Subject: Re: [PATCH v8 3/3] NFSD: add rpc_status netlink support

From: Lorenzo Bianconi <[email-masked]>
Date: Thu, 14 Sep 2023 13:41:17 +0200

[...]

> > +
> > +#ifdef CONFIG_NFSD_V4
> > +			if (rqstp->rq_vers == NFS4_VERSION &&
> > +			    rqstp->rq_proc == NFSPROC4_COMPOUND) {
> > +				/* NFSv4 compund */
> 
> nit: compound

ack, I will fix it.

> 
> > +				struct nfsd4_compoundargs *args;
> > +				int j;
> > +
> > +				args = rqstp->rq_argp;
> > +				genl_rqstp.opcnt = args->opcnt;
> > +				for (j = 0; j < genl_rqstp.opcnt; j++)
> > +					genl_rqstp.opnum[j] =
> > +						args->ops[j].opnum;
> > +			}
> > +#endif /* CONFIG_NFSD_V4 */
> > +
> > +			/*
> > +			 * Acquire rq_status_counter before reporting the rqst
> > +			 * fields to the user.
> > +			 */
> > +			if (smp_load_acquire(&rqstp->rq_status_counter) !=
> > +			    status_counter)
> > +				continue;
> > +
> > +			ret = nfsd_genl_rpc_status_compose_msg(skb, cb,
> > +							       &genl_rqstp);
> > +			if (ret)
> > +				goto out;
> > +		}
> > +	}
> > +
> > +	cb->args[0] = i;
> > +	cb->args[1] = rqstp_index;
> 
> I'm unsure if this is possible, but if the for loop above iterates zero
> times, or for all iterations (i < cb->args[0]), then rqstp_index will
> be used uninitialised here.

ack, thx for spotting it, I will fix it.

Regards,
Lorenzo

> 
> Flagged by Smatch.
> 
> > +	ret = skb->len;
> > +out:
> > +	rcu_read_unlock();
> > +
> > +	return ret;
> > +}
> 
> ...
> 
> > diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> > index 11c14faa6c67..d787bd38c053 100644
> > --- a/fs/nfsd/nfsd.h
> > +++ b/fs/nfsd/nfsd.h
> > @@ -62,6 +62,22 @@ struct readdir_cd {
> >  	__be32			err;	/* 0, nfserr, or nfserr_eof */
> >  };
> >  
> > +/* Maximum number of operations per session compound */
> > +#define NFSD_MAX_OPS_PER_COMPOUND	50
> > +
> > +struct nfsd_genl_rqstp {
> > +	struct sockaddr daddr;
> > +	struct sockaddr saddr;
> > +	unsigned long rq_flags;
> > +	ktime_t rq_stime;
> > +	__be32 rq_xid;
> > +	u32 rq_vers;
> > +	u32 rq_prog;
> > +	u32 rq_proc;
> > +	/* NFSv4 compund */
> 
> nit: compound
> 
> > +	u32 opnum[NFSD_MAX_OPS_PER_COMPOUND];
> > +	u16 opcnt;
> > +};
> >  
> >  extern struct svc_program	nfsd_program;
> >  extern const struct svc_version	nfsd_version2, nfsd_version3, nfsd_version4;
> 
> ...
>