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SubjectRe: [PATCH 5/8] ima: skip memory allocation for empty files
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On Fri, 2014-02-28 at 16:59 +0200, Dmitry Kasatkin wrote: 
> Memory allocation is unnecessary for empty files.
> This patch finalize the hash without memory allocation.
>
> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>

Thanks.

Mimi
> ---
> security/integrity/ima/ima_crypto.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index d257e36..1bde8e6 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -87,16 +87,20 @@ static int ima_calc_file_hash_tfm(struct file *file,
> if (rc != 0)
> return rc;
>
> - rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> - if (!rbuf) {
> - rc = -ENOMEM;
> + i_size = i_size_read(file_inode(file));
> +
> + if (i_size == 0)
> goto out;
> - }
> +
> + rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> + if (!rbuf)
> + return -ENOMEM;
> +
> if (!(file->f_mode & FMODE_READ)) {
> file->f_mode |= FMODE_READ;
> read = 1;
> }
> - i_size = i_size_read(file_inode(file));
> +
> while (offset < i_size) {
> int rbuf_len;
>
> @@ -113,12 +117,12 @@ static int ima_calc_file_hash_tfm(struct file *file,
> if (rc)
> break;
> }
> - kfree(rbuf);
> - if (!rc)
> - rc = crypto_shash_final(&desc.shash, hash->digest);
> if (read)
> file->f_mode &= ~FMODE_READ;
> + kfree(rbuf);
> out:
> + if (!rc)
> + rc = crypto_shash_final(&desc.shash, hash->digest);
> return rc;
> }
>




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