linux-ext4 - [PATCH] ext4: silence array overflow warning

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Message-ID: <20170718092702.bpk2k5qjg4cz2mqk@mwanda>
Date:   Tue, 18 Jul 2017 12:27:02 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     "Theodore Ts'o" <tytso@....edu>
Cc:     Andreas Dilger <adilger.kernel@...ger.ca>,
        linux-ext4@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] ext4: silence array overflow warning

I get a static checker warning:

    fs/ext4/ext4.h:3091 ext4_set_de_type()
    error: buffer overflow 'ext4_type_by_mode' 15 <= 15

It seems unlikely that we would hit this read overflow in real life, but
it's also simple enough to make the array 16 bytes instead of 15.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9ebde0cd632e..fbaeb441bed3 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3074,7 +3074,7 @@ extern int ext4_handle_dirty_dirent_node(handle_t *handle,
 					 struct inode *inode,
 					 struct buffer_head *bh);
 #define S_SHIFT 12
-static const unsigned char ext4_type_by_mode[S_IFMT >> S_SHIFT] = {
+static const unsigned char ext4_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {
 	[S_IFREG >> S_SHIFT]	= EXT4_FT_REG_FILE,
 	[S_IFDIR >> S_SHIFT]	= EXT4_FT_DIR,
 	[S_IFCHR >> S_SHIFT]	= EXT4_FT_CHRDEV,