Search users for one with a valid salt.

If the root account is locked (eg password "!!" or "*LK*") keep looking
until we find a user with a valid salt to use for crypting passwords of
invalid users.  ok djm@

Origin: upstream, https://anongit.mindrot.org/openssh.git/commit/?id=dbf788b4d9d9490a5fff08a7b09888272bb10fcc
Bug-Debian: https://bugs.debian.org/831902
Last-Update: 2016-07-22

Patch-Name: CVE-2016-6210-3.patch

1 files changed, 15 insertions, 9 deletions

diff --git a/openbsd-compat/xcrypt.c b/openbsd-compat/xcrypt.c
index 8913bb81a..cf6a9b99f 100644
--- a/openbsd-compat/xcrypt.c
+++ b/openbsd-compat/xcrypt.c
@@ -65,7 +65,9 @@
 
 /*
  * Pick an appropriate password encryption type and salt for the running
- * system.
+ * system by searching through accounts until we find one that has a valid
+ * salt.  Usually this will be root unless the root account is locked out.
+ * If we don't find one we return a traditional DES-based salt.
  */
 static const char *
 pick_salt(void)
@@ -78,14 +80,18 @@ pick_salt(void)
         if (salt[0] != '\0')
                 return salt;
         strlcpy(salt, "xx", sizeof(salt));
-        if ((pw = getpwuid(0)) == NULL)
-                return salt;
-        passwd = shadow_pw(pw);
-        if (passwd[0] != '$' || (p = strrchr(passwd + 1, '$')) == NULL)
-                return salt;  /* no $, DES */
-        typelen = p - passwd + 1;
-        strlcpy(salt, passwd, MIN(typelen, sizeof(salt)));
-        explicit_bzero(passwd, strlen(passwd));
+        setpwent();
+        while ((pw = getpwent()) != NULL) {
+                passwd = shadow_pw(pw);
+                if (passwd[0] == '$' && (p = strrchr(passwd+1, '$')) != NULL) {
+                        typelen = p - passwd + 1;
+                        strlcpy(salt, passwd, MIN(typelen, sizeof(salt)));
+                        explicit_bzero(passwd, strlen(passwd));
+                        goto out;
+                }
+        }
+ out:
+        endpwent();
         return salt;
 }