From patchwork Sat Jan 25 08:29:50 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Levi Zim via B4 Relay X-Patchwork-Id: 13950276 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6DC86206F21; Sat, 25 Jan 2025 08:30:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737793828; cv=none; b=C71S1W3oEKWlssVxgjlNd7DRzUiUqhDJO+tKFdkUChpjCUur5SkFVCDOiMgy88cHZfIKjWqm0ZknxKjETv/KWPOQvVRqszEk9qvAruEE9rVunDbGzfiXwzAjtmZKNYgLvsd2hlul334tKtkR+II5r+ohyFCOY5wRbou1sjPmZMI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737793828; c=relaxed/simple; bh=PyRhaQiSnZLjeNlZTzgwUCTGU9Zv+fo1gZ0pY6cwY5A=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=MQ4AeGC4mt40v0KmGe/Zjlk4R/vxrzLO+s+DoDalgA/GOFMZ2TZ5y0NEH0KRJrIboz0Av3dxm2ZTmU/AA99zT7qEGxd9witxHWl3vs6Lp4xXXDkYJnDKXI6RO4zupa0Ls0H2OkrPT0zpNNMtEuxKf6U+Xo0dap1PjJYMKjHrWGI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E9PlLrUp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E9PlLrUp" Received: by smtp.kernel.org (Postfix) with ESMTPS id 28110C4CEEB; Sat, 25 Jan 2025 08:30:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737793828; bh=PyRhaQiSnZLjeNlZTzgwUCTGU9Zv+fo1gZ0pY6cwY5A=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=E9PlLrUpOgzuaiemYFGgsHCq71K44WdedOABpmUvE0T2oaXJjYZQ7kqs3Hqeoo91Y egXzmza/s0NjuoBNGzwqjtZf8hVTYqz+b0+1K7iCCcU/uG7gIbwN2slNIAqc07oNo0 eJGauI24yOucx8H9hAm1dOhuLRfipKqyWHaHZP5QwmXlJ5yPyX7hz8RxQ3fEdjkz4P 6sR16xicHtVcv1r398AV2o1xpFMx0+deacOxH++tcVCWFSVVJ7N2PG8zVJwUVTUZgU 5Eme/f5GLTY8nvnRbi74Pv9/q+mtRUtBVutviCZn41BxMq6F9YYsO4IxGxl0hib9w8 SUkiDeKbzGxRQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BA73C0218D; Sat, 25 Jan 2025 08:30:28 +0000 (UTC) From: Levi Zim via B4 Relay Date: Sat, 25 Jan 2025 16:29:50 +0800 Subject: [PATCH bpf-next v2 3/7] bpf: Implement bpf_copy_from_user_dynptr helper Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250125-bpf_dynptr_probe-v2-3-c42c87f97afe@outlook.com> References: <20250125-bpf_dynptr_probe-v2-0-c42c87f97afe@outlook.com> In-Reply-To: <20250125-bpf_dynptr_probe-v2-0-c42c87f97afe@outlook.com> To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Matt Bobrowski , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Mykola Lysenko , Shuah Khan Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrii Nakryiko , Levi Zim X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=4919; i=rsworktech@outlook.com; h=from:subject:message-id; bh=PbsS7Vpr6USg1jk+KBsoBiOuzmKNN5IGam682v3+Quo=; b=owEBbQKS/ZANAwAIAW87mNQvxsnYAcsmYgBnlKEcWhxtdmFMeS8e/j2IAS0TMUqjsi0v1GWCl kfWJnx3yfKJAjMEAAEIAB0WIQQolnD5HDY18KF0JEVvO5jUL8bJ2AUCZ5ShHAAKCRBvO5jUL8bJ 2NIOEACF2vYKdtugfPkki7eYCvJ3omVjfA4rb1wl39Hq/qNTHLWNz+/Gvhm2ZrdyAaLaDrMWbFw 1Yhz9cbOPBTTCnaouVLGUHY6rFse1euFPZWduj1RCzNsdvsXHOyfGH0J6BMeXEMUeWNYPx3ttEP VpVe+XlWkhR3VHfLZvafAdgpjs/4NWstbC5AfFrrVxddA3e7zzlYqWX3nSx7Pz0aj5I+FVyYGL7 AH+/k4kScAiW0Zg3ztHF4KT9Zs4+j5kOuEGVh5PbWKMtWAucK7OPy+Ex37P7xZYBRBT3KbOGVsx zJMsn13Hz1DMZRaoZYs058VWLUm03dXkQe1SyrjFmRlURNdmSWiEl8CiYF5iUUK2Q0viniy1+0E AENGF5oWU+MXGtXZrZrJJmqZIOyvxsD7yeuVRoraqzkzNEFTFUVd/YUXBOYha+pNmDnpQQmvTJW WrYfhYiZvMlbb5r4hVCPcpcC/9UDqEg04O1pHgDCqqdgTNwheZ37i8NdNMeo+5fAtX5Zsz5bSN2 kXq49mID7+PqiJNGMGD5JKj3vn/NVEl0oRAwx/DVx+WUD85bbbn0nYBo6bABdRJHjwvDf60/iNY sCxSUOlPs398GNnM+ztvdA8dtpasLLWmiGJXczA1njfLrozvjSNG65Ioi5jexf+mPPggBi60hVj aDVlGDi7FYxYZpw== X-Developer-Key: i=rsworktech@outlook.com; a=openpgp; fpr=17AADD6726DDC58B8EE5881757670CCFA42CCF0A X-Endpoint-Received: by B4 Relay for rsworktech@outlook.com/default with auth_id=219 X-Original-From: Levi Zim Reply-To: rsworktech@outlook.com X-Patchwork-Delegate: bpf@iogearbox.net From: Levi Zim This patch add a helper function bpf_copy_from_user_dynptr: bpf_copy_from_user_dynptr(const struct bpf_dynptr *dst, u32 offset, u32 size, const void *user_ptr, u64 flags) It is useful for reading variable-length data from kernel memory into dynptr. Signed-off-by: Levi Zim --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 