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

[Heinz Mauelshagen]

On 03/22/2018 08:41 PM, Mike Snitzer wrote:

On Thu, Mar 22 2018 at  1:21pm -0400,
Heinz Mauelshagen <hei...@redhat.com> 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 <hei...@redhat.com>
---
  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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