--- /dev/null
+/*
+ Unix SMB/CIFS implementation.
+ uid/user handling
+ Copyright (C) Tim Potter 2000
+
+ 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 2 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, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+extern struct current_user current_user;
+
+struct sec_ctx {
+ uid_t uid;
+ uid_t gid;
+ int ngroups;
+ gid_t *groups;
+ NT_USER_TOKEN *token;
+};
+
+/* A stack of security contexts. We include the current context as being
+ the first one, so there is room for another MAX_SEC_CTX_DEPTH more. */
+
+static struct sec_ctx sec_ctx_stack[MAX_SEC_CTX_DEPTH + 1];
+static int sec_ctx_stack_ndx;
+
+/****************************************************************************
+ Become the specified uid.
+****************************************************************************/
+
+static BOOL become_uid(uid_t uid)
+{
+ /* Check for dodgy uid values */
+
+ if (uid == (uid_t)-1 ||
+ ((sizeof(uid_t) == 2) && (uid == (uid_t)65535))) {
+ static int done;
+
+ if (!done) {
+ DEBUG(1,("WARNING: using uid %d is a security risk\n",
+ (int)uid));
+ done = 1;
+ }
+ }
+
+ /* Set effective user id */
+
+ set_effective_uid(uid);
+
+ DO_PROFILE_INC(uid_changes);
+ return True;
+}
+
+/****************************************************************************
+ Become the specified gid.
+****************************************************************************/
+
+static BOOL become_gid(gid_t gid)
+{
+ /* Check for dodgy gid values */
+
+ if (gid == (gid_t)-1 || ((sizeof(gid_t) == 2) &&
+ (gid == (gid_t)65535))) {
+ static int done;
+
+ if (!done) {
+ DEBUG(1,("WARNING: using gid %d is a security risk\n",
+ (int)gid));
+ done = 1;
+ }
+ }
+
+ /* Set effective group id */
+
+ set_effective_gid(gid);
+ return True;
+}
+
+/****************************************************************************
+ Become the specified uid and gid.
+****************************************************************************/
+
+static BOOL become_id(uid_t uid, gid_t gid)
+{
+ return become_gid(gid) && become_uid(uid);
+}
+
+/****************************************************************************
+ Drop back to root privileges in order to change to another user.
+****************************************************************************/
+
+static void gain_root(void)
+{
+ if (non_root_mode()) {
+ return;
+ }
+
+ if (geteuid() != 0) {
+ set_effective_uid(0);
+
+ if (geteuid() != 0) {
+ DEBUG(0,
+ ("Warning: You appear to have a trapdoor "
+ "uid system\n"));
+ }
+ }
+
+ if (getegid() != 0) {
+ set_effective_gid(0);
+
+ if (getegid() != 0) {
+ DEBUG(0,
+ ("Warning: You appear to have a trapdoor "
+ "gid system\n"));
+ }
+ }
+}
+
+/****************************************************************************
+ Get the list of current groups.
+****************************************************************************/
+
+int get_current_groups(gid_t gid, int *p_ngroups, gid_t **p_groups)
+{
+ int i;
+ gid_t grp;
+ int ngroups;
+ gid_t *groups = NULL;
+
+ (*p_ngroups) = 0;
+ (*p_groups) = NULL;
+
+ /* this looks a little strange, but is needed to cope with
+ systems that put the current egid in the group list
+ returned from getgroups() (tridge) */
+ save_re_gid();
+ set_effective_gid(gid);
+ setgid(gid);
+
+ ngroups = sys_getgroups(0,&grp);
+ if (ngroups <= 0) {
+ goto fail;
+ }
+
+ if((groups = SMB_MALLOC_ARRAY(gid_t, ngroups+1)) == NULL) {
+ DEBUG(0,("setup_groups malloc fail !\n"));
+ goto fail;
+ }
+
+ if ((ngroups = sys_getgroups(ngroups,groups)) == -1) {
+ goto fail;
+ }
+
+ restore_re_gid();
+
+ (*p_ngroups) = ngroups;
+ (*p_groups) = groups;
+
+ DEBUG( 3, ( "get_current_groups: user is in %u groups: ", ngroups));
+ for (i = 0; i < ngroups; i++ ) {
+ DEBUG( 3, ( "%s%d", (i ? ", " : ""), (int)groups[i] ) );
+ }
+ DEBUG( 3, ( "\n" ) );
+
+ return ngroups;
+
+fail:
+ SAFE_FREE(groups);
+ restore_re_gid();
+ return -1;
+}
+
+/****************************************************************************
+ Initialize the groups a user belongs to.
