linux-ext4 - [PATCH 1/2] ext2: fix block range in ext2_data_block

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Date:   Tue, 23 Jul 2019 19:21:54 +0800
From:   Chengguang Xu <cgxu519@...o.com.cn>
To:     jack@...e.com
Cc:     linux-ext4@...r.kernel.org, Chengguang Xu <cgxu519@...o.com.cn>
Subject: [PATCH 1/2] ext2: fix block range in ext2_data_block_valid()

For block validity we should check the block range
from start_block to start_block + count - 1, so fix
the range in ext2_data_block_valid() and also modify
the count argument properly in calling place.

Signed-off-by: Chengguang Xu <cgxu519@...o.com.cn>
---
 fs/ext2/balloc.c | 6 +++---
 fs/ext2/xattr.c  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 547c165299c0..92e9a7489174 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -1203,13 +1203,13 @@ int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
 			  unsigned int count)
 {
 	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
-	    (start_blk + count < start_blk) ||
-	    (start_blk > le32_to_cpu(sbi->s_es->s_blocks_count)))
+	    (start_blk + count - 1 < start_blk) ||
+	    (start_blk + count - 1 >= le32_to_cpu(sbi->s_es->s_blocks_count)))
 		return 0;
 
 	/* Ensure we do not step over superblock */
 	if ((start_blk <= sbi->s_sb_block) &&
-	    (start_blk + count >= sbi->s_sb_block))
+	    (start_blk + count - 1 >= sbi->s_sb_block))
 		return 0;
 
 	return 1;
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 79369c13cc55..0456bc990b5e 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -794,7 +794,7 @@ ext2_xattr_delete_inode(struct inode *inode)
 	if (!EXT2_I(inode)->i_file_acl)
 		goto cleanup;
 
-	if (!ext2_data_block_valid(sbi, EXT2_I(inode)->i_file_acl, 0)) {
+	if (!ext2_data_block_valid(sbi, EXT2_I(inode)->i_file_acl, 1)) {
 		ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
 			"inode %ld: xattr block %d is out of data blocks range",
 			inode->i_ino, EXT2_I(inode)->i_file_acl);
-- 
2.20.1