On Thu, Oct 04, 2018 at 06:21:35PM -0400, Mimi Zohar wrote:
> On Wed, 2018-10-03 at 17:01 -0700, Eric Biggers wrote:
> > From: Eric Biggers <ebiggers@xxxxxxxxxx>
> >
> > The 12 character temporary buffer is not necessarily long enough to hold
> > a 'long' value. Increase it.
> >
> > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > ---
> > security/integrity/ima/ima_fs.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> > index ae9d5c766a3ce..4b50fe9c18edd 100644
> > --- a/security/integrity/ima/ima_fs.c
> > +++ b/security/integrity/ima/ima_fs.c
> > @@ -42,14 +42,15 @@ static int __init default_canonical_fmt_setup(char *str)
> > __setup("ima_canonical_fmt", default_canonical_fmt_setup);
> >
> > static int valid_policy = 1;
> > -#define TMPBUFLEN 12
> > +
> > static ssize_t ima_show_htable_value(char __user *buf, size_t count,
> > loff_t *ppos, atomic_long_t *val)
> > {
> > - char tmpbuf[TMPBUFLEN];
> > + /* temporary buffer that is plenty long enough */
> > + char tmpbuf[32];
>
> If the maximum value of long is 9,223,372,036,854,775,807, the largest
> string needed to represent this value is 20 characters. Should 32 be
> hardcoded like this?
>
> Mimi
>
There's no real cost to overestimating slightly here, and it's better than
trying to count exactly and getting it wrong (hint: it's actually more than 20
characters).
- Eric
