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authorAdrian Salido <salidoa@google.com>2017-04-27 10:32:55 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-05-08 07:46:02 +0200
commit3b9983bb354eb107808a1fcf2eac569fd51c0595 (patch)
tree8ff622ade779ffe274d23edc6b950349e998fd73
parentda1ce38aaac7f08d319b4b76130aa4fd27c4489f (diff)
dm ioctl: prevent stack leak in dm ioctl call
commit 4617f564c06117c7d1b611be49521a4430042287 upstream. When calling a dm ioctl that doesn't process any data (IOCTL_FLAGS_NO_PARAMS), the contents of the data field in struct dm_ioctl are left initialized. Current code is incorrectly extending the size of data copied back to user, causing the contents of kernel stack to be leaked to user. Fix by only copying contents before data and allow the functions processing the ioctl to override. Signed-off-by: Adrian Salido <salidoa@google.com> Reviewed-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/md/dm-ioctl.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 80a439543259..e503279c34fc 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1843,7 +1843,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
if (r)
goto out;
- param->data_size = sizeof(*param);
+ param->data_size = offsetof(struct dm_ioctl, data);
r = fn(param, input_param_size);
if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&