On 05/01/2016 22:59, Boris Ostrovsky wrote: > On 01/05/2016 05:42 PM, Andrew Cooper wrote: >> On 05/01/2016 22:26, Boris Ostrovsky wrote: >>> When copying boot command string for HVMlite guests we explicitly write >>> '\0' at MAX_GUEST_CMDLINE offset. Unless the string is close to >>> MAX_GUEST_CMDLINE in length this write will end up in the wrong place, >>> beyond the end of the mapped range. >>> >>> Instead we should test string's length early and error out if it is too >>> long. >>> >>> Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com> >> MAX_GUEST_CMDLINE is an arbitrary and incorrect restriction. It is >> sadly baked into the PV ABI, but I specifically want to avoid lumbering >> DMLite with the failings of PV. >> >> By the looks of it, the only bug is the use of MAX_GUEST_CMDLINE. The >> xc_map_foreign_range() call already accounts for sufficient space to >> store the string when mapping guest memory. > > Yes, I was also thinking about dropping it but ended up keeping it > mostly because it didn't feel right to blindly use strcpy().
Possibly add a comment explaining that the length has already been checked, and that sufficient space has been allocated, if that helps? One way or another, the use of strcpy() here is correct. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
