From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kay Sievers <kay.sievers@vrfy.org>
Date: Sat, 03 Jan 2004 23:07:21 +0000
Subject: Re: udev - Shouldn't we blacklist some devices?
Message-Id: <20040103230721.GA5235@vrfy.org>
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List-Id: <linux-hotplug.vger.kernel.org>
References: <20040103200753.GA4917@vrfy.org>
In-Reply-To: <20040103200753.GA4917@vrfy.org>
To: linux-hotplug@vger.kernel.org


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On Sat, Jan 03, 2004 at 01:48:57PM -0800, Greg KH wrote:
> On Sat, Jan 03, 2004 at 09:07:53PM +0100, Kay Sievers wrote:
> > While connecting my flash reader to the USB bus I get:
> > 
> > Jan  3 20:56:58 pim udev[31673]: sleep_for_dev: looking for '/sys/class/scsi_device/54:0:0:2/dev'
> > Jan  3 20:56:59 pim udev[31695]: sleep_for_dev: looking for '/sys/class/scsi_device/54:0:0:3/dev'
> > Jan  3 20:56:59 pim udev[31514]: sleep_for_dev: looking for '/sys/class/scsi_host/host54/dev'
> > 
> > Shouldn't we blacklist devices like  /sys/class/scsi_device/*, /sys/class/scsi_host/* ?
> 
> Yes we should, as we try to remove those device nodes when the devices
> get removed (look for the 'trying to remove host54' messages), which
> could be very dangerous.
> 

So, here we go:

Blacklist devices that we don't want to process, like:
/sys/class/scsi_device/*, /sys/class/scsi_host/*,
cause these devices are handled by the block device events we receive
and we don't try to remove non existing nodes.


thanks,
Kay

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diff -Nru a/udev.c b/udev.c
--- a/udev.c	Sat Jan  3 23:58:38 2004
+++ b/udev.c	Sat Jan  3 23:58:38 2004
@@ -139,12 +139,19 @@
 	return retval;
 }
 
+static char *dev_path_blacklist[] = {
+	"class/scsi_host",
+	"class/scsi_device",
+	""
+};
+
 static inline int udev_hotplug(int argc, char **argv)
 {
 	char *action;
 	char *devpath;
 	char *subsystem;
 	int retval = -EINVAL;
+	int i;
 
 	subsystem = argv[1];
 
@@ -160,6 +167,16 @@
 	    !strstr(devpath, "block")) {
 		dbg("not a block or class device");
 		goto exit;
+	}
+
+	/* skip blacklisted path */
+	i = 0;
+	while (dev_path_blacklist[i][0] != '\0') {
+		if (strstr(devpath, dev_path_blacklist[i])) {
+			dbg("device with path '%s' is blacklisted", devpath);
+			goto exit;
+		}
+		i++;
 	}
 
 	/* but we don't care about net class devices */

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