The pr_read_keys() interface has a u32 num_keys parameter. The SCSI PERSISTENT RESERVE IN command has a maximum READ KEYS service action size of 65536 bytes. Reject num_keys values that are too large to fit into the SCSI command. This will become important when pr_read_keys() is exposed to untrusted userspace via an ioctl. Signed-off-by: Stefan Hajnoczi --- drivers/scsi/sd.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 0252d3f6bed17..e436ed977cdb4 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1974,9 +1974,18 @@ static int sd_pr_read_keys(struct block_device *bdev, struct pr_keys *keys_info) { int result, i, data_offset, num_copy_keys; u32 num_keys = keys_info->num_keys; - int data_len = num_keys * 8 + 8; + int data_len; u8 *data; + /* + * Each reservation key takes 8 bytes and there is an 8-byte header + * before the reservation key list. The total size must fit into the + * 16-bit ALLOCATION LENGTH field. + */ + if (num_keys > (USHRT_MAX / 8) - 1) + return -EINVAL; + + data_len = num_keys * 8 + 8; data = kzalloc(data_len, GFP_KERNEL); if (!data) return -ENOMEM; -- 2.52.0