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authorMike Snitzer <snitzer@redhat.com>2018-03-29 23:31:32 -0400
committerMike Snitzer <snitzer@redhat.com>2018-03-29 23:31:32 -0400
commitda5dadb4f11660ca67580cd4a7420161266d6254 (patch)
tree6dacbd021d8c2d9f494aab81ee8a095fc22664ea
parente457edf0b21c873be827b7c2f6b8e1545485c415 (diff)
downloadlinux-sh-da5dadb4f11660ca67580cd4a7420161266d6254.tar.gz
dm: fix dropped return code from dm_get_bdev_for_ioctl
dm_get_bdev_for_ioctl()'s return of 0 or 1 must be the result from prepare_ioctl (1 means the ioctl was issued to a partition, 0 means it wasn't). Unfortunately commit 519049afea ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl") reused the variable 'r' to store the return from blkdev_get() that follows prepare_ioctl() -- whereby dropping prepare_ioctl()'s result on the floor. This can lead to an ioctl or persistent reservation being issued to a partition going unnoticed, which implies the extra permission check for CAP_SYS_RAWIO is skipped. Fix this by using a different variable to store blkdev_get()'s return. Fixes: 519049afea ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl") Reported-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r--drivers/md/dm.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 45328d8b2859..353ea0ede091 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -466,7 +466,7 @@ static int dm_get_bdev_for_ioctl(struct mapped_device *md,
{
struct dm_target *tgt;
struct dm_table *map;
- int srcu_idx, r;
+ int srcu_idx, r, r2;
retry:
r = -ENOTTY;
@@ -492,9 +492,11 @@ retry:
goto out;
bdgrab(*bdev);
- r = blkdev_get(*bdev, *mode, _dm_claim_ptr);
- if (r < 0)
+ r2 = blkdev_get(*bdev, *mode, _dm_claim_ptr);
+ if (r2 < 0) {
+ r = r2;
goto out;
+ }
dm_put_live_table(md, srcu_idx);
return r;