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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 07:49:43 +0200
commitde7b7a35c99e4eaeffd43c208b2cbbe5964bef7f (patch)
parent8dee04de5defe97c38aa07590b533c6b487df75e (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 a5a9b17f0f7f..5edc2a58edcc 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) &&