Re: rc4-hmac-md5 mount failure

[Tom Haynes <tdh@excfb.com>]

On 4/6/11 12:36 PM, Jim Rees wrote:
> Trond Myklebust wrote:
>
>    >  diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_
>    >  index 0326446..8a4d083c 100644
>    >  --- a/net/sunrpc/auth_gss/gss_krb5_mech.c
>    >  +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
>    >  @@ -422,7 +422,7 @@ static int
>    >   context_derive_keys_rc4(struct krb5_ctx *ctx)
>    >   {
>    >         struct crypto_hash *hmac;
>    >  -       char sigkeyconstant[] = "signaturekey";
>    >  +       static const char sigkeyconstant[] = "signaturekey";
>    >         int slen = strlen(sigkeyconstant) + 1;  /* include null terminator */
>    >         struct hash_desc desc;
>    >         struct scatterlist sg[1];
>    >
>    >  Solution: if this commit is undone, rc4-based mount works without
>    >  issues. verified with linux and windows clients.
>
>    Hi Olga,
>
>    Thanks for the report! I'll revert this commit in upstream and the
>    stable kernels.
>
> But why does this fix it?
> --

Because it is no longer on the stack?

If whatever referenced it lived longer than the call to 
context_derive_keys_rc4(),
then it would be referencing garbage.