| From 03662f439eecf156b87d05136d0c895fe0ebf737 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 7 Jun 2022 16:47:52 -0400 |
| Subject: SUNRPC: Fix the calculation of xdr->end in |
| xdr_get_next_encode_buffer() |
| |
| From: Chuck Lever <chuck.lever@oracle.com> |
| |
| [ Upstream commit 6c254bf3b637dd4ef4f78eb78c7447419c0161d7 ] |
| |
| I found that NFSD's new NFSv3 READDIRPLUS XDR encoder was screwing up |
| right at the end of the page array. xdr_get_next_encode_buffer() does |
| not compute the value of xdr->end correctly: |
| |
| * The check to see if we're on the final available page in xdr->buf |
| needs to account for the space consumed by @nbytes. |
| |
| * The new xdr->end value needs to account for the portion of @nbytes |
| that is to be encoded into the previous buffer. |
| |
| Fixes: 2825a7f90753 ("nfsd4: allow encoding across page boundaries") |
| Signed-off-by: Chuck Lever <chuck.lever@oracle.com> |
| Reviewed-by: NeilBrown <neilb@suse.de> |
| Reviewed-by: J. Bruce Fields <bfields@fieldses.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/sunrpc/xdr.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c |
| index dd547edee59f..06b4b76edd9d 100644 |
| --- a/net/sunrpc/xdr.c |
| +++ b/net/sunrpc/xdr.c |
| @@ -544,7 +544,11 @@ static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, |
| */ |
| xdr->p = (void *)p + frag2bytes; |
| space_left = xdr->buf->buflen - xdr->buf->len; |
| - xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE); |
| + if (space_left - nbytes >= PAGE_SIZE) |
| + xdr->end = (void *)p + PAGE_SIZE; |
| + else |
| + xdr->end = (void *)p + space_left - frag1bytes; |
| + |
| xdr->buf->page_len += frag2bytes; |
| xdr->buf->len += nbytes; |
| return p; |
| -- |
| 2.35.1 |
| |
