| Message ID | 20180815191405.GA29528@beast |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | isdn: Disable IIOCDBGVAR | expand |
From: Kees Cook <keescook@chromium.org> Date: Wed, 15 Aug 2018 12:14:05 -0700 > It was possible to directly leak the kernel address where the isdn_dev > structure pointer was stored. This is a kernel ASLR bypass for anyone > with access to the ioctl. The code had been present since the beginning > of git history, though this shouldn't ever be needed for normal operation, > therefore remove it. > > Reported-by: Al Viro <viro@zeniv.linux.org.uk> > Cc: Karsten Keil <isdn@linux-pingi.de> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > netdev doesn't like explict stable markings, so I'll just ask here that it > get included in -stable please. :) Applied and queued up for -stable, thanks :)
diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c index 7a501dbe7123..6a5b3f00f9ad 100644 --- a/drivers/isdn/i4l/isdn_common.c +++ b/drivers/isdn/i4l/isdn_common.c @@ -1640,13 +1640,7 @@ isdn_ioctl(struct file *file, uint cmd, ulong arg) } else return -EINVAL; case IIOCDBGVAR: - if (arg) { - if (copy_to_user(argp, &dev, sizeof(ulong))) - return -EFAULT; - return 0; - } else - return -EINVAL; - break; + return -EINVAL; default: if ((cmd & IIOCDRVCTL) == IIOCDRVCTL) cmd = ((cmd >> _IOC_NRSHIFT) & _IOC_NRMASK) & ISDN_DRVIOCTL_MASK;
It was possible to directly leak the kernel address where the isdn_dev structure pointer was stored. This is a kernel ASLR bypass for anyone with access to the ioctl. The code had been present since the beginning of git history, though this shouldn't ever be needed for normal operation, therefore remove it. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Karsten Keil <isdn@linux-pingi.de> Signed-off-by: Kees Cook <keescook@chromium.org> --- netdev doesn't like explict stable markings, so I'll just ask here that it get included in -stable please. :) --- drivers/isdn/i4l/isdn_common.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)