From patchwork Sun Aug 11 23:54:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jordan Rome X-Patchwork-Id: 13759906 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mout.perfora.net (mout.perfora.net [74.208.4.197]) (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 6D78928FC for ; Sun, 11 Aug 2024 23:55:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.208.4.197 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723420520; cv=none; b=m85N+WhCnL7sIjq86xJO5IVgZ7Ob4KCc/ITchBwA7Ecq118J9Tace3qpYVVTv+Ce0Cv9UzPwGcNVA1YabLd8Y5JK+CQrt5MhHQ24kKcnYwz9ypRY0KhLHg+2jdysw46GW5vaUkQaQ5+U+DV0wfdoRjk2P718D3AuY+yc1ZZhxnA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723420520; c=relaxed/simple; bh=x8E7p5JngwDCplc+KE3X4N+HweP7hFcTD89F0nDQjUo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=G1PkIu0T0bUIsmnnHLryvx9yqkQkKeAupqg3IhXp8UcJodH3IV4qiACblDPL6YFWxwMA3Saei9GWffHhTOMIx8J68FRAfxO1iXSZmA2aDig548SBmfA7R6hsx1KrPRUFP8H7CFOXI13nL1CNy9XOWbGfXmZxP5woJ3FB/iwMb7U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=jordanrome.com; spf=pass smtp.mailfrom=jordanrome.com; dkim=pass (2048-bit key) header.d=jordanrome.com header.i=linux@jordanrome.com header.b=R1yKAktJ; arc=none smtp.client-ip=74.208.4.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=jordanrome.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=jordanrome.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=jordanrome.com header.i=linux@jordanrome.com header.b="R1yKAktJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jordanrome.com; s=s1-ionos; t=1723420494; x=1724025294; i=linux@jordanrome.com; bh=Ff6ktVOqckV5nqh4tacjPnZQFaqla2tvY7n7gcen6rE=; h=X-UI-Sender-Class:From:To:Cc:Subject:Date:Message-ID: MIME-Version:Content-Transfer-Encoding:cc: content-transfer-encoding:content-type:date:from:message-id: mime-version:reply-to:subject:to; b=R1yKAktJn95yID+UmVmdVfz95e7s4WTCtl3AZ5C4IY8x/nXy6qwO84eUsv5a5XyV hbqomR/1SWY0vsBOCP2QqHjchyOD8FD72TBuiSVmkHyGCGOj95LRYY+c5TIm0xfb7 itNRLPaGtYofZwukFj4bWBmt7gAoDkfebEBvCN8MaKZ8uYAkoGFWHJOVHMgP5m7Fw Wh423sAPZJaFUBfDzGQi9LHFfL5HGKbCTEJlR8ARheccaDHOvH5CZqxnbSaLs3VHf aLic0D+CXZmGybePW4+wKDyrQiB2c3uJk8K/OwBu0fwWIpRG778McxWi9N6qDXtX8 llVbevhpbn83kUB/sg== X-UI-Sender-Class: 55c96926-9e95-11ee-ae09-1f7a4046a0f6 Received: from localhost ([173.252.127.1]) by mrelay.perfora.net (mreueus004 [74.208.5.2]) with ESMTPSA (Nemesis) id 1MuE0f-1sKNQx337d-014WX2; Mon, 12 Aug 2024 01:54:54 +0200 From: Jordan Rome To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Kernel Team , sinquersw@gmail.com Subject: [bpf-next v2 1/2] bpf: Add bpf_copy_from_user_str kfunc Date: Sun, 11 Aug 2024 16:54:38 -0700 Message-ID: <20240811235439.1862495-1-linux@jordanrome.com> X-Mailer: git-send-email 2.44.