On Fri, 2014-05-30 at 18:58 +0300, Dmitry Kasatkin wrote:
> On 28 May 2014 18:09, Mimi Zohar <zo...@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().
> >
> > Reported-by: Dmitry Kasatkin <d.kasat...@samsung.com>
> > Cc: David Howells <dhowe...@redhat.com>
> > Signed-off-by: Mimi Zohar <zo...@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..9e9a762 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;
> > }
> > @@ -87,6 +85,10 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
> > kfree(description);
> > description = NULL;
> > }
> > + if (description[0] == '.') {
> > + ret = -EPERM;
> > + goto error2;
> > + }
>
> 1. 3 lines above "discription = NULL" will cause kernel oops...
> It happens when using empty description... like:
>
> cat x509_ima.der | keyctl padd asymmetric "" keyid
Right, that should be 'else if'.
> 2. It prevents adding trusted keys to ".ima" from user space...
> This is NOT what we want... right?
It prevents creating a dot prefixed keyring.
Mimi
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