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ext4: only use i_size_high for regular files

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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
This commit is contained in:
Theodore Ts'o
2009-01-17 18:41:37 -05:00
parent c225aa57ff
commit 06a279d636
2 changed files with 7 additions and 4 deletions
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7
fs/ext4/ext4.h
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@@ -1206,8 +1206,11 @@ static inline void ext4_r_blocks_count_set(struct ext4_super_block *es,
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)