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Provags-ID: V03:K1:zStu9v21ajCsPy6iD5/qiuShcmYTJStVPkGnXlaIU1JaWE7UO/n 74OAvhvCiseOUXGiy8gS2uHtD6DJR6zonREQwRvoulvCJSIFAdhT7AUyYQptpNegI6WKCiT 0RYqkDhetgrBtLYrG03h/0QMVsIBItPjJl+OrbIaB2cX9SgmYx35jyqsIlhvOLHVE4oJKrX sOkSsp81r8yMWZOxCr7vA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:lSmbHtbUasg=;4P0U4osHVfHRkVeQZh82YTC39rw N5Ie0DP+GVrBRlGEthyWY8IkwiPC2Ymo+HHdt2XwrynLFxHRHcLOC+hOyAFbm/LVw+/tsbhE3 xA94FhAwaqlwbNuBxPXUKCO7p/+MR7m70vcHrs/+4w55tpwZ6fbZLqjOeYu1XQjCT4txIH2oL zYG7vFGJXXd8L+9VixNTf4Fv2RnZiR1jhpyH97kszmxD2apMZqd6VWd8K7EQLRuyhVgJlK5cT bjIjgA2P+UtZ7LWCfPRqbFyRWoZi67vRX9gvp2Qq794XJzkjxwd957NTHslj6b0QG1L8XOk83 ePxJv42DqRIBPN9pSaBBryHIzSv4Uy4oyociEtD+rfznXzIH8Yg3BO4z140B5mWqCqf5dbaVl BFw6Pl19DbKbcvt6AOc/WfRGxBggoqhmQbbNzSSNrPkOcpcXnljJPgu4/6d8dQfj0d2euHb/m kS4MxjLuv4BzeqFBUzlL07zPvg7OHDjfJU+p6o2xriUybbUM33KpeO5XlW2yQSwX7Svgl9fx9 IBhHndPldPFH4BbkGK8uiK/Lh8VxxgjgpDRsMtXNHYxH7cakSRQmS7417Nq1y3pdNaEd0nPw4 NdVIIs6nHplkr9NHgR5/XBWqOk/59WIH/yFZBcOQbLvDwDMOZIg8BQUDHYkE7mKjB2mIFzf+4 1WM/l100iyxZmEJMAGF6l1dGUE3P26E9EESIko8MoakzozknJ3PNlY0aSmVGJ369iMcJWL3Wf 6E5JzlM5NCLX3pV12EYenpMUaNOZ7OTrw== X-Patchwork-Delegate: bpf@iogearbox.net This adds a kfunc wrapper around strncpy_from_user, which can be called from sleepable BPF programs. This matches the non-sleepable 'bpf_probe_read_user_str' helper. Signed-off-by: Jordan Rome --- kernel/bpf/helpers.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) -- 2.44.1 diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index d02ae323996b..5eeb7c2ca622 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2939,6 +2939,37 @@ __bpf_kfunc void bpf_iter_bits_destroy(struct bpf_iter_bits *it) bpf_mem_free(&bpf_global_ma, kit->bits); } +/** + * bpf_copy_from_user_str() - Copy a string from an unsafe user address + * @dst: Destination address, in kernel space. This buffer must be at + * least @dst__szk bytes long. + * @dst__szk: Maximum number of bytes to copy, including the trailing NUL. + * @unsafe_ptr__ign: Source address, in user space. + * + * Copies a NUL-terminated string from userspace to BPF space. If user string is + * too long this will still ensure zero termination in the dst buffer unless + * buffer size is 0. + */ +__bpf_kfunc int bpf_copy_from_user_str(void *dst, u32 dst__szk, const void __user *unsafe_ptr__ign) +{ + int ret; + + if (unlikely(!dst__szk)) + return 0; + + ret = strncpy_from_user(dst, unsafe_ptr__ign, dst__szk); + if (unlikely(ret < 0)) { + memset(dst, 0, dst__szk); + } else if (ret >= dst__szk) { + ret = dst__szk; + ((char *)dst)[ret - 1] = '\0'; + } else if (ret > 0) { + ret++; + } + + return ret; +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -3024,6 +3055,7 @@ BTF_ID_FLAGS(func, bpf_preempt_enable) BTF_ID_FLAGS(func, bpf_iter_bits_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_bits_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_bits_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_copy_from_user_str, KF_SLEEPABLE) BTF_KFUNCS_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = {