RE: [PATCH] ima: Replace two seq_printf() calls by seq_puts() in ima_show_template_data_ascii()

David Laight
2019-07-03T09:16:50Z

From: Markus Elfring
> Sent: 02 July 2019 20:01
>
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Tue, 2 Jul 2019 20:52:21 +0200
>
> Two strings which did not contain a data format specification should be put
> into a sequence. Thus use the corresponding function “seq_puts”.
>
> This issue was detected by using the Coccinelle software.

The two calls are almost certainly absolutely equivalent.
So this is probably just a minor performance improvement in a code
path where it really doesn't matter.

> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> security/integrity/ima/ima_template_lib.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
> index 9fe0ef7f91e2..05636e9b19b1 100644
> --- a/security/integrity/ima/ima_template_lib.c
> +++ b/security/integrity/ima/ima_template_lib.c
> @@ -74,7 +74,7 @@ static void ima_show_template_data_ascii(struct seq_file *m,
> case DATA_FMT_DIGEST_WITH_ALGO:
> buf_ptr = strnchr(field_data->data, buflen, ':');
> if (buf_ptr != field_data->data)
> - seq_printf(m, "%s", field_data->data);
> + seq_puts(m, field_data->data);
>
> /* skip ':' and '\0' */
> buf_ptr += 2;

That code looks highly suspect!
It uses a bounded scan then assumes a '\0' terminated string.
It then adds 2 to a potentially NULL pointer.

About typical for 'security' code :-)

David

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