From: Chuck Lever <chuck.lever@xxxxxxxxxx> 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@xxxxxxxxxxxx> Reported-by: Zorro Lang <zlang@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sunrpc/xdr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -544,7 +544,7 @@ static __be32 *xdr_get_next_encode_buffe */ 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;
