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Unix SMB/CIFS implementation.
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Copyright (C) Andrew Tridgell 1992-1998
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program 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 the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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/* what user is current? */
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extern struct current_user current_user;
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/****************************************************************************
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Iterator functions for getting all gid's from current_user.
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****************************************************************************/
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gid_t get_current_user_gid_first(int *piterator)
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return current_user.ut.gid;
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gid_t get_current_user_gid_next(int *piterator)
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if (!current_user.ut.groups || *piterator >= current_user.ut.ngroups) {
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ret = current_user.ut.groups[*piterator];
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/****************************************************************************
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Become the guest user without changing the security context stack.
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****************************************************************************/
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BOOL change_to_guest(void)
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static struct passwd *pass=NULL;
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/* Don't need to free() this as its stored in a static */
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pass = getpwnam_alloc(NULL, lp_guestaccount());
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/* MWW: From AIX FAQ patch to WU-ftpd: call initgroups before
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initgroups(pass->pw_name, pass->pw_gid);
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set_sec_ctx(pass->pw_uid, pass->pw_gid, 0, NULL, NULL);
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current_user.conn = NULL;
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current_user.vuid = UID_FIELD_INVALID;
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/*******************************************************************
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Check if a username is OK.
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********************************************************************/
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static BOOL check_user_ok(connection_struct *conn, user_struct *vuser,int snum)
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struct vuid_cache_entry *ent = NULL;
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for (i=0;i<conn->vuid_cache.entries && i< VUID_CACHE_SIZE;i++) {
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if (conn->vuid_cache.array[i].vuid == vuser->vuid) {
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ent = &conn->vuid_cache.array[i];
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conn->read_only = ent->read_only;
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conn->admin_user = ent->admin_user;
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if (!user_ok_token(vuser->user.unix_name, vuser->nt_user_token, snum))
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readonly_share = is_share_read_only_for_token(vuser->user.unix_name,
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vuser->nt_user_token,
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if (!readonly_share &&
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!share_access_check(conn, snum, vuser, FILE_WRITE_DATA)) {
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/* smb.conf allows r/w, but the security descriptor denies
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* write. Fall back to looking at readonly. */
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readonly_share = True;
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DEBUG(5,("falling back to read-only access-evaluation due to "
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"security descriptor\n"));
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if (!share_access_check(conn, snum, vuser,
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FILE_READ_DATA : FILE_WRITE_DATA)) {
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i = conn->vuid_cache.entries % VUID_CACHE_SIZE;
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if (conn->vuid_cache.entries < VUID_CACHE_SIZE)
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conn->vuid_cache.entries++;
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ent = &conn->vuid_cache.array[i];
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ent->vuid = vuser->vuid;
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ent->read_only = readonly_share;
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ent->admin_user = token_contains_name_in_list(
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vuser->user.unix_name, NULL, vuser->nt_user_token,
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lp_admin_users(SNUM(conn)));
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conn->read_only = ent->read_only;
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conn->admin_user = ent->admin_user;
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/****************************************************************************
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Become the user of a connection number without changing the security context
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stack, but modify the current_user entries.
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****************************************************************************/
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BOOL change_to_user(connection_struct *conn, uint16 vuid)
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user_struct *vuser = get_valid_user_struct(vuid);
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BOOL must_free_token = False;
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NT_USER_TOKEN *token = NULL;
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DEBUG(2,("change_to_user: Connection not open\n"));
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* We need a separate check in security=share mode due to vuid
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* always being UID_FIELD_INVALID. If we don't do this then
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* in share mode security we are *always* changing uid's between
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* SMB's - this hurts performance - Badly.
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if((lp_security() == SEC_SHARE) && (current_user.conn == conn) &&
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(current_user.ut.uid == conn->uid)) {
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DEBUG(4,("change_to_user: Skipping user change - already "
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} else if ((current_user.conn == conn) &&
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(vuser != 0) && (current_user.vuid == vuid) &&
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(current_user.ut.uid == vuser->uid)) {
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DEBUG(4,("change_to_user: Skipping user change - already "
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if ((vuser) && !check_user_ok(conn, vuser, snum)) {
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DEBUG(2,("change_to_user: SMB user %s (unix user %s, vuid %d) "
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"not permitted access to share %s.\n",
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vuser->user.smb_name, vuser->user.unix_name, vuid,
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lp_servicename(snum)));
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if (conn->force_user) /* security = share sets this too */ {
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current_user.ut.groups = conn->groups;
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current_user.ut.ngroups = conn->ngroups;
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token = conn->nt_user_token;
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uid = conn->admin_user ? 0 : vuser->uid;
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current_user.ut.ngroups = vuser->n_groups;
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current_user.ut.groups = vuser->groups;
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token = vuser->nt_user_token;
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DEBUG(2,("change_to_user: Invalid vuid used %d in accessing "
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"share %s.\n",vuid, lp_servicename(snum) ));
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* See if we should force group for this service.
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* If so this overrides any group set in the force
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if((group_c = *lp_force_group(snum))) {
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token = dup_nt_token(NULL, token);
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DEBUG(0, ("dup_nt_token failed\n"));
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must_free_token = True;
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* Only force group if the user is a member of
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* the service group. Check the group memberships for
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* this user (we already have this) to
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* see if we should force the group.
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for (i = 0; i < current_user.ut.ngroups; i++) {
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if (current_user.ut.groups[i] == conn->gid) {
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gid_to_sid(&token->user_sids[1], gid);
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gid_to_sid(&token->user_sids[1], gid);
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set_sec_ctx(uid, gid, current_user.ut.ngroups, current_user.ut.groups,
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* Free the new token (as set_sec_ctx copies it).
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current_user.conn = conn;
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current_user.vuid = vuid;
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DEBUG(5,("change_to_user uid=(%d,%d) gid=(%d,%d)\n",
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(int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));
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/****************************************************************************
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Go back to being root without changing the security context stack,
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but modify the current_user entries.
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****************************************************************************/
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BOOL change_to_root_user(void)
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DEBUG(5,("change_to_root_user: now uid=(%d,%d) gid=(%d,%d)\n",
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(int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));
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current_user.conn = NULL;
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current_user.vuid = UID_FIELD_INVALID;
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/****************************************************************************
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Become the user of an authenticated connected named pipe.
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When this is called we are currently running as the connection
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user. Doesn't modify current_user.
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****************************************************************************/
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BOOL become_authenticated_pipe_user(pipes_struct *p)
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set_sec_ctx(p->pipe_user.ut.uid, p->pipe_user.ut.gid,
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p->pipe_user.ut.ngroups, p->pipe_user.ut.groups,
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p->pipe_user.nt_user_token);
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/****************************************************************************
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Unbecome the user of an authenticated connected named pipe.
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When this is called we are running as the authenticated pipe
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user and need to go back to being the connection user. Doesn't modify
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****************************************************************************/
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BOOL unbecome_authenticated_pipe_user(void)
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return pop_sec_ctx();
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/****************************************************************************
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Utility functions used by become_xxx/unbecome_xxx.
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****************************************************************************/
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connection_struct *conn;
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/* A stack of current_user connection contexts. */
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static struct conn_ctx conn_ctx_stack[MAX_SEC_CTX_DEPTH];
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static int conn_ctx_stack_ndx;
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static void push_conn_ctx(void)
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struct conn_ctx *ctx_p;
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/* Check we don't overflow our stack */
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if (conn_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
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DEBUG(0, ("Connection context stack overflow!\n"));
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smb_panic("Connection context stack overflow!\n");
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/* Store previous user context */
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ctx_p = &conn_ctx_stack[conn_ctx_stack_ndx];
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ctx_p->conn = current_user.conn;
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ctx_p->vuid = current_user.vuid;
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DEBUG(3, ("push_conn_ctx(%u) : conn_ctx_stack_ndx = %d\n",
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(unsigned int)ctx_p->vuid, conn_ctx_stack_ndx ));
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conn_ctx_stack_ndx++;
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static void pop_conn_ctx(void)
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struct conn_ctx *ctx_p;
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/* Check for stack underflow. */
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if (conn_ctx_stack_ndx == 0) {
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DEBUG(0, ("Connection context stack underflow!\n"));
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smb_panic("Connection context stack underflow!\n");
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conn_ctx_stack_ndx--;
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ctx_p = &conn_ctx_stack[conn_ctx_stack_ndx];
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current_user.conn = ctx_p->conn;
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current_user.vuid = ctx_p->vuid;
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ctx_p->vuid = UID_FIELD_INVALID;
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/****************************************************************************
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Temporarily become a root user. Must match with unbecome_root(). Saves and
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restores the connection context.
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****************************************************************************/
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void become_root(void)
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/* Unbecome the root user */
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void unbecome_root(void)
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/****************************************************************************
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Push the current security context then force a change via change_to_user().
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Saves and restores the connection context.
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****************************************************************************/
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BOOL become_user(connection_struct *conn, uint16 vuid)
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if (!change_to_user(conn, vuid)) {
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BOOL unbecome_user(void)
added
removed
source/smbd/uid.c
