From 76a477d3983640a233c7b51b601fb29b33d14295 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever@oracle.com>
Date: Thu, 30 Jun 2022 16:48:18 -0400
Subject: [PATCH] SUNRPC: Fix READ_PLUS crasher
commit a23dd544debcda4ee4a549ec7de59e85c3c8345c upstream.
Looks like there are still cases when "space_left - frag1bytes" can
legitimately exceed PAGE_SIZE. Ensure that xdr->end always remains
within the current encode buffer.
Reported-by: Bruce Fields <bfields@fieldses.org>
Reported-by: Zorro Lang <zlang@redhat.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216151
Fixes: 6c254bf3b637 ("SUNRPC: Fix the calculation of xdr->end in xdr_get_next_encode_buffer()")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sunrpc/xdr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index cb8740d156336..daa4165f11794 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -608,7 +608,7 @@ static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
*/
xdr->p = (void *)p + frag2bytes;
space_left = xdr->buf->buflen - xdr->buf->len;
- if (space_left - nbytes >= PAGE_SIZE)
+ if (space_left - frag1bytes >= PAGE_SIZE)
xdr->end = (void *)p + PAGE_SIZE;
else
xdr->end = (void *)p + space_left - frag1bytes;