+****************************************************************************/
+
+BOOL initialise_groups(char *user, uid_t uid, gid_t gid)
+{
+ struct sec_ctx *prev_ctx_p;
+ BOOL result = True;
+
+ if (non_root_mode()) {
+ return True;
+ }
+
+ become_root();
+
+ /* Call initgroups() to get user groups */
+
+ if (winbind_initgroups(user,gid) == -1) {
+ DEBUG(0,("Unable to initgroups. Error was %s\n", strerror(errno) ));
+ if (getuid() == 0) {
+ if (gid < 0 || gid > 32767 || uid < 0 || uid > 32767) {
+ DEBUG(0,("This is probably a problem with the account %s\n", user));
+ }
+ }
+ result = False;
+ goto done;
+ }
+
+ /* Store groups in previous user's security context. This will
+ always work as the become_root() call increments the stack
+ pointer. */
+
+ prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx - 1];
+
+ SAFE_FREE(prev_ctx_p->groups);
+ prev_ctx_p->ngroups = 0;
+
+ get_current_groups(gid, &prev_ctx_p->ngroups, &prev_ctx_p->groups);
+
+ done:
+ unbecome_root();
+
+ return result;
+}
+
+/****************************************************************************
+ Create a new security context on the stack. It is the same as the old
+ one. User changes are done using the set_sec_ctx() function.
+****************************************************************************/
+
+BOOL push_sec_ctx(void)
+{
+ struct sec_ctx *ctx_p;
+
+ /* Check we don't overflow our stack */
+
+ if (sec_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
+ DEBUG(0, ("Security context stack overflow!\n"));
+ smb_panic("Security context stack overflow!\n");
+ }
+
+ /* Store previous user context */
+
+ sec_ctx_stack_ndx++;
+
+ ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
+
+ ctx_p->uid = geteuid();
+ ctx_p->gid = getegid();
+
+ DEBUG(3, ("push_sec_ctx(%u, %u) : sec_ctx_stack_ndx = %d\n",
+ (unsigned int)ctx_p->uid, (unsigned int)ctx_p->gid, sec_ctx_stack_ndx ));
+
+ ctx_p->token = dup_nt_token(sec_ctx_stack[sec_ctx_stack_ndx-1].token);
+
+ ctx_p->ngroups = sys_getgroups(0, NULL);
+
+ if (ctx_p->ngroups != 0) {
+ if (!(ctx_p->groups = SMB_MALLOC_ARRAY(gid_t, ctx_p->ngroups))) {
+ DEBUG(0, ("Out of memory in push_sec_ctx()\n"));
+ delete_nt_token(&ctx_p->token);
+ return False;
+ }
+
+ sys_getgroups(ctx_p->ngroups, ctx_p->groups);
+ } else {
+ ctx_p->groups = NULL;
+ }
+
+ return True;
+}
+
+/****************************************************************************
+ Set the current security context to a given user.
+****************************************************************************/
+
+void set_sec_ctx(uid_t uid, gid_t gid, int ngroups, gid_t *groups, NT_USER_TOKEN *token)
+{
+ struct sec_ctx *ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
+
+ /* Set the security context */
+
+ DEBUG(3, ("setting sec ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
+ (unsigned int)uid, (unsigned int)gid, sec_ctx_stack_ndx));
+
+ debug_nt_user_token(DBGC_CLASS, 5, token);
+ debug_unix_user_token(DBGC_CLASS, 5, uid, gid, ngroups, groups);
+
+ gain_root();
+
+#ifdef HAVE_SETGROUPS
+ sys_setgroups(ngroups, groups);
+#endif
+
+ ctx_p->ngroups = ngroups;
+
+ SAFE_FREE(ctx_p->groups);
+ if (token && (token == ctx_p->token))
+ smb_panic("DUPLICATE_TOKEN");
+
+ delete_nt_token(&ctx_p->token);
+
+ ctx_p->groups = memdup(groups, sizeof(gid_t) * ngroups);
+ ctx_p->token = dup_nt_token(token);
+
+ become_id(uid, gid);
+
+ ctx_p->uid = uid;
+ ctx_p->gid = gid;
+
+ /* Update current_user stuff */
+
+ current_user.uid = uid;
+ current_user.gid = gid;
+ current_user.ngroups = ngroups;
+ current_user.groups = groups;
+ current_user.nt_user_token = ctx_p->token;
+}
+
+/****************************************************************************
+ Become root context.
