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-rw-r--r--net/sunrpc/xdr.c108
1 files changed, 80 insertions, 28 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index b256806d69cd..683f058b9061 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -436,13 +436,12 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
}
/**
- * xdr_shrink_pagelen
+ * xdr_shrink_pagelen - shrinks buf->pages by up to @len bytes
* @buf: xdr_buf
* @len: bytes to remove from buf->pages
*
- * Shrinks XDR buffer's page array buf->pages by
- * 'len' bytes. The extra data is not lost, but is instead
- * moved into the tail.
+ * The extra data is not lost, but is instead moved into buf->tail.
+ * Returns the actual number of bytes moved.
*/
static unsigned int
xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
@@ -455,8 +454,8 @@ xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
result = 0;
tail = buf->tail;
- BUG_ON (len > pglen);
-
+ if (len > buf->page_len)
+ len = buf-> page_len;
tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
/* Shift the tail first */
@@ -1119,6 +1118,7 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
base = 0;
} else {
base -= buf->head[0].iov_len;
+ subbuf->head[0].iov_base = buf->head[0].iov_base;
subbuf->head[0].iov_len = 0;
}
@@ -1131,6 +1131,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
base = 0;
} else {
base -= buf->page_len;
+ subbuf->pages = buf->pages;
+ subbuf->page_base = 0;
subbuf->page_len = 0;
}
@@ -1142,6 +1144,7 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
base = 0;
} else {
base -= buf->tail[0].iov_len;
+ subbuf->tail[0].iov_base = buf->tail[0].iov_base;
subbuf->tail[0].iov_len = 0;
}
@@ -1151,6 +1154,47 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
}
EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
+/**
+ * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
+ * @buf: buf to be trimmed
+ * @len: number of bytes to reduce "buf" by
+ *
+ * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
+ * that it's possible that we'll trim less than that amount if the xdr_buf is
+ * too small, or if (for instance) it's all in the head and the parser has
+ * already read too far into it.
+ */
+void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
+{
+ size_t cur;
+ unsigned int trim = len;
+
+ if (buf->tail[0].iov_len) {
+ cur = min_t(size_t, buf->tail[0].iov_len, trim);
+ buf->tail[0].iov_len -= cur;
+ trim -= cur;
+ if (!trim)
+ goto fix_len;
+ }
+
+ if (buf->page_len) {
+ cur = min_t(unsigned int, buf->page_len, trim);
+ buf->page_len -= cur;
+ trim -= cur;
+ if (!trim)
+ goto fix_len;
+ }
+
+ if (buf->head[0].iov_len) {
+ cur = min_t(size_t, buf->head[0].iov_len, trim);
+ buf->head[0].iov_len -= cur;
+ trim -= cur;
+ }
+fix_len:
+ buf->len -= (len - trim);
+}
+EXPORT_SYMBOL_GPL(xdr_buf_trim);
+
static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
{
unsigned int this_len;
@@ -1236,52 +1280,60 @@ xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
}
EXPORT_SYMBOL_GPL(xdr_encode_word);
-/* If the netobj starting offset bytes from the start of xdr_buf is contained
- * entirely in the head, pages, or tail, set object to point to it; otherwise
- * shift the buffer until it is contained entirely within the pages or tail.
+/**
+ * xdr_buf_read_mic() - obtain the address of the GSS mic from xdr buf
+ * @buf: pointer to buffer containing a mic
+ * @mic: on success, returns the address of the mic
+ * @offset: the offset in buf where mic may be found
+ *
+ * This function may modify the xdr buf if the mic is found to be straddling
+ * a boundary between head, pages, and tail. On success the mic can be read
+ * from the address returned. There is no need to free the mic.
+ *
+ * Return: Success returns 0, otherwise an integer error.
*/
-int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
+int xdr_buf_read_mic(struct xdr_buf *buf, struct xdr_netobj *mic, unsigned int offset)
{
struct xdr_buf subbuf;
unsigned int boundary;
- if (xdr_decode_word(buf, offset, &obj->len))
+ if (xdr_decode_word(buf, offset, &mic->len))
return -EFAULT;
offset += 4;
- /* Is the obj partially in the head? */
+ /* Is the mic partially in the head? */
boundary = buf->head[0].iov_len;
- if (offset < boundary && (offset + obj->len) > boundary)
+ if (offset < boundary && (offset + mic->len) > boundary)
xdr_shift_buf(buf, boundary - offset);
- /* Is the obj partially in the pages? */
+ /* Is the mic partially in the pages? */
boundary += buf->page_len;
- if (offset < boundary && (offset + obj->len) > boundary)
+ if (offset < boundary && (offset + mic->len) > boundary)
xdr_shrink_pagelen(buf, boundary - offset);
- if (xdr_buf_subsegment(buf, &subbuf, offset, obj->len))
+ if (xdr_buf_subsegment(buf, &subbuf, offset, mic->len))
return -EFAULT;
- /* Is the obj contained entirely in the head? */
- obj->data = subbuf.head[0].iov_base;
- if (subbuf.head[0].iov_len == obj->len)
+ /* Is the mic contained entirely in the head? */
+ mic->data = subbuf.head[0].iov_base;
+ if (subbuf.head[0].iov_len == mic->len)
return 0;
- /* ..or is the obj contained entirely in the tail? */
- obj->data = subbuf.tail[0].iov_base;
- if (subbuf.tail[0].iov_len == obj->len)
+ /* ..or is the mic contained entirely in the tail? */
+ mic->data = subbuf.tail[0].iov_base;
+ if (subbuf.tail[0].iov_len == mic->len)
return 0;
- /* Find a contiguous area in @buf to hold all of @obj */
- if (obj->len > buf->buflen - buf->len)
+ /* Find a contiguous area in @buf to hold all of @mic */
+ if (mic->len > buf->buflen - buf->len)
return -ENOMEM;
if (buf->tail[0].iov_len != 0)
- obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
+ mic->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
else
- obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
- __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
+ mic->data = buf->head[0].iov_base + buf->head[0].iov_len;
+ __read_bytes_from_xdr_buf(&subbuf, mic->data, mic->len);
return 0;
}
-EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
+EXPORT_SYMBOL_GPL(xdr_buf_read_mic);
/* Returns 0 on success, or else a negative error code. */
static int