From patchwork Tue Nov 24 15:12:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11929185 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFF68C2D0E4 for ; Tue, 24 Nov 2020 15:12:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55BA3206D4 for ; Tue, 24 Nov 2020 15:12:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="ibCi5X8J" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389465AbgKXPMQ (ORCPT ); Tue, 24 Nov 2020 10:12:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389453AbgKXPMQ (ORCPT ); Tue, 24 Nov 2020 10:12:16 -0500 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC892C0617A6 for ; Tue, 24 Nov 2020 07:12:14 -0800 (PST) Received: by mail-wr1-x442.google.com with SMTP id s8so22633042wrw.10 for ; Tue, 24 Nov 2020 07:12:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=4EcEA95lNa5ZZ+4yTLKOmHZRpqe2owrp9tTkgwACEiM=; b=ibCi5X8Jr3TncJq/YRtxicrO73AYf22K1o+IetPSD2hZZqoLFnXj4rZ9EU7AI5GcfD p1hLH3tYLKfG4l2BLazi3w4HwIoqZeSG5jYi/WeR1uV8A4j6SVqDNyS5S4L/yExAP05U Z0KANTbHysLXx2RsH0ZNKTICnEWqjOVyfxb6A= 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=4EcEA95lNa5ZZ+4yTLKOmHZRpqe2owrp9tTkgwACEiM=; b=RwLKChWUgR/f5Pt3uFuOnMBbiNWhIRh8rSpn7avJ57XKSVMdPPU3HlnonM/f+B1BHm yBWJe0Pv+A7grLqC2bJiWZMnePGRNvmHoLN3B2jMZXBMjnrBbTGhRc0WRqt7zamm2b4Q Ac3sJ5r3P/ioVpELqkp6oMLaC6L3vU/5c8hT0D91RjiN4u3u3ts/qMe4LnoGRUTrWY+U w7Nea1YpPMcLDqha6PGxUfJLkzt+Tz62tVGn8YoaDIlKuQgySrRY2kCdJgIxkEIbvkWo WSxxYRJ2s9Aehq6rIc3AMvHweW0N36ilEVDvkiSpWvXg2z4vNONKH1pzCR1Pw5s37uLJ 7VtQ== X-Gm-Message-State: AOAM531KFDuhqKaaqViUg9Ox7ZU+y0nKVr5rTOCfOXePFrvSsn7M3BVB XwLL5+vqZDdyS5e4N++Jdc8SgA== X-Google-Smtp-Source: ABdhPJy02kMVLnJkpuZyn2yL397Z2qctTyaciVDRACl/mjeQe14qrgcSahQ5IJCwkiUL2A4SszOUIw== X-Received: by 2002:a5d:690a:: with SMTP id t10mr5955851wru.203.1606230733342; Tue, 24 Nov 2020 07:12:13 -0800 (PST) Received: from kpsingh.c.googlers.com.com (203.75.199.104.bc.googleusercontent.com. [104.199.75.203]) by smtp.gmail.com with ESMTPSA id g131sm6353127wma.35.2020.11.24.07.12.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 07:12:12 -0800 (PST) From: KP Singh To: James Morris , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Florent Revest , Brendan Jackman , Mimi Zohar Subject: [PATCH bpf-next v3 1/3] ima: Implement ima_inode_hash Date: Tue, 24 Nov 2020 15:12:08 +0000 Message-Id: <20201124151210.1081188-2-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog In-Reply-To: <20201124151210.1081188-1-kpsingh@chromium.org> References: <20201124151210.1081188-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: From: KP Singh This is in preparation to add a helper for BPF LSM programs to use IMA hashes when attached to LSM hooks. There are LSM hooks like inode_unlink which do not have a struct file * argument and cannot use the existing ima_file_hash API. An inode based API is, therefore, useful in LSM based detections like an executable trying to delete itself which rely on the inode_unlink LSM hook. Moreover, the ima_file_hash function does nothing with the struct file pointer apart from calling file_inode on it and converting it to an inode. Signed-off-by: KP Singh Acked-by: Yonghong Song Acked-by: Mimi Zohar --- include/linux/ima.h | 6 +++ security/integrity/ima/ima_main.c | 78 +++++++++++++++++++++---------- 2 files changed, 60 insertions(+), 24 deletions(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index 8fa7bcfb2da2..7233a2751754 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -29,6 +29,7 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); extern void ima_post_path_mknod(struct dentry *dentry); extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); +extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size); extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); #ifdef CONFIG_IMA_KEXEC @@ -115,6 +116,11 @@ static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size) return -EOPNOTSUPP; } +static inline int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) +{ + return -EOPNOTSUPP; +} + static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {} #endif /* CONFIG_IMA */ diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2d1af8899cab..cb2deaa188e7 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -501,37 +501,14 @@ int ima_file_check(struct file *file, int mask) } EXPORT_SYMBOL_GPL(ima_file_check); -/** - * ima_file_hash - return the stored measurement if a file has been hashed and - * is in the iint cache. - * @file: pointer to the file - * @buf: buffer in which to store the hash - * @buf_size: length of the buffer - * - * On success, return the hash algorithm (as defined in the enum hash_algo). - * If buf is not NULL, this function also outputs the hash into buf. - * If the hash is larger than buf_size, then only buf_size bytes will be copied. - * It generally just makes sense to pass a buffer capable of holding the largest - * possible hash: IMA_MAX_DIGEST_SIZE. - * The file hash returned is based on the entire file, including the appended - * signature. - * - * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. - * If the parameters are incorrect, return -EINVAL. - */ -int ima_file_hash(struct file *file, char *buf, size_t buf_size) +static int __ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) { - struct inode *inode; struct integrity_iint_cache *iint; int hash_algo; - if (!file) - return -EINVAL; - if (!ima_policy_flag) return -EOPNOTSUPP; - inode = file_inode(file); iint = integrity_iint_find(inode); if (!iint) return -EOPNOTSUPP; @@ -558,8 +535,61 @@ int ima_file_hash(struct file *file, char *buf, size_t buf_size) return hash_algo; } + +/** + * ima_file_hash - return the stored measurement if a file has been hashed and + * is in the iint cache. + * @file: pointer to the file + * @buf: buffer in which to store the hash + * @buf_size: length of the buffer + * + * On success, return the hash algorithm (as defined in the enum hash_algo). + * If buf is not NULL, this function also outputs the hash into buf. + * If the hash is larger than buf_size, then only buf_size bytes will be copied. + * It generally just makes sense to pass a buffer capable of holding the largest + * possible hash: IMA_MAX_DIGEST_SIZE. + * The file hash returned is based on the entire file, including the appended + * signature. + * + * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. + * If the parameters are incorrect, return -EINVAL. + */ +int ima_file_hash(struct file *file, char *buf, size_t buf_size) +{ + if (!file) + return -EINVAL; + + return __ima_inode_hash(file_inode(file), buf, buf_size); +} EXPORT_SYMBOL_GPL(ima_file_hash); +/** + * ima_inode_hash - return the stored measurement if the inode has been hashed + * and is in the iint cache. + * @inode: pointer to the inode + * @buf: buffer in which to store the hash + * @buf_size: length of the buffer + * + * On success, return the hash algorithm (as defined in the enum hash_algo). + * If buf is not NULL, this function also outputs the hash into buf. + * If the hash is larger than buf_size, then only buf_size bytes will be copied. + * It generally just makes sense to pass a buffer capable of holding the largest + * possible hash: IMA_MAX_DIGEST_SIZE. + * The hash returned is based on the entire contents, including the appended + * signature. + * + * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. + * If the parameters are incorrect, return -EINVAL. + */ +int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) +{ + if (!inode) + return -EINVAL; + + return __ima_inode_hash(inode, buf, buf_size); +} +EXPORT_SYMBOL_GPL(ima_inode_hash); + /** * ima_post_create_tmpfile - mark newly created tmpfile as new * @file : newly created tmpfile From patchwork Tue Nov 24 15:12:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11929187 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 397B1C6379D for ; Tue, 24 Nov 2020 15:13:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9ED620757 for ; 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[104.199.75.203]) by smtp.gmail.com with ESMTPSA id g131sm6353127wma.35.2020.11.24.07.12.