Historically, crypt() returned the empty string on error, which

ensured that crypt("", "") would return "", which supported matcing
empty encrypted passwords with no additional code.  Some modern
versions of crypt() (such as glibc) return NULL on error so we need
an explicit test to match an empty plaintext password and an empty
encrypted password.

diff --git a/plugins/sudoers/auth/passwd.c b/plugins/sudoers/auth/passwd.c
index 09c2c97e0e175ac96bbf0cfb5d757fb704ff27cf..a7da4985a9e800d055e5371fc23685786b85389d 100644 (file)
--- a/plugins/sudoers/auth/passwd.c
+++ b/plugins/sudoers/auth/passwd.c
@@ -71,7 +71,9 @@ sudo_passwd_verify(struct passwd *pw, char *pass, sudo_auth *auth)
     int matched = 0;
     debug_decl(sudo_passwd_verify, SUDOERS_DEBUG_AUTH)
 
-    pw_len = strlen(pw_epasswd);
+    /* An empty plain-text password must match an empty encrypted password. */
+    if (pass[0] == '\0')
+       debug_return_int(pw_epasswd[0] ? AUTH_FAILURE : AUTH_SUCCESS);
 
 #ifdef HAVE_GETAUTHUID
     /* Ultrix shadow passwords may use crypt16() */
@@ -85,6 +87,7 @@ sudo_passwd_verify(struct passwd *pw, char *pass, sudo_auth *auth)
      * If this turns out not to be safe we will have to use OS #ifdef's (sigh).
      */
     sav = pass[8];
+    pw_len = strlen(pw_epasswd);
     if (pw_len == DESLEN || HAS_AGEINFO(pw_epasswd, pw_len))
        pass[8] = '\0';
 

diff --git a/plugins/sudoers/auth/secureware.c b/plugins/sudoers/auth/secureware.c
index 6039cdc7061c58322b6f71663f4d041b84398782..50ebdb07074dc957d5a7a70b0bcbedd2390bf7f8 100644 (file)
--- a/plugins/sudoers/auth/secureware.c
+++ b/plugins/sudoers/auth/secureware.c
@@ -75,6 +75,11 @@ sudo_secureware_verify(struct passwd *pw, char *pass, sudo_auth *auth)
     char *pw_epasswd = auth->data;
     char *epass = NULL;
     debug_decl(sudo_secureware_verify, SUDOERS_DEBUG_AUTH)
+
+    /* An empty plain-text password must match an empty encrypted password. */
+    if (pass[0] == '\0')
+       debug_return_int(pw_epasswd[0] ? AUTH_FAILURE : AUTH_SUCCESS);
+
 #ifdef __alpha
     {
        extern int crypt_type;