diff options
Diffstat (limited to 'net/sunrpc/xdr.c')
-rw-r--r-- | net/sunrpc/xdr.c | 97 |
1 files changed, 75 insertions, 22 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index db116fc8ff44..683f058b9061 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -1118,6 +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; } @@ -1130,6 +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; } @@ -1141,6 +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; } @@ -1150,6 +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; @@ -1235,52 +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 |