Messages in this thread | | | Date | Fri, 18 Sep 2020 14:13:42 +0200 | From | Petr Mladek <> | Subject | Re: [PATCH printk 2/3] printk: move dictionary keys to dev_printk_info |
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On Fri 2020-09-18 08:16:37, Rasmus Villemoes wrote: > On 17/09/2020 15.16, John Ogness wrote: > > > if (dev->class) > > subsys = dev->class->name; > > else if (dev->bus) > > subsys = dev->bus->name; > > else > > - return 0; > > + return; > > > > - pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys); > > - if (pos >= hdrlen) > > - goto overflow; > > + snprintf(dev_info->subsystem, sizeof(dev_info->subsystem), subsys); > > It's unlikely that subsys would contain a %, but this will be yet > another place to spend brain cycles ignoring if doing static analysis. > So can we not do this. Either of strXcpy() for X=s,l will do the same > thing, and likely faster.
Good point! Better be on the safe size in a generic printk() API.
Well, I am afraid that this would be only small drop in a huge lake. class->name and bus->name seems to be passed to %s in so many *print*() calls all over the kernel code.
IMHO, this is not the right place to prevent the problem. Dangerous names must be prevented when a new bus, class, device is added.
Best Rergards, Petr
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