Hello, Dear Sami Tolvanen.
Thank you for reply.
> I agree that we shouldn't allow this, at least not without a warning, but
> out of curiosity, do you actually have a situation where this could happen?
> One ideally shouldn't be passing untrusted parameters to dm-verity.
Of course, I don't think this will happen because they are dm-verity experts.
But since we are humans, I think this case could happen accidentally.
So it would be a good at preventing these cases.
> I don't have a strong opinion about this, but the documentation doesn't
> talk about verity modes, so perhaps this could be reworded to something
> like "Conflicting error handling parameters"?
Yes of course. That looks better.
I also had some ambiguous about how to express it.
This is because I couldn't find it in document.
The code says verity mode, so I wrote it down. never mind it :)
like this)
case DM_VERITY_MODE_LOGGING:
case DM_VERITY_MODE_RESTART:
case DM_VERITY_MODE_PANIC:
> On Thu, Mar 11, 2021 at 4:19 AM JeongHyeon Lee <jhs2.lee@xxxxxxxxxxx>
> wrote:
> >
> > If there are multiple verity mode when parsing the verity mode of dm
> > verity table, it will be set as the last one.
> > So set to 'allow only once' to prevent it.
>
> I agree that we shouldn't allow this, at least not without a warning, but
> out of curiosity, do you actually have a situation where this could happen?
> One ideally shouldn't be passing untrusted parameters to dm-verity.
>
> >
> > Signed-off-by: JeongHyeon Lee <jhs2.lee@xxxxxxxxxxx>
> > ---
> > drivers/md/dm-verity-target.c | 38
> > ++++++++++++++++++++++++++---------
> > 1 file changed, 28 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/md/dm-verity-target.c
> > b/drivers/md/dm-verity-target.c index 808a98ef624c..b76431dc7721
> > 100644
> > --- a/drivers/md/dm-verity-target.c
> > +++ b/drivers/md/dm-verity-target.c
> > @@ -893,6 +893,28 @@ static int verity_alloc_zero_digest(struct
> dm_verity *v)
> > return r;
> > }
> >
> > +static inline bool verity_is_verity_mode(const char *arg_name) {
> > + return (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING) ||
> > + !strcasecmp(arg_name, DM_VERITY_OPT_RESTART) ||
> > + !strcasecmp(arg_name, DM_VERITY_OPT_PANIC)); }
> > +
> > +static int verity_parse_verity_mode(struct dm_verity *v, const char
> > +*arg_name) {
> > + if (v->mode)
> > + return -EINVAL;
> > +
> > + if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING))
> > + v->mode = DM_VERITY_MODE_LOGGING;
> > + else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART))
> > + v->mode = DM_VERITY_MODE_RESTART;
> > + else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC))
> > + v->mode = DM_VERITY_MODE_PANIC;
> > +
> > + return 0;
> > +}
> > +
> > static int verity_parse_opt_args(struct dm_arg_set *as, struct
> dm_verity *v,
> > struct dm_verity_sig_opts
> > *verify_args) { @@ -916,16 +938,12 @@ static int
> > verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
> > arg_name = dm_shift_arg(as);
> > argc--;
> >
> > - if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
> > - v->mode = DM_VERITY_MODE_LOGGING;
> > - continue;
> > -
> > - } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
> > - v->mode = DM_VERITY_MODE_RESTART;
> > - continue;
> > -
> > - } else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC)) {
> > - v->mode = DM_VERITY_MODE_PANIC;
> > + if (verity_is_verity_mode(arg_name)) {
> > + r = verity_parse_verity_mode(v, arg_name);
> > + if (r) {
> > + ti->error = "Already verity mode set";
>
> I don't have a strong opinion about this, but the documentation doesn't
> talk about verity modes, so perhaps this could be reworded to something
> like "Conflicting error handling parameters"?
>
> > + return r;
> > + }
> > continue;
> >
> > } else if (!strcasecmp(arg_name,
> > DM_VERITY_OPT_IGN_ZEROES)) {
> > --
> > 2.17.1
> >
>
> Sami
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