Re: [RFC PATCH net-next 4/5] bpf/verifier: track signed and unsigned min/max values

2017-06-08 Thread Alexei Starovoitov
On Thu, Jun 08, 2017 at 04:23:24PM +0100, Edward Cree wrote: > On 08/06/17 03:40, Alexei Starovoitov wrote: > > On Wed, Jun 07, 2017 at 03:59:25PM +0100, Edward Cree wrote: > >> Allows us to, sometimes, combine information from a signed check of one > >> bound and an unsigned check of the other. >

Re: [RFC PATCH net-next 4/5] bpf/verifier: track signed and unsigned min/max values

2017-06-08 Thread Edward Cree
On 08/06/17 03:40, Alexei Starovoitov wrote: > On Wed, Jun 07, 2017 at 03:59:25PM +0100, Edward Cree wrote: >> Allows us to, sometimes, combine information from a signed check of one >> bound and an unsigned check of the other. >> We now track the full range of possible values, rather than restric

Re: [RFC PATCH net-next 4/5] bpf/verifier: track signed and unsigned min/max values

2017-06-07 Thread Alexei Starovoitov
On Wed, Jun 07, 2017 at 03:59:25PM +0100, Edward Cree wrote: > Allows us to, sometimes, combine information from a signed check of one > bound and an unsigned check of the other. > We now track the full range of possible values, rather than restricting > ourselves to [0, 1<<30) and considering an

[RFC PATCH net-next 4/5] bpf/verifier: track signed and unsigned min/max values

2017-06-07 Thread Edward Cree
Allows us to, sometimes, combine information from a signed check of one bound and an unsigned check of the other. We now track the full range of possible values, rather than restricting ourselves to [0, 1<<30) and considering anything beyond that as unknown. While this is probably not necessary