Messages in this thread | | | Date | Fri, 15 Oct 2021 15:36:17 +0800 | Subject | Re: Antw: [EXT] Re: [PATCH] scsi scsi_transport_iscsi.c: fix misuse of %llu in scsi_transport_iscsi.c | From | Guo Zhi <> |
| |
On 2021/10/11 23:29, Mike Christie wrote: > On 10/11/21 1:35 AM, Ulrich Windl wrote: >>>>> Joe Perches <joe@perches.com> schrieb am 09.10.2021 um 05:14 in Nachricht >> <5daf69b365e23ceecee911c4d0f2f66a0b9ec95c.camel@perches.com>: >>> On Sat, 2021-10-09 at 11:02 +0800, Guo Zhi wrote: >>>> Pointers should be printed with %p or %px rather than >>>> cast to (unsigned long long) and printed with %llu. >>>> Change %llu to %p to print the pointer into sysfs. >>> ][] >>>> diff --git a/drivers/scsi/scsi_transport_iscsi.c >>> b/drivers/scsi/scsi_transport_iscsi.c >>> [] >>>> @@ -129,8 +129,8 @@ show_transport_handle(struct device *dev, struct >>> device_attribute *attr, >>>> >>>> >>>> if (!capable(CAP_SYS_ADMIN)) >>>> return -EACCES; >>>> - return sysfs_emit(buf, "%llu\n", >>>> - (unsigned long long)iscsi_handle(priv->iscsi_transport)); >>>> + return sysfs_emit(buf, "%p\n", >>>> + iscsi_ptr(priv->iscsi_transport)); >>> iscsi_transport is a pointer isn't it? >>> >>> so why not just >>> >>> return sysfs_emit(buf, "%p\n", priv->iscsi_transport); >> Isn't the difference that %p outputs hex, while %u outputs decimal? >> > Yeah, I think this patch will break userspace, because it doesn't know it's > a pointer. It could be doing: > > sscanf(str, "%llu", &val); > > The value is just later passed back to the kernel to look up a driver in > iscsi_if_transport_lookup: > > list_for_each_entry(priv, &iscsi_transports, list) { > if (tt == priv->iscsi_transport) { > > so we could just replace priv->transport with an int and use an ida to assign > the value.
Taking security into consideration, We should not print kernel pointer into sysfs.
However if this is a special pointer to lookup a driver, It's really tricky for me to fix it,
as I don't have a scsi device to test my code.
Guo
| |