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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 07:44:13 +0200
commitd9684d5c04a6640c463c9531f238b759ff8d41ca (patch)
tree0d8f3bed27ad5fc77554ca61bc9cfab870b02504
parenta82c4da20443788041c089417b6ae7400af44dcf (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 0be9381365d7..63d64ca80bc0 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1839,7 +1839,7 @@ 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) &&