsid) || (!cwsid))
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return (0);
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/* compare the revision */
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if (ctsid->revision != cwsid->revision)
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return (0);
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/* compare all of the six auth values */
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for (i = 0; i < 6; ++i) {
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if (ctsid->authority[i] != cwsid->authority[i])
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return (0);
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}
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/* compare all of the subauth values if any */
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num_sat = ctsid->num_subauth;
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num_saw = cwsid->num_subauth;
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num_subauth = num_sat < num_saw ? num_sat : num_saw;
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if (num_subauth) {
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for (i = 0; i < num_subauth; ++i) {
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if (ctsid->sub_auth[i] != cwsid->sub_auth[i])
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return (0);
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}
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}
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return (1); /* sids compare/match */
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}
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/*
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change posix mode to reflect permissions
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pmode is the existing mode (we only want to overwrite part of this
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bits to set can be: S_IRWXU, S_IRWXG or S_IRWXO ie 00700 or 00070 or 00007
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*/
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static void access_flags_to_mode(__le32 ace_flags, int type, umode_t *pmode,
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umode_t *pbits_to_set)
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{
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__u32 flags = le32_to_cpu(ace_flags);
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/* the order of ACEs is important. The canonical order is to begin with
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DENY entries followed by ALLOW, otherwise an allow entry could be
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encountered first, making the subsequent deny entry like "dead code"
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which would be superflous since Windows stops when a match is made
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for the operation you are trying to perform for your user */
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/* For deny ACEs we change the mask so that subsequent allow access
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control entries do not turn on the bits we are denying */
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if (type == ACCESS_DENIED) {
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if (flags & GENERIC_ALL) {
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*pbits_to_set &= ~S_IRWXUGO;
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}
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if ((flags & GENERIC_WRITE) ||
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((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
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*pbits_to_set &= ~S_IWUGO;
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if ((flags & GENERIC_READ) ||
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((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
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*pbits_to_set &= ~S_IRUGO;
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if ((flags & GENERIC_EXECUTE) ||
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((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
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*pbits_to_set &= ~S_IXUGO;
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return;
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} else if (type != ACCESS_ALLOWED) {
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cERROR(1, ("unknown access control type %d", type));
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return;
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}
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/* else ACCESS_ALLOWED type */
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if (flags & GENERIC_ALL) {
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*pmode |= (S_IRWXUGO & (*pbits_to_set));
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#ifdef CONFIG_CIFS_DEBUG2
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cFYI(1, ("all perms"));
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#endif
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return;
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}
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if ((flags & GENERIC_WRITE) ||
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((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
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*pmode |= (S_IWUGO & (*pbits_to_set));
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if ((flags & GENERIC_READ) ||
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((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
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*pmode |= (S_IRUGO & (*pbits_to_set));
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if ((flags & GENERIC_EXECUTE) ||
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((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
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*pmode |= (S_IXUGO & (*pbits_to_set));
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#ifdef CONFIG_CIFS_DEBUG2
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cFYI(1, ("access flags 0x%x mode now 0x%x", flags, *pmode));
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#endif
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return;
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}
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/*
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Generate access flags to reflect permissions mode is the existing mode.
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This function is called for every ACE in the DACL whose SID matches
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with either owner or group or everyone.
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*/
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static void mode_to_access_flags(umode_t mode, umode_t bits_to_use,
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__u32 *pace_flags)
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{
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/* reset access mask */
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*pace_flags = 0x0;
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/* bits to use are either S_IRWXU or S_IRWXG or S_IRWXO */
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mode &= bits_to_use;
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/* check for R/W/X UGO since we do not know whose flags
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is this but we have cleared all the bits sans RWX for
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either user or group or other as per bits_to_use */
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if (mode & S_IRUGO)
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*pace_flags |= SET_FILE_READ_RIGHTS;
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if (mode & S_IWUGO)
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*pace_flags |= SET_FILE_WRITE_RIGHTS;
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if (mode & S_IXUGO)
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*pace_flags |= SET_FILE_EXEC_RIGHTS;
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#ifdef CONFIG_CIFS_DEBUG2
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cFYI(1, ("mode: 0x%x, access flags now 0x%x", mode, *pace_flags));
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#endif
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return;
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}
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#ifdef CONFIG_CIFS_DEBUG2
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static void dump_ace(struct cifs_ace *pace, char *end_of_acl)
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{
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int num_subauth;
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/* validate that we do not go past end of acl */
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if (le16_to_cpu(pace->size) < 16) {
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cERROR(1, ("ACE too small, %d", le16_to_cpu(pace->size)));
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return;
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}
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if (end_of_acl < (char *)pace + le16_to_cpu(pace->size)) {
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cERROR(1, ("ACL too small to parse ACE"));
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return;
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}
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num_subauth = pace->sid.num_subauth;
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if (num_subauth) {
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int i;
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cFYI(1, ("ACE revision %d num_auth %d type %d flags %d size %d",
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pace->sid.revision, pace->sid.num_subauth, pace->type,
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pace->flags, pace->size));
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for (i = 0; i < num_subauth; ++i) {
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cFYI(1, ("ACE sub_auth[%d]: 0x%x", i,
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le32_to_cpu(pace->sid.sub_auth[i])));
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}
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/* BB add length check to make sure that we do not have huge
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num auths and therefore go off the end */
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}
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return;
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}
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#endif
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static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
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struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
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struct inode *inode)
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{
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int i;
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int num_aces = 0;
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int acl_size;
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char *acl_base;
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struct cifs_ace **ppace;
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/* BB need to add parm so we can store the SID BB */
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if (!pdacl) {
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/* no DACL in the security descriptor, set
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all the permissions for user/group/other */
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inode->i_mode |= S_IRWXUGO;
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return;
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}
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/* validate that we do not go past end of acl */
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if (end_of_acl < (char *)pdacl + le16_to_cpu(pdacl->size)) {
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cERROR(1, ("ACL too small to parse DACL"));
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return;
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}
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#ifdef CONFIG_CIFS_DEBUG2
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cFYI(1, ("DACL revision %d size %d num aces %d",
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le16_to_cpu(pdacl->revision), le16_to_cpu(pdacl->size),
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le32_to_cpu(pdacl->num_aces)));
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#endif
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/* reset rwx permissions for user/group/other.
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Also, if num_aces is 0 i.e. DACL has no ACEs,
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user/group/other have no permissions */
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inode->i_mode &= ~(S_IRWXUGO);
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acl_base = (char *)pdacl;
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acl_size = sizeof(struct cifs_acl);
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num_aces = le32_to_cpu(pdacl->num_aces);
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if (num_aces > 0) {
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umode_t user_mask = S_IRWXU;
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umode_t group_mask = S_IRWXG;
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umode_t other_mask = S_IRWXO;
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ppace = kmalloc(num_aces * sizeof(struct cifs_ace *),
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GFP_KERNEL);
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/* cifscred->cecount = pdacl->num_aces;
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cifscred->aces = kmalloc(num_aces *
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sizeof(struct cifs_ace *), GFP_KERNEL);*/
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for (i = 0; i < num_aces; ++i) {
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ppace[i] = (struct cifs_ace *) (acl_base + acl_size);
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#ifdef CONFIG_CIFS_DEBUG2
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dump_ace(ppace[i], end_of_acl);
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#endif
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if (compare_sids(&(ppace[i]->sid), pownersid))
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access_flags_to_mode(ppace[i]->access_req,
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ppace[i]->type,
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&(inode->i_mode),
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&user_mask);
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if (compare_sids(&(ppace[i]->sid), pgrpsid))
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access_flags_to_mode(ppace[i]->access_req,
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ppace[i]->type,
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&(inode->i_mode),
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&group_mask);
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if (compare_sids(&(ppace[i]->sid), &sid_everyone))
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access_flags_to_mode(ppace[i]->access_req,
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ppace[i]->type,
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&(inode->i_mode),
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&other_mask);
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/* memcpy((void *)(&(cifscred->aces[i])),
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(void *)ppace[i],
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sizeof(struct cifs_ace)); */
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acl_base = (char *)ppace[i];
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acl_size = le16_to_cpu(ppace[i]->size);
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}
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kfree(ppace);
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}
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return;
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}
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static int parse_sid(struct cifs_sid *psid, char *end_of_acl)
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{
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/* BB need to add parm so we can store the SID BB */
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/* validate that we do not go past end of ACL - sid must be at least 8
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bytes long (assuming no sub-auths - e.g. the null SID */
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if (end_of_acl < (char *)psid + 8) {
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cERROR(1, ("ACL too small to parse SID %p", psid));
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return -EINVAL;
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}
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if (psid->num_subauth) {
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#ifdef CONFIG_CIFS_DEBUG2
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int i;
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cFYI(1, ("SID revision %d num_auth %d",
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psid->revision, psid->num_subauth));
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for (i = 0; i < psid->num_subauth; i++) {
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cFYI(1, ("SID sub_auth[%d]: 0x%x ", i,
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le32_to_cpu(psid->sub_auth[i])));
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}
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/* BB add length check to make sure that we do not have huge
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num auths and therefore go off the end */
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cFYI(1, ("RID 0x%x",
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le32_to_cpu(psid->sub_auth[psid->num_subauth-1])));
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#endif
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}
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return 0;
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}
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/* Convert CIFS ACL to POSIX form */
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static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
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struct inode *inode)
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{
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int rc;
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struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
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struct cifs_acl *dacl_ptr; /* no need for SACL ptr */
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char *end_of_acl = ((char *)pntsd) + acl_len;
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__u32 dacloffset;
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if ((inode == NULL) || (pntsd == NULL))
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return -EIO;
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owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
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le32_to_cpu(pntsd->osidoffset));
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group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
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le32_to_cpu(pntsd->gsidoffset));
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dacloffset = le32_to_cpu(pntsd->dacloffset);
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dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
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#ifdef CONFIG_CIFS_DEBUG2
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cFYI(1, ("revision %d type 0x%x ooffset 0x%x goffset 0x%x "
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"sacloffset 0x%x dacloffset 0x%x",
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pntsd->revision, pntsd->type, le32_to_cpu(pntsd->osidoffset),
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le32_to_cpu(pntsd->gsidoffset),
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le32_to_cpu(pntsd->sacloffset), dacloffset));
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#endif
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/* cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */
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rc = parse_sid(owner_sid_ptr, end_of_acl);
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if (rc)
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return rc;
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rc = parse_sid(group_sid_ptr, end_of_acl);
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if (rc)
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return rc;
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if (dacloffset)
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parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr,
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group_sid_ptr, inode);
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else
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cFYI(1, ("no ACL")); /* BB grant all or default perms? */
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/* cifscred->uid = owner_sid_ptr->rid;
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cifscred->gid = group_sid_ptr->rid;
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memcpy((void *)(&(cifscred->osid)), (void *)owner_sid_ptr,
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sizeof(struct cifs_sid));
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memcpy((void *)(&(cifscred->gsid)), (void *)group_sid_ptr,
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sizeof(struct cifs_sid)); */
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return (0);
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}
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/* Retrieve an ACL from the server */
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static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
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const char *path)
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{
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struct cifsFileInfo *open_file;
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int unlock_file = FALSE;
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int xid;
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int rc = -EIO;
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__u16 fid;
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struct super_block *sb;
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struct cifs_sb_info *cifs_sb;
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struct cifs_ntsd *pntsd = NULL;
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cFYI(1, ("get mode from ACL for %s", path));
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if (inode == NULL)
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return NULL;
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xid = GetXid();
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open_file = find_readable_file(CIFS_I(inode));
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sb = inode->i_sb;
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if (sb == NULL) {
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FreeXid(xid);
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return NULL;
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}
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cifs_sb = CIFS_SB(sb);
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if (open_file) {
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unlock_file = TRUE;
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fid = open_file->netfid;
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} else {
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int oplock = FALSE;
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/* open file */
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rc = CIFSSMBOpen(xid, cifs_sb->tcon, path, FILE_OPEN,
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READ_CONTROL, 0, &fid, &oplock, NULL,
|
|
cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
|
|
CIFS_MOUNT_MAP_SPECIAL_CHR);
|
|
if (rc != 0) {
|
|
cERROR(1, ("Unable to open file to get ACL"));
|
|
FreeXid(xid);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
|
|
cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
|
|
if (unlock_file == TRUE)
|
|
atomic_dec(&open_file->wrtPending);
|
|
else
|
|
CIFSSMBClose(xid, cifs_sb->tcon, fid);
|
|
|
|
FreeXid(xid);
|
|
return pntsd;
|
|
}
|
|
|
|
/* Translate the CIFS ACL (simlar to NTFS ACL) for a file into mode bits */
|
|
void acl_to_uid_mode(struct inode *inode, const char *path)
|
|
{
|
|
struct cifs_ntsd *pntsd = NULL;
|
|
u32 acllen = 0;
|
|
int rc = 0;
|
|
|
|
#ifdef CONFIG_CIFS_DEBUG2
|
|
cFYI(1, ("converting ACL to mode for %s", path));
|
|
#endif
|
|
pntsd = get_cifs_acl(&acllen, inode, path);
|
|
|
|
/* if we can retrieve the ACL, now parse Access Control Entries, ACEs */
|
|
if (pntsd)
|
|
rc = parse_sec_desc(pntsd, acllen, inode);
|
|
if (rc)
|
|
cFYI(1, ("parse sec desc failed rc = %d", rc));
|
|
|
|
kfree(pntsd);
|
|
return;
|
|
}
|
|
|
|
/* Convert mode bits to an ACL so we can update the ACL on the server */
|
|
int mode_to_acl(struct inode *inode, const char *path)
|
|
{
|
|
int rc = 0;
|
|
__u32 acllen = 0;
|
|
struct cifs_ntsd *pntsd = NULL;
|
|
|
|
cFYI(1, ("set ACL from mode for %s", path));
|
|
|
|
/* Get the security descriptor */
|
|
pntsd = get_cifs_acl(&acllen, inode, path);
|
|
|
|
/* Add/Modify the three ACEs for owner, group, everyone
|
|
while retaining the other ACEs */
|
|
|
|
/* Set the security descriptor */
|
|
|
|
|
|
kfree(pntsd);
|
|
return rc;
|
|
}
|
|
#endif /* CONFIG_CIFS_EXPERIMENTAL */
|
|
|