Re: [PATCH v2] dm raid: fix parse_raid_params() variable range issue

[Heinz Mauelshagen <heinzm@xxxxxxxxxx>]

On 03/22/2018 08:41 PM, Mike Snitzer wrote:
> On Thu, Mar 22 2018 at  1:21pm -0400,
> Heinz Mauelshagen <heinzm@xxxxxxxxxx> wrote:
>
> > This v2 addresses Mikulas' point about the variable range and folds in
> > "[PATCH] dm raid: use __within_range() more in parse_raid_params()":
> >
> > parse_raid_parames() compared variable "int value" with
> > INT_MAX to prevent overflow of mddev variables set.
> >
> > Change type to "long long value".
> Can you elaborate on the risk/issue that is being fixed here?

Fix addresses a coverity finding supporting the full,
positive range of the "struct mddev" int members
set here.  I.e. the "int" cast is compared with INT_MAX.

> User specifying a value that overflows an int?

No, kstroint() catches that.

> (also: see below for inline comment about last hunk)

See below...

> > Whilst on it, use __within_range() throughout and
> > add a sync min/max rate check.
> >
> > Signed-off-by: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
> > ---
> >   drivers/md/dm-raid.c | 16 +++++++++++-----
> >   1 file changed, 11 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> > index c1d1034ff7b7..c0e3d2aa9346 100644
> > --- a/drivers/md/dm-raid.c
> > +++ b/drivers/md/dm-raid.c
> > @@ -1141,7 +1141,7 @@ static int validate_raid_redundancy(struct raid_set *rs)
> >   static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
> >   			     unsigned int num_raid_params)
> >   {
> > -	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
> > +	long long value, raid10_format = ALGORITHM_RAID10_DEFAULT;
> >   	unsigned int raid10_copies = 2;
> >   	unsigned int i, write_mostly = 0;
> >   	unsigned int region_size = 0;
> > @@ -1153,7 +1153,7 @@ static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
> >   	arg = dm_shift_arg(as);
> >   	num_raid_params--; /* Account for chunk_size argument */
> >   
> > -	if (kstrtoint(arg, 10, &value) < 0) {
> > +	if (kstrtoll(arg, 10, &value) < 0) {
> >   		rs->ti->error = "Bad numerical argument given for chunk_size";
> >   		return -EINVAL;
> >   	}
> > @@ -1315,7 +1315,7 @@ static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
> >   		/*
> >   		 * Parameters with number values from here on.
> >   		 */
> > -		if (kstrtoint(arg, 10, &value) < 0) {
> > +		if (kstrtoll(arg, 10, &value) < 0) {
> >   			rs->ti->error = "Bad numerical argument given in raid params";
> >   			return -EINVAL;
> >   		}
> > @@ -1430,7 +1430,7 @@ static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
> >   				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
> >   				return -EINVAL;
> >   			}
> > -			if (value > INT_MAX) {
> > +			if (!__within_range(value, 0, INT_MAX)) {
> >   				rs->ti->error = "min_recovery_rate out of range";
> >   				return -EINVAL;
> >   			}
> > @@ -1440,7 +1440,7 @@ static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
> >   				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
> >   				return -EINVAL;
> >   			}
> > -			if (value > INT_MAX) {
> > +			if (!__within_range(value, 0, INT_MAX)) {
> >   				rs->ti->error = "max_recovery_rate out of range";
> >   				return -EINVAL;
> >   			}
> > @@ -1472,6 +1472,12 @@ static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
> >   		}
> >   	}
> >   
> > +	if (rs->md.sync_speed_max &&
> > +	    rs->md.sync_speed_max < rs->md.sync_speed_min) {
> > +		rs->ti->error = "sync speed max smaller than min";
> > +		return -EINVAL;
> > +	}
> > +
> >   	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
> >   	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
> >   		rs->ti->error = "sync and nosync are mutually exclusive";
> > --
> > 2.14.3
> Isn't this last hunk unrelated?

No, once using __within_range to ensure positive values
for sync min/max, this hunk ensures that those are sane
if both are set.

Heinz

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