s3-smbd: Added a change_to_user_by_session() function.
[nivanova/samba-autobuild/.git] / source3 / smbd / uid.c
index 3779c3f6088cb65dad18a334676fc5f1d566c54b..96c457482792f885902d04672a0929f433e6db5c 100644 (file)
    Unix SMB/CIFS implementation.
    uid/user handling
    Copyright (C) Andrew Tridgell 1992-1998
-   
+
    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 "system/passwd.h"
+#include "smbd/smbd.h"
+#include "smbd/globals.h"
+#include "../librpc/gen_ndr/netlogon.h"
+#include "libcli/security/security.h"
+#include "passdb/lookup_sid.h"
+#include "auth.h"
+#include "ntdomain.h"
 
 /* what user is current? */
 extern struct current_user current_user;
 
-/****************************************************************************
- Iterator functions for getting all gid's from current_user.
-****************************************************************************/
-
-gid_t get_current_user_gid_first(int *piterator)
-{
-       *piterator = 0;
-       return current_user.ut.gid;
-}
-
-gid_t get_current_user_gid_next(int *piterator)
-{
-       gid_t ret;
-
-       if (!current_user.ut.groups || *piterator >= current_user.ut.ngroups) {
-               return (gid_t)-1;
-       }
-
-       ret = current_user.ut.groups[*piterator];
-       (*piterator) += 1;
-       return ret;
-}
-
 /****************************************************************************
  Become the guest user without changing the security context stack.
 ****************************************************************************/
 
 bool change_to_guest(void)
 {
-       static struct passwd *pass=NULL;
+       struct passwd *pass;
 
+       pass = Get_Pwnam_alloc(talloc_tos(), lp_guestaccount());
        if (!pass) {
-               /* Don't need to free() this as its stored in a static */
-               pass = getpwnam_alloc(NULL, lp_guestaccount());
-               if (!pass)
-                       return(False);
+               return false;
        }
-       
+
 #ifdef AIX
        /* MWW: From AIX FAQ patch to WU-ftpd: call initgroups before 
           setting IDs */
        initgroups(pass->pw_name, pass->pw_gid);
 #endif
-       
+
        set_sec_ctx(pass->pw_uid, pass->pw_gid, 0, NULL, NULL);
-       
+
        current_user.conn = NULL;
        current_user.vuid = UID_FIELD_INVALID;
 
        TALLOC_FREE(pass);
-       pass = NULL;
-       
-       return True;
+
+       return true;
+}
+
+/****************************************************************************
+ talloc free the conn->session_info if not used in the vuid cache.
+****************************************************************************/
+
+static void free_conn_session_info_if_unused(connection_struct *conn)
+{
+       unsigned int i;
+
+       for (i = 0; i < VUID_CACHE_SIZE; i++) {
+               struct vuid_cache_entry *ent;
+               ent = &conn->vuid_cache.array[i];
+               if (ent->vuid != UID_FIELD_INVALID &&
+                               conn->session_info == ent->session_info) {
+                       return;
+               }
+       }
+       /* Not used, safe to free. */
+       TALLOC_FREE(conn->session_info);
 }
 
 /*******************************************************************
  Check if a username is OK.
+
+ This sets up conn->session_info with a copy related to this vuser that
+ later code can then mess with.
 ********************************************************************/
 
-static bool check_user_ok(connection_struct *conn, user_struct *vuser,int snum)
+static bool check_user_ok(connection_struct *conn,
+                       uint16_t vuid,
+                       const struct auth_serversupplied_info *session_info,
+                       int snum)
 {
+       bool valid_vuid = (vuid != UID_FIELD_INVALID);
        unsigned int i;
-       struct vuid_cache_entry *ent = NULL;
        bool readonly_share;
-       NT_USER_TOKEN *token;
+       bool admin_user;
 
-       for (i=0;i<conn->vuid_cache.entries && i< VUID_CACHE_SIZE;i++) {
-               if (conn->vuid_cache.array[i].vuid == vuser->vuid) {
+       if (valid_vuid) {
+               struct vuid_cache_entry *ent;
+
+               for (i=0; i<VUID_CACHE_SIZE; i++) {
                        ent = &conn->vuid_cache.array[i];
-                       conn->read_only = ent->read_only;
-                       conn->admin_user = ent->admin_user;
-                       return(True);
+                       if (ent->vuid == vuid) {
+                               free_conn_session_info_if_unused(conn);
+                               conn->session_info = ent->session_info;
+                               conn->read_only = ent->read_only;
+                               return(True);
+                       }
                }
        }
 
