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| author |   Frank Sorenson <sorenson@redhat.com> | 2018-10-30 15:10:40 -0500 |
|---|---|---|
| committer |   J. Bruce Fields <bfields@redhat.com> | 2018-11-05 11:52:06 -0500 |
| commit | 5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb (patch) | |
| tree | a7df55e7dba5e2d8da10dcc7c1de8e061e1e461c /net/sunrpc/xdr.c | |
| parent | Linux 4.20-rc1 (diff) | |
| download | linux-dev-5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb.tar.xz linux-dev-5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb.zip | |
sunrpc: correct the computation for page_ptr when truncating
When truncating the encode buffer, the page_ptr is getting
advanced, causing the next page to be skipped while encoding.
The page is still included in the response, so the response
contains a page of bogus data.
We need to adjust the page_ptr backwards to ensure we encode
the next page into the correct place.
We saw this triggered when concurrent directory modifications caused
nfsd4_encode_direct_fattr() to return nfserr_noent, and the resulting
call to xdr_truncate_encode() corrupted the READDIR reply.
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'net/sunrpc/xdr.c')
| -rw-r--r-- | net/sunrpc/xdr.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 2bbb8d38d2bf..5cfb9e0a18dc 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -673,11 +673,10 @@ void xdr_truncate_encode(struct xdr_stream *xdr, size_t len) WARN_ON_ONCE(xdr->iov); return; } - if (fraglen) { + if (fraglen) xdr->end = head->iov_base + head->iov_len; - xdr->page_ptr--; - } /* (otherwise assume xdr->end is already set) */ + xdr->page_ptr--; head->iov_len = len; buf->len = len; xdr->p = head->iov_base + head->iov_len; |