17 +++++++++++++++++ kernel/bpf/helpers.c | 42 ++++++++++++++++++++++++++++++++++++++++++ kernel/trace/bpf_trace.c | 2 ++ 4 files changed, 62 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 9d5ae8b4b7d82c4523bf0ab041d4b76bf134a106..d0412eaf63d69c0e437575c77008548edc692335 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3357,6 +3357,7 @@ extern const struct bpf_func_proto bpf_get_retval_proto; extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto; extern const struct bpf_func_proto bpf_cgrp_storage_get_proto; extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto; +extern const struct bpf_func_proto bpf_copy_from_user_dynptr_proto; const struct bpf_func_proto *tracing_prog_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index d7d7a9ddd5dca07ba89d81ba77101a704af3163b..f92cf809b50bc393d54eb0e8de2e1ce2a39e95d0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5835,6 +5835,22 @@ union bpf_attr { * support this helper, or if *flags* is not 0. * * Or other negative errors on failure reading user space memory. + * + * long bpf_copy_from_user_dynptr(const struct bpf_dynptr *dst, u32 offset, u32 size, const void *user_ptr, u64 flags) + * Description + * Read *size* bytes from user space address *user_ptr* and store + * the data in *dst* starting from *offset*. + * This is a wrapper of **copy_from_user**\ (). + * *flags* is currently unused. + * Return + * 0 on success. + * + * **-E2BIG** if *offset* + *len* exceeds the length of *src*'s data + * + * **-EINVAL** if *src* is an invalid dynptr or doesn't support this + * support this helper, or if *flags* is not 0. + * + * Or other negative errors on failure reading user space memory. */ #define ___BPF_FUNC_MAPPER(FN, ctx...) \ FN(unspec, 0, ##ctx) \ @@ -6051,6 +6067,7 @@ union bpf_attr { FN(cgrp_storage_delete, 211, ##ctx) \ FN(probe_read_kernel_dynptr, 212, ##ctx) \ FN(probe_read_user_dynptr, 213, ##ctx) \ + FN(copy_from_user_dynptr, 214, ##ctx) \ /* */ /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index ac563d09082e7c721999d7de035aabc000206a29..d756c80596315bd07fe6e71885b61efc8cb2ef4f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -676,6 +676,48 @@ const struct bpf_func_proto bpf_copy_from_user_proto = { .arg3_type = ARG_ANYTHING, }; +BPF_CALL_5(bpf_copy_from_user_dynptr, const struct bpf_dynptr_kern *, dst, + u32, offset, u32, size, const void __user *, user_ptr, u32, flags) +{ + enum bpf_dynptr_type type; + int err; + + if (!dst->data || __bpf_dynptr_is_rdonly(dst)) + return -EINVAL; + + err = bpf_dynptr_check_off_len(dst, offset, size); + if (err) + return err; + + type = bpf_dynptr_get_type(dst); + + switch (type) { + case BPF_DYNPTR_TYPE_LOCAL: + case BPF_DYNPTR_TYPE_RINGBUF: + if (flags) + return -EINVAL; + return ____bpf_copy_from_user(dst->data + dst->offset + offset, size, user_ptr); + case BPF_DYNPTR_TYPE_SKB: + case BPF_DYNPTR_TYPE_XDP: + return -EINVAL; + default: + WARN_ONCE(true, "%s: unknown dynptr type %d\n", __func__, type); + return -EFAULT; + } +} + +const struct bpf_func_proto bpf_copy_from_user_dynptr_proto = { + .func = bpf_copy_from_user_dynptr, + .gpl_only = false, + .might_sleep = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_ANYTHING, + .arg5_type = ARG_ANYTHING, +}; + BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size, const void __user *, user_ptr, struct task_struct *, tsk, u64, flags) { diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d9f704c1342773c74b2414be4adfc8271d6d364d..424931925fe3b02db083bc19cc64e19918b40c5a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1598,6 +1598,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_copy_from_user_proto; case BPF_FUNC_copy_from_user_task: return &bpf_copy_from_user_task_proto; + case BPF_FUNC_copy_from_user_dynptr: + return &bpf_copy_from_user_dynptr_proto; case BPF_FUNC_snprintf_btf: return &bpf_snprintf_btf_proto; case BPF_FUNC_per_cpu_ptr: