From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B581C433F5 for ; Mon, 11 Oct 2021 16:26:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E7E260EE5 for ; Mon, 11 Oct 2021 16:26:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231962AbhJKQ2X (ORCPT ); Mon, 11 Oct 2021 12:28:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231976AbhJKQ2X (ORCPT ); Mon, 11 Oct 2021 12:28:23 -0400 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4A14C06161C for ; Mon, 11 Oct 2021 09:26:22 -0700 (PDT) Received: by mail-ed1-x52b.google.com with SMTP id a25so54087074edx.8 for ; Mon, 11 Oct 2021 09:26:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20210112; h=from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=lPfLQeriQeS1w03uhCayH4gvwfaK5ehVrV0cIUrSzXI=; b=Wr0cBpM0zgdUWK81clXZt2RD4WMJJuA1H30fN7Gv+o0jw5twbU/CcY0R7q8p19GxW4 rFSR28aSbula/dFvF87AW7VIxM30k9bo3MVRW79DWvalK0YbQ/iYVCu4egSROeMRQJUo /EUS1p1KFaKTi6N7dghC94h8iIBO28HA9MycgMZ4u9Iw6xIM4yLyRDr7jv6R/Uu8TyVk ShT0iguVIJ+ssXqmOLCBEjcHenaGqz3tjuy2obBEHYb8sL9HrOVnui99qDB2vD5jdNeA g24Dntwymb/ilumO+gVNN4h59yN4ZUiiLx3sPlpLOaxnF7yoOTtmbF6HWPZoAcokw/yy a0uQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=lPfLQeriQeS1w03uhCayH4gvwfaK5ehVrV0cIUrSzXI=; b=z4W1MBuyKL6ELT2ye8ckdzSJcvwFhgMuIkjZdLHhqPtpbHqILebkPfhod4L15VD078 fgqHCIZWqqm4o6urXr29+npZzF1hP94C+XSinpYdT4ITc8LhDfK28LGnr3L7c6wZLZCh wQTwbsH269eVObtP+IRSIuVeNpuLjhSYy6NlIXG9aKsZjO0UG+U4XHlBKqa/jjH4RbWX 5W8vMZBZyqDBZ+xgZ98EoqULaXsVHP9WfMlRL0QAwkNJb8GHn67OZQ5RYwrjtU/Bd1UX C69LKXMbq3nNsicOEgl/4OMKZeTvHwwkY7PQhZeOSBm1u030kp2kjbzDCGlqM7BEOEpa 0IBw== X-Gm-Message-State: AOAM530be+YK/UBBm2SO02B0b0HqMxFABQ3zZzjQzgbzykCdlIkPKGb6 k9CLkxQhy1QeksZKBQlBUngwWkS0LBc= X-Google-Smtp-Source: ABdhPJy1/FkePu/HeI7k/pPf85B9OcbiNKzcB0lcb+bu17rrwAfcFKzcuQdHabqqV9v9rkGYYT90cg== X-Received: by 2002:aa7:c783:: with SMTP id n3mr42521580eds.122.1633969581329; Mon, 11 Oct 2021 09:26:21 -0700 (PDT) Received: from debianHome.localdomain (dynamic-077-010-085-058.77.10.pool.telefonica.de. [77.10.85.58]) by smtp.gmail.com with ESMTPSA id a1sm4489514edu.43.2021.10.11.09.26.20 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Oct 2021 09:26:20 -0700 (PDT) From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= To: selinux@vger.kernel.org Subject: [RFC PATCH 00/35] libsepol: add fuzzer for reading binary policies Date: Mon, 11 Oct 2021 18:24:58 +0200 Message-Id: <20211011162533.53404-1-cgzones@googlemail.com> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Add a libfuzz[1] based fuzzer testing the reading and parsing of binary policy files. This fuzzer will be run within the OSS-Fuzz service. Handle and reject a variety of edge cases causing crashes or resource leaks. The fifth patch ("libsepol/fuzz: limit element sizes for fuzzing") needs some discussion: To avoid oom reports from the fuzzer, caused by huge memory allocations, all identifiers are limited to a length of 2^16 for the fuzzer build only. Probably there should be a limit for the release build too. Is there a specification for the binary policy format saying something about the maximum length of identifiers? After a quick look at the kernel sources (most interesting is str_read()) I could not find any limits either. [1]: https://llvm.org/docs/LibFuzzer.html Christian Göttsche (35): cifuzz: enable report-unreproducible-crashes cifuzz: use the default runtime of 600 seconds libsepol/fuzz: silence secilc-fuzzer libsepol: add libfuzz based fuzzer for reading binary policies libsepol/fuzz: limit element sizes for fuzzing libsepol: use logging framework in conditional.c libsepol: use logging framework in ebitmap.c libsepol: use mallocarray wrapper to avoid overflows libsepol: use reallocarray wrapper to avoid overflows libsepol: add checks for read sizes libsepol: enforce avtab item limit libsepol: clean memory on conditional read failure libsepol: validate MLS levels libsepol: reject invalid fsuse types libsepol: reject invalid default targets libsepol: validate expanded user range and level libsepol: validate types libsepol: use size_t for indexes in strs helpers libsepol: reject abnormal huge sid ids libsepol: do not crash on class gaps libsepol: do not crash on user gaps libsepol: validate permission count of classes libsepol: resolve log message mismatch libsepol: zero member before potential dereference libsepol: validate avtab types libsepol: validate constraint expression operators and attributes libsepol: validate type of avtab type rules libsepol: validate ocontexts libsepol: validate genfs contexts libsepol: validate permissive types libsepol: validate policy properties libsepol: do not underflow on short format arguments libsepol: validate categories libsepol: use correct size for initial string list libsepol: do not create a string list with initial size zero .github/workflows/cifuzz.yml | 3 +- libsepol/fuzz/binpolicy-fuzzer.c | 63 +++++++ libsepol/fuzz/policy.bin | Bin 0 -> 1552 bytes libsepol/fuzz/secilc-fuzzer.c | 5 + libsepol/src/Makefile | 6 + libsepol/src/avtab.c | 6 + libsepol/src/conditional.c | 36 ++-- libsepol/src/ebitmap.c | 27 ++- libsepol/src/expand.c | 4 +- libsepol/src/hashtab.c | 4 +- libsepol/src/kernel_to_cil.c | 10 ++ libsepol/src/kernel_to_common.c | 23 ++- libsepol/src/kernel_to_common.h | 4 +- libsepol/src/kernel_to_conf.c | 13 +- libsepol/src/link.c | 3 +- libsepol/src/module.c | 4 +- libsepol/src/module_to_cil.c | 13 +- libsepol/src/optimize.c | 11 +- libsepol/src/policydb.c | 68 +++++++- libsepol/src/policydb_validate.c | 274 +++++++++++++++++++++++++++++-- libsepol/src/private.h | 27 ++- libsepol/src/services.c | 12 +- libsepol/src/sidtab.c | 3 +- libsepol/src/user_record.c | 8 +- libsepol/src/users.c | 12 +- libsepol/src/util.c | 11 +- libsepol/src/write.c | 2 +- scripts/oss-fuzz.sh | 19 ++- 28 files changed, 556 insertions(+), 115 deletions(-) create mode 100644 libsepol/fuzz/binpolicy-fuzzer.c create mode 100644 libsepol/fuzz/policy.bin -- 2.33.0