diff options
author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-06-20 09:58:35 -0400 |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-06-28 17:20:41 -0400 |
commit | bfeea1dc1c9238f9e5a17a265489ecd0d19f66bb (patch) | |
tree | 009163b2f4c0255599d3c781a833c2dcfaa621ed | |
parent | 1537693ceaa8d6484f1ce631bec85658bfa9816c (diff) | |
download | linux-bfeea1dc1c9238f9e5a17a265489ecd0d19f66bb.tar.bz2 |
SUNRPC: Don't decode beyond the end of the RPC reply message
Now that xdr_inline_decode() will automatically cross into the page
buffers, we need to ensure that it doesn't exceed the total reply
message length.
This patch sets up a counter that tracks the number of words
remaining in the reply message, and ensures that xdr_inline_decode,
xdr_read_pages and xdr_enter_page respect the end of message boundary.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
-rw-r--r-- | include/linux/sunrpc/xdr.h | 1 | ||||
-rw-r--r-- | net/sunrpc/xdr.c | 28 |
2 files changed, 22 insertions, 7 deletions
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index af70af333546..f1e7f884d1c3 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -205,6 +205,7 @@ struct xdr_stream { struct kvec *iov; /* pointer to the current kvec */ struct kvec scratch; /* Scratch buffer */ struct page **page_ptr; /* pointer to the current page */ + unsigned int nwords; /* Remaining decode buffer length */ }; /* diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 21d041cf7f65..5643feb6c645 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -630,12 +630,15 @@ void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p) xdr->buf = buf; xdr->scratch.iov_base = NULL; xdr->scratch.iov_len = 0; + xdr->nwords = XDR_QUADLEN(buf->len); if (buf->head[0].iov_len != 0) xdr_set_iov(xdr, buf->head, buf->len); else if (buf->page_len != 0) xdr_set_page_base(xdr, 0, buf->len); - if (p != NULL && p > xdr->p && xdr->end >= p) + if (p != NULL && p > xdr->p && xdr->end >= p) { + xdr->nwords -= p - xdr->p; xdr->p = p; + } } EXPORT_SYMBOL_GPL(xdr_init_decode); @@ -660,12 +663,14 @@ EXPORT_SYMBOL_GPL(xdr_init_decode_pages); static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes) { + unsigned int nwords = XDR_QUADLEN(nbytes); __be32 *p = xdr->p; - __be32 *q = p + XDR_QUADLEN(nbytes); + __be32 *q = p + nwords; - if (unlikely(q > xdr->end || q < p)) + if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p)) return NULL; xdr->p = q; + xdr->nwords -= nwords; return p; } @@ -746,9 +751,16 @@ void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) struct xdr_buf *buf = xdr->buf; struct kvec *iov; ssize_t shift; + unsigned int nwords = XDR_QUADLEN(len); unsigned int end; int padding; + if (xdr->nwords == 0) + return; + if (nwords > xdr->nwords) { + nwords = xdr->nwords; + len = nwords << 2; + } /* Realign pages to current pointer position */ iov = buf->head; shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p; @@ -758,15 +770,15 @@ void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) /* Truncate page data and move it into the tail */ if (buf->page_len > len) xdr_shrink_pagelen(buf, buf->page_len - len); - padding = (XDR_QUADLEN(len) << 2) - len; + padding = (nwords << 2) - len; xdr->iov = iov = buf->tail; /* Compute remaining message length. */ end = iov->iov_len; shift = buf->buflen - buf->len; - if (shift < end) + if (end > shift + padding) end -= shift; - else if (shift > 0) - end = 0; + else + end = padding; /* * Position current pointer at beginning of tail, and * set remaining message length. @@ -774,6 +786,7 @@ void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) xdr->p = (__be32 *)((char *)iov->iov_base + padding); xdr->end = (__be32 *)((char *)iov->iov_base + end); xdr->page_ptr = NULL; + xdr->nwords = XDR_QUADLEN(end - padding); } EXPORT_SYMBOL_GPL(xdr_read_pages); @@ -795,6 +808,7 @@ void xdr_enter_page(struct xdr_stream *xdr, unsigned int len) * set remaining message length. */ xdr_set_page_base(xdr, 0, len); + xdr->nwords += XDR_QUADLEN(xdr->buf->page_len); } EXPORT_SYMBOL_GPL(xdr_enter_page); |