Re: [RFC v2 bpf-next 2/5] bpf: return EOPNOTSUPP when map lookup isn't supported

2018-10-04 Thread Alexei Starovoitov 
On Fri, Oct 05, 2018 at 09:16:04AM +0900, Prashant Bhole wrote:
> 
> 
> On 10/5/2018 9:10 AM, Alexei Starovoitov wrote:
> > On Tue, Oct 02, 2018 at 02:35:16PM +0900, Prashant Bhole wrote:
> > > Return ERR_PTR(-EOPNOTSUPP) from map_lookup_elem() methods of below
> > > map types:
> > > - BPF_MAP_TYPE_PROG_ARRAY
> > > - BPF_MAP_TYPE_STACK_TRACE
> > > - BPF_MAP_TYPE_XSKMAP
> > > - BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH
> > > 
> > > Signed-off-by: Prashant Bhole 
> > > ---
> > >   kernel/bpf/arraymap.c | 2 +-
> > >   kernel/bpf/sockmap.c  | 2 +-
> > >   kernel/bpf/stackmap.c | 2 +-
> > >   kernel/bpf/xskmap.c   | 2 +-
> > >   4 files changed, 4 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
> > > index dded84cbe814..24583da9ffd1 100644
> > > --- a/kernel/bpf/arraymap.c
> > > +++ b/kernel/bpf/arraymap.c
> > > @@ -449,7 +449,7 @@ static void fd_array_map_free(struct bpf_map *map)
> > >   static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
> > >   {
> > > - return NULL;
> > > + return ERR_PTR(-EOPNOTSUPP);
> > 
> > last time we discussed that the verifier should make sure that
> > lookup is not called from bpf program for these map types.
> > I'd like to see test cases in test_verifier.c for these map types
> > to make sure we don't introduce crashes.
> 
> Hi Alexei,
> Patch 05/05 adds such tests in test_verifier.c. Please review those changes.

ahh. missed it. sorry about that. looking...

Re: [RFC v2 bpf-next 2/5] bpf: return EOPNOTSUPP when map lookup isn't supported

2018-10-04 Thread Alexei Starovoitov 
On Tue, Oct 02, 2018 at 02:35:16PM +0900, Prashant Bhole wrote:
> Return ERR_PTR(-EOPNOTSUPP) from map_lookup_elem() methods of below
> map types:
> - BPF_MAP_TYPE_PROG_ARRAY
> - BPF_MAP_TYPE_STACK_TRACE
> - BPF_MAP_TYPE_XSKMAP
> - BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH
> 
> Signed-off-by: Prashant Bhole 
> ---
>  kernel/bpf/arraymap.c | 2 +-
>  kernel/bpf/sockmap.c  | 2 +-
>  kernel/bpf/stackmap.c | 2 +-
>  kernel/bpf/xskmap.c   | 2 +-
>  4 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
> index dded84cbe814..24583da9ffd1 100644
> --- a/kernel/bpf/arraymap.c
> +++ b/kernel/bpf/arraymap.c
> @@ -449,7 +449,7 @@ static void fd_array_map_free(struct bpf_map *map)
>  
>  static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
>  {
> - return NULL;
> + return ERR_PTR(-EOPNOTSUPP);

last time we discussed that the verifier should make sure that
lookup is not called from bpf program for these map types.
I'd like to see test cases in test_verifier.c for these map types
to make sure we don't introduce crashes.

Re: [RFC v2 bpf-next 2/5] bpf: return EOPNOTSUPP when map lookup isn't supported

2018-10-04 Thread Prashant Bhole 




On 10/5/2018 9:10 AM, Alexei Starovoitov wrote:

On Tue, Oct 02, 2018 at 02:35:16PM +0900, Prashant Bhole wrote:

Return ERR_PTR(-EOPNOTSUPP) from map_lookup_elem() methods of below
map types:
- BPF_MAP_TYPE_PROG_ARRAY
- BPF_MAP_TYPE_STACK_TRACE
- BPF_MAP_TYPE_XSKMAP
- BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH

Signed-off-by: Prashant Bhole 
---
  kernel/bpf/arraymap.c | 2 +-
  kernel/bpf/sockmap.c  | 2 +-
  kernel/bpf/stackmap.c | 2 +-
  kernel/bpf/xskmap.c   | 2 +-
  4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index dded84cbe814..24583da9ffd1 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -449,7 +449,7 @@ static void fd_array_map_free(struct bpf_map *map)
  
  static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)

  {
-   return NULL;
+   return ERR_PTR(-EOPNOTSUPP);


last time we discussed that the verifier should make sure that
lookup is not called from bpf program for these map types.
I'd like to see test cases in test_verifier.c for these map types
to make sure we don't introduce crashes.


Hi Alexei,
Patch 05/05 adds such tests in test_verifier.c. Please review those 
changes. Thank you.


-Prashant

[RFC v2 bpf-next 2/5] bpf: return EOPNOTSUPP when map lookup isn't supported

2018-10-01 Thread Prashant Bhole 
Return ERR_PTR(-EOPNOTSUPP) from map_lookup_elem() methods of below
map types:
- BPF_MAP_TYPE_PROG_ARRAY
- BPF_MAP_TYPE_STACK_TRACE
- BPF_MAP_TYPE_XSKMAP
- BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH

Signed-off-by: Prashant Bhole 
---
 kernel/bpf/arraymap.c | 2 +-
 kernel/bpf/sockmap.c  | 2 +-
 kernel/bpf/stackmap.c | 2 +-
 kernel/bpf/xskmap.c   | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index dded84cbe814..24583da9ffd1 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -449,7 +449,7 @@ static void fd_array_map_free(struct bpf_map *map)
 
 static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
 {
-   return NULL;
+   return ERR_PTR(-EOPNOTSUPP);
 }
 
 /* only called from syscall */
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index d37a1a0a6e1e..5d0677d808ae 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -2096,7 +2096,7 @@ int sockmap_get_from_fd(const union bpf_attr *attr, int 
type,
 
 static void *sock_map_lookup(struct bpf_map *map, void *key)
 {
-   return NULL;
+   return ERR_PTR(-EOPNOTSUPP);
 }
 
 static int sock_map_update_elem(struct bpf_map *map,
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 8061a439ef18..b2ade10f7ec3 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -505,7 +505,7 @@ const struct bpf_func_proto bpf_get_stack_proto = {
 /* Called from eBPF program */
 static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
 {
-   return NULL;
+   return ERR_PTR(-EOPNOTSUPP);
 }
 
 /* Called from syscall */
diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 9f8463afda9c..ef0b7b6ef8a5 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -154,7 +154,7 @@ void __xsk_map_flush(struct bpf_map *map)
 
 static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
 {
-   return NULL;
+   return ERR_PTR(-EOPNOTSUPP);
 }
 
 static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
-- 
2.17.1