From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from OSPPR02CU001.outbound.protection.outlook.com (mail-norwayeastazon11013065.outbound.protection.outlook.com [40.107.159.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1363D481ABA; Thu, 11 Jun 2026 16:22:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.159.65 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781194930; cv=fail; b=EDgPiHH99PuHiZDnstveVlTfPi0SkONqp1/3soueq9bVWx+83q5NV3ADF+Mm8WTuvAFyoV81WkXj/Utexino4MyxSjgcFFCgVpm4kliIbMogT1m5XvvH3PWnTRb5iXBJL4FKwwVQ2CYykQr05iZYizGR+EQ/D74abP0/GSJzWe4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781194930; c=relaxed/simple; bh=YNHRJxU7pBEgkggxGz5sDX5HG43rBjCaNfca9paR2Fk=; h=From:Date:Subject:Content-Type:Message-Id:References:In-Reply-To: To:Cc:MIME-Version; b=KVaf+HBu0kWTEp8sFLO67GGVjiHVBy2diXYovJ3iuV0K8cuGrZcHKjECsuRcTBkYtbxt0VTTdZW1cpb0aAX99udyuODosnKYYD+VEpZsz5f9SeeQIHd3EkVrck5cWXJEtvfaz33S+iMaOQ2tCUq+aWsl13WjPZ7OG+KLg9SQYyw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=est.tech; spf=pass smtp.mailfrom=est.tech; dkim=pass (2048-bit key) header.d=est.tech header.i=@est.tech header.b=CtTaCVBb; arc=fail smtp.client-ip=40.107.159.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=est.tech Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=est.tech Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=est.tech header.i=@est.tech header.b="CtTaCVBb" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=frPrbC5IEkI2ApUDjmJOTqYZuz2RBKPWgMC2TmA84EsJUrYG/a9BSaqQUCQAtEr74kGi7bjPn/S1h8h8Lbas/0wgGyQScQx6+WEp35IQzYQHqyt2wWlNI1oOqKxTkpbY9lNqpxP5t32p10DLd4+q2kS1KZsAiZBLdiK3qghE5fSTsUbC6Zr1i2aTBzUZtc3sGf30/AiritkopI8fAdBfiEpgLx37HSX7X7fIchj3RVKVrqdGDTykDu2jL3W3Uiri+l0ubDNipWXCOrRIqMBDyHMAai0r2gUstgoz5JZ/+6FjPTixhrfIlvsWPEi0wLMMroGJ7e+uV/U31Q1J4mLddw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=psY6a90e3/sLp+Oj5S4FiGYhmUJhRZQVAjwBzfCgPHU=; b=K1pap0lZUjM8y8xTTCmKiItjGn+IM+L4flrCWHkw8Mo2r0uK9UQsQ64IVjB+j62W9MPxqXRV8NZP4eRb9QLqsPP6O+IfmU8/ABC5AeJWfC0aoHpLtSpZ9eiX0G0LMk8AurqdKkqdsRvak1CMa3DazM1XmwUa25zlkvnisBvw6uvWtXNdTk7HQvd/CLQ/n9WTnww26jR5KKe/emkrrUzO0/KoRxbyqcwt4Ut8zIWhrVB1b2Nebq3VHA+Bwsk3pR6tAOsIFXasLWc/p/jE5GOr8EEYxag3O6ajUKg56bA+vZVd+Dd+fVgrZSFWNDtvYvHXWJIt8WLZ37PLgyFudD4yAg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=est.tech; dmarc=pass action=none header.from=est.tech; dkim=pass header.d=est.tech; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=est.tech; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=psY6a90e3/sLp+Oj5S4FiGYhmUJhRZQVAjwBzfCgPHU=; b=CtTaCVBblVnx/w6HwDxzBjibcgvsRSCE49u8IH75LRohIiq8TgFWPrulRQeROVYYYUiR5QPkJhHdfWzk7NnkKUij9JWJZQ4kvQBEH6Oirs0OxL1dPzsk4JqKrHJwbWmaDdkj1ixKHN02R3rdrMfgvGKtKQwxJ8yjyiAawiAKaOE4jNOz0VOQHZn/vQymtF/O2NU4Sj+eQfdTcG2IEZNWWMXyoWCJaoTMFKQLC3GFDcY4gDkRdqoC6ddPzES7BiUd/9Flp8MrdkVFK+8LgxmL47Va7Q5+Zmlkvr8FfVSQWGcPHlDY+4PTTE1geMSWWvMo+/hH0kIeGgILCHTKB/DejQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=est.tech; Received: from DB9P189MB1754.EURP189.PROD.OUTLOOK.COM (2603:10a6:10:2a5::24) by PAWP189MB2829.EURP189.PROD.OUTLOOK.COM (2603:10a6:102:468::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.113.13; Thu, 11 Jun 2026 16:21:58 +0000 Received: from DB9P189MB1754.EURP189.PROD.OUTLOOK.COM ([fe80::2af4:a981:db81:d471]) by DB9P189MB1754.EURP189.PROD.OUTLOOK.COM ([fe80::2af4:a981:db81:d471%6]) with mapi id 15.21.0113.013; Thu, 11 Jun 2026 16:21:58 +0000 From: Yunseong Kim Date: Thu, 11 Jun 2026 18:21:14 +0200 Subject: [RFC PATCH v2 12/14] selftests/kcov_dataflow: add rust_ffi_contract test module Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260611-b4-kcov-dataflow-v2-v2-12-0a261da3987c@est.tech> References: <20260611-b4-kcov-dataflow-v2-v2-0-0a261da3987c@est.tech> In-Reply-To: <20260611-b4-kcov-dataflow-v2-v2-0-0a261da3987c@est.tech> To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Andrey Konovalov , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Kees Cook , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Jonathan Corbet , Shuah Khan , Yunseong Kim Cc: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org, llvm@lists.linux.dev, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, workflows@vger.kernel.org, linux-doc@vger.kernel.org, Yeoreum Yun X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1781194895; l=9250; i=yunseong.kim@est.tech; s=20260426; h=from:subject:message-id; bh=YNHRJxU7pBEgkggxGz5sDX5HG43rBjCaNfca9paR2Fk=; b=8cDztotREPor/G6xcbhmpILOlAgxGYlwU+i7il0yY4g3T/qI7SskicjdN3rMs9iPkQOnDAMXs HVC5MntnHluDLOk1wOBp80N2giabqVzG2JcEh5HlMCqyBCo5hq4mJ2L X-Developer-Key: i=yunseong.kim@est.tech; a=ed25519; pk=1nBUX92cvTaavYG1+MR073D+XMKhdOciBZcnf6h6qEo= X-ClientProxiedBy: GV3PEPF0001DBF0.SWEP280.PROD.OUTLOOK.COM (2603:10a6:158:400::315) To DB9P189MB1754.EURP189.PROD.OUTLOOK.COM (2603:10a6:10:2a5::24) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DB9P189MB1754:EE_|PAWP189MB2829:EE_ X-MS-Office365-Filtering-Correlation-Id: de428a95-98ca-42db-ea15-08dec7d58f8b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|23010399003|1800799024|376014|7416014|921020|56012099006|11063799006|3023799007|6133799003|18002099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DB9P189MB1754.EURP189.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230040)(366016)(23010399003)(1800799024)(376014)(7416014)(921020)(56012099006)(11063799006)(3023799007)(6133799003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WHg4RGc3ekdvR25zWjhQRUZPbUtMSXp4Q0d2dk1oU3UzdHk4YmVLUUZFakRL?= =?utf-8?B?UXM4SklDdlcxUnd1RWZ5MGR3ZEVzdGRrQm1LZmMwWDB6NkE2NnArSkdnVzVG?= =?utf-8?B?anYyNFY4WlhpOVU0TU41b0tML092aVRlSmpGNVgrclhsWkl6UkxNZDBOQWtm?= =?utf-8?B?YVNuTDQ4TS93M0pkN1RXeXVRclFibmk0L3dmc25ya2RRNFJwWUhLb1NzZmJN?= =?utf-8?B?MVJHeHFZbVRqOUNvbFRRNDIvLzdUQmhrVnpJem14SmtyN2FZV2Nrd3JPdWdu?= =?utf-8?B?cDVncEhncG5jN3QvZjZ1NjhiaFhJZVVCYkRURFZzallQRlFxZWtBMWEzOE5Q?= =?utf-8?B?QW9rYWxqVURvY1hLaHNMbnZleHBTQkNXMXExeEU3SlVrbEI4RDZNRWNPeWI3?= =?utf-8?B?a0kySUIybGlSMHBnZGkxNzRBWUdmZVJrUy9GaXNGR0kyN3NJcFdRTXFwMk1s?= =?utf-8?B?UTB1NWphMCtQM1U2aFNvT0drYjFqSFBDZWw0bDFqbXhkOHFITk10QTJ3YzJO?= =?utf-8?B?bFBmOGdqMzZIQXlUR3p0OHJuazdOeUNxSXZQdnozcDFoRFBNODJHTC9pQmJu?= =?utf-8?B?QUlyczR2ZnBLa3BMbEpyTGphU2ROSGJBaFVrL0F2VDJ4OXptd2hHRVp3d1hZ?= =?utf-8?B?Y3FXVHBQTTFCS0xIKzE2TEhRRlJHRzhsS29LK2tsbkJ1TlRDckhZSGFjRWVw?= =?utf-8?B?RVd0M0VEME9OWnhTeUhHQUg1TG9ucnVDa2lhMkQxanFLM2V1SUhORVYvVkU0?= =?utf-8?B?Mk1nblVLZU5WM2ltcUlZU0IrZ2lBZWVHY2tQSDFJbWhHNTZ4S1ZWNnU4U2VF?= =?utf-8?B?dDNmWnkxeDVHcXFjMnNKcjJodENmbEIzMDI2bUk1eDRFRVZ4WGJyZ05ncStx?= =?utf-8?B?NnEvME9vWjBWT0tZUDArRGhiY0NEZHBmK1lZbERuKzU1a3NSeE1jb2l0MFNM?= =?utf-8?B?SnFKbFozM2VoaWV0YjIxazhCYXI4MmhheVZhVXdIQUZTcWhxWTMzTWZ2SEVF?= =?utf-8?B?TXUvNExJTEE4VVhLOGpObUl5ckZuNExqeHdxZ2loQUZWSy8rVncwWGJ5ejND?= =?utf-8?B?WXpicGc3QTczUVVvUnpPOHNySDlodEZFbVFZYTBvaCtuRzVEODdDd3Ezay9B?= =?utf-8?B?ejZUVlZvK013bTFSbjJTKzBCZ1V2S2I4eFlNR3VHWkpJL0VkM3R2ZWtWazll?= =?utf-8?B?MldtYmlkZDdiZzlKSnkvYjc1TVlwcnlJLzhpQSs5VG1CSUo3SmpkL0FWM2Na?= =?utf-8?B?bzZ2YmRwVG9VeWg0K0NBSUdBcHlVVk52K1NlZms2aGNSY2MxNzZrYm84ckFa?= =?utf-8?B?OGYzaUFXQmVOOHVWOFZodDBBNHpYK3Z6aFhiWER5R3h6c0JXSGNYaGJvMys5?= =?utf-8?B?MmN5cTRzVTk1Ukd0VUs5QXI3U3NnNjloOXZDWmhKd2R0MmpLMGxZTmdBRm5K?= =?utf-8?B?NFpFRW53aVRCSG5Id2pUVUk1UWpGNEFyVXVoZnhLQzdRa01hVnloczNaQ1dm?= =?utf-8?B?T0hObmdrQkFaZDBxbnJpZUFCZmhnTGhPbStPcFJvTnZFYmloYldaajRTQldi?= =?utf-8?B?TUYxVXdvVW5ZZDA0VzhvRytRVXJuNTlIenhiMG9PSzBWWEt3dVU0OGxpZ09Q?= =?utf-8?B?Z0dDUmRHS2p0dytuMGVlTGhFSTVWOTZBeEE1NlMxNENHRGxieE1hZEhwRFov?= =?utf-8?B?ZmRqU2VkeWRKWTNEOVU3Y2trS2piZk1TWGtoS3cxQW9YYVpUMWlGYmx0Zy9N?= =?utf-8?B?cWNkeG1LZDVFdUpSN0FoREw3bWcwY1FIanR6MFlVZ01ibjB4RzBZMkk0Q0xE?= =?utf-8?B?MXhUS2gzYnFIWjhTcUpLbDJyWGVWMlN2dThXdllwRzF1SVI0T3E1WWNIa1Mz?= =?utf-8?B?WFhIMHlIRUpTVG5sVmJmT1JSRkFJMTl3SnBOeTdyb2VzM285cW1Ub2N2OURR?= =?utf-8?B?WSt6aDRUMUlnSVpGNjVxbW9vV2liWTVkM2dkWVBBTVBJa283dUg1dis5eEdD?= =?utf-8?B?VERnOHEydTZXN0NVN3puVTRGMDBOUVBLMnlHbkd3dW82QUZuSmpFVWFBakJs?= =?utf-8?B?STlXV0JvVlNWdmhmYzg2NzdrQjRDSFI1aXJsVElBYnpFZWwyM2JuT0VQNXRk?= =?utf-8?B?ajNNZGRRU1UzRkRmNTNTbU05b2tFSzdaZE5jRlBSL29ybTdzZGxOMGhoOXV6?= =?utf-8?B?dTMzU0lIL1FIYnRiYk9mTkwxNEFOUHMvTk5PbnVwUUpEbmVWT3h2RGxBSzZz?= =?utf-8?B?Qm1EQWRCS2FGWTFQazlqRllCcHYvaXRMT0NqYmhCaVVkakNMVWo4dHE0UHcv?= =?utf-8?B?QzJMYUVhOTQ0TUltT3VCaXlUTDlna2c2TFNxMEttbE9zeU9ZSlVBUT09?= X-OriginatorOrg: est.tech X-MS-Exchange-CrossTenant-Network-Message-Id: de428a95-98ca-42db-ea15-08dec7d58f8b X-MS-Exchange-CrossTenant-AuthSource: DB9P189MB1754.EURP189.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Jun 2026 16:21:58.4696 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: d2585e63-66b9-44b6-a76e-4f4b217d97fd X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 1q0q3A/Pd4ORrgMRBq3SzXpnXk0SNH0Xs70vb5CJoJvf7dvb/t3FIpACY2fmjV8zAEAbI5A3xCziuIu5Y2pefw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAWP189MB2829 Demonstrates FFI contract violation detection. A C callee returns success (0) but leaves buffer=NULL, violating the postcondition "ret==0 implies buffer!=NULL". kcov_dataflow captures struct fields at the boundary proving the violation without a crash or KASAN report. Test: make LLVM=1 CC=clang \ M=tools/testing/selftests/kcov_dataflow/rust_ffi_contract modules vng --user root --exec \ "python3 tools/testing/selftests/kcov_dataflow/trigger-view.py \ rust_ffi_contract -C 8 --ko \ tools/testing/selftests/kcov_dataflow/rust_ffi_contract/rust_ffi_contract.ko" Result: vfs_write(0x0) 0x0 = full_proxy_write() full_proxy_write(0x0, 0x1, 0x0) 0x8200080 = __debugfs_file_get() __debugfs_file_get(0x0) 0x0 = __debugfs_file_get() 0x0 = rust_ffi_trigger_write [rust_ffi_contract]() rust_ffi_trigger_write [rust_ffi_contract](0x0, 0x1, 0x0) ffi_alloc_buf [rust_ffi_contract](0xffffffff912288ad, 0x100, 0x0, 0x1) 0x0 = ffi_alloc_buf [rust_ffi_contract]() _printk(0x6f635f6966663601) vprintk(0x6f635f6966663601, 0x8) vprintk_default(0x6f635f6966663601, 0x8) vprintk_emit(0x0, 0xffffffff, 0x0) 0x0 = panic_on_this_cpu() 0x0 = _prb_read_valid() 0x0 = prb_read_valid() 0x0 = console_unlock() 0x3f = vprintk_emit() 0x3f = vprintk_default() 0x3f = vprintk() 0x3f = _printk() ffi_check_result [rust_ffi_contract](0x0) _printk(0x6f635f6966663301) vprintk(0x6f635f6966663301, 0x8) vprintk_default(0x6f635f6966663301, 0x8) vprintk_emit(0x0, 0xffffffff, 0x0) 0x0 = panic_on_this_cpu() 0x0 = _prb_read_valid() 0x0 = prb_read_valid() 0x0 = console_unlock() 0x3f = vprintk_emit() 0x3f = vprintk_default() 0x3f = vprintk() 0x3f = _printk() 0xfffffff2 = ffi_check_result [rust_ffi_contract]() 0x1 = rust_ffi_trigger_write [rust_ffi_contract]() 0x1 = full_proxy_write() 0x1 = vfs_write() 0x1 = ksys_write() 0x1 = __x64_sys_write() 0x0 = fpregs_assert_state_consistent() 0xba5748 = __x64_sys_close() file_close_fd(0x4) 0x0 = file_close_fd() Cc: Alexander Potapenko Assisted-by: Claude:claude-opus-4-6 [kiro-chat] Link: https://github.com/yskzalloc/kcov-dataflow/actions Signed-off-by: Yunseong Kim --- tools/testing/selftests/kcov_dataflow/Makefile | 2 +- tools/testing/selftests/kcov_dataflow/README.rst | 8 ++ .../kcov_dataflow/run_rust_ffi_contract.sh | 35 +++++++ .../kcov_dataflow/rust_ffi_contract/Makefile | 3 + .../rust_ffi_contract/rust_ffi_contract.c | 111 +++++++++++++++++++++ 5 files changed, 158 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kcov_dataflow/Makefile b/tools/testing/selftests/kcov_dataflow/Makefile index 3a42c54e954d..6412c90edfa1 100644 --- a/tools/testing/selftests/kcov_dataflow/Makefile +++ b/tools/testing/selftests/kcov_dataflow/Makefile @@ -1,4 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 TEST_GEN_PROGS := user_ioctl/user_ioctl -TEST_PROGS := run_eight_args_c.sh +TEST_PROGS := run_eight_args_c.sh run_rust_ffi_contract.sh include ../lib.mk diff --git a/tools/testing/selftests/kcov_dataflow/README.rst b/tools/testing/selftests/kcov_dataflow/README.rst index 61a41f3bd596..06a0c805cc74 100644 --- a/tools/testing/selftests/kcov_dataflow/README.rst +++ b/tools/testing/selftests/kcov_dataflow/README.rst @@ -48,3 +48,11 @@ eight_args_rust/ make LLVM=1 CC=clang M=tools/testing/selftests/kcov_dataflow/eight_args_rust modules python3 trigger-view.py eight_args_rust + +rust_ffi_contract/ + Demonstrates FFI contract violation detection. A callee returns + success but leaves buffer=NULL. kcov_dataflow captures struct + fields proving the violation:: + + make LLVM=1 CC=clang M=tools/testing/selftests/kcov_dataflow/rust_ffi_contract modules + python3 trigger-view.py rust_ffi_contract diff --git a/tools/testing/selftests/kcov_dataflow/run_rust_ffi_contract.sh b/tools/testing/selftests/kcov_dataflow/run_rust_ffi_contract.sh new file mode 100755 index 000000000000..8662e532296b --- /dev/null +++ b/tools/testing/selftests/kcov_dataflow/run_rust_ffi_contract.sh @@ -0,0 +1,35 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Test rust_ffi_contract module capture via kcov_dataflow +DIR="$(dirname "$0")" +KO="$DIR/rust_ffi_contract/rust_ffi_contract.ko" + +if [ ! -f "$KO" ]; then + echo "SKIP: $KO not found" + echo "Build: make LLVM=1 CC=clang M=...rust_ffi_contract modules"" + exit 4 # kselftest SKIP +fi + +if [ ! -e /sys/kernel/debug/kcov_dataflow ]; then + echo "SKIP: kcov_dataflow not available" + exit 4 +fi + +OUTPUT=$(python3 "$DIR/trigger-view.py" rust_ffi_contract --ko "$KO" --raw 2>&1) +RC=$? + +if [ $RC -ne 0 ]; then + echo "FAIL: trigger-and-view exited with $RC" + echo "$OUTPUT" + exit 1 +fi + +RECORDS=$(echo "$OUTPUT" | grep -c "^\[ENTRY\]\|^\[RET") +if [ "$RECORDS" -gt 0 ]; then + echo "PASS: captured $RECORDS records from rust_ffi_contract" + exit 0 +else + echo "FAIL: no records captured" + echo "$OUTPUT" + exit 1 +fi diff --git a/tools/testing/selftests/kcov_dataflow/rust_ffi_contract/Makefile b/tools/testing/selftests/kcov_dataflow/rust_ffi_contract/Makefile new file mode 100644 index 000000000000..d2a0261070b1 --- /dev/null +++ b/tools/testing/selftests/kcov_dataflow/rust_ffi_contract/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-m := rust_ffi_contract.o +KCOV_DATAFLOW_rust_ffi_contract.o := y diff --git a/tools/testing/selftests/kcov_dataflow/rust_ffi_contract/rust_ffi_contract.c b/tools/testing/selftests/kcov_dataflow/rust_ffi_contract/rust_ffi_contract.c new file mode 100644 index 000000000000..9cbb17c42195 --- /dev/null +++ b/tools/testing/selftests/kcov_dataflow/rust_ffi_contract/rust_ffi_contract.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * rust_ffi_contract.c - Demonstrates kcov_dataflow detecting an FFI + * contract violation at a function boundary. + * + * The pattern: caller passes a struct pointer to callee. Callee's + * contract says "returns 0 implies out->buffer is valid". A bug in + * the async path returns 0 but leaves buffer=NULL. + * + * kcov_dataflow captures: + * [ENTRY] ffi_alloc_buf(alloc={.buffer=NULL, .data_size=0}, 256, 16, 1) + * [RET] ffi_alloc_buf() = 0 + * [ENTRY] ffi_check_result(alloc={.buffer=NULL, ...}) + * ^ proves contract violated + * + * Write to /sys/kernel/debug/kcov_dataflow_test/rust_ffi_trigger to run. + */ +#include +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("FFI contract violation detection via kcov_dataflow"); + +struct ffi_alloc { + void *buffer; + u64 data_size; + u32 free_async; + u32 flags; +}; + +/* Prototypes */ +int ffi_alloc_buf(struct ffi_alloc *alloc, u64 data_size, + u64 offsets_size, int is_async); +int ffi_check_result(struct ffi_alloc *alloc); + +/* + * Callee with contract: returns 0 implies alloc->buffer is valid. + * BUG: async path with free_async==0 returns 0 but buffer stays NULL. + */ +noinline int ffi_alloc_buf(struct ffi_alloc *alloc, u64 data_size, + u64 offsets_size, int is_async) +{ + if (!is_async) { + alloc->buffer = kmalloc(data_size, GFP_KERNEL); + if (!alloc->buffer) + return -ENOMEM; + return 0; + } + /* BUG: returns success but buffer is NULL when pool empty */ + if (alloc->free_async == 0) { + alloc->buffer = NULL; + return 0; /* contract violation */ + } + alloc->buffer = kmalloc(data_size, GFP_KERNEL); + alloc->free_async--; + return 0; +} +EXPORT_SYMBOL(ffi_alloc_buf); + +/* Caller that trusts the contract */ +noinline int ffi_check_result(struct ffi_alloc *alloc) +{ + if (!alloc->buffer) { + pr_err("ffi_contract: VIOLATION detected - buffer is NULL after success\n"); + return -EFAULT; + } + kfree(alloc->buffer); + return 0; +} +EXPORT_SYMBOL(ffi_check_result); + +static struct dentry *test_dir; + +static ssize_t rust_ffi_trigger_write(struct file *f, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct ffi_alloc alloc = { .buffer = NULL, .data_size = 0, + .free_async = 0, .flags = 0 }; + int ret; + + /* Trigger the bug: is_async=1, free_async=0 */ + ret = ffi_alloc_buf(&alloc, 256, 16, 1); + pr_info("ffi_contract: ffi_alloc_buf returned %d, buffer=%p\n", + ret, alloc.buffer); + + if (ret == 0) + ffi_check_result(&alloc); + + return count; +} + +static const struct file_operations rust_ffi_trigger_fops = { + .write = rust_ffi_trigger_write, +}; + +static int __init ffi_contract_init(void) +{ + test_dir = debugfs_create_dir("kcov_dataflow_test", NULL); + debugfs_create_file("rust_ffi_trigger", 0200, test_dir, NULL, + &rust_ffi_trigger_fops); + return 0; +} + +static void __exit ffi_contract_exit(void) +{ + debugfs_remove_recursive(test_dir); +} + +module_init(ffi_contract_init); +module_exit(ffi_contract_exit); -- 2.43.0