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ext4 crypto: check for too-short encrypted file names

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An encrypted file name should never be shorter than an 16 bytes, the
AES block size.  The 3.10 crypto layer will oops and crash the kernel
if ciphertext shorter than the block size is passed to it.

Fortunately, in modern kernels the crypto layer will not crash the
kernel in this scenario, but nevertheless, it represents a corrupted
directory, and we should detect it and mark the file system as
corrupted so that e2fsck can fix this.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2015-07-17 11:33:16 -04:00
parent 806c24adf7
commit 27977b69e4
1 changed files with 4 additions and 0 deletions
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4
fs/ext4/crypto_fname.c
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@ -329,6 +329,10 @@ int _ext4_fname_disk_to_usr(struct inode *inode,
return oname->len;
}
}
if (iname->len < EXT4_CRYPTO_BLOCK_SIZE) {
EXT4_ERROR_INODE(inode, "encrypted inode too small");
return -EUCLEAN;
}
if (EXT4_I(inode)->i_crypt_info)
return ext4_fname_decrypt(inode, iname, oname);