2017-11-07 23:01:35

by Andrew W Elble

Subject: [PATCH] nfsd: check for use of the closed special stateid

Report on and prevent the use of the closed (invalid)
special stateid by clients.

Signed-off-by: Andrew Elble <[email protected]>
---
fs/nfsd/nfs4state.c | 32 ++++++++++++++++++++++++++++----
1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 755b33284979..2b637137fecd 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -73,6 +73,7 @@
#define ZERO_STATEID(stateid) (!memcmp((stateid), &zero_stateid, sizeof(stateid_t)))
#define ONE_STATEID(stateid) (!memcmp((stateid), &one_stateid, sizeof(stateid_t)))
#define CURRENT_STATEID(stateid) (!memcmp((stateid), &currentstateid, sizeof(stateid_t)))
+#define CLOSE_STATEID(stateid) (!memcmp((stateid), &close_stateid, sizeof(stateid_t)))

/* forward declarations */
static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner);
@@ -4875,13 +4876,35 @@ static __be32 nfsd4_check_openowner_confirmed(struct nfs4_ol_stateid *ols)
return nfs_ok;
}

+static inline __be32
+bad_special_stateid_check(struct nfs4_client *cl, stateid_t *stateid)
+{
+ if (CLOSE_STATEID(stateid)) {
+ char addr_str[INET6_ADDRSTRLEN];
+
+ rpc_ntop((struct sockaddr *)&cl->cl_addr, addr_str,
+ sizeof(addr_str));
+ pr_warn_ratelimited("NFSD: client %s using "
+ "invalid/closed stateid\n",
+ addr_str);
+ return nfserr_bad_stateid;
+ }
+
+ if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
+ return nfserr_bad_stateid;
+
+ return nfs_ok;
+}
+
static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
{
struct nfs4_stid *s;
- __be32 status = nfserr_bad_stateid;
+ __be32 status;

- if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
+ status = bad_special_stateid_check(cl, stateid);
+ if (status)
return status;
+ status = nfserr_bad_stateid;
/* Client debugging aid. */
if (!same_clid(&stateid->si_opaque.so_clid, &cl->cl_clientid)) {
char addr_str[INET6_ADDRSTRLEN];
@@ -4938,8 +4961,9 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
else if (typemask & NFS4_DELEG_STID)
typemask |= NFS4_REVOKED_DELEG_STID;

- if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
- return nfserr_bad_stateid;
+ status = bad_special_stateid_check(cstate->clp, stateid);
+ if (status)
+ return status;
status = lookup_clientid(&stateid->si_opaque.so_clid, cstate, nn);
if (status == nfserr_stale_clientid) {
if (cstate->session)
--
1.8.3.1

2017-11-09 14:01:38

by J. Bruce Fields

Subject: Re: [PATCH] nfsd: check for use of the closed special stateid

On Tue, Nov 07, 2017 at 06:01:23PM -0500, Andrew Elble wrote:
> Report on and prevent the use of the closed (invalid)
> special stateid by clients.
>
> Signed-off-by: Andrew Elble <[email protected]>
> ---
> fs/nfsd/nfs4state.c | 32 ++++++++++++++++++++++++++++----
> 1 file changed, 28 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 755b33284979..2b637137fecd 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -73,6 +73,7 @@
> #define ZERO_STATEID(stateid) (!memcmp((stateid), &zero_stateid, sizeof(stateid_t)))
> #define ONE_STATEID(stateid) (!memcmp((stateid), &one_stateid, sizeof(stateid_t)))
> #define CURRENT_STATEID(stateid) (!memcmp((stateid), &currentstateid, sizeof(stateid_t)))
> +#define CLOSE_STATEID(stateid) (!memcmp((stateid), &close_stateid, sizeof(stateid_t)))
>
> /* forward declarations */
> static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner);
> @@ -4875,13 +4876,35 @@ static __be32 nfsd4_check_openowner_confirmed(struct nfs4_ol_stateid *ols)
> return nfs_ok;
> }
>
> +static inline __be32
> +bad_special_stateid_check(struct nfs4_client *cl, stateid_t *stateid)
> +{
> + if (CLOSE_STATEID(stateid)) {
> + char addr_str[INET6_ADDRSTRLEN];
> +
> + rpc_ntop((struct sockaddr *)&cl->cl_addr, addr_str,
> + sizeof(addr_str));
> + pr_warn_ratelimited("NFSD: client %s using "
> + "invalid/closed stateid\n",
> + addr_str);

How useful is this? If we need it I'd rather it be a dprintk. (I'm
sort of reluctant to add new ways a badly behaved client could spam the
logs (the ratelimiting helps a little but not much).)

Seems fine otherwise.

--b.

> + return nfserr_bad_stateid;
> + }
> +
> + if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
> + return nfserr_bad_stateid;
> +
> + return nfs_ok;
> +}
> +
> static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
> {
> struct nfs4_stid *s;
> - __be32 status = nfserr_bad_stateid;
> + __be32 status;
>
> - if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
> + status = bad_special_stateid_check(cl, stateid);
> + if (status)
> return status;
> + status = nfserr_bad_stateid;
> /* Client debugging aid. */
> if (!same_clid(&stateid->si_opaque.so_clid, &cl->cl_clientid)) {
> char addr_str[INET6_ADDRSTRLEN];
> @@ -4938,8 +4961,9 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
> else if (typemask & NFS4_DELEG_STID)
> typemask |= NFS4_REVOKED_DELEG_STID;
>
> - if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
> - return nfserr_bad_stateid;
> + status = bad_special_stateid_check(cstate->clp, stateid);
> + if (status)
> + return status;
> status = lookup_clientid(&stateid->si_opaque.so_clid, cstate, nn);
> if (status == nfserr_stale_clientid) {
> if (cstate->session)
> --
> 1.8.3.1