[PING^2][PATCH] Use NSS_STATUS_TRYAGAIN to indicate insufficient buffer (BZ #16878)

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

Ping!

On Thu, May 15, 2014 at 02:12:32PM +0530, Siddhesh Poyarekar wrote:
> 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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