linux-kernel - [PATCH] SUNRPC: Fix integer overflow in decode_rc

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Message-ID: <a13af2ba-5f33-4e9c-905c-0e0369daea6c@suswa.mountain>
Date: Thu, 19 Sep 2024 11:50:33 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Trond Myklebust <trondmy@...nel.org>
Cc: Anna Schumaker <anna@...nel.org>, Benny Halevy <bhalevy@...asas.com>,
	linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH] SUNRPC: Fix integer overflow in decode_rc_list()

The math in "rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t)" could have an
integer overflow.  Add bounds checking on rc_list->rcl_nrefcalls to fix
that.

Fixes: 4aece6a19cf7 ("nfs41: cb_sequence xdr implementation")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
>From static analysis.

 fs/nfs/callback_xdr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 6df77f008d3f..fdeb0b34a3d3 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -375,6 +375,8 @@ static __be32 decode_rc_list(struct xdr_stream *xdr,
 
 	rc_list->rcl_nrefcalls = ntohl(*p++);
 	if (rc_list->rcl_nrefcalls) {
+		if (unlikely(rc_list->rcl_nrefcalls > xdr->buf->len))
+			goto out;
 		p = xdr_inline_decode(xdr,
 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
 		if (unlikely(p == NULL))
-- 
2.34.1