Re: [PATCH 5/5] gssd: scrape the acceptor name out of the context

[Steve Dickson <SteveD@redhat.com>]

Hey Jeff,

Just a couple nit.... 

On 04/10/2014 04:31 PM, Jeff Layton wrote:
> ...and pass it to the kernel in the downcall. Legacy kernels will just
> ignore the extra data, but with a proposed kernel patch the kernel will
> grab this info and use it to verify requests on the v4.0 callback
> channel.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  utils/gssd/gssd_proc.c | 39 ++++++++++++++++++++++++++++-----------
>  1 file changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
> index 7387cce010cf..d95e39416c28 100644
> --- a/utils/gssd/gssd_proc.c
> +++ b/utils/gssd/gssd_proc.c
> @@ -77,6 +77,7 @@
>  #include "context.h"
>  #include "nfsrpc.h"
>  #include "nfslib.h"
> +#include "gss_names.h"
>  
>  /*
>   * pollarray:
> @@ -683,16 +684,19 @@ parse_enctypes(char *enctypes)
>  
>  static void
>  do_downcall(int k5_fd, uid_t uid, struct authgss_private_data *pd,
> -	    gss_buffer_desc *context_token, OM_uint32 lifetime_rec)
> +	    gss_buffer_desc *context_token, OM_uint32 lifetime_rec,
> +	    gss_buffer_desc *acceptor)
>  {
>  	char    *buf = NULL, *p = NULL, *end = NULL;
>  	unsigned int timeout = context_timeout;
>  	unsigned int buf_size = 0;
>  
> -	printerr(1, "doing downcall lifetime_rec %u\n", lifetime_rec);
> +	printerr(1, "doing downcall: lifetime_rec=%u acceptor=%.*s\n",
> +		lifetime_rec, acceptor->length, acceptor->value);
>  	buf_size = sizeof(uid) + sizeof(timeout) + sizeof(pd->pd_seq_win) +
>  		sizeof(pd->pd_ctx_hndl.length) + pd->pd_ctx_hndl.length +
> -		sizeof(context_token->length) + context_token->length;
> +		sizeof(context_token->length) + context_token->length +
> +		acceptor->length;
>  	p = buf = malloc(buf_size);
>  	if (!buf)
>  		goto out_err;
> @@ -707,6 +711,8 @@ do_downcall(int k5_fd, uid_t uid, struct authgss_private_data *pd,
>  	if (WRITE_BYTES(&p, end, pd->pd_seq_win)) goto out_err;
>  	if (write_buffer(&p, end, &pd->pd_ctx_hndl)) goto out_err;
>  	if (write_buffer(&p, end, context_token)) goto out_err;
> +	if (acceptor->length > 0 &&
> +	    write_buffer(&p, end, acceptor)) goto out_err;
>  
>  	if (write(k5_fd, buf, p - buf) < p - buf) goto out_err;
>  	free(buf);
> @@ -1034,6 +1040,9 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
>  	gss_cred_id_t		gss_cred;
>  	OM_uint32		maj_stat, min_stat, lifetime_rec;
>  	pid_t			pid;
> +	gss_name_t		gacceptor;
> +	gss_OID			mech;
> +	gss_buffer_desc		acceptor  = {0};
>  
>  	pid = fork();
>  	switch(pid) {
> @@ -1174,15 +1183,22 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
>  		goto out_return_error;
>  	}
>  
> -	/* Grab the context lifetime to pass to the kernel. lifetime_rec
> -	 * is set to zero on error */
Why get rid of this comment instead of updating it? 

> -	maj_stat = gss_inquire_context(&min_stat, pd.pd_ctx, NULL, NULL,
> -				       &lifetime_rec, NULL, NULL, NULL, NULL);
> +	maj_stat = gss_inquire_context(&min_stat, pd.pd_ctx, NULL, &gacceptor,
> +				       &lifetime_rec, &mech, NULL, NULL, NULL);
>  
> -	if (maj_stat)
> -		printerr(1, "WARNING: Failed to inquire context for lifetme "
> -			    "maj_stat %u\n", maj_stat);
> +	if (maj_stat != GSS_S_COMPLETE) {
> +		printerr(1, "WARNING: Failed to inquire context "
> +			    "maj_stat (0x%x)\n", maj_stat);
> +	} else {
> +		get_hostbased_client_buffer(gacceptor, mech, &acceptor);
> +		gss_release_name(&min_stat, &gacceptor);
> +	}
>  
> +	/*
> +	 * The serialization can mean turning the ctx into a lucid context. If
> +	 * that happens then the original ctx is no longer valid, so we mustn't
> +	 * try to use if after this point.
I'm not sure what you are trying to say here... 

steved.

> +	 */
>  	if (serialize_context_for_kernel(&pd.pd_ctx, &token, &krb5oid, NULL)) {
>  		printerr(0, "WARNING: Failed to serialize krb5 context for "
>  			    "user with uid %d for server %s\n",
> @@ -1190,9 +1206,10 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
>  		goto out_return_error;
>  	}
>  
> -	do_downcall(fd, uid, &pd, &token, lifetime_rec);
> +	do_downcall(fd, uid, &pd, &token, lifetime_rec, &acceptor);
>  
>  out:
> +	gss_release_buffer(&min_stat, &acceptor);
>  	if (token.value)
>  		free(token.value);
>  #ifdef HAVE_AUTHGSS_FREE_PRIVATE_DATA
>