From: Dan Carpenter <dancarpenter@oracle.com> commit 5011c5a663b9c6d6aff3d394f11049b371199627 upstream. The problem is we're copying "inherit" from user space but we don't necessarily know that we're copying enough data for a 64 byte struct. Then the next problem is that 'inherit' has a variable size array at the end, and we have to verify that array is the size we expected. Fixes: 6f72c7e20dba ("Btrfs: add qgroup inheritance") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/btrfs/ioctl.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index f3658d6ea6571..1c053e10b33ba 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1842,7 +1842,10 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file, if (vol_args->flags & BTRFS_SUBVOL_RDONLY) readonly = true; if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) { - if (vol_args->size > PAGE_SIZE) { + u64 nums; + + if (vol_args->size < sizeof(*inherit) || + vol_args->size > PAGE_SIZE) { ret = -EINVAL; goto free_args; } @@ -1851,6 +1854,20 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file, ret = PTR_ERR(inherit); goto free_args; } + + if (inherit->num_qgroups > PAGE_SIZE || + inherit->num_ref_copies > PAGE_SIZE || + inherit->num_excl_copies > PAGE_SIZE) { + ret = -EINVAL; + goto free_inherit; + } + + nums = inherit->num_qgroups + 2 * inherit->num_ref_copies + + 2 * inherit->num_excl_copies; + if (vol_args->size != struct_size(inherit, qgroups, nums)) { + ret = -EINVAL; + goto free_inherit; + } } ret = btrfs_ioctl_snap_create_transid(file, vol_args->name, -- 2.25.1