On Thu, Jun 06, 2019 at 07:01:26AM +0200, Jiri Slaby wrote: > On 05. 06. 19, 17:35, Gen Zhang wrote: > > On Wed, Jun 05, 2019 at 08:41:11AM +0200, Jiri Slaby wrote: > >> On 31. 05. 19, 3:27, Gen Zhang wrote: > >>> In sg_write(), the opcode of the command is fetched the first time from > >>> the userspace by __get_user(). Then the whole command, the opcode > >>> included, is fetched again from userspace by __copy_from_user(). > >>> However, a malicious user can change the opcode between the two fetches. > >>> This can cause inconsistent data and potential errors as cmnd is used in > >>> the following codes. > >>> > >>> Thus we should check opcode between the two fetches to prevent this. > >>> > >>> Signed-off-by: Gen Zhang <blackgod016574@xxxxxxxxx> > >>> --- > >>> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c > >>> index d3f1531..a2971b8 100644 > >>> --- a/drivers/scsi/sg.c > >>> +++ b/drivers/scsi/sg.c > >>> @@ -694,6 +694,8 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos) > >>> hp->flags = input_size; /* structure abuse ... */ > >>> hp->pack_id = old_hdr.pack_id; > >>> hp->usr_ptr = NULL; > >>> + if (opcode != cmnd[0]) > >>> + return -EINVAL; > >>> if (__copy_from_user(cmnd, buf, cmd_size)) > >>> return -EFAULT; > >> > >> You are sending the same patches like a broken machine. Please STOP this > >> and give people some time to actually review your patches! (Don't expect > >> replies in days.) > >> > > Thanks for your reply. I resubmitted this one after 8-day-no-reply. I > > don't judge whether this is a short time period or not. I politely hope > > that you can reply more kindly. > > There is no reason to be offended. I am just asking you to wait a bit > more before reposting. 8 days is too few. My personal experience says to > give patches like these something close to a month, esp. during the > merge window. The issues are present for a long time, nobody hit them > during that timeframe, so there is no reason to haste. Thanks for your reply, and I will keep this in mind. > > > I am just a PhD candidate. All I did is submitting patches, discussing > > with maintainers in accordance with linux community rules for academic papers. > > Yes, despite I have no idea what "linux community rules for academic > papers" are. I mean, these patches come from a research project prototype. Submitting patches, and getting it applied can be demonstrated in the experiment part of research paper. Thanks Gen > > > I guess that you might be busy person and hope that submitting patches > > didn't bother you. > > It does not bother me at all. Patches are welcome, but newcomers tend to > send new versions of patches (or reposts) too quickly. It then leads to > wasting time of people where one person comments on one version and the > others don't see it and reply to some other. > > thanks, > -- > js > suse labs
