ext4: only use i_size_high for regular files
Directories are not allowed to be bigger than 2GB, so don't use
i_size_high for anything other than regular files. E2fsck should
complain about these inodes, but the simplest thing to do for the
kernel is to only use i_size_high for regular files.
This prevents an intentially corrupted filesystem from causing the
kernel to burn a huge amount of CPU and issuing error messages such
as:
EXT4-fs warning (device loop0): ext4_block_to_path: block 135090028 > max
Thanks to David Maciejak from Fortinet's FortiGuard Global Security
Research Team for reporting this issue.
http://bugzilla.kernel.org/show_bug.cgi?id=12375
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index c668e43..aafc9eb 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1206,8 +1206,11 @@
static inline loff_t ext4_isize(struct ext4_inode *raw_inode)
{
- return ((loff_t)le32_to_cpu(raw_inode->i_size_high) << 32) |
- le32_to_cpu(raw_inode->i_size_lo);
+ if (S_ISREG(le16_to_cpu(raw_inode->i_mode)))
+ return ((loff_t)le32_to_cpu(raw_inode->i_size_high) << 32) |
+ le32_to_cpu(raw_inode->i_size_lo);
+ else
+ return (loff_t) le32_to_cpu(raw_inode->i_size_lo);
}
static inline void ext4_isize_set(struct ext4_inode *raw_inode, loff_t i_size)