From: Ian Abbott <abbotti@mev.co.uk>
Date: Tue, 7 Jul 2015 16:06:52 +0000 (+0100)
Subject: staging: comedi: use CAP_SYS_ADMIN instead of CAP_NET_ADMIN
X-Git-Tag: firefly_0821_release~176^2~1221^2~692
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0e0d311ebd589e65b8e5559e067d0dd109ac3434;p=firefly-linux-kernel-4.4.55.git

staging: comedi: use CAP_SYS_ADMIN instead of CAP_NET_ADMIN

If the "comedi" module has been loaded with the
"comedi_num_legacy_minors" module parameter set to a non-zero value,
some reserved comedi devices get created.  These can be attached to a
low-level comedi driver using the `COMEDI_DEVCONFIG` ioctl command,
which checks for the `CAP_SYS_ADMIN` capability.  Of course, the comedi
device needs to be opened before the ioctl command can be sent.  If the
comedi device is unattached, `comedi_open()` currently requires the
`CAP_NET_ADMIN` capability.  It makes more sense to just require the
`CAP_SYS_ADMIN` capability here, so change it.

For the curious, commit a8f80e8ff94e ("Networking: use CAP_NET_ADMIN
when deciding to call request_module") changed this capability from
`CAP_SYS_MODULE` to `CAP_NET_ADMIN`, even though it doesn't seem
relevant here.  The original `CAP_SYS_MODULE` capability was due to the
function having some code to request a module using a "char-major-%i-%i"
alias, but that was never compiled in and was removed by commit
f30f2c2d417b ("staging: comedi: remove check for CONFIG_KMOD").

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 985d94b6cbfd..1679bfba25a9 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2599,8 +2599,8 @@ static int comedi_open(struct inode *inode, struct file *file)
 	cfp->dev = dev;
 
 	mutex_lock(&dev->mutex);
-	if (!dev->attached && !capable(CAP_NET_ADMIN)) {
-		dev_dbg(dev->class_dev, "not attached and not CAP_NET_ADMIN\n");
+	if (!dev->attached && !capable(CAP_SYS_ADMIN)) {
+		dev_dbg(dev->class_dev, "not attached and not CAP_SYS_ADMIN\n");
 		rc = -ENODEV;
 		goto out;
 	}