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-rw-r--r--lib/tcbfuncs.c604
1 files changed, 604 insertions, 0 deletions
diff --git a/lib/tcbfuncs.c b/lib/tcbfuncs.c
new file mode 100644
index 0000000..1ed5d03
--- /dev/null
+++ b/lib/tcbfuncs.c
@@ -0,0 +1,604 @@
+/*
+ * SPDX-FileCopyrightText: 2001 Rafal Wojtczuk, Solar Designer
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <tcb.h>
+#include <unistd.h>
+
+#include "config.h"
+
+#include "defines.h"
+#include "prototypes.h"
+#include "getdef.h"
+#include "shadowio.h"
+#include "tcbfuncs.h"
+
+#include "shadowlog_internal.h"
+
+#define SHADOWTCB_HASH_BY 1000
+#define SHADOWTCB_LOCK_SUFFIX ".lock"
+
+static /*@null@*//*@only@*/char *stored_tcb_user = NULL;
+
+shadowtcb_status shadowtcb_drop_priv (void)
+{
+ if (!getdef_bool ("USE_TCB")) {
+ return SHADOWTCB_SUCCESS;
+ }
+
+ if (NULL != stored_tcb_user) {
+ if (tcb_drop_priv (stored_tcb_user) == 0) {
+ return SHADOWTCB_SUCCESS;
+ }
+ }
+
+ return SHADOWTCB_FAILURE;
+}
+
+shadowtcb_status shadowtcb_gain_priv (void)
+{
+ if (!getdef_bool ("USE_TCB")) {
+ return SHADOWTCB_SUCCESS;
+ }
+
+ return (tcb_gain_priv () == 0) ? SHADOWTCB_SUCCESS : SHADOWTCB_FAILURE;
+}
+
+/* In case something goes wrong, we return immediately, not polluting the
+ * code with free(). All errors are fatal, so the application is expected
+ * to exit soon.
+ */
+#define OUT_OF_MEMORY do { \
+ fprintf (shadow_logfd, _("%s: out of memory\n"), shadow_progname); \
+ (void) fflush (shadow_logfd); \
+} while (false)
+
+/* Returns user's tcb directory path relative to TCB_DIR. */
+static /*@null@*/ char *shadowtcb_path_rel (const char *name, uid_t uid)
+{
+ char *ret;
+
+ if (!getdef_bool ("TCB_SYMLINKS") || uid < SHADOWTCB_HASH_BY) {
+ if (asprintf (&ret, "%s", name) == -1) {
+ OUT_OF_MEMORY;
+ return NULL;
+ }
+ } else if (uid < SHADOWTCB_HASH_BY * SHADOWTCB_HASH_BY) {
+ if (asprintf (&ret, ":%dK/%s",
+ uid / SHADOWTCB_HASH_BY, name) == -1) {
+ OUT_OF_MEMORY;
+ return NULL;
+ }
+ } else {
+ if (asprintf (&ret, ":%dM/:%dK/%s",
+ uid / (SHADOWTCB_HASH_BY * SHADOWTCB_HASH_BY),
+ (uid % (SHADOWTCB_HASH_BY * SHADOWTCB_HASH_BY)) / SHADOWTCB_HASH_BY,
+ name) == -1) {
+ OUT_OF_MEMORY;
+ return NULL;
+ }
+ }
+ return ret;
+}
+
+static /*@null@*/ char *shadowtcb_path_rel_existing (const char *name)
+{
+ char *path, *rval;
+ struct stat st;
+ char link[8192];
+ ssize_t ret;
+
+ if (asprintf (&path, TCB_DIR "/%s", name) == -1) {
+ OUT_OF_MEMORY;
+ return NULL;
+ }
+ if (lstat (path, &st) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot stat %s: %s\n"),
+ shadow_progname, path, strerror (errno));
+ free (path);
+ return NULL;
+ }
+ if (S_ISDIR (st.st_mode)) {
+ free (path);
+ rval = strdup (name);
+ if (NULL == rval) {
+ OUT_OF_MEMORY;
+ return NULL;
+ }
+ return rval;
+ }
+ if (!S_ISLNK (st.st_mode)) {
+ fprintf (shadow_logfd,
+ _("%s: %s is neither a directory, nor a symlink.\n"),
+ shadow_progname, path);
+ free (path);
+ return NULL;
+ }
+ ret = readlink (path, link, sizeof (link) - 1);
