On Mon, May 1, 2023 at 5:52 PM Daniel Rosenberg <drosen@xxxxxxxxxx> wrote: > > bpf_dynptr_slice(_rw) uses a user provided buffer if it can not provide > a pointer to a block of contiguous memory. This buffer is unused in the > case of local dynptrs, and may be unused in other cases as well. There > is no need to require the buffer, as the kfunc can just return NULL if > it was needed and not provided. > > This adds another kfunc annotation, __opt, which combines with __sz and > __szk to allow the buffer associated with the size to be NULL. If the > buffer is NULL, the verifier does not check that the buffer is of > sufficient size. > > Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> > --- LGTM Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > Documentation/bpf/kfuncs.rst | 23 ++++++++++++++++++++++- > include/linux/skbuff.h | 2 +- > kernel/bpf/helpers.c | 30 ++++++++++++++++++------------ > kernel/bpf/verifier.c | 17 +++++++++++++---- > 4 files changed, 54 insertions(+), 18 deletions(-) > [...]