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 07:12:13 -0800 (PST) From: KP Singh To: James Morris , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Florent Revest , Brendan Jackman , Mimi Zohar Subject: [PATCH bpf-next v3 2/3] bpf: Add a BPF helper for getting the IMA hash of an inode Date: Tue, 24 Nov 2020 15:12:09 +0000 Message-Id: <20201124151210.1081188-3-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog In-Reply-To: <20201124151210.1081188-1-kpsingh@chromium.org> References: <20201124151210.1081188-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: From: KP Singh Provide a wrapper function to get the IMA hash of an inode. This helper is useful in fingerprinting files (e.g executables on execution) and using these fingerprints in detections like an executable unlinking itself. Since the ima_inode_hash can sleep, it's only allowed for sleepable LSM hooks. Signed-off-by: KP Singh Acked-by: Yonghong Song --- include/uapi/linux/bpf.h | 11 +++++++++++ kernel/bpf/bpf_lsm.c | 26 ++++++++++++++++++++++++++ scripts/bpf_helpers_doc.py | 2 ++ tools/include/uapi/linux/bpf.h | 11 +++++++++++ 4 files changed, 50 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3ca6146f001a..c3458ec1f30a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3807,6 +3807,16 @@ union bpf_attr { * See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**) * Return * Current *ktime*. + * + * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size) + * Description + * Returns the stored IMA hash of the *inode* (if it's avaialable). + * If the hash is larger than *size*, then only *size* + * bytes will be copied to *dst* + * Return + * The **hash_algo** is returned on success, + * **-EOPNOTSUP** if IMA is disabled or **-EINVAL** if + * invalid arguments are passed. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3970,6 +3980,7 @@ union bpf_attr { FN(get_current_task_btf), \ FN(bprm_opts_set), \ FN(ktime_get_coarse_ns), \ + FN(ima_inode_hash), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index b4f27a874092..70e5e0b6d69d 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -15,6 +15,7 @@ #include #include #include +#include /* For every LSM hook that allows attachment of BPF programs, declare a nop * function where a BPF program can be attached. @@ -75,6 +76,29 @@ const static struct bpf_func_proto bpf_bprm_opts_set_proto = { .arg2_type = ARG_ANYTHING, }; +BPF_CALL_3(bpf_ima_inode_hash, struct inode *, inode, void *, dst, u32, size) +{ + return ima_inode_hash(inode, dst, size); +} + +static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog) +{ + return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id); +} + +BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode) + +const static struct bpf_func_proto bpf_ima_inode_hash_proto = { + .func = bpf_ima_inode_hash, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0], + .arg2_type = ARG_PTR_TO_UNINIT_MEM, + .arg3_type = ARG_CONST_SIZE, + .allowed = bpf_ima_inode_hash_allowed, +}; + static const struct bpf_func_proto * bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -97,6 +121,8 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_task_storage_delete_proto; case BPF_FUNC_bprm_opts_set: return &bpf_bprm_opts_set_proto; + case BPF_FUNC_ima_inode_hash: + return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL; default: return tracing_prog_func_proto(func_id, prog); } diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py index c5bc947a70ad..8b829748d488 100755 --- a/scripts/bpf_helpers_doc.py +++ b/scripts/bpf_helpers_doc.py @@ -436,6 +436,7 @@ class PrinterHelpers(Printer): 'struct xdp_md', 'struct path', 'struct btf_ptr', + 'struct inode', ] known_types = { '...', @@ -480,6 +481,7 @@ class PrinterHelpers(Printer): 'struct task_struct', 'struct path', 'struct btf_ptr', + 'struct inode', } mapped_types = { 'u8': '__u8', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3ca6146f001a..c3458ec1f30a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3807,6 +3807,16 @@ union bpf_attr { * See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**) * Return * Current *ktime*. + * + * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size) + * Description + * Returns the stored IMA hash of the *inode* (if it's avaialable). + * If the hash is larger than *size*, then only *size* + * bytes will be copied to *dst* + * Return + * The **hash_algo** is returned on success, + * **-EOPNOTSUP** if IMA is disabled or **-EINVAL** if + * invalid arguments are passed. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3970,6 +3980,7 @@ union bpf_attr { FN(get_current_task_btf), \ FN(bprm_opts_set), \ FN(ktime_get_coarse_ns), \ + FN(ima_inode_hash), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper From patchwork Tue Nov 24 15:12:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11929189 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB005C64E7B for ; Tue, 24 Nov 2020 15:13:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9679E206D4 for ; Tue, 24 Nov 2020 15:13:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="c/dkqqDE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389304AbgKXPMW (ORCPT ); Tue, 24 Nov 2020 10:12:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389580AbgKXPMR (ORCPT ); Tue, 24 Nov 2020 10:12:17 -0500 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70465C0613D6 for ; Tue, 24 Nov 2020 07:12:16 -0800 (PST) Received: by mail-wm1-x342.google.com with SMTP id x22so2710026wmc.5 for ; Tue, 24 Nov 2020 07:12:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=D7JMOLrkMMbgevNC61+0DIHgDGPPJS+bWf43N7huZE4=; b=c/dkqqDERVTz4nu8SZ1gJ/LT6g48/emtgI7ARP3cPql+gzxhR/llp/kIJuITTF1sZR fh+rmIb7R7TznZ8FVI9Z/LhFHPlPINvxoIPWfgt5ulrRAqAavc3Qv4HfO6kBv5NnsORC to35R6Dmw0QVByyXkQqnwjrPTPq79GJissoQM= 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=D7JMOLrkMMbgevNC61+0DIHgDGPPJS+bWf43N7huZE4=; b=PCOugh5qTS5vi1bbMf3zAgwPkCHGN0GDgVEFmSMhsZwvoCnX0C6EefGLiVkxTNeM7O RRHCdVlob0jD5oc5dZq9Q0HoKievYHixmZiu2Nc+nLw/W+J6gahorLzylh/yvjoDivrf /oFpMUJr1fGgItqjGXARWeYZRU+DlvuHo6TwFoeB6fssVgVcLpay2Do+idATkRO4iTSK /1XKKUa/R12SfPsfBh9XTJddaFzZZbGrZq2LKhtYF3Mv1AuAcdCi37hNGfn7oQcV2qwu 7Gv/ReAckQOctwHIcEf7VdyA0VughLTYavlwdvgnfFcB0z9Hj3pRDOoAV1pXJSSGgusv QegQ== X-Gm-Message-State: AOAM533Kc3OU0bFNOiE89rVcUJKT7IeqvImua/cAR8daDwojsXF2ilvP RdPc5CAbqz/CraTbpU1brChDRw== X-Google-Smtp-Source: ABdhPJwgYZ/acFThNsyVH2bB62qgxFgAVcLZ6MTj6oIq8/O6eWQRRAbFALJ3L2mumZdTfu17A2MgWg== X-Received: by 2002:a05:600c:22d5:: with SMTP id 21mr4944281wmg.33.1606230735161; Tue, 24 Nov 2020 07:12:15 -0800 (PST) Received: from kpsingh.c.googlers.com.com (203.75.199.104.bc.googleusercontent.com. [104.199.75.203]) by smtp.gmail.com with ESMTPSA id g131sm6353127wma.35.2020.11.24.07.12.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 07:12:14 -0800 (PST) From: KP Singh To: James Morris , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Florent Revest , Brendan Jackman , Mimi Zohar Subject: [PATCH bpf-next v3 3/3] bpf: Add a selftest for bpf_ima_inode_hash Date: Tue, 24 Nov 2020 15:12:10 +0000 Message-Id: <20201124151210.1081188-4-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog In-Reply-To: <20201124151210.1081188-1-kpsingh@chromium.org> References: <20201124151210.1081188-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: From: KP Singh The test does the following: - Mounts a loopback filesystem and appends the IMA policy to measure executions only on this file-system. Restricting the IMA policy to a particular filesystem prevents a system-wide IMA policy change. - Executes an executable copied to this loopback filesystem. - Calls the bpf_ima_inode_hash in the bprm_committed_creds hook and checks if the call succeeded and checks if a hash was calculated. The test shells out to the added ima_setup.sh script as the setup is better handled in a shell script and is more complicated to do in the test program or even shelling out individual commands from C. The list of required configs (i.e. IMA, SECURITYFS, IMA_{WRITE,READ}_POLICY) for running this test are also updated. Signed-off-by: KP Singh Acked-by: Yonghong Song --- tools/testing/selftests/bpf/config | 4 + tools/testing/selftests/bpf/ima_setup.sh | 80 +++++++++++++++++++ .../selftests/bpf/prog_tests/test_ima.c | 74 +++++++++++++++++ tools/testing/selftests/bpf/progs/ima.c | 28 +++++++ 4 files changed, 186 insertions(+) create mode 100644 tools/testing/selftests/bpf/ima_setup.sh create mode 100644 tools/testing/selftests/bpf/prog_tests/test_ima.c create mode 100644 tools/testing/selftests/bpf/progs/ima.c diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index 2118e23ac07a..365bf9771b07 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -39,3 +39,7 @@ CONFIG_BPF_JIT=y CONFIG_BPF_LSM=y CONFIG_SECURITY=y CONFIG_LIRC=y +CONFIG_IMA=y +CONFIG_SECURITYFS=y +CONFIG_IMA_WRITE_POLICY=y +CONFIG_IMA_READ_POLICY=y diff --git a/tools/testing/selftests/bpf/ima_setup.sh b/tools/testing/selftests/bpf/ima_setup.sh new file mode 100644 index 000000000000..15490ccc5e55 --- /dev/null +++ b/tools/testing/selftests/bpf/ima_setup.sh @@ -0,0 +1,80 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e +set -u + +IMA_POLICY_FILE="/sys/kernel/security/ima/policy" +TEST_BINARY="/bin/true" + +usage() +{ + echo "Usage: $0 " + exit 1 +} + +setup() +{ + local tmp_dir="$1" + local mount_img="${tmp_dir}/test.img" + local mount_dir="${tmp_dir}/mnt" + local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})" + mkdir -p ${mount_dir} + + dd if=/dev/zero of="${mount_img}" bs=1M count=10 + + local loop_device="$(losetup --find --show ${mount_img})" + + mkfs.ext4 "${loop_device}" + mount "${loop_device}" "${mount_dir}" + + cp "${TEST_BINARY}" "${mount_dir}" + local mount_uuid="$(blkid -s UUID -o value ${loop_device})" + echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${IMA_POLICY_FILE} +} + +cleanup() { + local tmp_dir="$1" + local mount_img="${tmp_dir}/test.img" + local mount_dir="${tmp_dir}/mnt" + + local loop_devices=$(losetup -j ${mount_img} -O NAME --noheadings) + for loop_dev in "${loop_devices}"; do + losetup -d $loop_dev + done + + umount ${mount_dir} + rm -rf ${tmp_dir} +} + +run() +{ + local tmp_dir="$1" + local mount_dir="${tmp_dir}/mnt" + local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})" + + exec "${copied_bin_path}" +} + +main() +{ + [[ $# -ne 2 ]] && usage + + local action="$1" + local tmp_dir="$2" + + [[ ! -d "${tmp_dir}" ]] && echo "Directory ${tmp_dir} doesn't exist" && exit 1 + + if [[ "${action}" == "setup" ]]; then + setup "${tmp_dir}" + elif [[ "${action}" == "cleanup" ]]; then + cleanup "${tmp_dir}" + elif [[ "${action}" == "run" ]]; then + run "${tmp_dir}" + else + echo "Unknown action: ${action}" + exit 1 + fi +} + +main "$@" diff --git a/tools/testing/selftests/bpf/prog_tests/test_ima.c b/tools/testing/selftests/bpf/prog_tests/test_ima.c new file mode 100644 index 000000000000..61fca681d524 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_ima.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ + +#include +#include +#include +#include +#include + +#include "ima.skel.h" + +static int run_measured_process(const char *measured_dir, u32 *monitored_pid) +{ + int child_pid, child_status; + + child_pid = fork(); + if (child_pid == 0) { + *monitored_pid = getpid(); + execlp("./ima_setup.sh", "./ima_setup.sh", "run", measured_dir, + NULL); + exit(errno); + + } else if (child_pid > 0) { + waitpid(child_pid, &child_status, 0); + return WEXITSTATUS(child_status); + } + + return -EINVAL; +} + +void test_test_ima(void) +{ + char measured_dir_template[] = "/tmp/ima_measuredXXXXXX"; + const char *measured_dir; + char cmd[256]; + + int err, duration = 0; + struct ima *skel = NULL; + + skel = ima__open_and_load(); + if (CHECK(!skel, "skel_load", "skeleton failed\n")) + goto close_prog; + + err = ima__attach(skel); + if (CHECK(err, "attach", "attach failed: %d\n", err)) + goto close_prog; + + measured_dir = mkdtemp(measured_dir_template); + if (CHECK(measured_dir == NULL, "mkdtemp", "err %d\n", errno)) + goto close_prog; + + snprintf(cmd, sizeof(cmd), "./ima_setup.sh setup %s", measured_dir); + if (CHECK_FAIL(system(cmd))) + goto close_clean; + + err = run_measured_process(measured_dir, &skel->bss->monitored_pid); + if (CHECK(err, "run_measured_process", "err = %d\n", err)) + goto close_clean; + + CHECK(skel->data->ima_hash_ret < 0, "ima_hash_ret", + "ima_hash_ret = %ld\n", skel->data->ima_hash_ret); + + CHECK(skel->bss->ima_hash == 0, "ima_hash", + "ima_hash = %lu\n", skel->bss->ima_hash); + +close_clean: + snprintf(cmd, sizeof(cmd), "./ima_setup.sh cleanup %s", measured_dir); + CHECK_FAIL(system(cmd)); +close_prog: + ima__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/ima.c b/tools/testing/selftests/bpf/progs/ima.c new file mode 100644 index 000000000000..86b21aff4bc5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/ima.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2020 Google LLC. + */ + +#include "vmlinux.h" +#include +#include +#include + +long ima_hash_ret = -1; +u64 ima_hash = 0; +u32 monitored_pid = 0; + +char _license[] SEC("license") = "GPL"; + +SEC("lsm.s/bprm_committed_creds") +int BPF_PROG(ima, struct linux_binprm *bprm) +{ + u32 pid = bpf_get_current_pid_tgid() >> 32; + + if (pid == monitored_pid) + ima_hash_ret = bpf_ima_inode_hash(bprm->file->f_inode, + &ima_hash, sizeof(ima_hash)); + + return 0; +}