From patchwork Wed Mar 4 15:47:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11420333 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8D67814B7 for ; Wed, 4 Mar 2020 15:48:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E3CA21D56 for ; Wed, 4 Mar 2020 15:48:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="YErib6GT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387969AbgCDPsA (ORCPT ); Wed, 4 Mar 2020 10:48:00 -0500 Received: from mail-wr1-f65.google.com ([209.85.221.65]:44640 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729791AbgCDPr6 (ORCPT ); Wed, 4 Mar 2020 10:47:58 -0500 Received: by mail-wr1-f65.google.com with SMTP id n7so2959069wrt.11 for ; Wed, 04 Mar 2020 07:47:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=z+5Ez1qQKbcq42hwIwx4yVFRxKG7D39lDDrIw5grt88=; b=YErib6GT5VIIjobJDwl9AXipjtvMVlEa8r6u9Hly9IMNXd5MmxEqhrwhRkpAFBpTw5 kELU0rxnmH6iBy+gIjs3ppyM9Qh/D1EadCQo0x9uAjwco/bcEDII91nFtCg7XTJJCrok kqEGCzYCiJ4puupd27CxK+S1bxke5gCb3OtAc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=z+5Ez1qQKbcq42hwIwx4yVFRxKG7D39lDDrIw5grt88=; b=aVi85mUsOQMYPolY0Yd7P1XeUBkmbDAnzDgiDZKFD3AWtBLps/CpGFn1GZfBKggss9 fw8NcVD9R7gbbFkY6KJCC69/jVaJZKf1vySMRvu9RntqnvQUxzICs15FeC5IfxP2SrDC WCWSCvt0Hnb+x9mq+whREBV4Fuji1CZ01/5UxrzaZafSochpJPf/2HykFuTtZRiWdKId bFHPOOL73IE8ZveQBSsOSUPpRXs+fntqb2Yigcjy2EhmOIQJE7nCBkvanSkZZpERBSqM poao120ftXvqfKenO4UR260QjnOut5xB+Tf6NJ2QWXBhD3PSPS3GWd2ftFuXlAPE0HZ1 lXKw== X-Gm-Message-State: ANhLgQ3i+qAlyU7LBMztuVMNF/omL/1jWP3rCwJOgeTRpuX5/wnE9hsc 8khQSDepNFYHfvvJHdsFPcWKvQqj9fc= X-Google-Smtp-Source: ADFU+vsUxjzbIEX9R914KDjsI/HzBW8ale8XFSqRRCX4A8/y6Mft3ya7FgdMIWOlY+OErYCIPhFEPQ== X-Received: by 2002:a5d:4692:: with SMTP id u18mr4722577wrq.206.1583336874872; Wed, 04 Mar 2020 07:47:54 -0800 (PST) Received: from kpsingh-kernel.localdomain ([2a00:79e1:abc:308:8ca0:6f80:af01:b24]) by smtp.gmail.com with ESMTPSA id u25sm4816091wml.17.2020.03.04.07.47.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Mar 2020 07:47:54 -0800 (PST) From: KP Singh To: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Paul Turner , Jann Horn , Florent Revest , Brendan Jackman Subject: [PATCH bpf-next v3 0/7] Introduce BPF_MODIFY_RET tracing progs Date: Wed, 4 Mar 2020 16:47:40 +0100 Message-Id: <20200304154747.23506-1-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: KP Singh v2 -> v3: * bpf_trampoline_update_progs -> bpf_trampoline_get_progs + const qualification. * Typos in commit messages. * Added Andrii's Acks. v1 -> v2: * Adressed Andrii's feedback. * Fixed a bug that Alexei noticed about nop generation. * Rebase. This was brought up in the KRSI v4 discussion and found to be useful both for security and tracing programs. https://lore.kernel.org/bpf/20200225193108.GB22391@chromium.org/ The modify_return programs are allowed for security hooks (with an extra CAP_MAC_ADMIN check) and functions whitelisted for error injection (ALLOW_ERROR_INJECTION). The "security_" check is expected to be cleaned up with the KRSI patch series. Here is an example of how a fmod_ret program behaves: int func_to_be_attached(int a, int b) { <--- do_fentry do_fmod_ret: if (ret != 0) goto do_fexit; original_function: } <--- do_fexit ALLOW_ERROR_INJECTION(func_to_be_attached, ERRNO) The fmod_ret program attached to this function can be defined as: SEC("fmod_ret/func_to_be_attached") int BPF_PROG(func_name, int a, int b, int ret) { // This will skip the original function logic. return -1; } KP Singh (7): bpf: Refactor trampoline update code bpf: JIT helpers for fmod_ret progs bpf: Introduce BPF_MODIFY_RETURN bpf: Attachment verification for BPF_MODIFY_RETURN tools/libbpf: Add support for BPF_MODIFY_RETURN bpf: Add test ops for BPF_PROG_TYPE_TRACING bpf: Add selftests for BPF_MODIFY_RETURN arch/x86/net/bpf_jit_comp.c | 279 +++++++++++++----- include/linux/bpf.h | 24 +- include/uapi/linux/bpf.h | 1 + kernel/bpf/bpf_struct_ops.c | 12 +- kernel/bpf/btf.c | 27 +- kernel/bpf/syscall.c | 1 + kernel/bpf/trampoline.c | 65 ++-- kernel/bpf/verifier.c | 32 ++ kernel/trace/bpf_trace.c | 1 + net/bpf/test_run.c | 57 +++- tools/include/uapi/linux/bpf.h | 1 + tools/lib/bpf/libbpf.c | 4 + .../selftests/bpf/prog_tests/fentry_fexit.c | 12 +- .../selftests/bpf/prog_tests/fentry_test.c | 14 +- .../selftests/bpf/prog_tests/fexit_test.c | 69 ++--- .../selftests/bpf/prog_tests/modify_return.c | 65 ++++ .../selftests/bpf/progs/modify_return.c | 49 +++ 17 files changed, 526 insertions(+), 187 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/modify_return.c create mode 100644 tools/testing/selftests/bpf/progs/modify_return.c