+ if (-1 == ret) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot read symbolic link %s: %s\n"),
+ shadow_progname, path, strerror (errno));
+ free (path);
+ return NULL;
+ }
+ free (path);
+ if ((size_t)ret >= sizeof(link) - 1) {
+ link[sizeof(link) - 1] = '\0';
+ fprintf (shadow_logfd,
+ _("%s: Suspiciously long symlink: %s\n"),
+ shadow_progname, link);
+ return NULL;
+ }
+ link[(size_t)ret] = '\0';
+ rval = strdup (link);
+ if (NULL == rval) {
+ OUT_OF_MEMORY;
+ return NULL;
+ }
+ return rval;
+}
+
+static /*@null@*/ char *shadowtcb_path (const char *name, uid_t uid)
+{
+ char *ret, *rel;
+
+ rel = shadowtcb_path_rel (name, uid);
+ if (NULL == rel) {
+ return NULL;
+ }
+ if (asprintf (&ret, TCB_DIR "/%s", rel) == -1) {
+ OUT_OF_MEMORY;
+ free (rel);
+ return NULL;
+ }
+ free (rel);
+ return ret;
+}
+
+static /*@null@*/ char *shadowtcb_path_existing (const char *name)
+{
+ char *ret, *rel;
+
+ rel = shadowtcb_path_rel_existing (name);
+ if (NULL == rel) {
+ return NULL;
+ }
+ if (asprintf (&ret, TCB_DIR "/%s", rel) == -1) {
+ OUT_OF_MEMORY;
+ free (rel);
+ return NULL;
+ }
+ free (rel);
+ return ret;
+}
+
+static shadowtcb_status mkdir_leading (const char *name, uid_t uid)
+{
+ char *ind, *dir, *ptr, *path = shadowtcb_path_rel (name, uid);
+ struct stat st;
+
+ if (NULL == path) {
+ return SHADOWTCB_FAILURE;
+ }
+ ptr = path;
+ if (stat (TCB_DIR, &st) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot stat %s: %s\n"),
+ shadow_progname, TCB_DIR, strerror (errno));
+ goto out_free_path;
+ }
+ while ((ind = strchr (ptr, '/'))) {
+ *ind = '\0';
+ if (asprintf (&dir, TCB_DIR "/%s", path) == -1) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if ((mkdir (dir, 0700) != 0) && (errno != EEXIST)) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot create directory %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ goto out_free_dir;
+ }
+ if (chown (dir, 0, st.st_gid) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change owner of %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ goto out_free_dir;
+ }
+ if (chmod (dir, 0711) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change mode of %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ goto out_free_dir;
+ }
+ free (dir);
+ *ind = '/';
+ ptr = ind + 1;
+ }
+ free (path);
+ return SHADOWTCB_SUCCESS;
+out_free_dir:
+ free (dir);
+out_free_path:
+ free (path);
+ return SHADOWTCB_FAILURE;
+}
+
+static shadowtcb_status unlink_suffs (const char *user)
+{
+ static char *suffs[] = { "+", "-", SHADOWTCB_LOCK_SUFFIX };
+ char *tmp;
+ int i;
+
+ for (i = 0; i < 3; i++) {
+ if (asprintf (&tmp, TCB_FMT "%s", user, suffs[i]) == -1) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if ((unlink (tmp) != 0) && (errno != ENOENT)) {
+ fprintf (shadow_logfd,
+ _("%s: unlink: %s: %s\n"),
+ shadow_progname, tmp, strerror (errno));
+ free (tmp);
+ return SHADOWTCB_FAILURE;
+ }
+ free (tmp);
+ }
+
+ return SHADOWTCB_SUCCESS;
+}
+
+/* path should be a relative existing tcb directory */
+static shadowtcb_status rmdir_leading (char *path)
+{
+ char *ind, *dir;
+ shadowtcb_status ret = SHADOWTCB_SUCCESS;
+ while ((ind = strrchr (path, '/'))) {
+ *ind = '\0';
+ if (asprintf (&dir, TCB_DIR "/%s", path) == -1) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if (rmdir (dir) != 0) {
+ if (errno != ENOTEMPTY) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot remove directory %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ ret = SHADOWTCB_FAILURE;
+ }
+ free (dir);
+ break;
+ }
+ free (dir);
+ }
+ return ret;
+}
+
+static shadowtcb_status move_dir (const char *user_newname, uid_t user_newid)
+{
+ char *olddir = NULL, *newdir = NULL;
+ char *real_old_dir = NULL, *real_new_dir = NULL;
+ char *real_old_dir_rel = NULL, *real_new_dir_rel = NULL;
+ uid_t old_uid, the_newid;
+ struct stat oldmode;
+ shadowtcb_status ret = SHADOWTCB_FAILURE;
+
+ if (NULL == stored_tcb_user) {
+ return SHADOWTCB_FAILURE;
+ }
+ if (asprintf (&olddir, TCB_DIR "/%s", stored_tcb_user) == -1) {
+ goto out_free_nomem;
+ }
+ if (stat (olddir, &oldmode) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot stat %s: %s\n"),
+ shadow_progname, olddir, strerror (errno));
+ goto out_free;
+ }
+ old_uid = oldmode.st_uid;
+ the_newid = (user_newid == -1) ? old_uid : user_newid;
+ real_old_dir = shadowtcb_path_existing (stored_tcb_user);
+ if (NULL == real_old_dir) {
+ goto out_free;
+ }
+ real_new_dir = shadowtcb_path (user_newname, the_newid);
+ if (NULL == real_new_dir) {
+ goto out_free;
+ }
+ if (strcmp (real_old_dir, real_new_dir) == 0) {
+ ret = SHADOWTCB_SUCCESS;
+ goto out_free;
+ }
+ real_old_dir_rel = shadowtcb_path_rel_existing (stored_tcb_user);
+ if (NULL == real_old_dir_rel) {
+ goto out_free;
+ }
+ if (mkdir_leading (user_newname, the_newid) == SHADOWTCB_FAILURE) {
+ goto out_free;
+ }
+ if (rename (real_old_dir, real_new_dir) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot rename %s to %s: %s\n"),
+ shadow_progname, real_old_dir, real_new_dir, strerror (errno));
+ goto out_free;
+ }
+ if (rmdir_leading (real_old_dir_rel) == SHADOWTCB_FAILURE) {
+ goto out_free;
+ }
+ if ((unlink (olddir) != 0) && (errno != ENOENT)) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot remove %s: %s\n"),
+ shadow_progname, olddir, strerror (errno));
+ goto out_free;
+ }
+ if (asprintf (&newdir, TCB_DIR "/%s", user_newname) == -1) {
+ goto out_free_nomem;
+ }
+ real_new_dir_rel = shadowtcb_path_rel (user_newname, the_newid);
+ if (NULL == real_new_dir_rel) {
+ goto out_free;
+ }
+ if ( (strcmp (real_new_dir, newdir) != 0)
+ && (symlink (real_new_dir_rel, newdir) != 0)) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot create symbolic link %s: %s\n"),
+ shadow_progname, real_new_dir_rel, strerror (errno));
+ goto out_free;
+ }
+ ret = SHADOWTCB_SUCCESS;
+ goto out_free;
+out_free_nomem:
+ OUT_OF_MEMORY;
+out_free:
+ free (olddir);
+ free (newdir);
+ free (real_old_dir);
+ free (real_new_dir);
+ free (real_old_dir_rel);
+ free (real_new_dir_rel);
+ return ret;
+}
+
+shadowtcb_status shadowtcb_set_user (const char* name)
+{
+ char *buf;
+ shadowtcb_status retval;
+
+ if (!getdef_bool ("USE_TCB")) {
+ return SHADOWTCB_SUCCESS;
+ }
+
+ free (stored_tcb_user);
+
+ stored_tcb_user = strdup (name);
+ if (NULL == stored_tcb_user) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if (asprintf (&buf, TCB_FMT, name) == -1) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+
+ retval = (spw_setdbname (buf) != 0) ? SHADOWTCB_SUCCESS : SHADOWTCB_FAILURE;
+ free (buf);
+ return retval;
+}
+
+/* tcb directory must be empty before shadowtcb_remove is called. */
+shadowtcb_status shadowtcb_remove (const char *name)
+{
+ shadowtcb_status ret = SHADOWTCB_SUCCESS;
+ char *path = shadowtcb_path_existing (name);
+ char *rel = shadowtcb_path_rel_existing (name);
+ if ((NULL == path) || (NULL == rel) || (rmdir (path) != 0)) {
+ return SHADOWTCB_FAILURE;
+ }
+ if (rmdir_leading (rel) == SHADOWTCB_FAILURE) {
+ return SHADOWTCB_FAILURE;
+ }
+ free (path);
+ free (rel);
+ if (asprintf (&path, TCB_DIR "/%s", name) == -1) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if ((unlink (path) != 0) && (errno != ENOENT)) {
+ ret = SHADOWTCB_FAILURE;
+ }
+ free (path);
+ return ret;
+}
+
+shadowtcb_status shadowtcb_move (/*@NULL@*/const char *user_newname, uid_t user_newid)
+{
+ struct stat dirmode, filemode;
+ char *tcbdir, *shadow;
+ shadowtcb_status ret = SHADOWTCB_FAILURE;
+
+ if (!getdef_bool ("USE_TCB")) {
+ return SHADOWTCB_SUCCESS;
+ }
+ if (NULL == stored_tcb_user) {
+ return SHADOWTCB_FAILURE;
+ }
+ if (NULL == user_newname) {
+ user_newname = stored_tcb_user;
+ }
+ if (move_dir (user_newname, user_newid) == SHADOWTCB_FAILURE) {
+ return SHADOWTCB_FAILURE;
+ }
+ if (-1 == user_newid) {
+ return SHADOWTCB_SUCCESS;
+ }
+ if ( (asprintf (&tcbdir, TCB_DIR "/%s", user_newname) == -1)
+ || (asprintf (&shadow, TCB_FMT, user_newname) == -1)) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if (stat (tcbdir, &dirmode) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot stat %s: %s\n"),
+ shadow_progname, tcbdir, strerror (errno));
+ goto out_free;
+ }
+ if (chown (tcbdir, 0, 0) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change owners of %s: %s\n"),
+ shadow_progname, tcbdir, strerror (errno));
+ goto out_free;
+ }
+ if (chmod (tcbdir, 0700) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change mode of %s: %s\n"),
+ shadow_progname, tcbdir, strerror (errno));
+ goto out_free;
+ }
+ if (lstat (shadow, &filemode) != 0) {
+ if (errno != ENOENT) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot lstat %s: %s\n"),
+ shadow_progname, shadow, strerror (errno));
+ goto out_free;
+ }
+ fprintf (shadow_logfd,
+ _("%s: Warning, user %s has no tcb shadow file.\n"),
+ shadow_progname, user_newname);
+ } else {
+ if (!S_ISREG (filemode.st_mode) ||
+ filemode.st_nlink != 1) {
+ fprintf (shadow_logfd,
+ _("%s: Emergency: %s's tcb shadow is not a "
+ "regular file with st_nlink=1.\n"
+ "The account is left locked.\n"),
+ shadow_progname, user_newname);
+ goto out_free;
+ }
+ if (chown (shadow, user_newid, filemode.st_gid) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change owner of %s: %s\n"),
+ shadow_progname, shadow, strerror (errno));
