On 13 January 2017 at 21:11, Nicholas Miell <nmiell@xxxxxxxxx> wrote: > On 01/13/2017 09:57 AM, Emil Velikov wrote: >> >> On 13 January 2017 at 11:34, Jan Vesely <jan.vesely@xxxxxxxxxxx> wrote: >>> >>> On Thu, 2017-01-12 at 18:16 -0800, Nicholas Miell wrote: >>>> >>>> From 714d07f600db39498c87d7816f4dd3a7e6d9bbca Mon Sep 17 00:00:00 2001 >>>> From: Nicholas Miell <nmiell@xxxxxxxxx> >>>> Date: Thu, 12 Jan 2017 15:43:07 -0800 >>>> Subject: [PATCH libdrm] xf86drm: fix valgrind warning in >>>> drmParsePciBusInfo >>>> >>>> The current implementation reads (up to) 513 bytes, overwrites the 513th >>>> byte with '\0' and then passes the buffer off to strstr() and sscanf() >>>> without ever initializing the middle bytes. This causes valgrind >>>> warnings and potentially fails to parse PCI_SLOT_NAME if the uevent is >>>> unexpectedly large. >>> >>> >>> a simpler fix should also get rid of the valgrind warning: >>> >>> - ret = read(fd, data, sizeof(data)); >>> - data[sizeof(data)-1] = '\0'; >>> + ret = read(fd, data, sizeof(data) - 1); >>> close(fd); >>> if (ret < 0) >>> return -errno >>> + data[ret] = '\0'; >>> >> We had this (better imho) patch a week or so ago. In either case the >> issue is virtually since (iirc) if the string is malformed we'll bail >> out either way. > > > Simpler, but potentially stops working in the future. It already stopped > working once. > Stopped working = it never worked since it was introduced (initially in mesa) circa 2014 ;-) That aside, Thierry has some helper(s) which we can reuse here. >>> I think that dynamic memory allocation is still a more robust approach. >>> >> Yes that might be the better solution, or one could even use >> getline(). The latter might be pushing it's only POSIX 2008. > > > POSIX isn't relevant, this is a Linux-specific function. > I'm well aware of that, it was me who added the guard or reviewed & pushed the commit ;-) As you may be aware other platforms also have sysfs - FreeBSD (and derivatives?), GNU Hurd and perhaps others. Things are kept Linux only since almost (nobody) running !Linux platform has bothered looking in libdrm for a long time. And it's not like I haven't poked people on a number of occasions :-P Emil _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
