Re: [PATCH 2/2] NFSv4: Use the net namespace uniquifier if it is set

[Dai Ngo <dai.ngo@xxxxxxxxxx>]

On 10/7/20 2:07 PM, trondmy@xxxxxxxxxx wrote:
> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>
> If a container sets a net namespace specific uniquifier, then use that
> in the setclientid/exchangeid process.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
>   fs/nfs/nfs4proc.c | 23 ++++++++++++++++++++---
>   1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 3a39887e0e6e..a1dd46e7440b 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -63,6 +63,7 @@
>   #include "callback.h"
>   #include "pnfs.h"
>   #include "netns.h"
> +#include "sysfs.h"
>   #include "nfs4idmap.h"
>   #include "nfs4session.h"
>   #include "fscache.h"
> @@ -6007,9 +6008,25 @@ static void nfs4_init_boot_verifier(const struct nfs_client *clp,
>   }
>   
>   static size_t
> -nfs4_get_uniquifier(char *buf, size_t buflen)
> +nfs4_get_uniquifier(struct nfs_client *clp, char *buf, size_t buflen)
>   {
> +	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
> +	struct nfs_netns_client *nn_clp = nn->nfs_client;
> +	const char *id;
> +	size_t len;
> +
>   	buf[0] = '\0';
> +
> +	if (nn_clp) {
> +		rcu_read_lock();
> +		id = rcu_dereference(nn_clp->identifier);
> +		if (id && *id != '\0')
> +			len = strlcpy(buf, id, buflen);
> +		rcu_read_unlock();
> +		if (len)

I think 'len' can be uninitialized here.

-Dai

> +			return len;
> +	}
> +
>   	if (nfs4_client_id_uniquifier[0] != '\0')
>   		return strlcpy(buf, nfs4_client_id_uniquifier, buflen);
>   	return 0;
> @@ -6034,7 +6051,7 @@ nfs4_init_nonuniform_client_string(struct nfs_client *clp)
>   		1;
>   	rcu_read_unlock();
>   
> -	buflen = nfs4_get_uniquifier(buf, sizeof(buf));
> +	buflen = nfs4_get_uniquifier(clp, buf, sizeof(buf));
>   	if (buflen)
>   		len += buflen + 1;
>   
> @@ -6081,7 +6098,7 @@ nfs4_init_uniform_client_string(struct nfs_client *clp)
>   	len = 10 + 10 + 1 + 10 + 1 +
>   		strlen(clp->cl_rpcclient->cl_nodename) + 1;
>   
> -	buflen = nfs4_get_uniquifier(buf, sizeof(buf));
> +	buflen = nfs4_get_uniquifier(clp, buf, sizeof(buf));
>   	if (buflen)
>   		len += buflen + 1;
>