Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Arnd Bergmann <arnd@kernel.org>
To:     Chuck Lever <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@kernel.org>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna@kernel.org>
Cc:     Arnd Bergmann <arnd@arndb.de>, Neil Brown <neilb@suse.de>,
        Olga Kornievskaia <kolga@netapp.com>,
        Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, Dan Carpenter <error27@gmail.com>,
        linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
Subject: [PATCH] sunrpc: avoid constant-out-of-range warning with clang
Date:   Mon,  3 Jul 2023 13:37:22 +0200
Message-Id: <20230703113737.694995-1-arnd@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Arnd Bergmann <arnd@arndb.de>

The overflow check in xdr_stream_decode_uint32_array() was added for
32-bit systems, but on 64-bit builds it causes a build warning when
building with clang and W=1:

In file included from init/do_mounts.c:22:
include/linux/sunrpc/xdr.h:778:10: error: result of comparison of constant 4611686018427387903 with expression of type '__u32' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
  778 |         if (len > SIZE_MAX / sizeof(*p))

Shut up the warning with a type cast.

Fixes: 23a9dbbe0faf1 ("NFSD: prevent integer overflow on 32 bit systems")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/sunrpc/xdr.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index f89ec4b5ea169..6736121ee6a03 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -775,7 +775,7 @@ xdr_stream_decode_uint32_array(struct xdr_stream *xdr,
 
 	if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
 		return -EBADMSG;
-	if (len > SIZE_MAX / sizeof(*p))
+	if ((size_t)len > SIZE_MAX / sizeof(*p))
 		return -EBADMSG;
 	p = xdr_inline_decode(xdr, len * sizeof(*p));
 	if (unlikely(!p))
-- 
2.39.2