2011-06-13 01:27:21

by Sid Moore

[permalink] [raw]
Subject: [Patch 1/1]: fixed a bug that EXCHGID4_FLAG_CONFIRMED_R is cleared in EXCHANGE_ID reply if incarnation is a confirmed client

On Sun, Jun 12, 2011 at 7:59 AM, J. Bruce Fields <[email protected]> wrote:
> On Sat, Jun 11, 2011 at 03:54:56PM +0800, Sid Moore wrote:
>> Hi
>>
>> on Linux NFSv4.1 server, nfsd4_exchange_id() is used for creating a
>> new client incarnation or updating a confirmed client incarnation. if
>> try to update a confirmed incarnation, EXCHGID4_FLAG_CONFIRMED_R
>> should be set in eir_flags according to section 18.35.3, RFC5661.
>>
>> but I found EXCHGID4_FLAG_CONFIRMED_R is cleared by "clid->flags =
>> new->cl_exchange_flags;", which is in nfsd4_set_ex_flags() called by
>> nfsd4_exchange_id().
>>
>> so the sematics of RFC5661 is broken? am I correct?
>
> On a quick glance.... I think you're correct. ?Patch welcomed.
>
> --b.
>

Hi, Bruce

I think the patch below might be able to fix this issue. I am not sure
what impact would be produced if EXCHGID4_FLAG_CONFIRMED_R directly
set on confirmed clients. So, I take a conservative way. Please review
it. Thanks.

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 6fb7283..4bd9281 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1394,6 +1394,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
char addr_str[INET6_ADDRSTRLEN];
nfs4_verifier verf = exid->verifier;
struct sockaddr *sa = svc_addr(rqstp);
+ int confirmed_clnt = 0;

rpc_ntop(sa, addr_str, sizeof(addr_str));
dprintk("%s rqstp=%p exid=%p clname.len=%u clname.data=%p "
@@ -1455,7 +1456,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
* Set bit when the owner id and verifier map to an already
* confirmed client id (18.35.3).
*/
- exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;
+ confirmed_clnt = 1;

/*
* Falling into 18.35.4 case 2, possible router replay.
@@ -1498,6 +1499,9 @@ out_copy:

exid->seqid = 1;
nfsd4_set_ex_flags(new, exid);
+ if (confirmed_clnt)
+ exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;
+

dprintk("nfsd4_exchange_id seqid %d flags %x\n",
new->cl_cs_slot.sl_seqid, new->cl_exchange_flags);

--
Sid


2011-06-13 21:10:00

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [Patch 1/1]: fixed a bug that EXCHGID4_FLAG_CONFIRMED_R is cleared in EXCHANGE_ID reply if incarnation is a confirmed client

On Mon, Jun 13, 2011 at 09:27:19AM +0800, Sid Moore wrote:
> On Sun, Jun 12, 2011 at 7:59 AM, J. Bruce Fields <[email protected]> wrote:
> > On Sat, Jun 11, 2011 at 03:54:56PM +0800, Sid Moore wrote:
> >> Hi
> >>
> >> on Linux NFSv4.1 server, nfsd4_exchange_id() is used for creating a
> >> new client incarnation or updating a confirmed client incarnation. if
> >> try to update a confirmed incarnation, EXCHGID4_FLAG_CONFIRMED_R
> >> should be set in eir_flags according to section 18.35.3, RFC5661.
> >>
> >> but I found EXCHGID4_FLAG_CONFIRMED_R is cleared by "clid->flags =
> >> new->cl_exchange_flags;", which is in nfsd4_set_ex_flags() called by
> >> nfsd4_exchange_id().
> >>
> >> so the sematics of RFC5661 is broken? am I correct?
> >
> > On a quick glance.... I think you're correct.  Patch welcomed.
> >
> > --b.
> >
>
> Hi, Bruce
>
> I think the patch below might be able to fix this issue. I am not sure
> what impact would be produced if EXCHGID4_FLAG_CONFIRMED_R directly
> set on confirmed clients. So, I take a conservative way. Please review
> it. Thanks.

Grepping for cl_exchange_flags on the server side.... I think it would
be fine just to set it directly. Would you mind trying that and
resending the patch if it works?

--b.

>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 6fb7283..4bd9281 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1394,6 +1394,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
> char addr_str[INET6_ADDRSTRLEN];
> nfs4_verifier verf = exid->verifier;
> struct sockaddr *sa = svc_addr(rqstp);
> + int confirmed_clnt = 0;
>
> rpc_ntop(sa, addr_str, sizeof(addr_str));
> dprintk("%s rqstp=%p exid=%p clname.len=%u clname.data=%p "
> @@ -1455,7 +1456,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
> * Set bit when the owner id and verifier map to an already
> * confirmed client id (18.35.3).
> */
> - exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;
> + confirmed_clnt = 1;
>
> /*
> * Falling into 18.35.4 case 2, possible router replay.
> @@ -1498,6 +1499,9 @@ out_copy:
>
> exid->seqid = 1;
> nfsd4_set_ex_flags(new, exid);
> + if (confirmed_clnt)
> + exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;
> +
>
> dprintk("nfsd4_exchange_id seqid %d flags %x\n",
> new->cl_cs_slot.sl_seqid, new->cl_exchange_flags);
>
> --
> Sid