From patchwork Tue Nov 8 19:52:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Francis Laniel X-Patchwork-Id: 13036803 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 8A97EC4332F for ; Tue, 8 Nov 2022 19:52:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229764AbiKHTw4 (ORCPT ); Tue, 8 Nov 2022 14:52:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229774AbiKHTwz (ORCPT ); Tue, 8 Nov 2022 14:52:55 -0500 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 120F67057F; Tue, 8 Nov 2022 11:52:53 -0800 (PST) Received: from pwmachine.numericable.fr (85-170-25-210.rev.numericable.fr [85.170.25.210]) by linux.microsoft.com (Postfix) with ESMTPSA id 100FB20B9F81; Tue, 8 Nov 2022 11:52:48 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 100FB20B9F81 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1667937172; bh=aV1rbRcoT8elrIFvcswWnTb6/2G/r5XMttMTu6HgEWE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rNA91l5NyZRNSqXKVvrOFtfVRTnClAzSHuIB0O3Egn/SS6gqzKq3v7ZKmQBR/jCpy mgmLPKxd59MfGA18pKlh2CT9mEP1YYypTZe/p83XNEV2xlMr6zqKrK9/5hjRy1klb0 USlF3Ft41AuAO7/QWRSjFyu3ezjq7SIq6BQwfc2U= From: Francis Laniel To: linux-kernel@vger.kernel.org Cc: Alban Crequy , Alban Crequy , Francis Laniel , Andrew Morton , Andrii Nakryiko , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , linux-mm@kvack.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [RFC PATCH v1 1/2] maccess: fix writing offset in case of fault in strncpy_from_kernel_nofault() Date: Tue, 8 Nov 2022 20:52:06 +0100 Message-Id: <20221108195211.214025-2-flaniel@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221108195211.214025-1-flaniel@linux.microsoft.com> References: <20221108195211.214025-1-flaniel@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Alban Crequy If a page fault occurs while copying the first byte, this function resets one byte before dst. As a consequence, an address could be modified and leaded to kernel crashes if case the modified address was accessed later. Signed-off-by: Alban Crequy Tested-by: Francis Laniel Reviewed-by: Andrew Morton --- mm/maccess.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.25.1 diff --git a/mm/maccess.c b/mm/maccess.c index 5f4d240f67ec..074f6b086671 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -97,7 +97,7 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) return src - unsafe_addr; Efault: pagefault_enable(); - dst[-1] = '\0'; + dst[0] = '\0'; return -EFAULT; } From patchwork Tue Nov 8 19:52:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Francis Laniel X-Patchwork-Id: 13036804 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 86569C4332F for ; Tue, 8 Nov 2022 19:53:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229795AbiKHTxI (ORCPT ); Tue, 8 Nov 2022 14:53:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229821AbiKHTxD (ORCPT ); Tue, 8 Nov 2022 14:53:03 -0500 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DA8E17057F; Tue, 8 Nov 2022 11:53:00 -0800 (PST) Received: from pwmachine.numericable.fr (85-170-25-210.rev.numericable.fr [85.170.25.210]) by linux.microsoft.com (Postfix) with ESMTPSA id E1FAA20B9F80; Tue, 8 Nov 2022 11:52:56 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E1FAA20B9F80 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1667937180; bh=lfm7BTt/ROEPRbGDPE3vy0AJuoRZ1875JpNL6uMTfxU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z6y0+aMF7SVBf0gFi1ICcf5FraX76ZRSz2ubkXhXtcPbw166bRHHw/TGxDIGh3txN SAQDO1pwq8hj3/PXrWZn3Uct6WoppsDGUInreNeOK8hBSmRrPvz9wrDBWvS0DhviDY 94IRSMcmuNH0IJPuoG0eAXnRTi0XMLf+eQc/qjrE= From: Francis Laniel To: linux-kernel@vger.kernel.org Cc: Alban Crequy , Alban Crequy , Francis Laniel , Andrew Morton , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , linux-mm@kvack.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [RFC PATCH v1 2/2] selftests: bpf: add a test when bpf_probe_read_kernel_str() returns EFAULT Date: Tue, 8 Nov 2022 20:52:07 +0100 Message-Id: <20221108195211.214025-3-flaniel@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221108195211.214025-1-flaniel@linux.microsoft.com> References: <20221108195211.214025-1-flaniel@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Alban Crequy This commit tests previous fix of bpf_probe_read_kernel_str(). Signed-off-by: Alban Crequy Signed-off-by: Francis Laniel Acked-by: Yonghong Song --- tools/testing/selftests/bpf/prog_tests/varlen.c | 7 +++++++ tools/testing/selftests/bpf/progs/test_varlen.c | 5 +++++ 2 files changed, 12 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/varlen.c b/tools/testing/selftests/bpf/prog_tests/varlen.c index dd324b4933db..4d7056f8f177 100644 --- a/tools/testing/selftests/bpf/prog_tests/varlen.c +++ b/tools/testing/selftests/bpf/prog_tests/varlen.c @@ -63,6 +63,13 @@ void test_varlen(void) CHECK_VAL(data->total4, size1 + size2); CHECK(memcmp(data->payload4, exp_str, size1 + size2), "content_check", "doesn't match!\n"); + + CHECK_VAL(bss->ret_bad_read, -EFAULT); + CHECK_VAL(data->payload_bad[0], 0x42); + CHECK_VAL(data->payload_bad[1], 0x42); + CHECK_VAL(data->payload_bad[2], 0); + CHECK_VAL(data->payload_bad[3], 0x42); + CHECK_VAL(data->payload_bad[4], 0x42); cleanup: test_varlen__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/test_varlen.c b/tools/testing/selftests/bpf/progs/test_varlen.c index 3987ff174f1f..20eb7d422c41 100644 --- a/tools/testing/selftests/bpf/progs/test_varlen.c +++ b/tools/testing/selftests/bpf/progs/test_varlen.c @@ -19,6 +19,7 @@ __u64 payload1_len1 = 0; __u64 payload1_len2 = 0; __u64 total1 = 0; char payload1[MAX_LEN + MAX_LEN] = {}; +__u64 ret_bad_read = 0; /* .data */ int payload2_len1 = -1; @@ -36,6 +37,8 @@ int payload4_len2 = -1; int total4= -1; char payload4[MAX_LEN + MAX_LEN] = { 1 }; +char payload_bad[5] = { 0x42, 0x42, 0x42, 0x42, 0x42 }; + SEC("raw_tp/sys_enter") int handler64_unsigned(void *regs) { @@ -61,6 +64,8 @@ int handler64_unsigned(void *regs) total1 = payload - (void *)payload1; + ret_bad_read = bpf_probe_read_kernel_str(payload_bad + 2, 1, (void *) -1); + return 0; }