linux-kernel - [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements

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Message-Id: <20200915160336.36107-1-colin.king@canonical.com>
Date:   Tue, 15 Sep 2020 17:03:36 +0100
From:   Colin King <colin.king@...onical.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        Christoph Hellwig <hch@...radead.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements

From: Colin Ian King <colin.king@...onical.com>

The comparison of signed char constants with unsigned char array
elements leads to checks that are always false. Fix this by declaring
the VBSF_MOUNT_SIGNATURE_BYTE* macros as octal unsigned int constants
rather than as signed char constants. (Argueably the U is not necessarily
required, but add it to be really clear of intent).

Addresses-Coverity: ("Operands don't affect result")
Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 fs/vboxsf/super.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index 25aade344192..986efcb29cc2 100644
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -21,10 +21,10 @@
 
 #define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
 
-#define VBSF_MOUNT_SIGNATURE_BYTE_0 ('\000')
-#define VBSF_MOUNT_SIGNATURE_BYTE_1 ('\377')
-#define VBSF_MOUNT_SIGNATURE_BYTE_2 ('\376')
-#define VBSF_MOUNT_SIGNATURE_BYTE_3 ('\375')
+#define VBSF_MOUNT_SIGNATURE_BYTE_0 0000U
+#define VBSF_MOUNT_SIGNATURE_BYTE_1 0377U
+#define VBSF_MOUNT_SIGNATURE_BYTE_2 0376U
+#define VBSF_MOUNT_SIGNATURE_BYTE_3 0375U
 
 static int follow_symlinks;
 module_param(follow_symlinks, int, 0444);
-- 
2.27.0