From ab4fb1d8f6e98575703474491538febff6b1a2c9 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 1 Dec 2025 16:43:26 -0500 Subject: scsi: sd: reject invalid pr_read_keys() num_keys values 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 Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe --- drivers/scsi/sd.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 0252d3f6bed1..32ae4898cea7 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1974,9 +1974,19 @@ 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 (check_mul_overflow(num_keys, 8, &data_len) || + check_add_overflow(data_len, 8, &data_len) || + data_len > USHRT_MAX) + return -EINVAL; + data = kzalloc(data_len, GFP_KERNEL); if (!data) return -ENOMEM; -- cgit v1.2.3