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authorFrank Sorenson <sorenson@redhat.com>2018-10-30 21:10:40 +0100
committerJ. Bruce Fields <bfields@redhat.com>2018-11-05 17:52:06 +0100
commit5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb (patch)
treea7df55e7dba5e2d8da10dcc7c1de8e061e1e461c
parentLinux 4.20-rc1 (diff)
downloadlinux-5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb.tar.xz
linux-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>
-rw-r--r--net/sunrpc/xdr.c5
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;