[PATCH 5.15.y] svcrdma: bound check rq_pages index in inline path

[Sasha Levin <sashal@kernel.org>]

From: Joshua Rogers <linux@joshua.hu>

[ Upstream commit d1bea0ce35b6095544ee82bb54156fc62c067e58 ]

svc_rdma_copy_inline_range indexed rqstp->rq_pages[rc_curpage] without
verifying rc_curpage stays within the allocated page array. Add guards
before the first use and after advancing to a new page.

Fixes: d7cc73972661 ("svcrdma: support multiple Read chunks per RPC")
Cc: stable@vger.kernel.org
Signed-off-by: Joshua Rogers <linux@joshua.hu>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ adapted rc_curpage and rq_maxpages fields to ri_pageno and RPCSVC_MAXPAGES constant ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/xprtrdma/svc_rdma_rw.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 50bf62f85166..bfa137ad7710 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -789,6 +789,9 @@ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info,
 	for (page_no = 0; page_no < numpages; page_no++) {
 		unsigned int page_len;
 
+		if (info->ri_pageno >= RPCSVC_MAXPAGES)
+			return -EINVAL;
+
 		page_len = min_t(unsigned int, remaining,
 				 PAGE_SIZE - info->ri_pageoff);
 
-- 
2.51.0