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@xxxxxxxxx>
---
drivers/staging/comedi/comedi_fops.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 985d94b..1679bfb 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;
}
--
2.1.4
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