Preserve KRB5CCNAME in zero_env() and add a paranoia check to make sure

we can't overflow new_env.

diff --git a/env.c b/env.c
index 58f3ded330c27c4aa50fd91cf343fd6c83e25862..4f38603499890e62caa20565474c3a29d65b9344 100644 (file)
--- a/env.c
+++ b/env.c
@@ -137,7 +137,7 @@ static size_t env_size;             /* size of new_environ in char **'s */
 static size_t env_len;         /* number of slots used, not counting NULL */
 
 /*
- * Zero out environment and replace with a minimal set of
+ * Zero out environment and replace with a minimal set of KRB5CCNAME
  * USER, LOGNAME, HOME, TZ, PATH (XXX - should just set path to default)
  * May set user_path, user_shell, and/or user_prompt as side effects.
  */
@@ -145,8 +145,9 @@ char **
 zero_env(envp)
     char **envp;
 {
-    static char *newenv[8];
+    static char *newenv[9];
     char **ep, **nep = newenv;
+    char **ne_last = &newenv[(sizeof(newenv) / sizeof(newenv[0])) - 1];
     extern char *prev_user;
 
     for (ep = envp; *ep; ep++) {
@@ -155,6 +156,10 @@ zero_env(envp)
                if (strncmp("HOME=", *ep, 5) == 0)
                    break;
                continue;
+           case 'K':
+               if (strncmp("KRB5CCNAME=", *ep, 11) == 0)
+                   break;
+               continue;
            case 'L':
                if (strncmp("LOGNAME=", *ep, 8) == 0)
                    break;
@@ -191,8 +196,12 @@ zero_env(envp)
            if (**nep == **ep)
                break;
        }
-       if (*nep == NULL)
-           *nep++ = *ep;
+       if (*nep == NULL) {
+           if (nep < ne_last)
+               *nep++ = *ep;
+           else
+               errorx(1, "internal error, attempt to write outside newenv");
+       }
     }
 
 #ifdef HAVE_LDAP
@@ -201,7 +210,10 @@ zero_env(envp)
      * or files in the current directory.
      *
      */             
-    *nep++ = "LDAPNOINIT=1";
+    if (nep < ne_last)
+       *nep++ = "LDAPNOINIT=1";
+    else
+       errorx(1, "internal error, attempt to write outside newenv");
 #endif
 
     return(&newenv[0]);