-       if (!user_ok_token(vuser->server_info->unix_name,
-                          vuser->server_info->ptok,
-                          snum))
+       if (!user_ok_token(session_info->unix_name,
+                          session_info->info3->base.domain.string,
+                          session_info->security_token, snum))
                return(False);
 
        readonly_share = is_share_read_only_for_token(
-               vuser->server_info->unix_name, vuser->server_info->ptok,
-               SNUM(conn));
-
-       token = conn->nt_user_token ?
-               conn->nt_user_token : vuser->server_info->ptok;
+               session_info->unix_name,
+               session_info->info3->base.domain.string,
+               session_info->security_token,
+               conn);
 
        if (!readonly_share &&
-           !share_access_check(token, lp_servicename(snum),
+           !share_access_check(session_info->security_token, lp_servicename(snum),
                                FILE_WRITE_DATA)) {
                /* smb.conf allows r/w, but the security descriptor denies
                 * write. Fall back to looking at readonly. */
@@ -119,162 +131,258 @@ static bool check_user_ok(connection_struct *conn, user_struct *vuser,int snum)
                         "security descriptor\n"));
        }
 
-       if (!share_access_check(token, lp_servicename(snum),
+       if (!share_access_check(session_info->security_token, lp_servicename(snum),
                                readonly_share ?
                                FILE_READ_DATA : FILE_WRITE_DATA)) {
                return False;
        }
 
-       i = conn->vuid_cache.entries % VUID_CACHE_SIZE;
-       if (conn->vuid_cache.entries < VUID_CACHE_SIZE)
-               conn->vuid_cache.entries++;
+       admin_user = token_contains_name_in_list(
+               session_info->unix_name,
+               session_info->info3->base.domain.string,
+               NULL, session_info->security_token, lp_admin_users(snum));
+
+       if (valid_vuid) {
+               struct vuid_cache_entry *ent =
+                       &conn->vuid_cache.array[conn->vuid_cache.next_entry];
+
+               conn->vuid_cache.next_entry =
+                       (conn->vuid_cache.next_entry + 1) % VUID_CACHE_SIZE;
+
+               TALLOC_FREE(ent->session_info);
 
-       ent = &conn->vuid_cache.array[i];
-       ent->vuid = vuser->vuid;
-       ent->read_only = readonly_share;
+               /*
+                * If force_user was set, all session_info's are based on the same
+                * username-based faked one.
+                */
 
-       ent->admin_user = token_contains_name_in_list(
-               vuser->server_info->unix_name, NULL, vuser->server_info->ptok,
-               lp_admin_users(SNUM(conn)));
+               ent->session_info = copy_serverinfo(
+                       conn, conn->force_user ? conn->session_info : session_info);
 
-       conn->read_only = ent->read_only;
-       conn->admin_user = ent->admin_user;
+               if (ent->session_info == NULL) {
+                       ent->vuid = UID_FIELD_INVALID;
+                       return false;
+               }
+
+               ent->vuid = vuid;
+               ent->read_only = readonly_share;
+               free_conn_session_info_if_unused(conn);
+               conn->session_info = ent->session_info;
+       }
+
+       conn->read_only = readonly_share;
+       if (admin_user) {
+               DEBUG(2,("check_user_ok: user %s is an admin user. "
+                       "Setting uid as %d\n",
+                       conn->session_info->unix_name,
+                       sec_initial_uid() ));
+               conn->session_info->utok.uid = sec_initial_uid();
+       }
 
