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: 13036811 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12D0BC4332F for ; Tue, 8 Nov 2022 19:52:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7D6168E0007; Tue, 8 Nov 2022 14:52:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7381F8E0001; Tue, 8 Nov 2022 14:52:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 600538E0007; Tue, 8 Nov 2022 14:52:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 520598E0001 for ; Tue, 8 Nov 2022 14:52:54 -0500 (EST) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 2E114C033E for ; Tue, 8 Nov 2022 19:52:54 +0000 (UTC) X-FDA: 80111323068.21.D0BA7C8 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by imf18.hostedemail.com (Postfix) with ESMTP id C57351C000A for ; Tue, 8 Nov 2022 19:52:53 +0000 (UTC) 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 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1667937173; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=aV1rbRcoT8elrIFvcswWnTb6/2G/r5XMttMTu6HgEWE=; b=Kad4fsFM9Zqkbo/lhlpFhAYvgpYJQbyizc7F0KnJ/yLiBpS1v3XfYDgLpQbzQqLNmUFiwz fCeFuW+VyGkw1JlirWVg04zPuzit5x8AkmLzD/KRwn11SMtdEu4ZrjEQbHgpXQMfkVt9Iy WwAjJEJHdqYbOElNTUBgwmQYjl0PqbI= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=linux.microsoft.com header.s=default header.b=rNA91l5N; spf=pass (imf18.hostedemail.com: domain of flaniel@linux.microsoft.com designates 13.77.154.182 as permitted sender) smtp.mailfrom=flaniel@linux.microsoft.com; dmarc=pass (policy=none) header.from=linux.microsoft.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667937173; a=rsa-sha256; cv=none; b=75JUZsSfsDYYOw7xIshCoQPQLSTsTJiTBE0SEGHIcoN8IqMNufz+EuoRZtAXhHJImlKJ0v sZ7BMBxbacuj53jgun4Jl2Pjax1vNSXNlCLl/4KZc5CVt30OZmziOJ/z+jACXplINMm+gD wK7YGJMQhfP02iNEPWoSohiEFfjv0j0= X-Rspam-User: X-Stat-Signature: 9dicpuqfqps4a8itqbc8exiket7dguuz X-Rspamd-Queue-Id: C57351C000A Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=linux.microsoft.com header.s=default header.b=rNA91l5N; spf=pass (imf18.hostedemail.com: domain of flaniel@linux.microsoft.com designates 13.77.154.182 as permitted sender) smtp.mailfrom=flaniel@linux.microsoft.com; dmarc=pass (policy=none) header.from=linux.microsoft.com X-Rspamd-Server: rspam07 X-HE-Tag: 1667937173-644080 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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: 13036812 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAB93C433FE for ; Tue, 8 Nov 2022 19:53:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 628A78E0008; 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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 ARC-Seal: i=1; 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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; }