login: ask passwords even for wrong usernames.

# size busybox_old busybox_unstripped
   text    data     bss     dec     hex filename
 680099    2704   15648  698451   aa853 busybox_old
 680110    2704   15648  698462   aa85e busybox_unstripped

2 files changed, 11 insertions, 7 deletions

diff --git a/libbb/correct_password.c b/libbb/correct_password.c
index c515b26af..af6ff076d 100644
--- a/libbb/correct_password.c
+++ b/libbb/correct_password.c
@@ -31,9 +31,10 @@
 #include "libbb.h"
 
 /* Ask the user for a password.
-   Return 1 if the user gives the correct password for entry PW,
-   0 if not.  Return 1 without asking for a password if run by UID 0
-   or if PW has an empty password.  */
+ * Return 1 if the user gives the correct password for entry PW,
+ * 0 if not.  Return 1 without asking if PW has an empty password.
+ *
+ * NULL pw means "just fake it for login with bad username" */
 
 int correct_password(const struct passwd *pw)
 {
@@ -46,6 +47,9 @@ int correct_password(const struct passwd *pw)
         char buffer[256];
 #endif
 
+        correct = "aa"; /* fake salt. crypt() can choke otherwise */
+        if (!pw)
+                goto fake_it; /* "aa" will never match */
         correct = pw->pw_passwd;
 #if ENABLE_FEATURE_SHADOWPASSWDS
         if (LONE_CHAR(pw->pw_passwd, 'x') || LONE_CHAR(pw->pw_passwd, '*')) {
@@ -59,6 +63,7 @@ int correct_password(const struct passwd *pw)
         if (!correct || correct[0] == '\0')
                 return 1;
 
+ fake_it:
         unencrypted = bb_askpass(0, "Password: ");
         if (!unencrypted) {
                 return 0;
diff --git a/loginutils/login.c b/loginutils/login.c
index 142695008..b6924b641 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -276,8 +276,8 @@ int login_main(int argc, char **argv)
 
                 pw = getpwnam(username);
                 if (!pw) {
-                        safe_strncpy(username, "UNKNOWN", sizeof(username));
-                        goto auth_failed;
+                        strcpy(username, "UNKNOWN");
+                        goto fake_it;
                 }
 
                 if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*')
@@ -292,11 +292,10 @@ int login_main(int argc, char **argv)
                 /* Don't check the password if password entry is empty (!) */
                 if (!pw->pw_passwd[0])
                         break;
-
+ fake_it:
                 /* authorization takes place here */
                 if (correct_password(pw))
                         break;
-
  auth_failed:
                 opt &= ~LOGIN_OPT_f;
                 bb_do_delay(FAIL_DELAY);