        return(True);
 }
 
+/****************************************************************************
+ Clear a vuid out of the connection's vuid cache
+ This is only called on SMBulogoff.
+****************************************************************************/
+
+void conn_clear_vuid_cache(connection_struct *conn, uint16_t vuid)
+{
+       int i;
+
+       for (i=0; i<VUID_CACHE_SIZE; i++) {
+               struct vuid_cache_entry *ent;
+
+               ent = &conn->vuid_cache.array[i];
+
+               if (ent->vuid == vuid) {
+                       ent->vuid = UID_FIELD_INVALID;
+                       /*
+                        * We need to keep conn->session_info around
+                        * if it's equal to ent->session_info as a SMBulogoff
+                        * is often followed by a SMBtdis (with an invalid
+                        * vuid). The debug code (or regular code in
+                        * vfs_full_audit) wants to refer to the
+                        * conn->session_info pointer to print debug
+                        * statements. Theoretically this is a bug,
+                        * as once the vuid is gone the session_info
+                        * on the conn struct isn't valid any more,
+                        * but there's enough code that assumes
+                        * conn->session_info is never null that
+                        * it's easier to hold onto the old pointer
+                        * until we get a new sessionsetupX.
+                        * As everything is hung off the
+                        * conn pointer as a talloc context we're not
+                        * leaking memory here. See bug #6315. JRA.
+                        */
+                       if (conn->session_info == ent->session_info) {
+                               ent->session_info = NULL;
+                       } else {
+                               TALLOC_FREE(ent->session_info);
+                       }
+                       ent->read_only = False;
+               }
+       }
+}
+
 /****************************************************************************
  Become the user of a connection number without changing the security context
  stack, but modify the current_user entries.
 ****************************************************************************/
 
-bool change_to_user(connection_struct *conn, uint16 vuid)
+static bool change_to_user_internal(connection_struct *conn,
+                                   const struct auth_serversupplied_info *session_info,
+                                   uint16_t vuid)
 {
-       user_struct *vuser = get_valid_user_struct(vuid);
        int snum;
        gid_t gid;
        uid_t uid;
        char group_c;
-       bool must_free_token = False;
-       NT_USER_TOKEN *token = NULL;
        int num_groups = 0;
        gid_t *group_list = NULL;
-       
-       if (!conn) {
-               DEBUG(2,("change_to_user: Connection not open\n"));
-               return(False);
-       }
-
-       /*
-        * We need a separate check in security=share mode due to vuid
-        * always being UID_FIELD_INVALID. If we don't do this then
-        * in share mode security we are *always* changing uid's between
-        * SMB's - this hurts performance - Badly.
-        */
-
-       if((lp_security() == SEC_SHARE) && (current_user.conn == conn) &&
-          (current_user.ut.uid == conn->uid)) {
-               DEBUG(4,("change_to_user: Skipping user change - already "
-                        "user\n"));
-               return(True);
-       } else if ((current_user.conn == conn) && 
-                  (vuser != 0) && (current_user.vuid == vuid) && 
-                  (current_user.ut.uid == vuser->server_info->uid)) {
-               DEBUG(4,("change_to_user: Skipping user change - already "
-                        "user\n"));
-               return(True);
-       }
+       bool ok;
 
        snum = SNUM(conn);
 
-       if ((vuser) && !check_user_ok(conn, vuser, snum)) {
-               DEBUG(2,("change_to_user: SMB user %s (unix user %s, vuid %d) "
+       ok = check_user_ok(conn, vuid, session_info, snum);
+       if (!ok) {
+               DEBUG(2,("SMB user %s (unix user %s) "
                         "not permitted access to share %s.\n",
-                        vuser->server_info->sanitized_username,
-                        vuser->server_info->unix_name, vuid,
+                        session_info->sanitized_username,
+                        session_info->unix_name,
                         lp_servicename(snum)));
-               return False;
+               return false;
        }
 
-       if (conn->force_user) /* security = share sets this too */ {
-               uid = conn->uid;
-               gid = conn->gid;
-               group_list = conn->groups;
-               num_groups = conn->ngroups;
-               token = conn->nt_user_token;
-       } else if (vuser) {
-               uid = conn->admin_user ? 0 : vuser->server_info->uid;
-               gid = vuser->server_info->gid;
-               num_groups = vuser->server_info->n_groups;
-               group_list  = vuser->server_info->groups;
-               token = vuser->server_info->ptok;
-       } else {
-               DEBUG(2,("change_to_user: Invalid vuid used %d in accessing "
-                        "share %s.\n",vuid, lp_servicename(snum) ));
-               return False;
-       }
+       uid = conn->session_info->utok.uid;
+       gid = conn->session_info->utok.gid;
+       num_groups = conn->session_info->utok.ngroups;
+       group_list  = conn->session_info->utok.groups;
 
        /*
-        * See if we should force group for this service.
-        * If so this overrides any group set in the force
-        * user code.
+        * See if we should force group for this service. If so this overrides
+        * any group set in the force user code.
         */
-
        if((group_c = *lp_force_group(snum))) {
 
-               token = dup_nt_token(NULL, token);
-               if (token == NULL) {
-                       DEBUG(0, ("dup_nt_token failed\n"));
-                       return False;
-               }
-               must_free_token = True;
+               SMB_ASSERT(conn->force_group_gid != (gid_t)-1);
 
