From c35a5cfb41509c2214228aa321509ffd91cbf063 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 17 Oct 2019 20:39:21 +0100 Subject: [PATCH] scsi: sg: sg_read(): simplify reading ->pack_id of userland sg_io_hdr_t We don't need to allocate a temporary buffer and read the entire structure in it, only to fetch a single field and free what we'd allocated. Just use get_user() and be done with it... Link: https://lore.kernel.org/r/20191017193925.25539-4-viro@ZenIV.linux.org.uk Signed-off-by: Al Viro Acked-by: Douglas Gilbert Signed-off-by: Martin K. Petersen --- drivers/scsi/sg.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 4c62237..2d30e89 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -441,17 +441,8 @@ sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos) } if (old_hdr->reply_len < 0) { if (count >= SZ_SG_IO_HDR) { - sg_io_hdr_t *new_hdr; - new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL); - if (!new_hdr) { - retval = -ENOMEM; - goto free_old_hdr; - } - retval =__copy_from_user - (new_hdr, buf, SZ_SG_IO_HDR); - req_pack_id = new_hdr->pack_id; - kfree(new_hdr); - if (retval) { + sg_io_hdr_t __user *p = (void __user *)buf; + if (get_user(req_pack_id, &p->pack_id)) { retval = -EFAULT; goto free_old_hdr; } -- 2.7.4