From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
... just use copy_from_user(). We copy only SZ_SG_IO_HDR bytes,
so that would, strictly speaking, loosen the check. However,
for call chains via ->write() the caller has actually checked
the entire range and SG_IO passes exactly SZ_SG_IO_HDR for count.
So no visible behaviour changes happen if we check only what
we really need for copyin.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sg.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 2d30e89075e9..3702f66493f7 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -717,8 +717,6 @@ sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
if (count < SZ_SG_IO_HDR)
return -EINVAL;
- if (!access_ok(buf, count))
- return -EFAULT; /* protects following copy_from_user()s + get_user()s */
sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
if (!(srp = sg_add_request(sfp))) {
@@ -728,7 +726,7 @@ sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
}
srp->sg_io_owned = sg_io_owned;
hp = &srp->header;
- if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
+ if (copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
sg_remove_request(sfp, srp);
return -EFAULT;
}
--
2.11.0
