[hackers] [ubase] passwd: prevent segfault when running as root || John Regan

[git]

commit 4f1b54dd92aa858432f648fc886700f7b369ed84
Author:     John Regan <j...@jrjrtech.com>
AuthorDate: Sat Sep 29 14:28:37 2018 -0400
Commit:     sin <s...@2f30.org>
CommitDate: Wed Jan 30 11:57:49 2019 +0000

    passwd: prevent segfault when running as root
    
    When running as root, passwd attempts to compare the new password to
    the old password, without having grabbed the old passwd.
    
    This checks if the previous password hash was grabbed before comparing
    it against the new password hash.

diff --git a/passwd.c b/passwd.c
index 52b70a8..afbba9c 100644
--- a/passwd.c
+++ b/passwd.c
@@ -235,11 +235,14 @@ newpass:
                eprintf("getpass:");
        if (inpass[0] == '\0')
                eprintf("no password supplied\n");
-       p = crypt(inpass, prevhash);
-       if (!p)
-               eprintf("crypt:");
-       if (cryptpass1 && strcmp(cryptpass1, p) == 0)
-               eprintf("password left unchanged\n");
+
+       if(prevhash) {
+               p = crypt(inpass, prevhash);
+               if (!p)
+                       eprintf("crypt:");
+               if (cryptpass1 && strcmp(cryptpass1, p) == 0)
+                       eprintf("password left unchanged\n");
+       }
        gensalt(salt + strlen(salt));
        p = crypt(inpass, salt);
        if (!p)