[PING][PATCH] Use NSS_STATUS_TRYAGAIN to indicate insufficient buffer (BZ #16878)

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

Ping!

On Wed, Apr 30, 2014 at 02:43:30PM +0530, Siddhesh Poyarekar wrote:
> The netgroups nss modules in the glibc tree use NSS_STATUS_UNAVAIL
> (with errno as ERANGE) when the supplied buffer does not have
> sufficient space for the result.  This is wrong, because the canonical
> way to indicate insufficient buffer is to set the errno to ERANGE and
> the status to NSS_STATUS_TRYAGAIN, as is used by all other modules.
> 
> This fixes nscd behaviour when the nss_ldap module returns
> NSS_STATUS_TRYAGAIN to indicate that a netgroup entry is too long to
> fit into the supplied buffer.  A reproducer is present on the bz
> #16878, which I used to verify that the problem is fixed.  Many thanks
> to Michael Weiser for the reproducer and analysis.
> 
> Siddhesh
> 
> 	[BZ #16878]
> 	* nscd/netgroupcache.c (addgetnetgrentX): Look for
> 	NSS_STATUS_TRYAGAIN to indicate insufficient buffer space.
> 	* nscd/nss_files/files-netgrp.c (_nss_netgroup_parseline): Use
> 	NSS_STATUS_TRYAGAIN to indicate insufficient buffer space.
> 
> ---
>  nscd/netgroupcache.c         | 14 ++++++++------
>  nss/nss_files/files-netgrp.c |  2 +-
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/nscd/netgroupcache.c b/nscd/netgroupcache.c
> index b3d40e9..edab174 100644
> --- a/nscd/netgroupcache.c
> +++ b/nscd/netgroupcache.c
> @@ -197,11 +197,6 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req,
>  		    int e;
>  		    status = getfct.f (&data, buffer + buffilled,
>  				       buflen - buffilled - req->key_len, &e);
> -		    if (status == NSS_STATUS_RETURN
> -			|| status == NSS_STATUS_NOTFOUND)
> -		      /* This was either the last one for this group or the
> -			 group was empty.  Look at next group if available.  */
> -		      break;
>  		    if (status == NSS_STATUS_SUCCESS)
>  		      {
>  			if (data.type == triple_val)
> @@ -320,11 +315,18 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req,
>  			      }
>  			  }
>  		      }
> -		    else if (status == NSS_STATUS_UNAVAIL && e == ERANGE)
> +		    else if (status == NSS_STATUS_TRYAGAIN && e == ERANGE)
>  		      {
>  			buflen *= 2;
>  			buffer = xrealloc (buffer, buflen);
>  		      }
> +		    else if (status == NSS_STATUS_RETURN
> +			     || status == NSS_STATUS_NOTFOUND
> +			     || status == NSS_STATUS_UNAVAIL)
> +		      /* This was either the last one for this group or the
> +			 group was empty or the NSS module had an internal
> +			 failure.  Look at next group if available.  */
> +		      break;
>  		  }
>  
>  	      enum nss_status (*endfct) (struct __netgrent *);
> diff --git a/nss/nss_files/files-netgrp.c b/nss/nss_files/files-netgrp.c
> index 34eae4c..bc0b367 100644
> --- a/nss/nss_files/files-netgrp.c
> +++ b/nss/nss_files/files-netgrp.c
> @@ -252,7 +252,7 @@ _nss_netgroup_parseline (char **cursor, struct __netgrent *result,
>    if (cp - host > buflen)
>      {
>        *errnop = ERANGE;
> -      status = NSS_STATUS_UNAVAIL;
> +      status = NSS_STATUS_TRYAGAIN;
>      }
>    else
>      {
> -- 
> 1.8.3.1
>

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