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Mercier" X-Patchwork-Id: 13112840 X-Patchwork-Delegate: paul@paul-moore.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AE94C05027 for ; Mon, 23 Jan 2023 19:19:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231485AbjAWTTC (ORCPT ); Mon, 23 Jan 2023 14:19:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232446AbjAWTS3 (ORCPT ); Mon, 23 Jan 2023 14:18:29 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1205AE397 for ; Mon, 23 Jan 2023 11:18:17 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id p51-20020a056a0026f300b0058df209da03so5751770pfw.15 for ; Mon, 23 Jan 2023 11:18:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=z2WhRnZzQgS7vry+Z+wffN8GNT/+GwBkd2a3cKemc3A=; b=qIoHkzSJgScPAOmXRPybmkkxLYzr2DadvdaoU+21L1WVU3YW/Hmjf98YSxQck6Cojl hSJIB90Oc/J5PhcPthu37nMpMkmKvUecOx+8XcN0o61N3c9FSHsypWEcnKqeCpO8oZn5 5t2GLdXEZE6+Kn1L/RgqPV6+knFah8Sty5ttQeslTrfM6XTfbVGpIJuSS4JTguGrEf+K 02GyI8CR+Za0guqiCqlg7dAfcw68H5UFF1O5CbDXUC7fdVcQj+I00pYkk/UsWsyDil4n wMUZxRBLOsVMt7lEWJwwaO1NERbypePie8xI/PldXEjxtDPpICffELsttwq1JrA5YUun L0Tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=z2WhRnZzQgS7vry+Z+wffN8GNT/+GwBkd2a3cKemc3A=; b=JbFXMReiUAIWoDwihx3yXHEychSHDkXmF2imZF/YPyAuzgRXxHsLGedYi2OoI06Slq vKDpKPpUUBRJAKfu77Db3CsEcYrs7fO+Fj1WYtXoumf2RclzAGFfk5xuTiTBR+wdJ+cp YOCABqyq0SJ/p0N77IPAA/OuY+g9pfc3dwdtD5F/rawT0dlOD48//H62l8hQI3q7VI/9 y+JcjMK4JKefg8yEzaYpRBzX912c0iO2H96RueD/7pLr5B0R3C8+BEVrpotXEEOpG4EP 9KYFoQjby1sKI3Kd1KioTLjIScjwDNDBr3BW+mCj2ZAn4M79GytjCnT8dxS+zG5avAcH C7Xg== X-Gm-Message-State: AFqh2krDvjQxNa4h/XG18EJSqaC4ceDNQUNtAOoqa/9Uk8PgJBW0yXJF Yh+w8A93Ut282/cakeo0ne8l3r//G9ojjfc= X-Google-Smtp-Source: AMrXdXsNa09AO4Arg6ZBRXKwo+WF/qUZjQHNXFX5rA6KWe8BFUhOpIiYlW4PW5subPRyzOFWH3Ah7qsET8UrWsU= X-Received: from tj.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:53a]) (user=tjmercier job=sendgmr) by 2002:aa7:8a0b:0:b0:58d:bffa:db35 with SMTP id m11-20020aa78a0b000000b0058dbffadb35mr2968935pfa.34.1674501496540; Mon, 23 Jan 2023 11:18:16 -0800 (PST) Date: Mon, 23 Jan 2023 19:17:26 +0000 In-Reply-To: <20230123191728.2928839-1-tjmercier@google.com> Mime-Version: 1.0 References: <20230123191728.2928839-1-tjmercier@google.com> X-Mailer: git-send-email 2.39.0.246.g2a6d74b583-goog Message-ID: <20230123191728.2928839-5-tjmercier@google.com> Subject: [PATCH v2 4/4] security: binder: Add binder object flags to selinux_binder_transfer_file From: "T.J. Mercier" To: tjmercier@google.com, Greg Kroah-Hartman , " =?utf-8?q?Arve_Hj=C3=B8nnev=C3=A5g?= " , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Carlos Llamas , Suren Baghdasaryan , Paul Moore , James Morris , "Serge E. Hallyn" , Stephen Smalley , Eric Paris Cc: hannes@cmpxchg.org, daniel.vetter@ffwll.ch, android-mm@google.com, jstultz@google.com, jeffv@google.com, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: Any process can cause a memory charge transfer to occur to any other process when transmitting a file descriptor through binder. This should only be possible for central allocator processes, so the binder object flags are added to the security_binder_transfer_file hook so that LSMs can enforce restrictions on charge transfers. Signed-off-by: T.J. Mercier --- drivers/android/binder.c | 2 +- include/linux/lsm_hook_defs.h | 2 +- include/linux/lsm_hooks.h | 5 ++++- include/linux/security.h | 6 ++++-- security/security.c | 4 ++-- security/selinux/hooks.c | 13 ++++++++++++- security/selinux/include/classmap.h | 2 +- 7 files changed, 25 insertions(+), 9 deletions(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 5e707974793f..7b1bb23b6b79 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2270,7 +2270,7 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, __u32 flags, ret = -EBADF; goto err_fget; } - ret = security_binder_transfer_file(proc->cred, target_proc->cred, file); + ret = security_binder_transfer_file(proc->cred, target_proc->cred, file, flags); if (ret < 0) { ret = -EPERM; goto err_security; diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index ed6cb2ac55fa..84ee61089f7b 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -32,7 +32,7 @@ LSM_HOOK(int, 0, binder_transaction, const