redonkable/alistair23-linux
redonkable/alistair23-linux
1
0
Fork 0
Code Releases Activity

scsi: sg: sg_new_write(): don't bother with access_ok

Browse source 
... 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.

Link: https://lore.kernel.org/r/20191017193925.25539-5-viro@ZenIV.linux.org.uk
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Al Viro 2019-10-17 20:39:22 +01:00 committed by Martin K. Petersen
parent c35a5cfb41
commit d9fc5617bc
1 changed files with 1 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/scsi/sg.c
View file

@ -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;
}