On Wed, May 27, 2020 at 09:41:01PM -0500, Justin Hibbits wrote: > On Thu, 28 May 2020 00:49:03 +0000 (UTC) > Brandon Bergren <bdra...@freebsd.org> wrote: > > > Author: bdragon > > Date: Thu May 28 00:49:02 2020 > > New Revision: 361568 > > URL: https://svnweb.freebsd.org/changeset/base/361568 > > > > Log: > > [PowerPC] Fix radix crash when passing -1 from userspace > > > > Found by running libc tests with radix enabled. > > > > Detect unsigned integer wrapping with a postcondition. > > > > Note: Radix MMU is not enabled by default yet. > > > > Sponsored by: Tag1 Consulting, Inc. > > > > Modified: > > head/sys/powerpc/aim/mmu_radix.c > > > > Modified: head/sys/powerpc/aim/mmu_radix.c > > ============================================================================== > > --- head/sys/powerpc/aim/mmu_radix.c Wed May 27 23:20:35 > > 2020 (r361567) +++ head/sys/powerpc/aim/mmu_radix.c Thu > > May 28 00:49:02 2020 (r361568) @@ -6000,7 +6000,8 @@ > > mmu_radix_kremove(vm_offset_t va) int mmu_radix_map_user_ptr(pmap_t > > pm, volatile const void *uaddr, void **kaddr, size_t ulen, size_t > > *klen) { > > - if ((uintptr_t)uaddr + ulen >= VM_MAXUSER_ADDRESS) > > + if ((uintptr_t)uaddr + ulen >= VM_MAXUSER_ADDRESS || > > + (uintptr_t)uaddr + ulen < (uintptr_t)uaddr) > > return (EFAULT); > > > > *kaddr = (void *)(uintptr_t)uaddr; > > Wouldn't > > if ((uintptr_t)uaddr >= VM_MAXUSER_ADDRESS || > (uintptr_t)uaddr + ulen >= VM_MAXUSER_ADDRESS) > > be more appropriate?
The committed change is the canonical way to detect unsigned overflow, so I think it is fine and does not depend on specific values of VM_MAXUSER_ADDRESS. _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
