From patchwork Thu Sep 8 00:02:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 12969486 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0156C38145 for ; Thu, 8 Sep 2022 00:07:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229541AbiIHAHn (ORCPT ); Wed, 7 Sep 2022 20:07:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230052AbiIHAHn (ORCPT ); Wed, 7 Sep 2022 20:07:43 -0400 Received: from 66-220-155-178.mail-mxout.facebook.com (66-220-155-178.mail-mxout.facebook.com [66.220.155.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BE11B2CE2 for ; Wed, 7 Sep 2022 17:07:41 -0700 (PDT) Received: by devbig010.atn6.facebook.com (Postfix, from userid 115148) id BA509117037C7; Wed, 7 Sep 2022 17:07:27 -0700 (PDT) From: Joanne Koong To: bpf@vger.kernel.org Cc: daniel@iogearbox.net, martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, Kernel-team@fb.com, Joanne Koong Subject: [PATCH bpf-next v1 4/8] bpf: Add bpf_dynptr_get_size and bpf_dynptr_get_offset Date: Wed, 7 Sep 2022 17:02:50 -0700 Message-Id: <20220908000254.3079129-5-joannelkoong@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220908000254.3079129-1-joannelkoong@gmail.com> References: <20220908000254.3079129-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add two new helper functions: bpf_dynptr_get_size and bpf_dynptr_get_offset. bpf_dynptr_get_size returns the number of usable bytes in a dynptr and bpf_dynptr_get_offset returns the current offset into the dynptr. Signed-off-by: Joanne Koong --- include/uapi/linux/bpf.h | 25 ++++++++++++++++++++ kernel/bpf/helpers.c | 42 ++++++++++++++++++++++++++++++---- tools/include/uapi/linux/bpf.h | 25 ++++++++++++++++++++ 3 files changed, 88 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 90b6d0744df2..4ca07cf500d2 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5485,6 +5485,29 @@ union bpf_attr { * Return * True if the dynptr is read-only and a valid dynptr, * else false. + * + * long bpf_dynptr_get_size(struct bpf_dynptr *ptr) + * Description + * Get the size of *ptr*. + * + * Size refers to the number of usable bytes. For example, + * if *ptr* was initialized with 100 bytes and its + * offset was advanced by 40 bytes, then the size will be + * 60 bytes. + * + * *ptr* must be an initialized dynptr. + * Return + * The size of the dynptr on success, -EINVAL if the dynptr is + * invalid. + * + * long bpf_dynptr_get_offset(struct bpf_dynptr *ptr) + * Description + * Get the offset of the dynptr. + * + * *ptr* must be an initialized dynptr. + * Return + * The offset of the dynptr on success, -EINVAL if the dynptr is + * invalid. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5703,6 +5726,8 @@ union bpf_attr { FN(dynptr_trim), \ FN(dynptr_is_null), \ FN(dynptr_is_rdonly), \ + FN(dynptr_get_size), \ + FN(dynptr_get_offset), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 8729383d0966..62ed27444b73 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1418,7 +1418,7 @@ static enum bpf_dynptr_type bpf_dynptr_get_type(const struct bpf_dynptr_kern *pt return (ptr->size & ~(DYNPTR_RDONLY_BIT)) >> DYNPTR_TYPE_SHIFT; } -static u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr) +static u32 __bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr) { return ptr->size & DYNPTR_SIZE_MASK; } @@ -1451,7 +1451,7 @@ void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr) static int bpf_dynptr_check_off_len(struct bpf_dynptr_kern *ptr, u32 offset, u32 len) { - u32 size = bpf_dynptr_get_size(ptr); + u32 size = __bpf_dynptr_get_size(ptr); if (len > size || offset > size - len) return -E2BIG; @@ -1660,7 +1660,7 @@ BPF_CALL_2(bpf_dynptr_advance, struct bpf_dynptr_kern *, ptr, u32, len) if (!ptr->data) return -EINVAL; - size = bpf_dynptr_get_size(ptr); + size = __bpf_dynptr_get_size(ptr); if (len > size) return -ERANGE; @@ -1687,7 +1687,7 @@ BPF_CALL_2(bpf_dynptr_trim, struct bpf_dynptr_kern *, ptr, u32, len) if (!ptr->data) return -EINVAL; - size = bpf_dynptr_get_size(ptr); + size = __bpf_dynptr_get_size(ptr); if (len > size) return -ERANGE; @@ -1732,6 +1732,36 @@ static const struct bpf_func_proto bpf_dynptr_is_rdonly_proto = { .arg1_type = ARG_PTR_TO_DYNPTR, }; +BPF_CALL_1(bpf_dynptr_get_size, struct bpf_dynptr_kern *, ptr) +{ + if (!ptr->data) + return -EINVAL; + + return __bpf_dynptr_get_size(ptr); +} + +static const struct bpf_func_proto bpf_dynptr_get_size_proto = { + .func = bpf_dynptr_get_size, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_DYNPTR, +}; + +BPF_CALL_1(bpf_dynptr_get_offset, struct bpf_dynptr_kern *, ptr) +{ + if (!ptr->data) + return -EINVAL; + + return ptr->offset; +} + +static const struct bpf_func_proto bpf_dynptr_get_offset_proto = { + .func = bpf_dynptr_get_offset, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_DYNPTR, +}; + const struct bpf_func_proto bpf_get_current_task_proto __weak; const struct bpf_func_proto bpf_get_current_task_btf_proto __weak; const struct bpf_func_proto bpf_probe_read_user_proto __weak; @@ -1812,6 +1842,10 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_dynptr_is_null_proto; case BPF_FUNC_dynptr_is_rdonly: return &bpf_dynptr_is_rdonly_proto; + case BPF_FUNC_dynptr_get_size: + return &bpf_dynptr_get_size_proto; + case BPF_FUNC_dynptr_get_offset: + return &bpf_dynptr_get_offset_proto; default: break; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 90b6d0744df2..4ca07cf500d2 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5485,6 +5485,29 @@ union bpf_attr { * Return * True if the dynptr is read-only and a valid dynptr, * else false. + * + * long bpf_dynptr_get_size(struct bpf_dynptr *ptr) + * Description + * Get the size of *ptr*. + * + * Size refers to the number of usable bytes. For example, + * if *ptr* was initialized with 100 bytes and its + * offset was advanced by 40 bytes, then the size will be + * 60 bytes. + * + * *ptr* must be an initialized dynptr. + * Return + * The size of the dynptr on success, -EINVAL if the dynptr is + * invalid. + * + * long bpf_dynptr_get_offset(struct bpf_dynptr *ptr) + * Description + * Get the offset of the dynptr. + * + * *ptr* must be an initialized dynptr. + * Return + * The offset of the dynptr on success, -EINVAL if the dynptr is + * invalid. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5703,6 +5726,8 @@ union bpf_attr { FN(dynptr_trim), \ FN(dynptr_is_null), \ FN(dynptr_is_rdonly), \ + FN(dynptr_get_size), \ + FN(dynptr_get_offset), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper