diff options
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/cache.h | 3 | ||||
| -rw-r--r-- | fs/nfsd/nfscache.c | 65 | ||||
| -rw-r--r-- | fs/nfsd/nfssvc.c | 11 |
3 files changed, 56 insertions, 23 deletions
diff --git a/fs/nfsd/cache.h b/fs/nfsd/cache.h index f21259ead64b..3c07d587ae9e 100644 --- a/fs/nfsd/cache.h +++ b/fs/nfsd/cache.h @@ -82,7 +82,8 @@ int nfsd_drc_slab_create(void); void nfsd_drc_slab_free(void); int nfsd_reply_cache_init(struct nfsd_net *); void nfsd_reply_cache_shutdown(struct nfsd_net *); -int nfsd_cache_lookup(struct svc_rqst *); +int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start, + unsigned int len); void nfsd_cache_update(struct svc_rqst *, int, __be32 *); int nfsd_reply_cache_stats_show(struct seq_file *m, void *v); diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index 3e64a3d50a1c..f53335ae0ab2 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -311,33 +311,53 @@ nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc) return prune_cache_entries(nn); } -/* - * 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; } @@ -408,6 +428,8 @@ out: /** * 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 * * Try to find an entry matching the current call in the cache. When none * is found, we try to grab the oldest expired entry off the LRU list. If @@ -420,7 +442,8 @@ out: * %RC_REPLY: Reply from cache * %RC_DROPIT: Do not process the request further */ -int nfsd_cache_lookup(struct svc_rqst *rqstp) +int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start, + unsigned int len) { struct nfsd_net *nn; struct svc_cacherep *rp, *found; @@ -435,7 +458,7 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp) 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, diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index ca2a9d0eefc2..f6cc99af8192 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -1027,6 +1027,7 @@ out: int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) { const struct svc_procedure *proc = rqstp->rq_procinfo; + unsigned int start, len; __be32 *nfs_reply; /* @@ -1036,10 +1037,18 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) rqstp->rq_cachetype = proc->pc_cachetype; svcxdr_init_decode(rqstp); + + /* + * ->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; - switch (nfsd_cache_lookup(rqstp)) { + switch (nfsd_cache_lookup(rqstp, start, len)) { case RC_DOIT: break; case RC_REPLY: |