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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3CFEC4332F for ; Tue, 26 Apr 2022 19:02:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D2AA16B0078; Tue, 26 Apr 2022 15:02:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CD93B6B007B; Tue, 26 Apr 2022 15:02:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B7A476B007E; Tue, 26 Apr 2022 15:02:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id AAEA36B0078 for ; Tue, 26 Apr 2022 15:02:31 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 8391461225 for ; Tue, 26 Apr 2022 19:02:31 +0000 (UTC) X-FDA: 79399951302.12.6309528 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf17.hostedemail.com (Postfix) with ESMTP id 030634004A for ; Tue, 26 Apr 2022 19:02:23 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 33B1D619D0; Tue, 26 Apr 2022 19:02:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D94E5C385AA; Tue, 26 Apr 2022 19:02:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650999750; bh=V4+udKpGUEb7EfiAhVQ52/X71aaDypSDTq4SjL343KA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HcCG59JEncqwTYRMUvNjRne4WENd5Oot9aquwZBg2/Te5urwAqepNbfjqwULBxVJ7 p6nWWBMwykloCL9N9XdptXk7438gcHrhm2SRPisNQfy3lYIP3hLJMSqnYf/e8JIHRs hiQArOC85dcL7RTluTe0iNBiVJTdlZqYSFHd6BseKC37d+1pySkA3kBsa2zclTgb6R jaqvKeTXmecfOxRn3RJzXQvEj40TeE1tQNiYBRUs8FDglvgy1zikn6a6Dz6KQXXy6U 4vethufERFTrVuSH2X9hf4NHtExOo8YslYLelc7x1P47j6GZi04QUwiaoXlOKkqcny UJhumzFzrm/lw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sidhartha Kumar , Shuah Khan , Andrew Morton , Linus Torvalds , Sasha Levin , shuah@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 15/15] selftest/vm: verify remap destination address in mremap_test Date: Tue, 26 Apr 2022 15:02:14 -0400 Message-Id: <20220426190216.2351413-15-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220426190216.2351413-1-sashal@kernel.org> References: <20220426190216.2351413-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit X-Stat-Signature: q3oz1epw68pz68mecxdhhwcaji5eab47 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 030634004A X-Rspam-User: Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=HcCG59JE; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf17.hostedemail.com: domain of sashal@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sashal@kernel.org X-HE-Tag: 1650999743-868713 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: Sidhartha Kumar [ Upstream commit 18d609daa546c919fd36b62a7b510c18de4b4af8 ] Because mremap does not have a MAP_FIXED_NOREPLACE flag, it can destroy existing mappings. This causes a segfault when regions such as text are remapped and the permissions are changed. Verify the requested mremap destination address does not overlap any existing mappings by using mmap's MAP_FIXED_NOREPLACE flag. Keep incrementing the destination address until a valid mapping is found or fail the current test once the max address is reached. Link: https://lkml.kernel.org/r/20220420215721.4868-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- tools/testing/selftests/vm/mremap_test.c | 42 ++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/vm/mremap_test.c b/tools/testing/selftests/vm/mremap_test.c index 2b3b4f15185f..e3ce33a9954e 100644 --- a/tools/testing/selftests/vm/mremap_test.c +++ b/tools/testing/selftests/vm/mremap_test.c @@ -10,6 +10,7 @@ #include #include #include +#include #include "../kselftest.h" @@ -65,6 +66,30 @@ enum { .expect_failure = should_fail \ } +/* + * Returns false if the requested remap region overlaps with an + * existing mapping (e.g text, stack) else returns true. + */ +static bool is_remap_region_valid(void *addr, unsigned long long size) +{ + void *remap_addr = NULL; + bool ret = true; + + /* Use MAP_FIXED_NOREPLACE flag to ensure region is not mapped */ + remap_addr = mmap(addr, size, PROT_READ | PROT_WRITE, + MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED, + -1, 0); + + if (remap_addr == MAP_FAILED) { + if (errno == EEXIST) + ret = false; + } else { + munmap(remap_addr, size); + } + + return ret; +} + /* Returns mmap_min_addr sysctl tunable from procfs */ static unsigned long long get_mmap_min_addr(void) { @@ -112,8 +137,8 @@ static void *get_source_mapping(struct config c) goto retry; src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE, - MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED, - -1, 0); + MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED, + -1, 0); if (src_addr == MAP_FAILED) { if (errno == EPERM || errno == EEXIST) goto retry; @@ -180,9 +205,20 @@ static long long remap_region(struct config c, unsigned int threshold_mb, if (!((unsigned long long) addr & c.dest_alignment)) addr = (void *) ((unsigned long long) addr | c.dest_alignment); + /* Don't destroy existing mappings unless expected to overlap */ + while (!is_remap_region_valid(addr, c.region_size) && !c.overlapping) { + /* Check for unsigned overflow */ + if (addr + c.dest_alignment < addr) { + ksft_print_msg("Couldn't find a valid region to remap to\n"); + ret = -1; + goto out; + } + addr += c.dest_alignment; + } + clock_gettime(CLOCK_MONOTONIC, &t_start); dest_addr = mremap(src_addr, c.region_size, c.region_size, - MREMAP_MAYMOVE|MREMAP_FIXED, (char *) addr); + MREMAP_MAYMOVE|MREMAP_FIXED, (char *) addr); clock_gettime(CLOCK_MONOTONIC, &t_end); if (dest_addr == MAP_FAILED) { -- 2.35.1