passwd: fix bug: we are trying to update shadow even if user's record is in passwd!

getspnam is guilty, it lies that user record exists in shadow.

2 files changed, 19 insertions, 9 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 82cee380b..b438ec25f 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -482,10 +482,10 @@ int get_uidgid(struct bb_uidgid_t*, const char*, int numeric_ok);
 /* chown-like handling of "user[:[group]" */
 void parse_chown_usergroup_or_die(struct bb_uidgid_t *u, char *user_group);
 /* bb_getpwuid, bb_getgrgid:
-bb_getXXXid(buf, bufsz, id) - copy user/group name or id
-                as a string to buf, return user/group name or NULL
-bb_getXXXid(NULL, 0, id) - return user/group name or NULL
-bb_getXXXid(NULL, -1, id) - return user/group name or exit
+ * bb_getXXXid(buf, bufsz, id) - copy user/group name or id
+ *              as a string to buf, return user/group name or NULL
+ * bb_getXXXid(NULL, 0, id) - return user/group name or NULL
+ * bb_getXXXid(NULL, -1, id) - return user/group name or exit
 */
 char *bb_getpwuid(char *name, int bufsize, long uid);
 char *bb_getgrgid(char *group, int bufsize, long gid);
diff --git a/loginutils/passwd.c b/loginutils/passwd.c
index a293ee926..4f7094aec 100644
--- a/loginutils/passwd.c
+++ b/loginutils/passwd.c
@@ -127,15 +127,16 @@ int passwd_main(int argc, char **argv)
                 bb_error_msg_and_die("%s can't change password for %s", myname, name);
         }
 
-        filename = bb_path_passwd_file;
 #if ENABLE_FEATURE_SHADOWPASSWDS
-        if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)) {
+        /* getspnam_r() can lie! Even if user isn't in shadow, it can
+         * return success (pwd field was seen set to "!" in this case) */
+        if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)
+         || LONE_CHAR(spw.sp_pwdp, '!')) {
                 /* LOGMODE_BOTH */
                 bb_error_msg("no record of %s in %s, using %s",
                                 name, bb_path_shadow_file,
                                 bb_path_passwd_file);
         } else {
-                filename = bb_path_shadow_file;
                 pw->pw_passwd = spw.sp_pwdp;
         }
 #endif
@@ -175,8 +176,17 @@ int passwd_main(int argc, char **argv)
         signal(SIGQUIT, SIG_IGN);
         umask(077);
         xsetuid(0);
-        rc = update_passwd(filename, name, newp);
-        logmode = LOGMODE_BOTH;
+
+#if ENABLE_FEATURE_SHADOWPASSWDS
+        filename = bb_path_shadow_file;
+        rc = update_passwd(bb_path_shadow_file, name, newp);
+        if (rc == 0) /* no lines updated, no errors detected */
+#endif
+        {
+                filename = bb_path_passwd_file;
+                rc = update_passwd(bb_path_passwd_file, name, newp);
+        }
+        /* LOGMODE_BOTH */
         if (rc < 0)
                 bb_error_msg_and_die("cannot update password file %s",
                                 filename);