| Message ID | 20181024200549.8516-7-daniel@iogearbox.net |
|---|---|
| State | Accepted, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | Batch of direct packet access fixes for BPF | expand |
On 10/24/18 3:05 PM, Daniel Borkmann wrote: > Commit f1a2e44a3aec ("bpf: add queue and stack maps") added helpers > with ARG_PTR_TO_UNINIT_MAP_VALUE. Meaning, the helper is supposed to > fill the map value buffer with data instead of reading from it like > in other helpers such as map update. However, given the buffer is > allowed to be uninitialized (since we fill it in the helper anyway), > it also means that the helper is obliged to wipe the memory in case > of an error in order to not allow for leaking uninitialized memory. > Given pop/peek is both handled inside __{stack,queue}_map_get(), > lets wipe it there on error case, that is, empty stack/queue. > > Fixes: f1a2e44a3aec ("bpf: add queue and stack maps") > Signed-off-by: Daniel Borkmann<daniel@iogearbox.net> > Acked-by: Alexei Starovoitov<ast@kernel.org> > Cc: Mauricio Vasquez B<mauricio.vasquez@polito.it> Thanks for the fix Daniel. Acked-by: Mauricio Vasquez B<mauricio.vasquez@polito.it>
diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c index 12a93fb..8bbd72d 100644 --- a/kernel/bpf/queue_stack_maps.c +++ b/kernel/bpf/queue_stack_maps.c @@ -122,6 +122,7 @@ static int __queue_map_get(struct bpf_map *map, void *value, bool delete) raw_spin_lock_irqsave(&qs->lock, flags); if (queue_stack_map_is_empty(qs)) { + memset(value, 0, qs->map.value_size); err = -ENOENT; goto out; } @@ -151,6 +152,7 @@ static int __stack_map_get(struct bpf_map *map, void *value, bool delete) raw_spin_lock_irqsave(&qs->lock, flags); if (queue_stack_map_is_empty(qs)) { + memset(value, 0, qs->map.value_size); err = -ENOENT; goto out; }
Commit f1a2e44a3aec ("bpf: add queue and stack maps") added helpers with ARG_PTR_TO_UNINIT_MAP_VALUE. Meaning, the helper is supposed to fill the map value buffer with data instead of reading from it like in other helpers such as map update. However, given the buffer is allowed to be uninitialized (since we fill it in the helper anyway), it also means that the helper is obliged to wipe the memory in case of an error in order to not allow for leaking uninitialized memory. Given pop/peek is both handled inside __{stack,queue}_map_get(), lets wipe it there on error case, that is, empty stack/queue. Fixes: f1a2e44a3aec ("bpf: add queue and stack maps") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Mauricio Vasquez B <mauricio.vasquez@polito.it> --- kernel/bpf/queue_stack_maps.c | 2 ++ 1 file changed, 2 insertions(+)