+****************************************************************************/
+
+void set_root_sec_ctx(void)
+{
+ /* May need to worry about supplementary groups at some stage */
+
+ set_sec_ctx(0, 0, 0, NULL, NULL);
+}
+
+/****************************************************************************
+ Pop a security context from the stack.
+****************************************************************************/
+
+BOOL pop_sec_ctx(void)
+{
+ struct sec_ctx *ctx_p;
+ struct sec_ctx *prev_ctx_p;
+
+ /* Check for stack underflow */
+
+ if (sec_ctx_stack_ndx == 0) {
+ DEBUG(0, ("Security context stack underflow!\n"));
+ smb_panic("Security context stack underflow!\n");
+ }
+
+ ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
+
+ /* Clear previous user info */
+
+ ctx_p->uid = (uid_t)-1;
+ ctx_p->gid = (gid_t)-1;
+
+ SAFE_FREE(ctx_p->groups);
+ ctx_p->ngroups = 0;
+
+ delete_nt_token(&ctx_p->token);
+
+ /* Pop back previous user */
+
+ sec_ctx_stack_ndx--;
+
+ gain_root();
+
+ prev_ctx_p = &sec_ctx_stack[sec_ctx_stack_ndx];
+
+#ifdef HAVE_SETGROUPS
+ sys_setgroups(prev_ctx_p->ngroups, prev_ctx_p->groups);
+#endif
+
+ become_id(prev_ctx_p->uid, prev_ctx_p->gid);
+
+ /* Update current_user stuff */
+
+ current_user.uid = prev_ctx_p->uid;
+ current_user.gid = prev_ctx_p->gid;
+ current_user.ngroups = prev_ctx_p->ngroups;
+ current_user.groups = prev_ctx_p->groups;
+ current_user.nt_user_token = prev_ctx_p->token;
+
+ DEBUG(3, ("pop_sec_ctx (%u, %u) - sec_ctx_stack_ndx = %d\n",
+ (unsigned int)geteuid(), (unsigned int)getegid(), sec_ctx_stack_ndx));
+
+ return True;
+}
+
+/* Initialise the security context system */
+
+void init_sec_ctx(void)
+{
+ int i;
+ struct sec_ctx *ctx_p;
+
+ /* Initialise security context stack */
+
+ memset(sec_ctx_stack, 0, sizeof(struct sec_ctx) * MAX_SEC_CTX_DEPTH);
+
+ for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
+ sec_ctx_stack[i].uid = (uid_t)-1;
+ sec_ctx_stack[i].gid = (gid_t)-1;
+ }
+
+ /* Initialise first level of stack. It is the current context */
+ ctx_p = &sec_ctx_stack[0];
+
+ ctx_p->uid = geteuid();
+ ctx_p->gid = getegid();
+
+ get_current_groups(ctx_p->gid, &ctx_p->ngroups, &ctx_p->groups);
+
+ ctx_p->token = NULL; /* Maps to guest user. */
+
+ /* Initialise current_user global */
+
+ current_user.uid = ctx_p->uid;
+ current_user.gid = ctx_p->gid;
+ current_user.ngroups = ctx_p->ngroups;
+ current_user.groups = ctx_p->groups;
+
+ /* The conn and vuid are usually taken care of by other modules.
+ We initialise them here. */
+
+ current_user.conn = NULL;
+ current_user.vuid = UID_FIELD_INVALID;
+ current_user.nt_user_token = NULL;
+}
projects / samba / blobdiff