sunrpc: implement rfc2203 rpcsec_gss seqnum cache

This implements a sequence number cache of the last three (right now
hardcoded) sent sequence numbers for a given XID, as suggested by the
RFC.

From RFC2203 5.3.3.1:

"Note that the sequence number algorithm requires that the client
increment the sequence number even if it is retrying a request with
the same RPC transaction identifier.  It is not infrequent for
clients to get into a situation where they send two or more attempts
and a slow server sends the reply for the first attempt. With
RPCSEC_GSS, each request and reply will have a unique sequence
number. If the client wishes to improve turn around time on the RPC
call, it can cache the RPCSEC_GSS sequence number of each request it
sends. Then when it receives a response with a matching RPC
transaction identifier, it can compute the checksum of each sequence
number in the cache to try to match the checksum in the reply's
verifier."

Signed-off-by: Nikhil Jha <njha@janestreet.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 81b952649d35e3ad4fa8c7e77388ac2ceb44ce60..f46d1fb8f71ae22233f15691b2cf312f73656d9d 100644 (file)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -30,6 +30,8 @@
 #define RPC_MAXCWND(xprt)      ((xprt)->max_reqs << RPC_CWNDSHIFT)
 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
 
+#define RPC_GSS_SEQNO_ARRAY_SIZE 3U
+
 enum rpc_display_format_t {
        RPC_DISPLAY_ADDR = 0,
        RPC_DISPLAY_PORT,
@@ -66,7 +68,8 @@ struct rpc_rqst {
        struct rpc_cred *       rq_cred;        /* Bound cred */
        __be32                  rq_xid;         /* request XID */
        int                     rq_cong;        /* has incremented xprt->cong */
-       u32                     rq_seqno;       /* gss seq no. used on req. */
+       u32                     rq_seqnos[RPC_GSS_SEQNO_ARRAY_SIZE];    /* past gss req seq nos. */
+       unsigned int            rq_seqno_count; /* number of entries in rq_seqnos */
        int                     rq_enc_pages_num;
        struct page             **rq_enc_pages; /* scratch pages for use by
                                                   gss privacy code */
@@ -119,6 +122,18 @@ struct rpc_rqst {
 #define rq_svec                        rq_snd_buf.head
 #define rq_slen                        rq_snd_buf.len
 
+static inline int xprt_rqst_add_seqno(struct rpc_rqst *req, u32 seqno)
+{
+       if (likely(req->rq_seqno_count < RPC_GSS_SEQNO_ARRAY_SIZE))
+               req->rq_seqno_count++;
+
+       /* Shift array to make room for the newest element at the beginning */
+       memmove(&req->rq_seqnos[1], &req->rq_seqnos[0],
+               (RPC_GSS_SEQNO_ARRAY_SIZE - 1) * sizeof(req->rq_seqnos[0]));
+       req->rq_seqnos[0] = seqno;
+       return 0;
+}
+
 /* RPC transport layer security policies */
 enum xprtsec_policies {
        RPC_XPRTSEC_NONE = 0,

diff --git a/include/trace/events/rpcgss.h b/include/trace/events/rpcgss.h
index b0b6300a0cabdbaf1c08460a474aaf092b548e53..8aeae06cf434d05547b4cffb14f01901cfba4142 100644 (file)
--- a/include/trace/events/rpcgss.h
+++ b/include/trace/events/rpcgss.h
@@ -409,7 +409,7 @@ TRACE_EVENT(rpcgss_seqno,
                __entry->task_id = task->tk_pid;
                __entry->client_id = task->tk_client->cl_clid;
                __entry->xid = be32_to_cpu(rqst->rq_xid);
-               __entry->seqno = rqst->rq_seqno;
+               __entry->seqno = *rqst->rq_seqnos;
        ),
 
        TP_printk(SUNRPC_TRACE_TASK_SPECIFIER " xid=0x%08x seqno=%u",
@@ -440,7 +440,7 @@ TRACE_EVENT(rpcgss_need_reencode,
                __entry->client_id = task->tk_client->cl_clid;
                __entry->xid = be32_to_cpu(task->tk_rqstp->rq_xid);
                __entry->seq_xmit = seq_xmit;
-               __entry->seqno = task->tk_rqstp->rq_seqno;
+               __entry->seqno = *task->tk_rqstp->rq_seqnos;
                __entry->ret = ret;
        ),
 

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 5d331383047b79b9f6dcd699c87287453c1a5f49..751af7b024f9d258f64c1ef3086bff64339173f8 100644 (file)
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1100,7 +1100,7 @@ TRACE_EVENT(xprt_transmit,
                __entry->client_id = rqst->rq_task->tk_client ?
                        rqst->rq_task->tk_client->cl_clid : -1;
                __entry->xid = be32_to_cpu(rqst->rq_xid);
-               __entry->seqno = rqst->rq_seqno;
+               __entry->seqno = *rqst->rq_seqnos;
                __entry->status = status;
        ),
 

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 369310909fc98596c8a06db8ac3c976a719ca7b2..0fa244f16876f3c434fd507b4d53c5eefd748ce4 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1545,6 +1545,7 @@ static int gss_marshal(struct rpc_task *task, struct xdr_stream *xdr)
        struct kvec     iov;
        struct xdr_buf  verf_buf;
        int status;
+       u32 seqno;
 
        /* Credential */
 
@@ -1556,15 +1557,16 @@ static int gss_marshal(struct rpc_task *task, struct xdr_stream *xdr)
        cred_len = p++;
 
        spin_lock(&ctx->gc_seq_lock);
-       req->rq_seqno = (ctx->gc_seq < MAXSEQ) ? ctx->gc_seq++ : MAXSEQ;
+       seqno = (ctx->gc_seq < MAXSEQ) ? ctx->gc_seq++ : MAXSEQ;
+       xprt_rqst_add_seqno(req, seqno);
        spin_unlock(&ctx->gc_seq_lock);
-       if (req->rq_seqno == MAXSEQ)
+       if (*req->rq_seqnos == MAXSEQ)
                goto expired;
        trace_rpcgss_seqno(task);
 
        *p++ = cpu_to_be32(RPC_GSS_VERSION);
        *p++ = cpu_to_be32(ctx->gc_proc);
-       *p++ = cpu_to_be32(req->rq_seqno);
+       *p++ = cpu_to_be32(*req->rq_seqnos);
        *p++ = cpu_to_be32(gss_cred->gc_service);
        p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
        *cred_len = cpu_to_be32((p - (cred_len + 1)) << 2);
@@ -1678,17 +1680,31 @@ gss_refresh_null(struct rpc_task *task)
        return 0;
 }
 
+static u32
+gss_validate_seqno_mic(struct gss_cl_ctx *ctx, u32 seqno, __be32 *seq, __be32 *p, u32 len)
+{
+       struct kvec iov;
+       struct xdr_buf verf_buf;
+       struct xdr_netobj mic;
+
+       *seq = cpu_to_be32(seqno);
+       iov.iov_base = seq;
+       iov.iov_len = 4;
+       xdr_buf_from_iov(&iov, &verf_buf);
+       mic.data = (u8 *)p;
+       mic.len = len;
+       return gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
+}
+
 static int
 gss_validate(struct rpc_task *task, struct xdr_stream *xdr)
 {
        struct rpc_cred *cred = task->tk_rqstp->rq_cred;
        struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
        __be32          *p, *seq = NULL;
-       struct kvec     iov;
-       struct xdr_buf  verf_buf;
-       struct xdr_netobj mic;
        u32             len, maj_stat;
        int             status;
+       int             i = 1; /* don't recheck the first item */
 
        p = xdr_inline_decode(xdr, 2 * sizeof(*p));
        if (!p)
@@ -1705,13 +1721,10 @@ gss_validate(struct rpc_task *task, struct xdr_stream *xdr)
        seq = kmalloc(4, GFP_KERNEL);
        if (!seq)
                goto validate_failed;
-       *seq = cpu_to_be32(task->tk_rqstp->rq_seqno);
-       iov.iov_base = seq;
-       iov.iov_len = 4;
-       xdr_buf_from_iov(&iov, &verf_buf);
-       mic.data = (u8 *)p;
-       mic.len = len;
-       maj_stat = gss_verify_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
+       maj_stat = gss_validate_seqno_mic(ctx, task->tk_rqstp->rq_seqnos[0], seq, p, len);
+       /* RFC 2203 5.3.3.1 - compute the checksum of each sequence number in the cache */
+       while (unlikely(maj_stat == GSS_S_BAD_SIG && i < task->tk_rqstp->rq_seqno_count))
+               maj_stat = gss_validate_seqno_mic(ctx, task->tk_rqstp->rq_seqnos[i], seq, p, len);
        if (maj_stat == GSS_S_CONTEXT_EXPIRED)
                clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
        if (maj_stat)
@@ -1750,7 +1763,7 @@ gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
        if (!p)
                goto wrap_failed;
        integ_len = p++;
-       *p = cpu_to_be32(rqstp->rq_seqno);
+       *p = cpu_to_be32(*rqstp->rq_seqnos);
 
