[PATCH] RPC: fix accounting bug in the case of a truncated RPC message
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 0f5b7a5..5d1eed2 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -160,7 +160,7 @@
typedef size_t (*skb_read_actor_t)(skb_reader_t *desc, void *to, size_t len);
-extern int xdr_partial_copy_from_skb(struct xdr_buf *, unsigned int,
+extern ssize_t xdr_partial_copy_from_skb(struct xdr_buf *, unsigned int,
skb_reader_t *, skb_read_actor_t);
struct socket;
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 65b268d..b3ac3f7 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -176,21 +176,23 @@
xdr->buflen += len;
}
-int
+ssize_t
xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base,
skb_reader_t *desc,
skb_read_actor_t copy_actor)
{
struct page **ppage = xdr->pages;
unsigned int len, pglen = xdr->page_len;
+ ssize_t copied = 0;
int ret;
len = xdr->head[0].iov_len;
if (base < len) {
len -= base;
ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
+ copied += ret;
if (ret != len || !desc->count)
- return 0;
+ goto out;
base = 0;
} else
base -= len;
@@ -214,8 +216,11 @@
* are small by default but can get huge. */
if (unlikely(*ppage == NULL)) {
*ppage = alloc_page(GFP_ATOMIC);
- if (unlikely(*ppage == NULL))
- return -ENOMEM;
+ if (unlikely(*ppage == NULL)) {
+ if (copied == 0)
+ copied = -ENOMEM;
+ goto out;
+ }
}
len = PAGE_CACHE_SIZE;
@@ -233,16 +238,17 @@
}
flush_dcache_page(*ppage);
kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
+ copied += ret;
if (ret != len || !desc->count)
- return 0;
+ goto out;
ppage++;
} while ((pglen -= len) != 0);
copy_tail:
len = xdr->tail[0].iov_len;
if (base < len)
- copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
-
- return 0;
+ copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
+out:
+ return copied;
}
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index a180ed4..ef941e7 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -823,10 +823,15 @@
{
if (len > desc->count)
len = desc->count;
- if (skb_copy_bits(desc->skb, desc->offset, p, len))
+ if (skb_copy_bits(desc->skb, desc->offset, p, len)) {
+ dprintk("RPC: failed to copy %zu bytes from skb. %zu bytes remain\n",
+ len, desc->count);
return 0;
+ }
desc->offset += len;
desc->count -= len;
+ dprintk("RPC: copied %zu bytes from skb. %zu bytes remain\n",
+ len, desc->count);
return len;
}
@@ -865,6 +870,8 @@
static void
tcp_check_recm(struct rpc_xprt *xprt)
{
+ dprintk("RPC: xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u, tcp_flags = %lx\n",
+ xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen, xprt->tcp_flags);
if (xprt->tcp_offset == xprt->tcp_reclen) {
xprt->tcp_flags |= XPRT_COPY_RECM;
xprt->tcp_offset = 0;
@@ -909,7 +916,7 @@
struct rpc_rqst *req;
struct xdr_buf *rcvbuf;
size_t len;
- int r;
+ ssize_t r;
/* Find and lock the request corresponding to this xid */
spin_lock(&xprt->sock_lock);
@@ -932,15 +939,17 @@
my_desc.count = len;
r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
&my_desc, tcp_copy_data);
- desc->count -= len;
- desc->offset += len;
+ desc->count -= r;
+ desc->offset += r;
} else
r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
desc, tcp_copy_data);
- xprt->tcp_copied += len;
- xprt->tcp_offset += len;
- if (r < 0) {
+ if (r > 0) {
+ xprt->tcp_copied += r;
+ xprt->tcp_offset += r;
+ }
+ if (r != len) {
/* Error when copying to the receive buffer,
* usually because we weren't able to allocate
* additional buffer pages. All we can do now
@@ -951,9 +960,18 @@
* be discarded.
*/
xprt->tcp_flags &= ~XPRT_COPY_DATA;
+ dprintk("RPC: XID %08x truncated request\n",
+ ntohl(xprt->tcp_xid));
+ dprintk("RPC: xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
+ xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
goto out;
}
+ dprintk("RPC: XID %08x read %u bytes\n",
+ ntohl(xprt->tcp_xid), r);
+ dprintk("RPC: xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
+ xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
+
if (xprt->tcp_copied == req->rq_private_buf.buflen)
xprt->tcp_flags &= ~XPRT_COPY_DATA;
else if (xprt->tcp_offset == xprt->tcp_reclen) {
@@ -961,12 +979,12 @@
xprt->tcp_flags &= ~XPRT_COPY_DATA;
}
+out:
if (!(xprt->tcp_flags & XPRT_COPY_DATA)) {
dprintk("RPC: %4d received reply complete\n",
req->rq_task->tk_pid);
xprt_complete_rqst(xprt, req, xprt->tcp_copied);
}
-out:
spin_unlock(&xprt->sock_lock);
tcp_check_recm(xprt);
}
@@ -985,6 +1003,7 @@
desc->count -= len;
desc->offset += len;
xprt->tcp_offset += len;
+ dprintk("RPC: discarded %u bytes\n", len);
tcp_check_recm(xprt);
}