struct cred *from, LSM_HOOK(int, 0, binder_transfer_binder, const struct cred *from, const struct cred *to) LSM_HOOK(int, 0, binder_transfer_file, const struct cred *from, - const struct cred *to, struct file *file) + const struct cred *to, struct file *file, u32 binder_object_flags) LSM_HOOK(int, 0, ptrace_access_check, struct task_struct *child, unsigned int mode) LSM_HOOK(int, 0, ptrace_traceme, struct task_struct *parent) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 0a5ba81f7367..d57977336ae8 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1381,9 +1381,12 @@ * Return 0 if permission is granted. * @binder_transfer_file: * Check whether @from is allowed to transfer @file to @to. + * If @binder_object_flags indicates a memory charge transfer for @file, then + * permission for the charge transfer can be checked as well. * @from contains the struct cred for the sending process. - * @file contains the struct file being transferred. * @to contains the struct cred for the receiving process. + * @file contains the struct file being transferred. + * @binder_object_flags contains the flags associated with the binder object. * Return 0 if permission is granted. * * @ptrace_access_check: diff --git a/include/linux/security.h b/include/linux/security.h index 5b67f208f7de..c4b80fc8d104 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -269,7 +269,8 @@ int security_binder_transaction(const struct cred *from, int security_binder_transfer_binder(const struct cred *from, const struct cred *to); int security_binder_transfer_file(const struct cred *from, - const struct cred *to, struct file *file); + const struct cred *to, struct file *file, + u32 binder_object_flags); int security_ptrace_access_check(struct task_struct *child, unsigned int mode); int security_ptrace_traceme(struct task_struct *parent); int security_capget(struct task_struct *target, @@ -542,7 +543,8 @@ static inline int security_binder_transfer_binder(const struct cred *from, static inline int security_binder_transfer_file(const struct cred *from, const struct cred *to, - struct file *file) + struct file *file, + u32 binder_object_flags) { return 0; } diff --git a/security/security.c b/security/security.c index d1571900a8c7..12ccaca744c0 100644 --- a/security/security.c +++ b/security/security.c @@ -796,9 +796,9 @@ int security_binder_transfer_binder(const struct cred *from, } int security_binder_transfer_file(const struct cred *from, - const struct cred *to, struct file *file) + const struct cred *to, struct file *file, u32 binder_object_flags) { - return call_int_hook(binder_transfer_file, 0, from, to, file); + return call_int_hook(binder_transfer_file, 0, from, to, file, binder_object_flags); } int security_ptrace_access_check(struct task_struct *child, unsigned int mode) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 3c5be76a9199..d4cfca3c9a3b 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -88,6 +88,7 @@ #include #include #include /* for hashlen_string() */ +#include #include #include #include @@ -2029,7 +2030,8 @@ static int selinux_binder_transfer_binder(const struct cred *from, static int selinux_binder_transfer_file(const struct cred *from, const struct cred *to, - struct file *file) + struct file *file, + u32 binder_object_flags) { u32 sid = cred_sid(to); struct file_security_struct *fsec = selinux_file(file); @@ -2038,6 +2040,15 @@ static int selinux_binder_transfer_file(const struct cred *from, struct common_audit_data ad; int rc; + if (binder_object_flags & BINDER_FD_FLAG_XFER_CHARGE) { + rc = avc_has_perm(&selinux_state, + cred_sid(from), sid, + SECCLASS_BINDER, BINDER__TRANSFER_CHARGE, + NULL); + if (rc) + return rc; + } + ad.type = LSM_AUDIT_DATA_PATH; ad.u.path = file->f_path; diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index a3c380775d41..2eef180d10d7 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -172,7 +172,7 @@ const struct security_class_mapping secclass_map[] = { { "tun_socket", { COMMON_SOCK_PERMS, "attach_queue", NULL } }, { "binder", { "impersonate", "call", "set_context_mgr", "transfer", - NULL } }, + "transfer_charge", NULL } }, { "cap_userns", { COMMON_CAP_PERMS, NULL } }, { "cap2_userns",