        if (rpcauth_wrap_req_encode(task, xdr))
                goto wrap_failed;
@@ -1847,7 +1860,7 @@ gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
        if (!p)
                goto wrap_failed;
        opaque_len = p++;
-       *p = cpu_to_be32(rqstp->rq_seqno);
+       *p = cpu_to_be32(*rqstp->rq_seqnos);
 
        if (rpcauth_wrap_req_encode(task, xdr))
                goto wrap_failed;
@@ -2001,7 +2014,7 @@ gss_unwrap_resp_integ(struct rpc_task *task, struct rpc_cred *cred,
        offset = rcv_buf->len - xdr_stream_remaining(xdr);
        if (xdr_stream_decode_u32(xdr, &seqno))
                goto unwrap_failed;
-       if (seqno != rqstp->rq_seqno)
+       if (seqno != *rqstp->rq_seqnos)
                goto bad_seqno;
        if (xdr_buf_subsegment(rcv_buf, &gss_data, offset, len))
                goto unwrap_failed;
@@ -2045,7 +2058,7 @@ unwrap_failed:
        trace_rpcgss_unwrap_failed(task);
        goto out;
 bad_seqno:
-       trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, seqno);
+       trace_rpcgss_bad_seqno(task, *rqstp->rq_seqnos, seqno);
        goto out;
 bad_mic:
        trace_rpcgss_verify_mic(task, maj_stat);
@@ -2077,7 +2090,7 @@ gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
        if (maj_stat != GSS_S_COMPLETE)
                goto bad_unwrap;
        /* gss_unwrap decrypted the sequence number */
-       if (be32_to_cpup(p++) != rqstp->rq_seqno)
+       if (be32_to_cpup(p++) != *rqstp->rq_seqnos)
                goto bad_seqno;
 
        /* gss_unwrap redacts the opaque blob from the head iovec.
@@ -2093,7 +2106,7 @@ unwrap_failed:
        trace_rpcgss_unwrap_failed(task);
        return -EIO;
 bad_seqno:
-       trace_rpcgss_bad_seqno(task, rqstp->rq_seqno, be32_to_cpup(--p));
+       trace_rpcgss_bad_seqno(task, *rqstp->rq_seqnos, be32_to_cpup(--p));
        return -EIO;
 bad_unwrap:
        trace_rpcgss_unwrap(task, maj_stat);
@@ -2118,14 +2131,14 @@ gss_xmit_need_reencode(struct rpc_task *task)
        if (!ctx)
                goto out;
 
-       if (gss_seq_is_newer(req->rq_seqno, READ_ONCE(ctx->gc_seq)))
+       if (gss_seq_is_newer(*req->rq_seqnos, READ_ONCE(ctx->gc_seq)))
                goto out_ctx;
 
        seq_xmit = READ_ONCE(ctx->gc_seq_xmit);
-       while (gss_seq_is_newer(req->rq_seqno, seq_xmit)) {
+       while (gss_seq_is_newer(*req->rq_seqnos, seq_xmit)) {
                u32 tmp = seq_xmit;
 
-               seq_xmit = cmpxchg(&ctx->gc_seq_xmit, tmp, req->rq_seqno);
+               seq_xmit = cmpxchg(&ctx->gc_seq_xmit, tmp, *req->rq_seqnos);
                if (seq_xmit == tmp) {
                        ret = false;
                        goto out_ctx;
@@ -2134,7 +2147,7 @@ gss_xmit_need_reencode(struct rpc_task *task)
 
        win = ctx->gc_win;
        if (win > 0)
-               ret = !gss_seq_is_newer(req->rq_seqno, seq_xmit - win);
+               ret = !gss_seq_is_newer(*req->rq_seqnos, seq_xmit - win);
 
 out_ctx:
        gss_put_ctx(ctx);

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 0eab154655116964b3158b6a037af2359f28cd5f..d5e0cdcad9e0c9bc7ce1ec1534f0ed07254866eb 100644 (file)
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1365,7 +1365,7 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
                                INIT_LIST_HEAD(&req->rq_xmit2);
                                goto out;
                        }
-               } else if (!req->rq_seqno) {
+               } else if (req->rq_seqno_count == 0) {
                        list_for_each_entry(pos, &xprt->xmit_queue, rq_xmit) {
                                if (pos->rq_task->tk_owner != task->tk_owner)
                                        continue;
@@ -1898,6 +1898,7 @@ xprt_request_init(struct rpc_task *task)
        req->rq_snd_buf.bvec = NULL;
        req->rq_rcv_buf.bvec = NULL;
        req->rq_release_snd_buf = NULL;
+       req->rq_seqno_count = 0;
        xprt_init_majortimeo(task, req, task->tk_client->cl_timeout);
 
        trace_xprt_reserve(req);