code review 63010043: ogle/probe: add overflow checks for validRead and valid...

ogle/probe: add overflow checks for validRead and validWrite.

[nigeltao, 2014-02-13 07:01:30]

Hello r@golang.org,

I'd like you to review this change to
https://code.google.com/p/ogle

[r, 2014-02-13 16:22:51]

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go
File probe/probe.go (right):

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go#newcode26
probe/probe.go:26: if size < 0 || uint64(^uintptr(0)-p) < uint64(size) {
is this enough?

if p + uintptr(size) < p { ... }

[r, 2014-02-13 20:09:21]

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go
File probe/probe.go (right):

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go#newcode26
probe/probe.go:26: if size < 0 || uint64(^uintptr(0)-p) < uint64(size) {

seems to be. see  http://play.golang.org/p/M1QrJ42ZvR

[nigeltao, 2014-02-13 23:04:33]

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go
File probe/probe.go (right):

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go#newcode26
probe/probe.go:26: if size < 0 || uint64(^uintptr(0)-p) < uint64(size) {
On 2014/02/13 16:22:52, r wrote:
> is this enough?
> 
> if p + uintptr(size) < p { ... }

If uintptr is 32-bit and int is 64-bit (yeah, unlikely, but still possible,
right?), then this isn't enough if e.g. size is 1<<32 + 1.

[r, 2014-02-13 23:25:54]

LGTM

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go
File probe/probe.go (right):

https://codereview.appspot.com/63010043/diff/40001/probe/probe.go#newcode26
probe/probe.go:26: if size < 0 || uint64(^uintptr(0)-p) < uint64(size) {
On 2014/02/13 23:04:33, nigeltao wrote:
> On 2014/02/13 16:22:52, r wrote:
> > is this enough?
> > 
> > if p + uintptr(size) < p { ... }
> 
> If uintptr is 32-bit and int is 64-bit (yeah, unlikely, but still possible,
> right?), then this isn't enough if e.g. size is 1<<32 + 1.

fine. jeez.

[nigeltao, 2014-02-14 02:24:33]

*** Submitted as https://code.google.com/p/ogle/source/detail?r=11112a8e1795 ***

ogle/probe: add overflow checks for validRead and validWrite.

LGTM=r
R=r
https://codereview.appspot.com/63010043