| From c4414104f31f080da508eaa50087c73880793c9b Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 9 Jun 2021 17:07:29 -0400 |
| Subject: sunrpc: Avoid a KASAN slab-out-of-bounds bug in xdr_set_page_base() |
| |
| From: Anna Schumaker <Anna.Schumaker@Netapp.com> |
| |
| [ Upstream commit 6d1c0f3d28f98ea2736128ed3e46821496dc3a8c ] |
| |
| This seems to happen fairly easily during READ_PLUS testing on NFS v4.2. |
| I found that we could end up accessing xdr->buf->pages[pgnr] with a pgnr |
| greater than the number of pages in the array. So let's just return |
| early if we're setting base to a point at the end of the page data and |
| let xdr_set_tail_base() handle setting up the buffer pointers instead. |
| |
| Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> |
| Fixes: 8d86e373b0ef ("SUNRPC: Clean up helpers xdr_set_iov() and xdr_set_page_base()") |
| Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/sunrpc/xdr.c | 7 +++---- |
| 1 file changed, 3 insertions(+), 4 deletions(-) |
| |
| diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c |
| index 3964ff74ee51..ca10ba2626f2 100644 |
| --- a/net/sunrpc/xdr.c |
| +++ b/net/sunrpc/xdr.c |
| @@ -1230,10 +1230,9 @@ static unsigned int xdr_set_page_base(struct xdr_stream *xdr, |
| void *kaddr; |
| |
| maxlen = xdr->buf->page_len; |
| - if (base >= maxlen) { |
| - base = maxlen; |
| - maxlen = 0; |
| - } else |
| + if (base >= maxlen) |
| + return 0; |
| + else |
| maxlen -= base; |
| if (len > maxlen) |
| len = maxlen; |
| -- |
| 2.30.2 |
| |
