From patchwork Tue Sep 10 11:55:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126208 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 231A2C4740A for ; Tue, 10 Sep 2019 11:56:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2DA8208E4 for ; Tue, 10 Sep 2019 11:56:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="Q0Kaw0aK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731908AbfIJL41 (ORCPT ); Tue, 10 Sep 2019 07:56:27 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:40791 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730510AbfIJL4Z (ORCPT ); Tue, 10 Sep 2019 07:56:25 -0400 Received: by mail-wr1-f65.google.com with SMTP id w13so19613128wru.7 for ; Tue, 10 Sep 2019 04:56:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lBurlrFx9NApN8HZXacuxACjRWwabjr3caQe3nHYfOw=; b=Q0Kaw0aKuZh6JKp4CnFHajfh/KoDL65xY1A3dfXqWnw4AllFop46Yyi667Eb31Yixz bUGKATekwkZveLZqkXzHMHfXMmuoLtvU5Z/qmCEajalJxZNZxUdU7CgoCDDEHtyZt+MT sBKDUrgZvW6oULiILCPpZZpiriwGuxI3E4fl8= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=lBurlrFx9NApN8HZXacuxACjRWwabjr3caQe3nHYfOw=; b=n0XZYMYIFX1Kw1LoxLtuirgj5uRIiKXvgo/uINQhkE8pzJMc2GmIHJAq13bgsZqu6h KuCWJ0aGTvmr0vTj6kTUb90Z5JRRwEghFXw+XLp0fNjcW9LXQXfawTRQHLTAsNk9SfX2 bji84zj139B0dS5ryD2V6sDtqDcpjtAZNeje2l/Xa4QruNUCys8VM7fcMilm7viVCS2I 5lN2uH97nvaTZhKuUq+uO0X9hy37nDMMz7nQtd+UBxoQOkEbuwNZAM7gJiXidqxhgw5N ATM+tDk0IaHMhxtDC4AqOHfwB5Se0Neqn7d7jIoZmFBzASaNm1vpE5xx6i0j9zY4t6Cd 3rZg== X-Gm-Message-State: APjAAAWertLUSPfmgmxO79gp0j3iPnO2cQrnjBjr0Q3o1Ag1CCnfDPV/ ujrk9/tLeo6zBWexi80fli/Hm1T7a+w= X-Google-Smtp-Source: APXvYqwryehlOVJaXOszzD6q1im3sis23Rsk48FLKSO/q65Oy3onJ/O04Z3dY67MtlwB+Nif8ujPPw== X-Received: by 2002:adf:e48f:: with SMTP id i15mr2908802wrm.26.1568116583227; Tue, 10 Sep 2019 04:56:23 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:22 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 01/14] krsi: Add a skeleton and config options for the KRSI LSM Date: Tue, 10 Sep 2019 13:55:14 +0200 Message-Id: <20190910115527.5235-2-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh The LSM can be enabled by: - Enabling CONFIG_SECURITY_KRSI. - Adding "krsi" to the CONFIG_LSM string. Signed-off-by: KP Singh --- MAINTAINERS | 5 +++++ security/Kconfig | 1 + security/Makefile | 2 ++ security/krsi/Kconfig | 22 ++++++++++++++++++++++ security/krsi/Makefile | 1 + security/krsi/krsi.c | 24 ++++++++++++++++++++++++ 6 files changed, 55 insertions(+) create mode 100644 security/krsi/Kconfig create mode 100644 security/krsi/Makefile create mode 100644 security/krsi/krsi.c diff --git a/MAINTAINERS b/MAINTAINERS index 9cbcf167bdd0..8e0364391d8b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9002,6 +9002,11 @@ F: include/linux/kprobes.h F: include/asm-generic/kprobes.h F: kernel/kprobes.c +KRSI SECURITY MODULE +M: KP Singh +S: Supported +F: security/krsi/ + KS0108 LCD CONTROLLER DRIVER M: Miguel Ojeda Sandonis S: Maintained diff --git a/security/Kconfig b/security/Kconfig index 0d65594b5196..febf7953803f 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -236,6 +236,7 @@ source "security/tomoyo/Kconfig" source "security/apparmor/Kconfig" source "security/loadpin/Kconfig" source "security/yama/Kconfig" +source "security/krsi/Kconfig" source "security/safesetid/Kconfig" source "security/integrity/Kconfig" diff --git a/security/Makefile b/security/Makefile index c598b904938f..25779ce89bf2 100644 --- a/security/Makefile +++ b/security/Makefile @@ -9,6 +9,7 @@ subdir-$(CONFIG_SECURITY_SMACK) += smack subdir-$(CONFIG_SECURITY_TOMOYO) += tomoyo subdir-$(CONFIG_SECURITY_APPARMOR) += apparmor subdir-$(CONFIG_SECURITY_YAMA) += yama +subdir-$(CONFIG_SECURITY_KRSI) += krsi subdir-$(CONFIG_SECURITY_LOADPIN) += loadpin subdir-$(CONFIG_SECURITY_SAFESETID) += safesetid @@ -25,6 +26,7 @@ obj-$(CONFIG_AUDIT) += lsm_audit.o obj-$(CONFIG_SECURITY_TOMOYO) += tomoyo/ obj-$(CONFIG_SECURITY_APPARMOR) += apparmor/ obj-$(CONFIG_SECURITY_YAMA) += yama/ +obj-$(CONFIG_SECURITY_KRSI) += krsi/ obj-$(CONFIG_SECURITY_LOADPIN) += loadpin/ obj-$(CONFIG_SECURITY_SAFESETID) += safesetid/ obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o diff --git a/security/krsi/Kconfig b/security/krsi/Kconfig new file mode 100644 index 000000000000..bf5eab4355af --- /dev/null +++ b/security/krsi/Kconfig @@ -0,0 +1,22 @@ +config SECURITY_KRSI + bool "Runtime Security Instrumentation (BPF-based MAC and audit policy)" + depends on SECURITY + depends on SECURITYFS + depends on BPF + depends on BPF_SYSCALL + help + This selects the Kernel Runtime Security Instrumentation + LSM which allows dynamic instrumentation of the security hooks with + eBPF programs. The LSM creates per-hook files in securityfs to which + eBPF programs can be attached. + + If you are unsure how to answer this question, answer N. + +config SECURITY_KRSI_ENFORCE + bool "Deny operations based on the evaluation of the attached programs" + depends on SECURITY_KRSI + help + eBPF programs attached to hooks can be used for both auditing and + enforcement. Enabling enforcement implies that the evaluation result + from the attached eBPF programs will allow and deny the operation + guarded by the security hook. diff --git a/security/krsi/Makefile b/security/krsi/Makefile new file mode 100644 index 000000000000..73320e8d16f8 --- /dev/null +++ b/security/krsi/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SECURITY_KRSI) := krsi.o diff --git a/security/krsi/krsi.c b/security/krsi/krsi.c new file mode 100644 index 000000000000..9ce4f56fb78d --- /dev/null +++ b/security/krsi/krsi.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +static int krsi_process_execution(struct linux_binprm *bprm) +{ + return 0; +} + +static struct security_hook_list krsi_hooks[] __lsm_ro_after_init = { + LSM_HOOK_INIT(bprm_check_security, krsi_process_execution), +}; + +static int __init krsi_init(void) +{ + security_add_hooks(krsi_hooks, ARRAY_SIZE(krsi_hooks), "krsi"); + pr_info("eBPF and LSM are friends now.\n"); + return 0; +} + +DEFINE_LSM(krsi) = { + .name = "krsi", + .init = krsi_init, +}; From patchwork Tue Sep 10 11:55:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126209 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AD32C3A5A2 for ; Tue, 10 Sep 2019 11:56:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 021112084D for ; Tue, 10 Sep 2019 11:56:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="QS51rrwY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732031AbfIJL4c (ORCPT ); Tue, 10 Sep 2019 07:56:32 -0400 Received: from mail-wr1-f42.google.com ([209.85.221.42]:39524 "EHLO mail-wr1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731884AbfIJL42 (ORCPT ); Tue, 10 Sep 2019 07:56:28 -0400 Received: by mail-wr1-f42.google.com with SMTP id t16so19620896wra.6 for ; Tue, 10 Sep 2019 04:56:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=pLJjYP1MYZ5Grpv+ShfvxxQJ0LT2gSMMnI/wBw8xz3g=; b=QS51rrwYwcJoe4+24GwRHHVMqMeXsTE54fUIhjbc1X5Gq+NzXDwJcWkAXLRxS9ugwb 5G9duwPv6NvZLbkHCIcwMVnQu+QBrhWm4wDKo8Yoi/h56zMNzs2cJlaBCap8e+1kN7OP XDz4S4i2wY8VH/8IVCJXFYsFFcDETEnqXoZtM= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=pLJjYP1MYZ5Grpv+ShfvxxQJ0LT2gSMMnI/wBw8xz3g=; b=skIodaLaS5UR7tWgQFzbFl0H3qn3r84H/nzkVcLvpMyjjtfChcbDYwn6i95Jh6Xf7/ IngLtFuJErZCiwMwKi4MrIF/hr9NzPHhHbBz0ZWkC4uMhmEMay2B2sbSMDoAOoz1F9fW lPTaqqya/J4l8RbC2fwwSPm8JwIwSHu9eODZnCDer5TxlOqrigNMmnC0+eeBE8OyhRrI yJzJq+3g50hu+kGDaA4VNlAVg4HakmuaHbdav0/+5NfsArO1uxlRPLoCrZrBPnPDxzpy 2BjJD02OB6MHk89PJR5/RJ/pw1ARLpraw3ydL36uIEqZtY/QuudVVYa30pTjDtHEmG2M V4ZA== X-Gm-Message-State: APjAAAXKqChk2fTIcQmTXaeTTXnHVMJhJrYn62O1W52u9l7i8O3t8bPl zh13+zmm7RQL7OddZoPlgUIfm79DZZU= X-Google-Smtp-Source: APXvYqwOG047syseWRc2VMwNZUDgQPGtjwe5XxRakqNhR8trEgOBjooO3kdOK7zJI821xK6j9IV5bw== X-Received: by 2002:a5d:4745:: with SMTP id o5mr22298390wrs.125.1568116585087; Tue, 10 Sep 2019 04:56:25 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:24 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 02/14] krsi: Introduce types for KRSI eBPF Date: Tue, 10 Sep 2019 13:55:15 +0200 Message-Id: <20190910115527.5235-3-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh KRSI intrdocues a new eBPF program type BPF_PROG_TYPE_KRSI with an expected attach type of BPF_KRSI. An -EINVAL error is returned if an attachment is requested. Signed-off-by: KP Singh --- include/linux/bpf_types.h | 3 +++ include/uapi/linux/bpf.h | 2 ++ kernel/bpf/syscall.c | 6 ++++++ security/krsi/Makefile | 2 +- security/krsi/ops.c | 10 ++++++++++ 5 files changed, 22 insertions(+), 1 deletion(-) create mode 100644 security/krsi/ops.c diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index eec5aeeeaf92..129594c09b5c 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -38,6 +38,9 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2) #ifdef CONFIG_INET BPF_PROG_TYPE(BPF_PROG_TYPE_SK_REUSEPORT, sk_reuseport) #endif +#ifdef CONFIG_SECURITY_KRSI +BPF_PROG_TYPE(BPF_PROG_TYPE_KRSI, krsi) +#endif BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index a5aa7d3ac6a1..32ab38f1a2fe 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -171,6 +171,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_CGROUP_SYSCTL, BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, BPF_PROG_TYPE_CGROUP_SOCKOPT, + BPF_PROG_TYPE_KRSI, }; enum bpf_attach_type { @@ -197,6 +198,7 @@ enum bpf_attach_type { BPF_CGROUP_UDP6_RECVMSG, BPF_CGROUP_GETSOCKOPT, BPF_CGROUP_SETSOCKOPT, + BPF_KRSI, __MAX_BPF_ATTACH_TYPE }; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 5d141f16f6fa..f38a539f7e67 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1915,6 +1915,9 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_LIRC_MODE2: ptype = BPF_PROG_TYPE_LIRC_MODE2; break; + case BPF_KRSI: + ptype = BPF_PROG_TYPE_KRSI; + break; case BPF_FLOW_DISSECTOR: ptype = BPF_PROG_TYPE_FLOW_DISSECTOR; break; @@ -1946,6 +1949,9 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_PROG_TYPE_LIRC_MODE2: ret = lirc_prog_attach(attr, prog); break; + case BPF_PROG_TYPE_KRSI: + ret = -EINVAL; + break; case BPF_PROG_TYPE_FLOW_DISSECTOR: ret = skb_flow_dissector_bpf_prog_attach(attr, prog); break; diff --git a/security/krsi/Makefile b/security/krsi/Makefile index 73320e8d16f8..660cc1f422fd 100644 --- a/security/krsi/Makefile +++ b/security/krsi/Makefile @@ -1 +1 @@ -obj-$(CONFIG_SECURITY_KRSI) := krsi.o +obj-$(CONFIG_SECURITY_KRSI) := krsi.o ops.o diff --git a/security/krsi/ops.c b/security/krsi/ops.c new file mode 100644 index 000000000000..f2de3bd9621e --- /dev/null +++ b/security/krsi/ops.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +const struct bpf_prog_ops krsi_prog_ops = { +}; + +const struct bpf_verifier_ops krsi_verifier_ops = { +}; From patchwork Tue Sep 10 11:55:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126222 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4EEA6C3A5A2 for ; Tue, 10 Sep 2019 11:57:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 269412084D for ; Tue, 10 Sep 2019 11:57:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="U2yeuy49" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732253AbfIJL4d (ORCPT ); Tue, 10 Sep 2019 07:56:33 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:43664 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731924AbfIJL42 (ORCPT ); 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[213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:26 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 03/14] bpf: krsi: sync BPF UAPI header with tools Date: Tue, 10 Sep 2019 13:55:16 +0200 Message-Id: <20190910115527.5235-4-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh Signed-off-by: KP Singh --- tools/include/uapi/linux/bpf.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index a5aa7d3ac6a1..32ab38f1a2fe 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -171,6 +171,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_CGROUP_SYSCTL, BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, BPF_PROG_TYPE_CGROUP_SOCKOPT, + BPF_PROG_TYPE_KRSI, }; enum bpf_attach_type { @@ -197,6 +198,7 @@ enum bpf_attach_type { BPF_CGROUP_UDP6_RECVMSG, BPF_CGROUP_GETSOCKOPT, BPF_CGROUP_SETSOCKOPT, + BPF_KRSI, __MAX_BPF_ATTACH_TYPE }; From patchwork Tue Sep 10 11:55:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126221 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D3A0C3A5A2 for ; Tue, 10 Sep 2019 11:57:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF1B92084D for ; Tue, 10 Sep 2019 11:57:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="aE3lyKZ7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732852AbfIJL4e (ORCPT ); Tue, 10 Sep 2019 07:56:34 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:40811 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731955AbfIJL4a (ORCPT ); Tue, 10 Sep 2019 07:56:30 -0400 Received: by mail-wr1-f67.google.com with SMTP id w13so19613692wru.7 for ; Tue, 10 Sep 2019 04:56:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=neu1+SNcx3+JCL0eDuwZqNrNaVee6BTW6AWaLZCdbp4=; b=aE3lyKZ76kk0jH5fvUUBsWVhrptGL+yyoArZZ/LYIyxLKjUsI3xcSWR/3CoI7o4geo /i/t/VFvVXi5My78PegN4xOs3dR1JpxwoZJK569R3IIjMrNvWO5a39fQ7dv+f/dY3Fpn amkaj9Rl3iCRNkW23DZ49u7Fguh5Tf0RlWVOU= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=neu1+SNcx3+JCL0eDuwZqNrNaVee6BTW6AWaLZCdbp4=; b=i/1cxFXYx1W+/gKQX8oGJjcJeQ8ZI4GrNhFBNgBaUdzOqkS+KXdMJC+dviVibOfMaP 41aQelzwRQmIExqznXMtlDUNuEmJeibOUAxOqMoSd28ILWtYuVGysGRYFQ1Q9NM4QueC ljsFf5Eoc4+WxVkPZ6Roc++gYBNm/Gh0dmP+mqWWbd7SCudXBj4A3RA40oTBIoyTTHvn Rrh/zp8tE4i7hK3lMhjYtOjFex5Eb3Iilc/R9qXcPY8I9DXUtzO5qsQ5tD/pC4kzaN9F L+zkGX7jX3ewEKVa9EphP7wHu2mV16Mr5BEYrtbFzCoxYh/wAyIlet8H2sHHKvKw9Zd6 4aCA== X-Gm-Message-State: APjAAAVwNQApN7pL0W/RxF+D6XXC6iX56r8UGGP3TbNBwqO1d3wT3LTV EFUng2d2ldD7lNge8ad6p9EHkdSBLsY= X-Google-Smtp-Source: APXvYqz0I8AKSm98TOHLRk9qzO54R/9/vbhmrvD8H96WG5P1Y90KCbbnzpJnNJ733VZXkbnkVhXZGA== X-Received: by 2002:adf:ce81:: with SMTP id r1mr25914250wrn.114.1568116588890; Tue, 10 Sep 2019 04:56:28 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:28 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 04/14] krsi: Add support in libbpf for BPF_PROG_TYPE_KRSI Date: Tue, 10 Sep 2019 13:55:17 +0200 Message-Id: <20190910115527.5235-5-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh Update the libbpf library with functionality to load and attach a program type BPF_PROG_TYPE_KRSI. Since the bpf_prog_load does not allow the specification of an expected attach type, it's recommended to use bpf_prog_load_xattr and set the expected attach type as KRSI. Signed-off-by: KP Singh --- tools/lib/bpf/libbpf.c | 4 ++++ tools/lib/bpf/libbpf.h | 2 ++ tools/lib/bpf/libbpf.map | 2 ++ tools/lib/bpf/libbpf_probes.c | 1 + 4 files changed, 9 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2b57d7ea7836..3cc86bbc68cd 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2676,6 +2676,7 @@ static bool bpf_prog_type__needs_kver(enum bpf_prog_type type) case BPF_PROG_TYPE_PERF_EVENT: case BPF_PROG_TYPE_CGROUP_SYSCTL: case BPF_PROG_TYPE_CGROUP_SOCKOPT: + case BPF_PROG_TYPE_KRSI: return false; case BPF_PROG_TYPE_KPROBE: default: @@ -3536,6 +3537,7 @@ bool bpf_program__is_##NAME(const struct bpf_program *prog) \ } \ BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER); +BPF_PROG_TYPE_FNS(krsi, BPF_PROG_TYPE_KRSI); BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE); BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS); BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT); @@ -3590,6 +3592,8 @@ static const struct { BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT), BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT), BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL), + BPF_APROG_SEC("krsi", BPF_PROG_TYPE_KRSI, + BPF_KRSI), BPF_APROG_SEC("cgroup_skb/ingress", BPF_PROG_TYPE_CGROUP_SKB, BPF_CGROUP_INET_INGRESS), BPF_APROG_SEC("cgroup_skb/egress", BPF_PROG_TYPE_CGROUP_SKB, diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 5cbf459ece0b..8781d29b4035 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -261,6 +261,7 @@ LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog); LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog); LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog); LIBBPF_API int bpf_program__set_perf_event(struct bpf_program *prog); +LIBBPF_API int bpf_program__set_krsi(struct bpf_program *prog); LIBBPF_API void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type); LIBBPF_API void @@ -275,6 +276,7 @@ LIBBPF_API bool bpf_program__is_sched_cls(const struct bpf_program *prog); LIBBPF_API bool bpf_program__is_sched_act(const struct bpf_program *prog); LIBBPF_API bool bpf_program__is_xdp(const struct bpf_program *prog); LIBBPF_API bool bpf_program__is_perf_event(const struct bpf_program *prog); +LIBBPF_API bool bpf_program__is_krsi(const struct bpf_program *prog); /* * No need for __attribute__((packed)), all members of 'bpf_map_def' diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index f9d316e873d8..75b8fe419c11 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -68,6 +68,7 @@ LIBBPF_0.0.1 { bpf_prog_test_run_xattr; bpf_program__fd; bpf_program__is_kprobe; + bpf_program__is_krsi; bpf_program__is_perf_event; bpf_program__is_raw_tracepoint; bpf_program__is_sched_act; @@ -85,6 +86,7 @@ LIBBPF_0.0.1 { bpf_program__set_expected_attach_type; bpf_program__set_ifindex; bpf_program__set_kprobe; + bpf_program__set_krsi; bpf_program__set_perf_event; bpf_program__set_prep; bpf_program__set_priv; diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index ace1a0708d99..cc515a36794d 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -102,6 +102,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, case BPF_PROG_TYPE_FLOW_DISSECTOR: case BPF_PROG_TYPE_CGROUP_SYSCTL: case BPF_PROG_TYPE_CGROUP_SOCKOPT: + case BPF_PROG_TYPE_KRSI: default: break; } From patchwork Tue Sep 10 11:55:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126210 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CF98C4740A for ; 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[213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:30 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 05/14] krsi: Initialize KRSI hooks and create files in securityfs Date: Tue, 10 Sep 2019 13:55:18 +0200 Message-Id: <20190910115527.5235-6-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh The LSM creates files in securityfs for each hook registered with the LSM. /sys/kernel/security/bpf/ The initialization of the hooks is done collectively in an internal header "hooks.h" which results in: * Creation of a file for the hook in the securityfs. * Allocation of a krsi_hook data structure which stores a pointer to the dentry of the newly created file in securityfs. * A pointer to the krsi_hook data structure is stored in the private d_fsdata of dentry of the file created in securityFS. These files will later be used to specify an attachment target during BPF_PROG_LOAD. Signed-off-by: KP Singh --- security/krsi/Makefile | 4 +- security/krsi/include/hooks.h | 21 ++++++++ security/krsi/include/krsi_fs.h | 19 +++++++ security/krsi/include/krsi_init.h | 45 ++++++++++++++++ security/krsi/krsi.c | 16 +++++- security/krsi/krsi_fs.c | 88 +++++++++++++++++++++++++++++++ 6 files changed, 191 insertions(+), 2 deletions(-) create mode 100644 security/krsi/include/hooks.h create mode 100644 security/krsi/include/krsi_fs.h create mode 100644 security/krsi/include/krsi_init.h create mode 100644 security/krsi/krsi_fs.c diff --git a/security/krsi/Makefile b/security/krsi/Makefile index 660cc1f422fd..4586241f16e1 100644 --- a/security/krsi/Makefile +++ b/security/krsi/Makefile @@ -1 +1,3 @@ -obj-$(CONFIG_SECURITY_KRSI) := krsi.o ops.o +obj-$(CONFIG_SECURITY_KRSI) := krsi.o krsi_fs.o ops.o + +ccflags-y := -I$(srctree)/security/krsi -I$(srctree)/security/krsi/include diff --git a/security/krsi/include/hooks.h b/security/krsi/include/hooks.h new file mode 100644 index 000000000000..e070c452b5de --- /dev/null +++ b/security/krsi/include/hooks.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * The hooks for the KRSI LSM are declared in this file. + * + * This header MUST NOT be included directly and should + * be only used to initialize the hooks lists. + * + * Format: + * + * KRSI_HOOK_INIT(TYPE, NAME, LSM_HOOK, KRSI_HOOK_FN) + * + * KRSI adds one layer of indirection between the name of the hook and the name + * it exposes to the userspace in Security FS to prevent the userspace from + * breaking in case the name of the hook changes in the kernel or if there's + * another LSM hook that maps better to the represented security behaviour. + */ +KRSI_HOOK_INIT(PROCESS_EXECUTION, + process_execution, + bprm_check_security, + krsi_process_execution) diff --git a/security/krsi/include/krsi_fs.h b/security/krsi/include/krsi_fs.h new file mode 100644 index 000000000000..38134661d8d6 --- /dev/null +++ b/security/krsi/include/krsi_fs.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _KRSI_FS_H +#define _KRSI_FS_H + +#include +#include +#include + +bool is_krsi_hook_file(struct file *f); + +/* + * The name of the directory created in securityfs + * + * /sys/kernel/security/ + */ +#define KRSI_SFS_NAME "krsi" + +#endif /* _KRSI_FS_H */ diff --git a/security/krsi/include/krsi_init.h b/security/krsi/include/krsi_init.h new file mode 100644 index 000000000000..68755182a031 --- /dev/null +++ b/security/krsi/include/krsi_init.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _KRSI_INIT_H +#define _KRSI_INIT_H + +#include "krsi_fs.h" + +enum krsi_hook_type { + PROCESS_EXECUTION, + __MAX_KRSI_HOOK_TYPE, /* delimiter */ +}; + +extern int krsi_fs_initialized; +/* + * The LSM creates one file per hook. + * + * A pointer to krsi_hook data structure is stored in the + * private fsdata of the dentry of the per-hook file created + * in securityfs. + */ +struct krsi_hook { + /* + * The name of the security hook, a file with this name will be created + * in the securityfs. + */ + const char *name; + /* + * The type of the LSM hook, the LSM uses this to index the list of the + * hooks to run the eBPF programs that may have been attached. + */ + enum krsi_hook_type h_type; + /* + * The dentry of the file created in securityfs. + */ + struct dentry *h_dentry; +}; + +extern struct krsi_hook krsi_hooks_list[]; + +#define krsi_for_each_hook(hook) \ + for ((hook) = &krsi_hooks_list[0]; \ + (hook) < &krsi_hooks_list[__MAX_KRSI_HOOK_TYPE]; \ + (hook)++) + +#endif /* _KRSI_INIT_H */ diff --git a/security/krsi/krsi.c b/security/krsi/krsi.c index 9ce4f56fb78d..77d7e2f91172 100644 --- a/security/krsi/krsi.c +++ b/security/krsi/krsi.c @@ -2,13 +2,27 @@ #include +#include "krsi_init.h" + +struct krsi_hook krsi_hooks_list[] = { + #define KRSI_HOOK_INIT(TYPE, NAME, H, I) \ + [TYPE] = { \ + .h_type = TYPE, \ + .name = #NAME, \ + }, + #include "hooks.h" + #undef KRSI_HOOK_INIT +}; + static int krsi_process_execution(struct linux_binprm *bprm) { return 0; } static struct security_hook_list krsi_hooks[] __lsm_ro_after_init = { - LSM_HOOK_INIT(bprm_check_security, krsi_process_execution), + #define KRSI_HOOK_INIT(T, N, HOOK, IMPL) LSM_HOOK_INIT(HOOK, IMPL), + #include "hooks.h" + #undef KRSI_HOOK_INIT }; static int __init krsi_init(void) diff --git a/security/krsi/krsi_fs.c b/security/krsi/krsi_fs.c new file mode 100644 index 000000000000..604f826cee5c --- /dev/null +++ b/security/krsi/krsi_fs.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include + +#include "krsi_fs.h" +#include "krsi_init.h" + +extern struct krsi_hook krsi_hooks_list[]; + +static struct dentry *krsi_dir; + +static const struct file_operations krsi_hook_ops = { + .llseek = generic_file_llseek, +}; + +int krsi_fs_initialized; + +bool is_krsi_hook_file(struct file *f) +{ + return f->f_op == &krsi_hook_ops; +} + +static void __init krsi_free_hook(struct krsi_hook *h) +{ + securityfs_remove(h->h_dentry); + h->h_dentry = NULL; +} + +static int __init krsi_init_hook(struct krsi_hook *h, struct dentry *parent) +{ + struct dentry *h_dentry; + int ret; + + h_dentry = securityfs_create_file(h->name, 0600, parent, + NULL, &krsi_hook_ops); + + if (IS_ERR(h_dentry)) + return PTR_ERR(h_dentry); + h_dentry->d_fsdata = h; + h->h_dentry = h_dentry; + return 0; + +error: + securityfs_remove(h_dentry); + return ret; +} + +static int __init krsi_fs_init(void) +{ + + struct krsi_hook *hook; + int ret; + + krsi_dir = securityfs_create_dir(KRSI_SFS_NAME, NULL); + if (IS_ERR(krsi_dir)) { + ret = PTR_ERR(krsi_dir); + pr_err("Unable to create krsi sysfs dir: %d\n", ret); + krsi_dir = NULL; + return ret; + } + + /* + * If there is an error in initializing a hook, the initialization + * logic makes sure that it has been freed, but this means that + * cleanup should be called for all the other hooks. The cleanup + * logic handles uninitialized data. + */ + krsi_for_each_hook(hook) { + ret = krsi_init_hook(hook, krsi_dir); + if (ret < 0) + goto error; + } + + krsi_fs_initialized = 1; + return 0; +error: + krsi_for_each_hook(hook) + krsi_free_hook(hook); + securityfs_remove(krsi_dir); + return ret; +} + +late_initcall(krsi_fs_init); From patchwork Tue Sep 10 11:55:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126219 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0024C3A5A2 for ; Tue, 10 Sep 2019 11:57:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC8CF21019 for ; Tue, 10 Sep 2019 11:57:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="PnzCgXjN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387677AbfIJL4i (ORCPT ); Tue, 10 Sep 2019 07:56:38 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:43686 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731955AbfIJL4g (ORCPT ); Tue, 10 Sep 2019 07:56:36 -0400 Received: by mail-wr1-f65.google.com with SMTP id q17so14903772wrx.10 for ; Tue, 10 Sep 2019 04:56:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=khTLae9RCwkUqy9+7uO8vTkotEuqqfm01bDE7aGuRNw=; b=PnzCgXjNvnuPNnTWHRjmLY/R+M3PqGR3Yjz+BOo6oYQ/vgpY2KdtwLmOY34jos2X0H X3rOTwaix0gt/O6HYjtB2s8QAbKS5Tpe2mzz7c305PYW4/zqsnVcjd1V6fP+pL3S0Yri w/9zPw+SNOhM23ea/k4eAC3E1R2AUiDZNF0r4= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=khTLae9RCwkUqy9+7uO8vTkotEuqqfm01bDE7aGuRNw=; b=R/D/NpCfedrqdrN6dvkVvO7V5m8ORfnF6ITjDTBpaQOOlpSUziw/xw9KlL4X1gDaOU G0WhJeWKQqS7GstIeEkphTTj1v7YauCGwxKirehGHzKHA3pID0SVnQ+GJNBeRk1Ybxr0 wlc+wlwIDu9BpVkn32vRrDAliZnYKIyzMG7sTZ1PlURBoW7dyNyZC3n0pLglOuuRbREg 1uQtEx+CciCE1pQ8T0a7CzTlvEGJ4PIxIh+d/imwRJ9HeqKxFp2ENtMu1VW/nskix1C3 OMn0AcGOzRdt+EE+HJ0GvPqcXPr4fXEU038RLbLQzbKIJtZbIIm4ojToZAU3wcjpGrWW sLvg== X-Gm-Message-State: APjAAAWk2JkAa8UKeK+LF3MzLVevPmVVL0diRTeqVqj5G8F5YIDceUvL jIb57A88RXeLSt+d6QaB5pVZnxsK/fk= X-Google-Smtp-Source: APXvYqxOn37aSDhqXLhP48ScKpNZDRSV1bh9pheAfKkJ1p3R44n3jR0uNlENRSQPjhBnLLFHHeyaFA== X-Received: by 2002:adf:ee10:: with SMTP id y16mr22300305wrn.47.1568116592680; Tue, 10 Sep 2019 04:56:32 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:32 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 06/14] krsi: Implement eBPF operations, attachment and execution Date: Tue, 10 Sep 2019 13:55:19 +0200 Message-Id: <20190910115527.5235-7-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh A user space program can attach an eBPF program by: hook_fd = open("/sys/kernel/security/krsi/process_execution", O_RDWR) prog_fd = bpf(BPF_PROG_LOAD, ...) bpf(BPF_PROG_ATTACH, hook_fd, prog_fd) When such an attach call is received, the attachment logic looks up the dentry and appends the program to the bpf_prog_array. The BPF programs are stored in a bpf_prog_array and writes to the array are guarded by a mutex. The eBPF programs are executed as a part of the LSM hook they are attached to. If any of the eBPF programs return an error (-ENOPERM) the action represented by the hook is denied. Signed-off-by: KP Singh --- include/linux/krsi.h | 18 ++++++ kernel/bpf/syscall.c | 3 +- security/krsi/include/krsi_init.h | 51 +++++++++++++++ security/krsi/krsi.c | 13 +++- security/krsi/krsi_fs.c | 28 ++++++++ security/krsi/ops.c | 102 ++++++++++++++++++++++++++++++ 6 files changed, 213 insertions(+), 2 deletions(-) create mode 100644 include/linux/krsi.h diff --git a/include/linux/krsi.h b/include/linux/krsi.h new file mode 100644 index 000000000000..c7d1790d0c1f --- /dev/null +++ b/include/linux/krsi.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _KRSI_H +#define _KRSI_H + +#include + +#ifdef CONFIG_SECURITY_KRSI +int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog); +#else +static inline int krsi_prog_attach(const union bpf_attr *attr, + struct bpf_prog *prog) +{ + return -EINVAL; +} +#endif /* CONFIG_SECURITY_KRSI */ + +#endif /* _KRSI_H */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index f38a539f7e67..ab063ed84258 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include #include @@ -1950,7 +1951,7 @@ static int bpf_prog_attach(const union bpf_attr *attr) ret = lirc_prog_attach(attr, prog); break; case BPF_PROG_TYPE_KRSI: - ret = -EINVAL; + ret = krsi_prog_attach(attr, prog); break; case BPF_PROG_TYPE_FLOW_DISSECTOR: ret = skb_flow_dissector_bpf_prog_attach(attr, prog); diff --git a/security/krsi/include/krsi_init.h b/security/krsi/include/krsi_init.h index 68755182a031..4e17ecacd4ed 100644 --- a/security/krsi/include/krsi_init.h +++ b/security/krsi/include/krsi_init.h @@ -5,12 +5,29 @@ #include "krsi_fs.h" +#include + enum krsi_hook_type { PROCESS_EXECUTION, __MAX_KRSI_HOOK_TYPE, /* delimiter */ }; extern int krsi_fs_initialized; + +struct krsi_bprm_ctx { + struct linux_binprm *bprm; +}; + +/* + * krsi_ctx is the context that is passed to all KRSI eBPF + * programs. + */ +struct krsi_ctx { + union { + struct krsi_bprm_ctx bprm_ctx; + }; +}; + /* * The LSM creates one file per hook. * @@ -33,10 +50,44 @@ struct krsi_hook { * The dentry of the file created in securityfs. */ struct dentry *h_dentry; + /* + * The mutex must be held when updating the progs attached to the hook. + */ + struct mutex mutex; + /* + * The eBPF programs that are attached to this hook. + */ + struct bpf_prog_array __rcu *progs; }; extern struct krsi_hook krsi_hooks_list[]; +static inline int krsi_run_progs(enum krsi_hook_type t, struct krsi_ctx *ctx) +{ + struct bpf_prog_array_item *item; + struct bpf_prog *prog; + struct krsi_hook *h = &krsi_hooks_list[t]; + int ret, retval = 0; + + preempt_disable(); + rcu_read_lock(); + + item = rcu_dereference(h->progs)->items; + while ((prog = READ_ONCE(item->prog))) { + ret = BPF_PROG_RUN(prog, ctx); + if (ret < 0) { + retval = ret; + goto out; + } + item++; + } + +out: + rcu_read_unlock(); + preempt_enable(); + return IS_ENABLED(CONFIG_SECURITY_KRSI_ENFORCE) ? retval : 0; +} + #define krsi_for_each_hook(hook) \ for ((hook) = &krsi_hooks_list[0]; \ (hook) < &krsi_hooks_list[__MAX_KRSI_HOOK_TYPE]; \ diff --git a/security/krsi/krsi.c b/security/krsi/krsi.c index 77d7e2f91172..d3a4a361c192 100644 --- a/security/krsi/krsi.c +++ b/security/krsi/krsi.c @@ -1,6 +1,9 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include +#include +#include #include "krsi_init.h" @@ -16,7 +19,15 @@ struct krsi_hook krsi_hooks_list[] = { static int krsi_process_execution(struct linux_binprm *bprm) { - return 0; + int ret; + struct krsi_ctx ctx; + + ctx.bprm_ctx = (struct krsi_bprm_ctx) { + .bprm = bprm, + }; + + ret = krsi_run_progs(PROCESS_EXECUTION, &ctx); + return ret; } static struct security_hook_list krsi_hooks[] __lsm_ro_after_init = { diff --git a/security/krsi/krsi_fs.c b/security/krsi/krsi_fs.c index 604f826cee5c..3ba18b52ce85 100644 --- a/security/krsi/krsi_fs.c +++ b/security/krsi/krsi_fs.c @@ -5,6 +5,8 @@ #include #include #include +#include +#include #include #include "krsi_fs.h" @@ -27,12 +29,29 @@ bool is_krsi_hook_file(struct file *f) static void __init krsi_free_hook(struct krsi_hook *h) { + struct bpf_prog_array_item *item; + /* + * This function is __init so we are guarranteed that there will be + * no concurrent access. + */ + struct bpf_prog_array *progs = rcu_dereference_raw(h->progs); + + if (progs) { + item = progs->items; + while (item->prog) { + bpf_prog_put(item->prog); + item++; + } + bpf_prog_array_free(progs); + } + securityfs_remove(h->h_dentry); h->h_dentry = NULL; } static int __init krsi_init_hook(struct krsi_hook *h, struct dentry *parent) { + struct bpf_prog_array __rcu *progs; struct dentry *h_dentry; int ret; @@ -41,6 +60,15 @@ static int __init krsi_init_hook(struct krsi_hook *h, struct dentry *parent) if (IS_ERR(h_dentry)) return PTR_ERR(h_dentry); + + mutex_init(&h->mutex); + progs = bpf_prog_array_alloc(0, GFP_KERNEL); + if (!progs) { + ret = -ENOMEM; + goto error; + } + + RCU_INIT_POINTER(h->progs, progs); h_dentry->d_fsdata = h; h->h_dentry = h_dentry; return 0; diff --git a/security/krsi/ops.c b/security/krsi/ops.c index f2de3bd9621e..cf4d06189aa1 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c @@ -1,10 +1,112 @@ // SPDX-License-Identifier: GPL-2.0 +#include +#include #include #include +#include +#include + +#include "krsi_init.h" +#include "krsi_fs.h" + +extern struct krsi_hook krsi_hooks_list[]; + +static struct krsi_hook *get_hook_from_fd(int fd) +{ + struct fd f = fdget(fd); + struct krsi_hook *h; + int ret; + + if (!f.file) { + ret = -EBADF; + goto error; + } + + if (!is_krsi_hook_file(f.file)) { + ret = -EINVAL; + goto error; + } + + /* + * The securityfs dentry never disappears, so we don't need to take a + * reference to it. + */ + h = file_dentry(f.file)->d_fsdata; + if (WARN_ON(!h)) { + ret = -EINVAL; + goto error; + } + fdput(f); + return h; + +error: + fdput(f); + return ERR_PTR(ret); +} + +int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + struct bpf_prog_array *old_array; + struct bpf_prog_array *new_array; + struct krsi_hook *h; + int ret = 0; + + h = get_hook_from_fd(attr->target_fd); + if (IS_ERR(h)) + return PTR_ERR(h); + + mutex_lock(&h->mutex); + old_array = rcu_dereference_protected(h->progs, + lockdep_is_held(&h->mutex)); + + ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); + if (ret < 0) { + ret = -ENOMEM; + goto unlock; + } + + rcu_assign_pointer(h->progs, new_array); + bpf_prog_array_free(old_array); + +unlock: + mutex_unlock(&h->mutex); + return ret; +} const struct bpf_prog_ops krsi_prog_ops = { }; +static bool krsi_prog_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + /* + * KRSI is conservative about any direct access in eBPF to + * prevent the users from depending on the internals of the kernel and + * aims at providing a rich eco-system of safe eBPF helpers as an API + * for accessing relevant information from the context. + */ + return false; +} + +static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id + func_id, + const struct bpf_prog + *prog) +{ + switch (func_id) { + case BPF_FUNC_map_lookup_elem: + return &bpf_map_lookup_elem_proto; + case BPF_FUNC_get_current_pid_tgid: + return &bpf_get_current_pid_tgid_proto; + default: + return NULL; + } +} + const struct bpf_verifier_ops krsi_verifier_ops = { + .get_func_proto = krsi_prog_func_proto, + .is_valid_access = krsi_prog_is_valid_access, }; From patchwork Tue Sep 10 11:55:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126211 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AF0FC3A5A2 for ; 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[213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:34 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 07/14] krsi: Check for premissions on eBPF attachment Date: Tue, 10 Sep 2019 13:55:20 +0200 Message-Id: <20190910115527.5235-8-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh Add validation checks for the attachment of eBPF programs. The following permissions are required: - CAP_SYS_ADMIN to load eBPF programs - CAP_MAC_ADMIN (to update the policy of an LSM) - The securityfs file being a KRSI hook and writable (O_RDWR) Signed-off-by: KP Singh --- security/krsi/ops.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/security/krsi/ops.c b/security/krsi/ops.c index cf4d06189aa1..a61508b7018f 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c @@ -23,11 +23,31 @@ static struct krsi_hook *get_hook_from_fd(int fd) goto error; } + /* + * Only CAP_MAC_ADMIN users are allowed to make + * changes to LSM hooks + */ + if (!capable(CAP_MAC_ADMIN)) { + ret = -EPERM; + goto error; + } + if (!is_krsi_hook_file(f.file)) { ret = -EINVAL; goto error; } + /* + * It's wrong to attach the program to the hook + * if the file is not opened for a write. Note that, + * this is an EBADF and not an EPERM because the file + * has been opened with an incorrect mode. + */ + if (!(f.file->f_mode & FMODE_WRITE)) { + ret = -EBADF; + goto error; + } + /* * The securityfs dentry never disappears, so we don't need to take a * reference to it. From patchwork Tue Sep 10 11:55:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126220 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D81B3C4740A for ; Tue, 10 Sep 2019 11:57:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4A4C21019 for ; Tue, 10 Sep 2019 11:57:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="lIcQYf/a" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393179AbfIJL5V (ORCPT ); Tue, 10 Sep 2019 07:57:21 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:47010 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733236AbfIJL4i (ORCPT ); Tue, 10 Sep 2019 07:56:38 -0400 Received: by mail-wr1-f67.google.com with SMTP id d17so6860478wrq.13 for ; Tue, 10 Sep 2019 04:56:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=oVQ7Tct8tU0DJx5s8h1k7biDl9I5KG0OFqo1Lpd86hc=; b=lIcQYf/amVBtQDfTxCxyvYoyuo7sxkZenk0YeowuFnzDH6o8iHr3Ldayw8ch8W5+Fa dRQYIkfrm5mFDKNUvGJOYCBnZmxaTxgckK4gIyg2wybSvUgyFr4Qyup1A5rGGxMnbdAf TujF0G6HNz/U56ZKm3MxmHZ9PCEw9y/TPRj+g= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=oVQ7Tct8tU0DJx5s8h1k7biDl9I5KG0OFqo1Lpd86hc=; b=KWC5jEAk03V2U9nE6PYuI9SFgeovjv/rcUAeO1VdLpbEBP4GMmwEQgCWh63bWMXSoK XERnyVhMIxvfRfQSQ5vM3f6L+vJnviT5C1o143zmBLgvhZQ+4gX5zMfNSMrUeyPtha/A bYfYTDzsI89rqy6C0aVo5t1eeT3vyL8i4WY0tQztdDE4RMJZ49+qRPL1k7u9toUam+mY bXRRTwYnBfwGDRe4ggmAruEFep+8wgGl/bGasjSoxUn2uSXrb3LYtAbKaXL0MHHKV54j +ew8rz1uiKlAOYQLqcW/ePpK5iHukFfy8JMq4NVl/CjWPxJw/9VOY4jOEOVIs1jmDYez JdOQ== X-Gm-Message-State: APjAAAX2h6HUGzSw6rdJJqiG1xob3u+CGKReVjOnPk5csHfMr23eeEYY ussNLl3LhEdXdo7C4Xgbwj21iRGBuHw= X-Google-Smtp-Source: APXvYqxsMV7T7MYZDqZj7+zf1X42YUxNEluEUNSWA8evGhzEfC93r4n95G3TeHM62hd43tXfDYT1jw== X-Received: by 2002:adf:e947:: with SMTP id m7mr26846741wrn.178.1568116596374; Tue, 10 Sep 2019 04:56:36 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:35 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 08/14] krsi: Show attached program names in hook read handler. Date: Tue, 10 Sep 2019 13:55:21 +0200 Message-Id: <20190910115527.5235-9-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh For inspectability the system administrator should be able to view the list of active KRSI programs: bash # cat /sys/kernel/security/krsi/process_execution bpf_prog1 Signed-off-by: KP Singh --- security/krsi/krsi_fs.c | 76 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 75 insertions(+), 1 deletion(-) diff --git a/security/krsi/krsi_fs.c b/security/krsi/krsi_fs.c index 3ba18b52ce85..0ebf4fabe935 100644 --- a/security/krsi/krsi_fs.c +++ b/security/krsi/krsi_fs.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -16,8 +17,81 @@ extern struct krsi_hook krsi_hooks_list[]; static struct dentry *krsi_dir; +static void *seq_start(struct seq_file *m, loff_t *pos) + __acquires(rcu) +{ + struct krsi_hook *h; + struct dentry *dentry; + struct bpf_prog_array *progs; + struct bpf_prog_array_item *item; + + /* + * rcu_read_lock() must be held before any return statement + * because the stop() will always be called and thus call + * rcu_read_unlock() + */ + rcu_read_lock(); + + dentry = file_dentry(m->file); + h = dentry->d_fsdata; + if (WARN_ON(!h)) + return ERR_PTR(-EFAULT); + + progs = rcu_dereference(h->progs); + if ((*pos) >= bpf_prog_array_length(progs)) + return NULL; + + item = progs->items + *pos; + if (!item->prog) + return NULL; + + return item; +} + +static void *seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct bpf_prog_array_item *item = v; + + item++; + ++*pos; + + if (!item->prog) + return NULL; + + return item; +} + +static void seq_stop(struct seq_file *m, void *v) + __releases(rcu) +{ + rcu_read_unlock(); +} + +static int show_prog(struct seq_file *m, void *v) +{ + struct bpf_prog_array_item *item = v; + + seq_printf(m, "%s\n", item->prog->aux->name); + return 0; +} + +static const struct seq_operations seq_ops = { + .show = show_prog, + .start = seq_start, + .next = seq_next, + .stop = seq_stop, +}; + +static int hook_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &seq_ops); +} + static const struct file_operations krsi_hook_ops = { - .llseek = generic_file_llseek, + .open = hook_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, }; int krsi_fs_initialized; From patchwork Tue Sep 10 11:55:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126212 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 620F7C3A5A2 for ; Tue, 10 Sep 2019 11:56:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38B002171F for ; 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[213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:37 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 09/14] krsi: Add a helper function for bpf_perf_event_output Date: Tue, 10 Sep 2019 13:55:22 +0200 Message-Id: <20190910115527.5235-10-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh This helper is mapped to the existing operation BPF_FUNC_perf_event_output. An example usage of this function would be: #define BUF_SIZE 64; struct bpf_map_def SEC("maps") perf_map = { .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, .key_size = sizeof(int), .value_size = sizeof(u32), .max_entries = MAX_CPUS, }; SEC("krsi") int bpf_prog1(void *ctx) { char buf[BUF_SIZE]; int len; u64 flags = BPF_F_CURRENT_CPU; /* some logic that fills up buf with len data*/ len = fill_up_buf(buf); if (len < 0) return len; if (len > BU) return 0; bpf_perf_event_output(ctx, &perf_map, flags, buf len); return 0; } A sample program that showcases the use of bpf_perf_event_output is added later. Signed-off-by: KP Singh --- security/krsi/ops.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/security/krsi/ops.c b/security/krsi/ops.c index a61508b7018f..57bd304a03f4 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c @@ -111,6 +111,26 @@ static bool krsi_prog_is_valid_access(int off, int size, return false; } +BPF_CALL_5(krsi_event_output, void *, log, + struct bpf_map *, map, u64, flags, void *, data, u64, size) +{ + if (unlikely(flags & ~(BPF_F_INDEX_MASK))) + return -EINVAL; + + return bpf_event_output(map, flags, data, size, NULL, 0, NULL); +} + +static const struct bpf_func_proto krsi_event_output_proto = { + .func = krsi_event_output, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_MEM, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog @@ -121,6 +141,8 @@ static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id return &bpf_map_lookup_elem_proto; case BPF_FUNC_get_current_pid_tgid: return &bpf_get_current_pid_tgid_proto; + case BPF_FUNC_perf_event_output: + return &krsi_event_output_proto; default: return NULL; } From patchwork Tue Sep 10 11:55:23 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126213 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23F9EC3A5A2 for ; Tue, 10 Sep 2019 11:56:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5EA0208E4 for ; Tue, 10 Sep 2019 11:56:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="L/JcmoL9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392977AbfIJL4r (ORCPT ); Tue, 10 Sep 2019 07:56:47 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:35640 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388243AbfIJL4o (ORCPT ); Tue, 10 Sep 2019 07:56:44 -0400 Received: by mail-wr1-f66.google.com with SMTP id g7so19677259wrx.2 for ; Tue, 10 Sep 2019 04:56:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Xx8OQzLGeYj3y8P8kHo1vFFB3UBFSHmtM6b5jQ7aUbc=; b=L/JcmoL9YFbmK7b5Ew8OA1Fu7G6qYLk08zlfibWCYa5wLOBEtncRKjJHOAC/3GgUNH tyH4p/RGx2W8u2s5Z5zmnBfGz80YsBhI+p+vULHEpkDHhJg+ymK5RN5K/0jBPlXyb2Yh 0Dwg1BkJ5ku6v9PobnKdYpGahlhHlgU675J58= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=Xx8OQzLGeYj3y8P8kHo1vFFB3UBFSHmtM6b5jQ7aUbc=; b=i5GOl7L/F+P/8DklAlgKa0onddThKWDtgfhpA6yjo0UfhvwD5M0mTrM9ar1YwkCuwB DiBk419NTnnzbwjSSy/0+6NcRF5aGhIrOYLQ0pCgFinyvY7qAVBOUEddZoIG/k5iVKRG zQTMq8C4dktOzU5CxhPjU5k1aAK1g+Qu9/Z98rTko6mCZ43BxJxEUkEOMWic4WipR8t+ 73xyx2LGzCjGzvZYwWUghFQ8T+XjwRR4FgEb8qbILE/w2iVT4NfZRow9bOmyMYxpNl+P tX3TrhNJal5CTTgN1R9S4MLbJHgqUATx0Y6+d3R4G/LXacIE8eo47io5NBoLwKhFwZtF yhLQ== X-Gm-Message-State: APjAAAUjxoP29ctGxl7HsVv6xglfT8kfvbksgR5cMYiIzLyra5372Fqg wb9srFvqmIdbdlFbklqOBUk00fYuXJM= X-Google-Smtp-Source: APXvYqwNk6DvXrD4yaS/Fc0Y482stWXQP2rzXiEmcLEygo6h6UhjTxAsjVjo58V1vhNDVNYvKl8pLw== X-Received: by 2002:adf:e852:: with SMTP id d18mr24404287wrn.225.1568116600270; Tue, 10 Sep 2019 04:56:40 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:39 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 10/14] krsi: Handle attachment of the same program Date: Tue, 10 Sep 2019 13:55:23 +0200 Message-Id: <20190910115527.5235-11-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh Allow the userspace to attach a newer version of a program without having duplicates of the same program. If BPF_F_ALLOW_OVERRIDE is passed, the attachment logic compares the name of the new program to the names of existing attached programs. The names are only compared till a "__" (or '\0', if there is no "__"). If a successful match is found, the existing program is replaced with the newer attachment. ./krsi Attaches "env_dumper__v1" followed by "env_dumper__v2" to the process_execution hook of the KRSI LSM. ./krsi ./krsi Before: cat /sys/kernel/security/krsi/process_execution env_dumper__v1 env_dumper__v2 After: cat /sys/kernel/security/krsi/process_execution env_dumper__v2 Signed-off-by: KP Singh --- security/krsi/ops.c | 53 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 52 insertions(+), 1 deletion(-) diff --git a/security/krsi/ops.c b/security/krsi/ops.c index 57bd304a03f4..1f4df920139c 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c @@ -65,11 +65,52 @@ static struct krsi_hook *get_hook_from_fd(int fd) return ERR_PTR(ret); } +/* + * match_prog_name matches the name of the program till "__" + * or the end of the string is encountered. This allows + * a different version of the same program to be loaded. + * + * For example: + * + * env_dumper__v1 is matched with env_dumper__v2 + * + */ +static bool match_prog_name(char *a, char *b) +{ + int m, n; + char *end; + + end = strstr(a, "__"); + n = end ? end - a : strlen(a); + + end = strstr(b, "__"); + m = end ? end - b : strlen(b); + + if (m != n) + return false; + + return strncmp(a, b, n) == 0; +} + +static struct bpf_prog *find_attached_prog(struct bpf_prog_array *array, + struct bpf_prog *prog) +{ + struct bpf_prog_array_item *item = array->items; + + for (; item->prog; item++) { + if (match_prog_name(item->prog->aux->name, prog->aux->name)) + return item->prog; + } + + return NULL; +} + int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) { struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; struct krsi_hook *h; + struct bpf_prog *old_prog; int ret = 0; h = get_hook_from_fd(attr->target_fd); @@ -79,8 +120,18 @@ int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) mutex_lock(&h->mutex); old_array = rcu_dereference_protected(h->progs, lockdep_is_held(&h->mutex)); + /* + * Check if a matching program with already exists and replace + * the existing program will be overridden if BPF_F_ALLOW_OVERRIDE + * is specified in the attach flags. + */ + old_prog = find_attached_prog(old_array, prog); + if (old_prog && !(attr->attach_flags & BPF_F_ALLOW_OVERRIDE)) { + ret = -EEXIST; + goto unlock; + } - ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); + ret = bpf_prog_array_copy(old_array, old_prog, prog, &new_array); if (ret < 0) { ret = -ENOMEM; goto unlock; From patchwork Tue Sep 10 11:55:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126214 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F19BDC3A5A2 for ; Tue, 10 Sep 2019 11:56:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFB3E208E4 for ; Tue, 10 Sep 2019 11:56:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="CHldEZZf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393018AbfIJL4t (ORCPT ); Tue, 10 Sep 2019 07:56:49 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:35648 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388328AbfIJL4o (ORCPT ); Tue, 10 Sep 2019 07:56:44 -0400 Received: by mail-wr1-f67.google.com with SMTP id g7so19677429wrx.2 for ; Tue, 10 Sep 2019 04:56:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=goHxQO5WE56PjZrElqp9mWD4UyL0ez4HVWRIM6UzU3c=; b=CHldEZZfNkVRxXOpA/ZEWOkGHLNYox5M0eQi+ih3ANNwJcZssMhLi1RvrKo6pFLpIu O0krOoKt/DkqNYVlPOFbFJ/LCVr2AyI88WBCpVC/zADylr9USKLI3of2dqtzmKkjm1EM AkCKEJMXkpFGE+nb6HJM6DAYeR0LzGOGEhFgg= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=goHxQO5WE56PjZrElqp9mWD4UyL0ez4HVWRIM6UzU3c=; b=W1wYPboGaUHhBkIj1E3WOcACLYJzjTXwzg5z1HTdBaKKnaJr40z63T5sqT8wZCwumi 1GRhNKOfCSlvPPeNX+NYJpekd3npL4cR7Vo8VpuKn1CA+tyL19BqU/ebl7Hf+HyjVhgg 1cC/v1GmnPmBx3Q9MhJVUQWoDOBNJ31/TRVlH6u5Fb8ylbgkPRPOk1nHuGKQyES/YF/+ 8AxHjXLtbEhtyE86urCdgb7MXpGt81HY+8oQUzHEIIOsYMcf7IMRTyEGnL+XAwJRYirx OIv43s4y/hsBWoibvtIpjoPbqBecHwMMnSUUNGvOwyCIAM+IMMgiAVzpHd4eT67AiDRz 6x8g== X-Gm-Message-State: APjAAAU6+PjBE5sPqbO7+7ur81nYiOOkpifZvpw185WIaPB0yp8IK3xX 7Z+ta2a2/ZzXusd/hw2zKk4vK3RloBM= X-Google-Smtp-Source: APXvYqy41deBTxwWe2+aWhU+4LiCXFDvi6WI4YCLje4OsKhs9MTrTG1c6KpCz0h80p4KZoQRWYOFwg== X-Received: by 2002:a5d:4fcf:: with SMTP id h15mr25996339wrw.237.1568116602133; Tue, 10 Sep 2019 04:56:42 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:41 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 11/14] krsi: Pin argument pages in bprm_check_security hook Date: Tue, 10 Sep 2019 13:55:24 +0200 Message-Id: <20190910115527.5235-12-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh Pin the memory allocated to the the argv + envv for the new process and passes it in the context to the eBPF programs attached to the hook. The get_user_pages_remote cannot be called from an eBPF helper because the helpers run in atomic context and the get_user_pages_remote function can sleep. The following heuristics can be added as an optimization: - Don't pin the pages if no eBPF programs are attached. - Don't pin the pages if none of the eBPF programs depend on the information. This would require introspection of the byte-code and checking if certain helpers are called. Signed-off-by: KP Singh --- security/krsi/include/krsi_init.h | 3 ++ security/krsi/krsi.c | 56 +++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff --git a/security/krsi/include/krsi_init.h b/security/krsi/include/krsi_init.h index 4e17ecacd4ed..6152847c3b08 100644 --- a/security/krsi/include/krsi_init.h +++ b/security/krsi/include/krsi_init.h @@ -16,6 +16,9 @@ extern int krsi_fs_initialized; struct krsi_bprm_ctx { struct linux_binprm *bprm; + char *arg_pages; + unsigned long num_arg_pages; + unsigned long max_arg_offset; }; /* diff --git a/security/krsi/krsi.c b/security/krsi/krsi.c index d3a4a361c192..00a7150c1b22 100644 --- a/security/krsi/krsi.c +++ b/security/krsi/krsi.c @@ -4,6 +4,8 @@ #include #include #include +#include +#include #include "krsi_init.h" @@ -17,6 +19,53 @@ struct krsi_hook krsi_hooks_list[] = { #undef KRSI_HOOK_INIT }; +static int pin_arg_pages(struct krsi_bprm_ctx *ctx) +{ + int ret = 0; + char *kaddr; + struct page *page; + unsigned long i, pos, num_arg_pages; + struct linux_binprm *bprm = ctx->bprm; + char *buf; + + /* + * The bprm->vma_pages does not have the correct count + * for execution that is done by a kernel thread using the UMH. + * vm_pages is updated in acct_arg_size and bails + * out if current->mm is NULL (which is the case for a kernel thread). + * It's safer to use vma_pages(struct linux_binprm*) to get the + * actual number + */ + num_arg_pages = vma_pages(bprm->vma); + if (!num_arg_pages) + return -ENOMEM; + + buf = kmalloc_array(num_arg_pages, PAGE_SIZE, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + for (i = 0; i < num_arg_pages; i++) { + pos = ALIGN_DOWN(bprm->p, PAGE_SIZE) + i * PAGE_SIZE; + ret = get_user_pages_remote(current, bprm->mm, pos, 1, + FOLL_FORCE, &page, NULL, NULL); + if (ret <= 0) { + kfree(buf); + return -ENOMEM; + } + + kaddr = kmap(page); + memcpy(buf + i * PAGE_SIZE, kaddr, PAGE_SIZE); + kunmap(page); + put_page(page); + } + + ctx->arg_pages = buf; + ctx->num_arg_pages = num_arg_pages; + ctx->max_arg_offset = num_arg_pages * PAGE_SIZE; + + return 0; +} + static int krsi_process_execution(struct linux_binprm *bprm) { int ret; @@ -26,7 +75,14 @@ static int krsi_process_execution(struct linux_binprm *bprm) .bprm = bprm, }; + ret = pin_arg_pages(&ctx.bprm_ctx); + if (ret < 0) + goto out_arg_pages; + ret = krsi_run_progs(PROCESS_EXECUTION, &ctx); + kfree(ctx.bprm_ctx.arg_pages); + +out_arg_pages: return ret; } From patchwork Tue Sep 10 11:55:25 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126217 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3ACF1C4740A for ; Tue, 10 Sep 2019 11:57:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFF2521479 for ; Tue, 10 Sep 2019 11:57:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="HWPU3GzU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393146AbfIJL5I (ORCPT ); Tue, 10 Sep 2019 07:57:08 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:41695 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391089AbfIJL4r (ORCPT ); Tue, 10 Sep 2019 07:56:47 -0400 Received: by mail-wr1-f65.google.com with SMTP id h7so18603843wrw.8 for ; Tue, 10 Sep 2019 04:56:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=YfOGR22A4l38lkUXccDczpuDVTPqgcNTsRkizO9Fy14=; b=HWPU3GzU3QVDWGFcOkzkKogiWC5zNxa38kUeFlNO9Kv0qUPHCTbSerropijK0SpZSN K/tSAc/9Oz+hLKCio0IEWK860DNV+gZDHBlDbqUjgdz4U7Db7F2HtGcT0V4b5XbfHCw6 a0n8yMrG4npPrn6SWvm2vaGruTF3DZBFh4q1w= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=YfOGR22A4l38lkUXccDczpuDVTPqgcNTsRkizO9Fy14=; b=aq47sfs4a85yHoF/GBZJmWbGZpOwjxAipQ4OlqSDVivw9J3ndGD9V/BUWJSKoWal8L 7kGs4OKalZKdZ5Qzr2gJltX1fKFn2KqEkmaQxcO2IHtLyT2c9HJJPrXjQtfi4hnz4ldC aVVIAd1w2kN243XLgAOfX96l+i9VTLemTgHKCjgyODNCF8tYEFRMCivGPNiKPaHv3RR0 e/Drq5sbQY/1Ej3CCiW6HBDAp7QeQ0LJqhMfiqWINO5HA+ZHVCpp3d3uSm91aqGSP/Wj Qcf6UiQKmNCfXz12sPZ7pKqqEVMDJ1XKbrqR0jJscZWqZDWZZSIMpHHTbUS0aj+fBJ+t kW+w== X-Gm-Message-State: APjAAAWNuKcx3bJ1atNsCnVhtc6RFZy/GY2+sL3ZrN75KWeyPDqNdTd0 mDwYcxf4xLbO/F2tBH/LMpnnsL5aAfA= X-Google-Smtp-Source: APXvYqwBvCNY+UARdEFe9ujlmg+pek1+2O0NHRq9kph8SAZQWqBrnPDrZyO43r/LIcfKjWSRpLGvmw== X-Received: by 2002:adf:e48f:: with SMTP id i15mr2910963wrm.26.1568116604037; Tue, 10 Sep 2019 04:56:44 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:43 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 12/14] krsi: Add an eBPF helper function to get the value of an env variable Date: Tue, 10 Sep 2019 13:55:25 +0200 Message-Id: <20190910115527.5235-13-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh The helper returns the value of the environment variable in the buffer that is passed to it. If the var is set multiple times, the helper returns all the values as null separated strings. If the buffer is too short for these values, the helper tries to fill it the best it can and guarantees that the value returned in the buffer is always null terminated. After the buffer is filled, the helper keeps counting the number of times the environment variable is set in the envp. The return value of the helper is an u64 value which carries two pieces of information. * The upper 32 bits are a u32 value signifying the number of times the environment variable is set in the envp. * The lower 32 bits are a s32 value signifying the number of bytes written to the buffer or an error code. Since the value of the environment variable can be very long and exceed what can be allocated on the BPF stack, a per-cpu array can be used instead: struct bpf_map_def SEC("maps") env_map = { .type = BPF_MAP_TYPE_PERCPU_ARRAY, .key_size = sizeof(u32), .value_size = 4096, .max_entries = 1, }; SEC("prgrm") int bpf_prog1(void *ctx) { u32 map_id = 0; u64 times_ret; s32 ret; char name[48] = "LD_PRELOAD"; char *map_value = bpf_map_lookup_elem(&env_map, &map_id); if (!map_value) return 0; // Read the lower 32 bits for the return value times_ret = krsi_get_env_var(ctx, name, 48, map_value, 4096); ret = times_ret & 0xffffffff; if (ret < 0) return ret; return 0; } Signed-off-by: KP Singh --- include/uapi/linux/bpf.h | 42 ++++++- security/krsi/ops.c | 129 ++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 42 ++++++- tools/testing/selftests/bpf/bpf_helpers.h | 3 + 4 files changed, 214 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 32ab38f1a2fe..a4ef07956e07 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2715,6 +2715,45 @@ union bpf_attr { * **-EPERM** if no permission to send the *sig*. * * **-EAGAIN** if bpf program can try again. + * + * u64 krsi_get_env_var(void *ctx, char *name, char *buf, + * size_t name_len, size_t buf_len) + * Description + * This helper can be used as a part of the + * process_execution hook of the KRSI LSM in + * programs of type BPF_PROG_TYPE_KRSI. + * + * The helper returns the value of the environment + * variable with the provided "name" for process that's + * going to be executed in the passed buffer, "buf". If the var + * is set multiple times, the helper returns all + * the values as null separated strings. + * + * If the buffer is too short for these values, the helper + * tries to fill it the best it can and guarantees that the value + * returned in the buffer is always null terminated. + * After the buffer is filled, the helper keeps counting the number + * of times the environment variable is set in the envp. + * + * Return: + * + * The return value of the helper is an u64 value + * which carries two pieces of information: + * + * The upper 32 bits are a u32 value signifying + * the number of times the environment variable + * is set in the envp. + * The lower 32 bits are an s32 value signifying + * the number of bytes written to the buffer or an error code: + * + * **-ENOMEM** if the kernel is unable to allocate memory + * for pinning the argv and envv. + * + * **-E2BIG** if the value is larger than the size of the + * destination buffer. The higher bits will still + * the number of times the variable was set in the envp. + * + * **-EINVAL** if name is not a NULL terminated string. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2826,7 +2865,8 @@ union bpf_attr { FN(strtoul), \ FN(sk_storage_get), \ FN(sk_storage_delete), \ - FN(send_signal), + FN(send_signal), \ + FN(krsi_get_env_var), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/security/krsi/ops.c b/security/krsi/ops.c index 1f4df920139c..1db94dfaac15 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c @@ -6,6 +6,8 @@ #include #include #include +#include +#include #include "krsi_init.h" #include "krsi_fs.h" @@ -162,6 +164,131 @@ static bool krsi_prog_is_valid_access(int off, int size, return false; } +static char *array_next_entry(char *array, unsigned long *offset, + unsigned long end) +{ + char *entry; + unsigned long current_offset = *offset; + + if (current_offset >= end) + return NULL; + + /* + * iterate on the array till the null byte is encountered + * and check for any overflows. + */ + entry = array + current_offset; + while (array[current_offset]) { + if (unlikely(++current_offset >= end)) + return NULL; + } + + /* + * Point the offset to the next element in the array. + */ + *offset = current_offset + 1; + + return entry; +} + +static u64 get_env_var(struct krsi_ctx *ctx, char *name, char *dest, + u32 n_size, u32 size) +{ + s32 ret = 0; + u32 num_vars = 0; + int i, name_len; + struct linux_binprm *bprm = ctx->bprm_ctx.bprm; + int argc = bprm->argc; + int envc = bprm->envc; + unsigned long end = ctx->bprm_ctx.max_arg_offset; + unsigned long offset = bprm->p % PAGE_SIZE; + char *buf = ctx->bprm_ctx.arg_pages; + char *curr_dest = dest; + char *entry; + + if (unlikely(!buf)) + return -ENOMEM; + + for (i = 0; i < argc; i++) { + entry = array_next_entry(buf, &offset, end); + if (!entry) + return 0; + } + + name_len = strlen(name); + for (i = 0; i < envc; i++) { + entry = array_next_entry(buf, &offset, end); + if (!entry) + return 0; + + if (!strncmp(entry, name, name_len)) { + num_vars++; + + /* + * There is no need to do further copying + * if the buffer is already full. Just count how many + * times the environment variable is set. + */ + if (ret == -E2BIG) + continue; + + if (entry[name_len] != '=') + continue; + + /* + * Move the buf pointer by name_len + 1 + * (for the "=" sign) + */ + entry += name_len + 1; + ret = strlcpy(curr_dest, entry, size); + + if (ret >= size) { + ret = -E2BIG; + continue; + } + + /* + * strlcpy just returns the length of the string copied. + * The remaining space needs to account for the added + * null character. + */ + curr_dest += ret + 1; + size -= ret + 1; + /* + * Update ret to be the current number of bytes written + * to the destination + */ + ret = curr_dest - dest; + } + } + + return (u64) num_vars << 32 | (u32) ret; +} + +BPF_CALL_5(krsi_get_env_var, struct krsi_ctx *, ctx, char *, name, u32, n_size, + char *, dest, u32, size) +{ + char *name_end; + + name_end = memchr(name, '\0', n_size); + if (!name_end) + return -EINVAL; + + memset(dest, 0, size); + return get_env_var(ctx, name, dest, n_size, size); +} + +static const struct bpf_func_proto krsi_get_env_var_proto = { + .func = krsi_get_env_var, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE_OR_ZERO, + .arg4_type = ARG_PTR_TO_UNINIT_MEM, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + BPF_CALL_5(krsi_event_output, void *, log, struct bpf_map *, map, u64, flags, void *, data, u64, size) { @@ -192,6 +319,8 @@ static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id return &bpf_map_lookup_elem_proto; case BPF_FUNC_get_current_pid_tgid: return &bpf_get_current_pid_tgid_proto; + case BPF_FUNC_krsi_get_env_var: + return &krsi_get_env_var_proto; case BPF_FUNC_perf_event_output: return &krsi_event_output_proto; default: diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 32ab38f1a2fe..a4ef07956e07 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2715,6 +2715,45 @@ union bpf_attr { * **-EPERM** if no permission to send the *sig*. * * **-EAGAIN** if bpf program can try again. + * + * u64 krsi_get_env_var(void *ctx, char *name, char *buf, + * size_t name_len, size_t buf_len) + * Description + * This helper can be used as a part of the + * process_execution hook of the KRSI LSM in + * programs of type BPF_PROG_TYPE_KRSI. + * + * The helper returns the value of the environment + * variable with the provided "name" for process that's + * going to be executed in the passed buffer, "buf". If the var + * is set multiple times, the helper returns all + * the values as null separated strings. + * + * If the buffer is too short for these values, the helper + * tries to fill it the best it can and guarantees that the value + * returned in the buffer is always null terminated. + * After the buffer is filled, the helper keeps counting the number + * of times the environment variable is set in the envp. + * + * Return: + * + * The return value of the helper is an u64 value + * which carries two pieces of information: + * + * The upper 32 bits are a u32 value signifying + * the number of times the environment variable + * is set in the envp. + * The lower 32 bits are an s32 value signifying + * the number of bytes written to the buffer or an error code: + * + * **-ENOMEM** if the kernel is unable to allocate memory + * for pinning the argv and envv. + * + * **-E2BIG** if the value is larger than the size of the + * destination buffer. The higher bits will still + * the number of times the variable was set in the envp. + * + * **-EINVAL** if name is not a NULL terminated string. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2826,7 +2865,8 @@ union bpf_attr { FN(strtoul), \ FN(sk_storage_get), \ FN(sk_storage_delete), \ - FN(send_signal), + FN(send_signal), \ + FN(krsi_get_env_var), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h index f804f210244e..ecebdb772a9d 100644 --- a/tools/testing/selftests/bpf/bpf_helpers.h +++ b/tools/testing/selftests/bpf/bpf_helpers.h @@ -303,6 +303,9 @@ static int (*bpf_get_numa_node_id)(void) = static int (*bpf_probe_read_str)(void *ctx, __u32 size, const void *unsafe_ptr) = (void *) BPF_FUNC_probe_read_str; +static unsigned long long (*krsi_get_env_var)(void *ctx, + void *name, __u32 n_size, void *buf, __u32 size) = + (void *) BPF_FUNC_krsi_get_env_var; static unsigned int (*bpf_get_socket_uid)(void *ctx) = (void *) BPF_FUNC_get_socket_uid; static unsigned int (*bpf_set_hash)(void *ctx, __u32 hash) = From patchwork Tue Sep 10 11:55:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126216 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E4F4C3A5A2 for ; Tue, 10 Sep 2019 11:57:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 19EAA21019 for ; Tue, 10 Sep 2019 11:57:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="bTp1PUS3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393129AbfIJL5C (ORCPT ); Tue, 10 Sep 2019 07:57:02 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:43739 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392956AbfIJL4s (ORCPT ); Tue, 10 Sep 2019 07:56:48 -0400 Received: by mail-wr1-f66.google.com with SMTP id q17so14905237wrx.10 for ; Tue, 10 Sep 2019 04:56:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=s9oggadqo//5FtNHKx2jdFdUWzoATro1ikb31coyYYI=; b=bTp1PUS3Z5bMMkdNcaOM8y5T4F95uMErsTVg+BHYorLfez9asaBj35Nw53EDM9sdT/ zXW1RzFperDXJiDwvRRF4nStFyFc7fxonUqN8MDZNtgFzsGokPc7C318EssXZhVkv4pL EFTPPlfz0Q2d1J/WJs6mVW8E2jXTWOhd8wNyc= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=s9oggadqo//5FtNHKx2jdFdUWzoATro1ikb31coyYYI=; b=CQYl48D6XbFNYUv+ekXJFK92YKtLrHJTVQNMekqN2+5nO4eCarYoBaZLIj3SkQ/+P0 1P+wGAU4CZLofOUeqC/SMjTJFY5bNff/+vjLv7v7qXkIqrMvb3qlo6fL66UT3QjoT8po yA1r+rLU/d5wbi5PntHq0LBqK+lAnOLzabJg/uacJ9q1mLLKmvEpu5B2D0JiEdjbp8ak w4uPZ5VFU9aMG/2KQ1tGAyUhd4pnbrR+BTfrRaZ5xDaRG+k0MDR3IwjmZbWR20HlSFPj ichvGavXhNnJlp6ljm3NcoSc0Vy6w/0O1Z4C+P3t3XN8vSTOXFB/Jn2Dwpw8yJUxwgox FJAw== X-Gm-Message-State: APjAAAUYMKEjnk4OS81PcO9EeP5/sBp6vhW1uVsFtcG8F0FCWKJbhLoa j2Io/jn93BRJT5Rm1ITkugLCpnOu1KY= X-Google-Smtp-Source: APXvYqxVfjrIddTA8bsV5am8Cb4uN3Xue2sI0Y2t94RDurY57DjHjCKpgbH0KcvKK5FQZimJkzyHsg== X-Received: by 2002:adf:e7cc:: with SMTP id e12mr25354235wrn.299.1568116605922; Tue, 10 Sep 2019 04:56:45 -0700 (PDT) Received: from kpsingh-kernel.c.hoisthospitality.com (110.8.30.213.rev.vodafone.pt. [213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:45 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 13/14] krsi: Provide an example to read and log environment variables Date: Tue, 10 Sep 2019 13:55:26 +0200 Message-Id: <20190910115527.5235-14-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh * The program takes the name of an environment variable as an argument. * An eBPF program is loaded and attached to the process_execution hook. * The name of the environment variable passed is updated in a eBPF per-cpu map. * The eBPF program uses the krsi_get_env_var helper to get the the value of this variable and logs the result to the perf events buffer. * The user-space program listens to the perf events and prints the values. Example execution: ./krsi LD_PRELOAD [p_pid=123] LD_PRELOAD is not set [p_pid=456] LD_PRELOAD=/lib/bad.so [p_pid=789] WARNING! LD_PRELOAD is set 2 times [p_pid=789] LD_PRELOAD=/lib/decoy.so [p_pid=789] LD_PRELOAD=/lib/bad.so In a separate session the following [1, 2, 3] exec system calls are made where: [1, 2, 3] char *argv[] = {"/bin/ls", 0}; [1] char *envp = {0}; [2] char *envp = {"LD_PRELOAD=/lib/bad.so", 0}; [3] char *envp = {"LD_PRELOAD=/lib/decoy.so, "LD_PRELOAD=/lib/bad.so", 0}; This example demonstrates that user-space is free to choose the format in which the data is logged and can use very specific helpers like krsi_get_env_var to populate only the data that is required. Signed-off-by: KP Singh --- MAINTAINERS | 3 + samples/bpf/.gitignore | 1 + samples/bpf/Makefile | 3 + samples/bpf/krsi_helpers.h | 31 ++++++ samples/bpf/krsi_kern.c | 52 ++++++++++ samples/bpf/krsi_user.c | 202 +++++++++++++++++++++++++++++++++++++ 6 files changed, 292 insertions(+) create mode 100644 samples/bpf/krsi_helpers.h create mode 100644 samples/bpf/krsi_kern.c create mode 100644 samples/bpf/krsi_user.c diff --git a/MAINTAINERS b/MAINTAINERS index 8e0364391d8b..ec378abb4c23 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9005,6 +9005,9 @@ F: kernel/kprobes.c KRSI SECURITY MODULE M: KP Singh S: Supported +F: samples/bpf/krsi_helpers.h +F: samples/bpf/krsi_kern.c +F: samples/bpf/krsi_user.c F: security/krsi/ KS0108 LCD CONTROLLER DRIVER diff --git a/samples/bpf/.gitignore b/samples/bpf/.gitignore index 74d31fd3c99c..6bbf5a04877f 100644 --- a/samples/bpf/.gitignore +++ b/samples/bpf/.gitignore @@ -2,6 +2,7 @@ cpustat fds_example hbm ibumad +krsi lathist lwt_len_hist map_perf_test diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 1d9be26b4edd..33d3bef17549 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -8,6 +8,7 @@ hostprogs-y := test_lru_dist hostprogs-y += sock_example hostprogs-y += fds_example hostprogs-y += sockex1 +hostprogs-y += krsi hostprogs-y += sockex2 hostprogs-y += sockex3 hostprogs-y += tracex1 @@ -62,6 +63,7 @@ TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o fds_example-objs := fds_example.o sockex1-objs := sockex1_user.o +krsi-objs := krsi_user.o $(TRACE_HELPERS) sockex2-objs := sockex2_user.o sockex3-objs := bpf_load.o sockex3_user.o tracex1-objs := bpf_load.o tracex1_user.o @@ -113,6 +115,7 @@ hbm-objs := bpf_load.o hbm.o $(CGROUP_HELPERS) # Tell kbuild to always build the programs always := $(hostprogs-y) always += sockex1_kern.o +always += krsi_kern.o always += sockex2_kern.o always += sockex3_kern.o always += tracex1_kern.o diff --git a/samples/bpf/krsi_helpers.h b/samples/bpf/krsi_helpers.h new file mode 100644 index 000000000000..3007bfd6212e --- /dev/null +++ b/samples/bpf/krsi_helpers.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _KRSI_HELPERS_H +#define _KRSI_HELPERS_H + +#define __bpf_percpu_val_align __aligned(8) + +#define ENV_VAR_NAME_MAX_LEN 48 +#define ENV_VAR_VAL_MAX_LEN 4096 + +#define MAX_CPUS 128 + +#define __LOWER(x) (x & 0xffffffff) +#define __UPPER(x) (x >> 32) + +struct krsi_env_value { + // The name of the environment variable. + char name[ENV_VAR_NAME_MAX_LEN]; + // The value of the environment variable (if set). + char value[ENV_VAR_VAL_MAX_LEN]; + // Indicates if an overflow occurred while reading the value of the + // of the environment variable. This means that an -E2BIG was received + // from the krsi_get_env_var helper. + bool overflow; + // The number of times the environment variable was set. + __u32 times; + // The PID of the parent process. + __u32 p_pid; +} __bpf_percpu_val_align; + +#endif // _KRSI_HELPERS_H diff --git a/samples/bpf/krsi_kern.c b/samples/bpf/krsi_kern.c new file mode 100644 index 000000000000..087a6f0cc81d --- /dev/null +++ b/samples/bpf/krsi_kern.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include "bpf_helpers.h" +#include "krsi_helpers.h" + +#define MAX_CPUS 128 + +struct bpf_map_def SEC("maps") env_map = { + .type = BPF_MAP_TYPE_PERCPU_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(struct krsi_env_value), + .max_entries = 1, +}; + +struct bpf_map_def SEC("maps") perf_map = { + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, + .key_size = sizeof(int), + .value_size = sizeof(u32), + .max_entries = MAX_CPUS, +}; + +SEC("krsi") +int env_dumper(void *ctx) +{ + u64 times_ret; + s32 ret; + u32 map_id = 0; + char *map_value; + struct krsi_env_value *env; + + env = bpf_map_lookup_elem(&env_map, &map_id); + if (!env) + return -ENOMEM; + times_ret = krsi_get_env_var(ctx, env->name, ENV_VAR_NAME_MAX_LEN, + env->value, ENV_VAR_VAL_MAX_LEN); + ret = __LOWER(times_ret); + if (ret == -E2BIG) + env->overflow = true; + else if (ret < 0) + return ret; + + env->times = __UPPER(times_ret); + env->p_pid = bpf_get_current_pid_tgid(); + bpf_perf_event_output(ctx, &perf_map, BPF_F_CURRENT_CPU, env, + sizeof(struct krsi_env_value)); + + return 0; +} +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/krsi_user.c b/samples/bpf/krsi_user.c new file mode 100644 index 000000000000..1fad29bf017a --- /dev/null +++ b/samples/bpf/krsi_user.