@@ -84,8 +84,8 @@ int nfsd_net_reply_cache_init(struct nfsd_net *nn);
void nfsd_net_reply_cache_destroy(struct nfsd_net *nn);
int nfsd_reply_cache_init(struct nfsd_net *);
void nfsd_reply_cache_shutdown(struct nfsd_net *);
-int nfsd_cache_lookup(struct svc_rqst *rqstp,
- struct nfsd_cacherep **cacherep);
+int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start,
+ unsigned int len, struct nfsd_cacherep **cacherep);
void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp,
int cachetype, __be32 *statp);
int nfsd_reply_cache_stats_show(struct seq_file *m, void *v);
@@ -368,33 +368,52 @@ nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
return freed;
}
-/*
- * Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes
+/**
+ * nfsd_cache_csum - Checksum incoming NFS Call arguments
+ * @buf: buffer containing a whole RPC Call message
+ * @start: starting byte of the NFS Call header
+ * @remaining: size of the NFS Call header, in bytes
+ *
+ * Compute a weak checksum of the leading bytes of an NFS procedure
+ * call header to help verify that a retransmitted Call matches an
+ * entry in the duplicate reply cache.
+ *
+ * To avoid assumptions about how the RPC message is laid out in
+ * @buf and what else it might contain (eg, a GSS MIC suffix), the
+ * caller passes us the exact location and length of the NFS Call
+ * header.
+ *
+ * Returns a 32-bit checksum value, as defined in RFC 793.
*/
-static __wsum
-nfsd_cache_csum(struct svc_rqst *rqstp)
+static __wsum nfsd_cache_csum(struct xdr_buf *buf, unsigned int start,
+ unsigned int remaining)
{
+ unsigned int base, len;
+ struct xdr_buf subbuf;
+ __wsum csum = 0;
+ void *p;
int idx;
- unsigned int base;
- __wsum csum;
- struct xdr_buf *buf = &rqstp->rq_arg;
- const unsigned char *p = buf->head[0].iov_base;
- size_t csum_len = min_t(size_t, buf->head[0].iov_len + buf->page_len,
- RC_CSUMLEN);
- size_t len = min(buf->head[0].iov_len, csum_len);
+
+ if (remaining > RC_CSUMLEN)
+ remaining = RC_CSUMLEN;
+ if (xdr_buf_subsegment(buf, &subbuf, start, remaining))
+ return csum;
/* rq_arg.head first */
- csum = csum_partial(p, len, 0);
- csum_len -= len;
+ if (subbuf.head[0].iov_len) {
+ len = min_t(unsigned int, subbuf.head[0].iov_len, remaining);
+ csum = csum_partial(subbuf.head[0].iov_base, len, csum);
+ remaining -= len;
+ }
/* Continue into page array */
- idx = buf->page_base / PAGE_SIZE;
- base = buf->page_base & ~PAGE_MASK;
- while (csum_len) {
- p = page_address(buf->pages[idx]) + base;
- len = min_t(size_t, PAGE_SIZE - base, csum_len);
+ idx = subbuf.page_base / PAGE_SIZE;
+ base = subbuf.page_base & ~PAGE_MASK;
+ while (remaining) {
+ p = page_address(subbuf.pages[idx]) + base;
+ len = min_t(unsigned int, PAGE_SIZE - base, remaining);
csum = csum_partial(p, len, csum);
- csum_len -= len;
+ remaining -= len;
base = 0;
++idx;
}
@@ -465,6 +484,8 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct nfsd_cacherep *key,
/**
* nfsd_cache_lookup - Find an entry in the duplicate reply cache
* @rqstp: Incoming Call to find
+ * @start: starting byte in @rqstp->rq_arg of the NFS Call header
+ * @len: size of the NFS Call header, in bytes
* @cacherep: OUT: DRC entry for this request
*
* Try to find an entry matching the current call in the cache. When none
@@ -478,7 +499,8 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct nfsd_cacherep *key,
* %RC_REPLY: Reply from cache
* %RC_DROPIT: Do not process the request further
*/
-int nfsd_cache_lookup(struct svc_rqst *rqstp, struct nfsd_cacherep **cacherep)
+int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start,
+ unsigned int len, struct nfsd_cacherep **cacherep)
{
struct nfsd_net *nn;
struct nfsd_cacherep *rp, *found;
@@ -494,7 +516,7 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp, struct nfsd_cacherep **cacherep)
goto out;
}
- csum = nfsd_cache_csum(rqstp);
+ csum = nfsd_cache_csum(&rqstp->rq_arg, start, len);
/*
* Since the common case is a cache miss followed by an insert,
@@ -1047,6 +1047,7 @@ int nfsd_dispatch(struct svc_rqst *rqstp)
const struct svc_procedure *proc = rqstp->rq_procinfo;
__be32 *statp = rqstp->rq_accept_statp;
struct nfsd_cacherep *rp;
+ unsigned int start, len;
__be32 *nfs_reply;
/*
@@ -1055,11 +1056,18 @@ int nfsd_dispatch(struct svc_rqst *rqstp)
*/
rqstp->rq_cachetype = proc->pc_cachetype;
+ /*
+ * ->pc_decode advances the argument stream past the NFS
+ * Call header, so grab the header's starting location and
+ * size now for the call to nfsd_cache_lookup().
+ */
+ start = xdr_stream_pos(&rqstp->rq_arg_stream);
+ len = xdr_stream_remaining(&rqstp->rq_arg_stream);
if (!proc->pc_decode(rqstp, &rqstp->rq_arg_stream))
goto out_decode_err;
rp = NULL;
- switch (nfsd_cache_lookup(rqstp, &rp)) {
+ switch (nfsd_cache_lookup(rqstp, start, len, &rp)) {
case RC_DOIT:
break;
case RC_REPLY: