LinuxTV Patchwork dvb: usb: fix use after free in dvb_usb_device_exit

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Submitter Oliver Neukum
Date April 30, 2019, 1:07 p.m.
Message ID <20190430130736.9191-1-oneukum@suse.com>
Download mbox | patch
Permalink /patch/55952/
State New
Delegated to: Sean Young
Headers show

Comments

Oliver Neukum - April 30, 2019, 1:07 p.m.
dvb_usb_device_exit() frees and uses the device name in that order
Fix by storing the name in a buffer before freeing it

v2: fixed style issues
v3: strscpy used and variable names changed
v4: really use strscpy everywhere

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reported-by: syzbot+26ec41e9f788b3eba396@syzkaller.appspotmail.com
---
 drivers/media/usb/dvb-usb/dvb-usb-init.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
index 99951e02a880..dd063a736df5 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
@@ -287,12 +287,15 @@  EXPORT_SYMBOL(dvb_usb_device_init);
 void dvb_usb_device_exit(struct usb_interface *intf)
 {
 	struct dvb_usb_device *d = usb_get_intfdata(intf);
-	const char *name = "generic DVB-USB module";
+	const char *default_name = "generic DVB-USB module";
+	char name[40];
 
 	usb_set_intfdata(intf, NULL);
 	if (d != NULL && d->desc != NULL) {
-		name = d->desc->name;
+		strscpy(name, d->desc->name, sizeof(name));
 		dvb_usb_exit(d);
+	} else {
+		strscpy(name, default_name, sizeof(name));
 	}
 	info("%s successfully deinitialized and disconnected.", name);
 

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