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "bpf/libbpf.h" +#include +#include +#include +#include +#include +#include +#include + +#include "perf-sys.h" +#include "trace_helpers.h" +#include "krsi_helpers.h" + +#define LSM_HOOK_PATH "/sys/kernel/security/krsi/process_execution" + +static int pmu_fds[MAX_CPUS]; +static struct perf_event_mmap_page *headers[MAX_CPUS]; + +static int print_env(void *d, int size) +{ + struct krsi_env_value *env = d; + int times = env->times; + char *next = env->value; + size_t total = 0; + + if (env->times > 1) + printf("[p_pid=%u] WARNING! %s is set %u times\n", + env->p_pid, env->name, env->times); + + /* + * krsi_get_env_var ensures that even overflows + * are null terminated. Incase of an overflow, + * this logic tries to print as much information + * that was gathered. + */ + while (times && total < ENV_VAR_NAME_MAX_LEN) { + next += total; + if (env->overflow) + printf("[p_pid=%u] OVERFLOW! %s=%s\n", + env->p_pid, env->name, next); + else + printf("[p_pid=%u] %s=%s\n", + env->p_pid, env->name, next); + times--; + total += strlen(next) + 1; + } + + if (!env->times) + printf("p_pid=%u] %s is not set\n", + env->p_pid, env->name); + + return LIBBPF_PERF_EVENT_CONT; +} + +static int open_perf_events(int map_fd, int num) +{ + int i; + struct perf_event_attr attr = { + .sample_type = PERF_SAMPLE_RAW, + .type = PERF_TYPE_SOFTWARE, + .config = PERF_COUNT_SW_BPF_OUTPUT, + .wakeup_events = 1, /* get an fd notification for every event */ + }; + + for (i = 0; i < num; i++) { + int key = i; + int ret; + + ret = sys_perf_event_open(&attr, -1 /*pid*/, i/*cpu*/, + -1/*group_fd*/, 0); + if (ret < 0) + return ret; + pmu_fds[i] = ret; + ret = bpf_map_update_elem(map_fd, &key, &pmu_fds[i], BPF_ANY); + if (ret < 0) + return ret; + ioctl(pmu_fds[i], PERF_EVENT_IOC_ENABLE, 0); + } + return 0; +} + +static int update_env_map(struct bpf_object *prog_obj, const char *env_var_name, + int numcpus) +{ + struct bpf_map *map; + struct krsi_env_value *env; + int map_fd; + int key = 0, ret = 0, i; + + map = bpf_object__find_map_by_name(prog_obj, "env_map"); + if (!map) + return -EINVAL; + + map_fd = bpf_map__fd(map); + if (map_fd < 0) + return map_fd; + + env = malloc(numcpus * sizeof(struct krsi_env_value)); + if (!env) { + ret = -ENOMEM; + goto out; + } + + for (i = 0; i < numcpus; i++) + strcpy(env[i].name, env_var_name); + + ret = bpf_map_update_elem(map_fd, &key, env, BPF_ANY); + if (ret < 0) + goto out; + +out: + free(env); + return ret; +} + +int main(int argc, char **argv) +{ + struct bpf_object *prog_obj; + const char *env_var_name; + struct bpf_prog_load_attr attr; + int prog_fd, target_fd, map_fd; + int ret, i, numcpus; + struct bpf_map *map; + char filename[PATH_MAX]; + struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; + + + if (argc != 2) + errx(EXIT_FAILURE, "Usage %s env_var_name\n", argv[0]); + + env_var_name = argv[1]; + if (strlen(env_var_name) > ENV_VAR_NAME_MAX_LEN - 1) + errx(EXIT_FAILURE, + " cannot be more than %d in length", + ENV_VAR_NAME_MAX_LEN - 1); + + + setrlimit(RLIMIT_MEMLOCK, &r); + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + memset(&attr, 0, sizeof(struct bpf_prog_load_attr)); + attr.prog_type = BPF_PROG_TYPE_KRSI; + attr.expected_attach_type = BPF_KRSI; + attr.file = filename; + + /* Attach the BPF program to the given hook */ + target_fd = open(LSM_HOOK_PATH, O_RDWR); + if (target_fd < 0) + err(EXIT_FAILURE, "Failed to open target file"); + + if (bpf_prog_load_xattr(&attr, &prog_obj, &prog_fd)) + err(EXIT_FAILURE, "Failed to load eBPF program"); + + numcpus = get_nprocs(); + if (numcpus > MAX_CPUS) + numcpus = MAX_CPUS; + + ret = update_env_map(prog_obj, env_var_name, numcpus); + if (ret < 0) + err(EXIT_FAILURE, "Failed to update env map"); + + map = bpf_object__find_map_by_name(prog_obj, "perf_map"); + if (!map) + err(EXIT_FAILURE, + "Finding the perf event map in obj file failed"); + + map_fd = bpf_map__fd(map); + if (map_fd < 0) + err(EXIT_FAILURE, "Failed to get fd for perf events map"); + + ret = bpf_prog_attach(prog_fd, target_fd, BPF_KRSI, + BPF_F_ALLOW_OVERRIDE); + if (ret < 0) + err(EXIT_FAILURE, "Failed to attach prog to LSM hook"); + + ret = open_perf_events(map_fd, numcpus); + if (ret < 0) + err(EXIT_FAILURE, "Failed to open perf events handler"); + + for (i = 0; i < numcpus; i++) { + ret = perf_event_mmap_header(pmu_fds[i], &headers[i]); + if (ret < 0) + err(EXIT_FAILURE, "perf_event_mmap_header"); + } + + ret = perf_event_poller_multi(pmu_fds, headers, numcpus, print_env); + if (ret < 0) + err(EXIT_FAILURE, "Failed to poll perf events"); + + return EXIT_SUCCESS; +} From patchwork Tue Sep 10 11:55:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1126215 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7095FC3A5A2 for ; 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[213.30.8.110]) by smtp.gmail.com with ESMTPSA id q19sm23732935wra.89.2019.09.10.04.56.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2019 04:56:47 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [RFC v1 14/14] krsi: Pin arg pages only when needed Date: Tue, 10 Sep 2019 13:55:27 +0200 Message-Id: <20190910115527.5235-15-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org> References: <20190910115527.5235-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KP Singh Adds a callback which is called when a new program is attached to a hook. The callback registered by the process_exection hook checks if a program that has calls to a helper that requires pages to be pinned (eg. krsi_get_env_var). Signed-off-by: KP Singh --- include/linux/krsi.h | 1 + security/krsi/include/hooks.h | 5 ++- security/krsi/include/krsi_init.h | 7 ++++ security/krsi/krsi.c | 62 ++++++++++++++++++++++++++++--- security/krsi/ops.c | 10 ++++- 5 files changed, 77 insertions(+), 8 deletions(-) diff --git a/include/linux/krsi.h b/include/linux/krsi.h index c7d1790d0c1f..e443d0309764 100644 --- a/include/linux/krsi.h +++ b/include/linux/krsi.h @@ -7,6 +7,7 @@ #ifdef CONFIG_SECURITY_KRSI int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog); +extern const struct bpf_func_proto krsi_get_env_var_proto; #else static inline int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) diff --git a/security/krsi/include/hooks.h b/security/krsi/include/hooks.h index e070c452b5de..38293125ff99 100644 --- a/security/krsi/include/hooks.h +++ b/security/krsi/include/hooks.h @@ -8,7 +8,7 @@ * * Format: * - * KRSI_HOOK_INIT(TYPE, NAME, LSM_HOOK, KRSI_HOOK_FN) + * KRSI_HOOK_INIT(TYPE, NAME, LSM_HOOK, KRSI_HOOK_FN, CALLBACK) * * KRSI adds one layer of indirection between the name of the hook and the name * it exposes to the userspace in Security FS to prevent the userspace from @@ -18,4 +18,5 @@ KRSI_HOOK_INIT(PROCESS_EXECUTION, process_execution, bprm_check_security, - krsi_process_execution) + krsi_process_execution, + krsi_process_execution_cb) diff --git a/security/krsi/include/krsi_init.h b/security/krsi/include/krsi_init.h index 6152847c3b08..99801d5b273a 100644 --- a/security/krsi/include/krsi_init.h +++ b/security/krsi/include/krsi_init.h @@ -31,6 +31,8 @@ struct krsi_ctx { }; }; +typedef int (*krsi_prog_attach_t) (struct bpf_prog_array *); + /* * The LSM creates one file per hook. * @@ -61,6 +63,11 @@ struct krsi_hook { * The eBPF programs that are attached to this hook. */ struct bpf_prog_array __rcu *progs; + /* + * The attach callback is called before a new program is attached + * to the hook and is passed the updated bpf_prog_array as an argument. + */ + krsi_prog_attach_t attach_callback; }; extern struct krsi_hook krsi_hooks_list[]; diff --git a/security/krsi/krsi.c b/security/krsi/krsi.c index 00a7150c1b22..a4443d7aa150 100644 --- a/security/krsi/krsi.c +++ b/security/krsi/krsi.c @@ -5,15 +5,65 @@ #include #include #include +#include #include #include "krsi_init.h" +/* + * need_arg_pages is only updated in bprm_check_security_cb + * when a mutex on krsi_hook for bprm_check_security is already + * held. need_arg_pages avoids pinning pages when no program + * that needs them is attached to the hook. + */ +static bool need_arg_pages; + +/* + * Checks if the instruction is a BPF_CALL to an eBPF helper located + * at the given address. + */ +static inline bool bpf_is_call_to_func(struct bpf_insn *insn, + void *func_addr) +{ + u8 opcode = BPF_OP(insn->code); + + if (opcode != BPF_CALL) + return false; + + if (insn->src_reg == BPF_PSEUDO_CALL) + return false; + + /* + * The BPF verifier updates the value of insn->imm from the + * enum bpf_func_id to the offset of the address of helper + * from the __bpf_call_base. + */ + return __bpf_call_base + insn->imm == func_addr; +} + +static int krsi_process_execution_cb(struct bpf_prog_array *array) +{ + struct bpf_prog_array_item *item = array->items; + struct bpf_prog *p; + const struct bpf_func_proto *proto = &krsi_get_env_var_proto; + int i; + + while ((p = READ_ONCE(item->prog))) { + for (i = 0; i < p->len; i++) { + if (bpf_is_call_to_func(&p->insnsi[i], proto->func)) + need_arg_pages = true; + } + item++; + } + return 0; +} + struct krsi_hook krsi_hooks_list[] = { - #define KRSI_HOOK_INIT(TYPE, NAME, H, I) \ + #define KRSI_HOOK_INIT(TYPE, NAME, H, I, CB) \ [TYPE] = { \ .h_type = TYPE, \ .name = #NAME, \ + .attach_callback = CB, \ }, #include "hooks.h" #undef KRSI_HOOK_INIT @@ -75,9 +125,11 @@ static int krsi_process_execution(struct linux_binprm *bprm) .bprm = bprm, }; - ret = pin_arg_pages(&ctx.bprm_ctx); - if (ret < 0) - goto out_arg_pages; + if (READ_ONCE(need_arg_pages)) { + ret = pin_arg_pages(&ctx.bprm_ctx); + if (ret < 0) + goto out_arg_pages; + } ret = krsi_run_progs(PROCESS_EXECUTION, &ctx); kfree(ctx.bprm_ctx.arg_pages); @@ -87,7 +139,7 @@ static int krsi_process_execution(struct linux_binprm *bprm) } static struct security_hook_list krsi_hooks[] __lsm_ro_after_init = { - #define KRSI_HOOK_INIT(T, N, HOOK, IMPL) LSM_HOOK_INIT(HOOK, IMPL), + #define KRSI_HOOK_INIT(T, N, HOOK, IMPL, CB) LSM_HOOK_INIT(HOOK, IMPL), #include "hooks.h" #undef KRSI_HOOK_INIT }; diff --git a/security/krsi/ops.c b/security/krsi/ops.c index 1db94dfaac15..2de682371eff 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c @@ -139,6 +139,14 @@ int krsi_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) goto unlock; } + if (h->attach_callback) { + ret = h->attach_callback(new_array); + if (ret < 0) { + bpf_prog_array_free(new_array); + goto unlock; + } + } + rcu_assign_pointer(h->progs, new_array); bpf_prog_array_free(old_array); @@ -278,7 +286,7 @@ BPF_CALL_5(krsi_get_env_var, struct krsi_ctx *, ctx, char *, name, u32, n_size, return get_env_var(ctx, name, dest, n_size, size); } -static const struct bpf_func_proto krsi_get_env_var_proto = { +const struct bpf_func_proto krsi_get_env_var_proto = { .func = krsi_get_env_var, .gpl_only = true, .ret_type = RET_INTEGER,