-               if(group_c == '+') {
+               if (group_c == '+') {
+                       int i;
 
                        /*
-                        * Only force group if the user is a member of
-                        * the service group. Check the group memberships for
-                        * this user (we already have this) to
-                        * see if we should force the group.
+                        * Only force group if the user is a member of the
+                        * service group. Check the group memberships for this
+                        * user (we already have this) to see if we should force
+                        * the group.
                         */
-
-                       int i;
                        for (i = 0; i < num_groups; i++) {
-                               if (group_list[i] == conn->gid) {
-                                       gid = conn->gid;
-                                       gid_to_sid(&token->user_sids[1], gid);
+                               if (group_list[i] == conn->force_group_gid) {
+                                       conn->session_info->utok.gid =
+                                               conn->force_group_gid;
+                                       gid = conn->force_group_gid;
+                                       gid_to_sid(&conn->session_info->security_token
+                                                  ->sids[1], gid);
                                        break;
                                }
                        }
                } else {
-                       gid = conn->gid;
-                       gid_to_sid(&token->user_sids[1], gid);
+                       conn->session_info->utok.gid = conn->force_group_gid;
+                       gid = conn->force_group_gid;
+                       gid_to_sid(&conn->session_info->security_token->sids[1],
+                                  gid);
                }
        }
-       
-       /* Now set current_user since we will immediately also call
-          set_sec_ctx() */
 
+       /*Set current_user since we will immediately also call set_sec_ctx() */
        current_user.ut.ngroups = num_groups;
-       current_user.ut.groups  = group_list;   
+       current_user.ut.groups  = group_list;
+
+       set_sec_ctx(uid,
+                   gid,
+                   current_user.ut.ngroups,
+                   current_user.ut.groups,
+                   conn->session_info->security_token);
+
+       current_user.conn = conn;
+       current_user.vuid = vuid;
+
+       DEBUG(5, ("Impersonated user: uid=(%d,%d), gid=(%d,%d)\n",
+                (int)getuid(),
+                (int)geteuid(),
+                (int)getgid(),
+                (int)getegid()));
+
+       return true;
+}
+
+bool change_to_user(connection_struct *conn, uint16_t vuid)
+{
+       const struct auth_serversupplied_info *session_info = NULL;
+       user_struct *vuser;
+       int snum = SNUM(conn);
+
+       if (!conn) {
+               DEBUG(2,("Connection not open\n"));
+               return(False);
+       }
 
-       set_sec_ctx(uid, gid, current_user.ut.ngroups, current_user.ut.groups,
-                   token);
+       vuser = get_valid_user_struct(conn->sconn, vuid);
 
        /*
-        * Free the new token (as set_sec_ctx copies it).
+        * We need a separate check in security=share mode due to vuid
+        * always being UID_FIELD_INVALID. If we don't do this then
+        * in share mode security we are *always* changing uid's between
+        * SMB's - this hurts performance - Badly.
         */
 
-       if (must_free_token)
-               TALLOC_FREE(token);
+       if((lp_security() == SEC_SHARE) && (current_user.conn == conn) &&
+          (current_user.ut.uid == conn->session_info->utok.uid)) {
+               DEBUG(4,("Skipping user change - already "
+                        "user\n"));
+               return(True);
+       } else if ((current_user.conn == conn) &&
+                  (vuser != NULL) && (current_user.vuid == vuid) &&
+                  (current_user.ut.uid == vuser->session_info->utok.uid)) {
+               DEBUG(4,("Skipping user change - already "
+                        "user\n"));
+               return(True);
+       }
 
-       current_user.conn = conn;
-       current_user.vuid = vuid;
+       session_info = vuser ? vuser->session_info : conn->session_info;
 
