Re: [RFC PATCH v5 1/4] KEYS: special dot prefixed keyring name bug fix

Dmitry Kasatkin
2014-06-06T21:48:58Z

On 3 June 2014 20:58, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
> Dot prefixed keyring names are supposed to be reserved for the
> kernel, but add_key() calls key_get_type_from_user(), which
> incorrectly verifies the 'type' field, not the 'description' field.
> This patch verifies the 'description' field isn't dot prefixed,
> when creating a new keyring, and removes the dot prefix test in
> key_get_type_from_user().
>
> Changelog v5:
> - Only prevent userspace from creating a dot prefixed keyring, not
> regular keys - Dmitry
>
> Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
> Cc: David Howells <dhowells@redhat.com>
> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
> ---
> security/keys/keyctl.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
> index cd5bd0c..62a9952 100644
> --- a/security/keys/keyctl.c
> +++ b/security/keys/keyctl.c
> @@ -37,8 +37,6 @@ static int key_get_type_from_user(char *type,
> return ret;
> if (ret == 0 || ret >= len)
> return -EINVAL;
> - if (type[0] == '.')
> - return -EPERM;
> type[len - 1] = '\0';
> return 0;
> }
> @@ -86,6 +84,10 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
> if (!*description) {
> kfree(description);
> description = NULL;
> + } else if ((description[0] == '.') &&
> + (strncmp(type, "keyring", 7) == 0)) {
> + ret = -EPERM;
> + goto error2;
> }
> }
>
> --
> 1.8.1.4
>
> --
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I think it does not another problem...
It is not only prevent creating new keyring with ".abc" name but also
prevent adding new key...

this is wrong...

- Dmitry