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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 07:47:55 +0200
commita0d50c80a29e13a56f9830d0b4bc6e333fc09da2 (patch)
parent7ad6de43deda083f1eab1e9a5cc48166e4ee52f5 (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>
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 966eb4b61aed..a68c650aad11 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1847,7 +1847,7 @@ 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) &&