-       DEBUG(5,("change_to_user uid=(%d,%d) gid=(%d,%d)\n",
-                (int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));
-  
-       return(True);
+       if (session_info == NULL) {
+               /* Invalid vuid sent - even with security = share. */
+               DEBUG(2,("Invalid vuid %d used on "
+                        "share %s.\n", vuid, lp_servicename(snum) ));
+               return false;
+       }
+
+       /* security = share sets force_user. */
+       if (!conn->force_user && vuser == NULL) {
+               DEBUG(2,("Invalid vuid used %d in accessing "
+                       "share %s.\n", vuid, lp_servicename(snum) ));
+               return False;
+       }
+
+       return change_to_user_internal(conn, session_info, vuid);
+}
+
+bool change_to_user_by_session(connection_struct *conn,
+                              const struct auth_serversupplied_info *session_info)
+{
+       SMB_ASSERT(conn != NULL);
+       SMB_ASSERT(session_info != NULL);
+
+       if ((current_user.conn == conn) &&
+           (current_user.ut.uid == session_info->utok.uid)) {
+               DEBUG(7, ("Skipping user change - already user\n"));
+
+               return true;
+       }
+
+       return change_to_user_internal(conn, session_info, UID_FIELD_INVALID);
 }
 
 /****************************************************************************
@@ -301,14 +409,14 @@ bool change_to_root_user(void)
  user. Doesn't modify current_user.
 ****************************************************************************/
 
-bool become_authenticated_pipe_user(pipes_struct *p)
+bool become_authenticated_pipe_user(struct pipes_struct *p)
 {
        if (!push_sec_ctx())
                return False;
 
-       set_sec_ctx(p->pipe_user.ut.uid, p->pipe_user.ut.gid, 
-                   p->pipe_user.ut.ngroups, p->pipe_user.ut.groups,
-                   p->pipe_user.nt_user_token);
+       set_sec_ctx(p->session_info->utok.uid, p->session_info->utok.gid,
+                   p->session_info->utok.ngroups, p->session_info->utok.groups,
+                   p->session_info->security_token);
 
        return True;
 }
@@ -329,34 +437,24 @@ bool unbecome_authenticated_pipe_user(void)
  Utility functions used by become_xxx/unbecome_xxx.
 ****************************************************************************/
 
-struct conn_ctx {
-       connection_struct *conn;
-       uint16 vuid;
-};
-/* A stack of current_user connection contexts. */
-static struct conn_ctx conn_ctx_stack[MAX_SEC_CTX_DEPTH];
-static int conn_ctx_stack_ndx;
-
 static void push_conn_ctx(void)
 {
        struct conn_ctx *ctx_p;
+
        /* Check we don't overflow our stack */
+
        if (conn_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
                DEBUG(0, ("Connection context stack overflow!\n"));
                smb_panic("Connection context stack overflow!\n");
        }
+
        /* Store previous user context */
        ctx_p = &conn_ctx_stack[conn_ctx_stack_ndx];
+
        ctx_p->conn = current_user.conn;
        ctx_p->vuid = current_user.vuid;
-       DEBUG(3, ("push_conn_ctx(%u) : conn_ctx_stack_ndx = %d\n",
+
+       DEBUG(4, ("push_conn_ctx(%u) : conn_ctx_stack_ndx = %d\n",
                (unsigned int)ctx_p->vuid, conn_ctx_stack_ndx ));
 
        conn_ctx_stack_ndx++;
@@ -365,7 +463,7 @@ static void push_conn_ctx(void)
 static void pop_conn_ctx(void)
 {
        struct conn_ctx *ctx_p;
+
        /* Check for stack underflow. */
 
        if (conn_ctx_stack_ndx == 0) {
@@ -436,3 +534,46 @@ bool unbecome_user(void)
        pop_conn_ctx();
        return True;
 }
+
+/****************************************************************************
+ Return the current user we are running effectively as on this connection.
+ I'd like to make this return conn->session_info->utok.uid, but become_root()
+ doesn't alter this value.
+****************************************************************************/
+
+uid_t get_current_uid(connection_struct *conn)
+{
+       return current_user.ut.uid;
+}
+
+/****************************************************************************
+ Return the current group we are running effectively as on this connection.
+ I'd like to make this return conn->session_info->utok.gid, but become_root()
+ doesn't alter this value.
+****************************************************************************/
+
+gid_t get_current_gid(connection_struct *conn)
+{
+       return current_user.ut.gid;
+}
+
+/****************************************************************************
+ Return the UNIX token we are running effectively as on this connection.
+ I'd like to make this return &conn->session_info->utok, but become_root()
+ doesn't alter this value.
+****************************************************************************/
+
+const struct security_unix_token *get_current_utok(connection_struct *conn)
+{
+       return &current_user.ut;
+}
+
+const struct security_token *get_current_nttok(connection_struct *conn)
+{
+       return current_user.nt_user_token;
+}
+
+uint16_t get_current_vuid(connection_struct *conn)
+{
+       return current_user.vuid;
+}