From e8d70b321ecc9b23d09b8df63e38a2f73160c209 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 15 Nov 2019 08:39:07 -0500 Subject: SUNRPC: Fix another issue with MIC buffer space xdr_shrink_pagelen() BUG's when @len is larger than buf->page_len. This can happen when xdr_buf_read_mic() is given an xdr_buf with a small page array (like, only a few bytes). Instead, just cap the number of bytes that xdr_shrink_pagelen() will move. Fixes: 5f1bc39979d ("SUNRPC: Fix buffer handling of GSS MIC ... ") Signed-off-by: Chuck Lever Reviewed-by: Benjamin Coddington Signed-off-by: Trond Myklebust --- net/sunrpc/xdr.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'net/sunrpc') diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 14ba9e72a204..f3104be8ff5d 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 */ -- cgit v1.2.3-59-g8ed1b