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From:   Jan Kara <jack@suse.cz>
To:     Ted Tso <tytso@mit.edu>
Cc:     <linux-ext4@vger.kernel.org>, Lukas Czerner <lczerner@redhat.com>,
        Salvatore Bonaccorso <carnil@debian.org>,
        Jan Kara <jack@suse.cz>, stable@vger.kernel.org
Subject: [PATCH] ext4: Fix check for block being out of directory size
Date:   Mon, 22 Aug 2022 13:48:32 +0200
Message-Id: <20220822114832.1482-1-jack@suse.cz>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The check in __ext4_read_dirblock() for block being outside of directory
size was wrong because it compared block number against directory size
in bytes. Fix it.

Fixes: 65f8ea4cd57d ("ext4: check if directory block is within i_size")
CVE: CVE-2022-1184
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3a31b662f661..bc2e0612ec32 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -126,7 +126,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
 	struct ext4_dir_entry *dirent;
 	int is_dx_block = 0;
 
-	if (block >= inode->i_size) {
+	if (block >= inode->i_size >> inode->i_blkbits) {
 		ext4_error_inode(inode, func, line, block,
 		       "Attempting to read directory block (%u) that is past i_size (%llu)",
 		       block, inode->i_size);
-- 
2.35.3