+ goto out_free;
+ }
+ if (chmod (shadow, filemode.st_mode & 07777) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change mode of %s: %s\n"),
+ shadow_progname, shadow, strerror (errno));
+ goto out_free;
+ }
+ }
+ if (unlink_suffs (user_newname) == SHADOWTCB_FAILURE) {
+ goto out_free;
+ }
+ if (chown (tcbdir, user_newid, dirmode.st_gid) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change owner of %s: %s\n"),
+ shadow_progname, tcbdir, strerror (errno));
+ goto out_free;
+ }
+ if (chmod (tcbdir, dirmode.st_mode & 07777) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change mode of %s: %s\n"),
+ shadow_progname, tcbdir, strerror (errno));
+ goto out_free;
+ }
+ ret = SHADOWTCB_SUCCESS;
+out_free:
+ free (tcbdir);
+ free (shadow);
+ return ret;
+}
+
+shadowtcb_status shadowtcb_create (const char *name, uid_t uid)
+{
+ char *dir, *shadow;
+ struct stat tcbdir_stat;
+ gid_t shadowgid, authgid;
+ struct group *gr;
+ int fd;
+ shadowtcb_status ret = SHADOWTCB_FAILURE;
+
+ if (!getdef_bool ("USE_TCB")) {
+ return SHADOWTCB_SUCCESS;
+ }
+ if (stat (TCB_DIR, &tcbdir_stat) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot stat %s: %s\n"),
+ shadow_progname, TCB_DIR, strerror (errno));
+ return SHADOWTCB_FAILURE;
+ }
+ shadowgid = tcbdir_stat.st_gid;
+ authgid = shadowgid;
+ if (getdef_bool ("TCB_AUTH_GROUP")) {
+ gr = getgrnam ("auth");
+ if (NULL != gr) {
+ authgid = gr->gr_gid;
+ }
+ }
+
+ if ( (asprintf (&dir, TCB_DIR "/%s", name) == -1)
+ || (asprintf (&shadow, TCB_FMT, name) == -1)) {
+ OUT_OF_MEMORY;
+ return SHADOWTCB_FAILURE;
+ }
+ if (mkdir (dir, 0700) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: mkdir: %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ goto out_free;
+ }
+ fd = open (shadow, O_RDWR | O_CREAT | O_TRUNC, 0600);
+ if (fd < 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot open %s: %s\n"),
+ shadow_progname, shadow, strerror (errno));
+ goto out_free;
+ }
+ close (fd);
+ if (chown (shadow, 0, authgid) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change owner of %s: %s\n"),
+ shadow_progname, shadow, strerror (errno));
+ goto out_free;
+ }
+ if (chmod (shadow, (mode_t) ((authgid == shadowgid) ? 0600 : 0640)) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change mode of %s: %s\n"),
+ shadow_progname, shadow, strerror (errno));
+ goto out_free;
+ }
+ if (chown (dir, 0, authgid) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change owner of %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ goto out_free;
+ }
+ if (chmod (dir, (mode_t) ((authgid == shadowgid) ? 02700 : 02710)) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: Cannot change mode of %s: %s\n"),
+ shadow_progname, dir, strerror (errno));
+ goto out_free;
+ }
+ if ( (shadowtcb_set_user (name) == SHADOWTCB_FAILURE)
+ || (shadowtcb_move (NULL, uid) == SHADOWTCB_FAILURE)) {
+ goto out_free;
+ }
+ ret = SHADOWTCB_SUCCESS;
+out_free:
+ free (dir);
+ free (shadow);
+ return ret;
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-10 18:16:35 +0000