diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 8d368fa353f9..42e06d1b492d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1448,6 +1448,13 @@ u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr) return ptr->size & DYNPTR_SIZE_MASK; } +static void bpf_dynptr_set_size(struct bpf_dynptr_kern *ptr, u32 new_size) +{ + u32 metadata = ptr->size & ~DYNPTR_SIZE_MASK; + + ptr->size = new_size | metadata; +} + int bpf_dynptr_check_size(u32 size) { return size > DYNPTR_MAX_SIZE ? -E2BIG : 0; @@ -2297,6 +2304,24 @@ __bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr_kern *ptr, u32 o return bpf_dynptr_slice(ptr, offset, buffer, buffer__szk); } +__bpf_kfunc int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 end) +{ + u32 size; + + if (!ptr->data || start > end) + return -EINVAL; + + size = bpf_dynptr_get_size(ptr); + + if (start > size || end > size) + return -ERANGE; + + ptr->offset += start; + bpf_dynptr_set_size(ptr, end - start); + + return 0; +} + __bpf_kfunc void *bpf_cast_to_kern_ctx(void *obj) { return obj; @@ -2369,6 +2394,7 @@ BTF_ID_FLAGS(func, bpf_dynptr_slice_rdwr, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_num_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_SET8_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = {