ext4: add check for wraparound in ext4_data_block_valid()

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: add check for wraparound in ext4_data_block_valid()
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
1585d8d8 · Theodore Ts'o · 6eebee62 · 1585d8d8
Commit 1585d8d8 authored Nov 22, 2009 by Theodore Ts'o
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fs/ext4/block_validity.c fs/ext4/block_validity.c +1 -0

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--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -228,6 +228,7 @@ int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
 	struct rb_node *n = sbi->system_blks.rb_node;
 	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
+	    (start_blk + count < start_blk) ||
 	    (start_blk + count > ext4_blocks_count(sbi->s_es)))
 		return 0;
 	while (n) {