From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (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 268161865E2; Wed, 16 Oct 2024 08:49:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729068584; cv=none; b=jV16jkJjqb0j2PZPPFJ7Uede+l6kJKXcywNChKjUsWj6Jt1aDWafHuR3hYBUDh2tcfjBG26Sd2tWQrFfr3LwYtn2BaW48Zx9Keu9Msu4qhv+3gY1FA6BVia9N38An+puXk3uFUxYBFmzvnZlicdS2EeblWsNG/uWLDSjVeDa5pY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729068584; c=relaxed/simple; bh=vkvuwCURHLuwXxOfCJFJX0cte944VNl4VhcckEIF+Kg=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=GGKXvzJ4WuBbd8gb2xXCxbd3EHRXwaPORe/dEm3U535pSVWeF7icPDmSBWYB91bqomIwH6RCKHXEDca1AoU8SW8hkysOO+gW7x3/O88jWD5EbTxsrPi/ZKIN0u/Ryd+ZojA5LqTusdwFYboIxnske24qm4wgqqEJWsGG42nzcs8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.17]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4XT4Py1lmHz20q7J; Wed, 16 Oct 2024 16:48:54 +0800 (CST) Received: from kwepemd200010.china.huawei.com (unknown [7.221.188.124]) by mail.maildlp.com (Postfix) with ESMTPS id 4AC8C1A0188; Wed, 16 Oct 2024 16:49:38 +0800 (CST) Received: from [10.174.162.134] (10.174.162.134) by kwepemd200010.china.huawei.com (7.221.188.124) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Wed, 16 Oct 2024 16:49:37 +0800 Subject: Re: [PATCH v3] ACPI: GTDT: Tighten the check for the array of platform timer structures To: Lorenzo Pieralisi CC: , , , , , , , , , , References: <20241015152602.184108-1-zhengzengkai@huawei.com> From: Zheng Zengkai Message-ID: <4cea2a07-49b0-7703-4cdf-49ded9a2c9e4@huawei.com> Date: Wed, 16 Oct 2024 16:49:36 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemd200010.china.huawei.com (7.221.188.124) Hi Lorenzo, ÔÚ 2024/10/16 0:44, Lorenzo Pieralisi дµÀ: > On Tue, Oct 15, 2024 at 11:26:02PM +0800, Zheng Zengkai wrote: >> As suggested by Marc and Lorenzo, first we need to check whether the > I would just describe the change, the tags and Link: are there to > describe this patch history. Do you mean that the previous patch below also need to be listed in this change log history? https://lore.kernel.org/all/20240930030716.179992-1-zhengzengkai@huawei.com/ >> platform_timer entry pointer is within gtdt bounds (< gtdt_end) before >> de-referencing what it points at to detect the length of the platform >> timer struct and then check that the length of current platform_timer >> struct is also valid, i.e. the length is not zero and within gtdt_end. >> Now next_platform_timer() only checks against gtdt_end for the entry of >> subsequent platform timer without checking the length of it and will >> not report error if the check failed and the existing check in function >> acpi_gtdt_init() is also not enough. >> >> Modify the for_each_platform_timer() iterator and use it combined with >> a dedicated check function platform_timer_valid() to do the check >> against table length (gtdt_end) for each element of platform timer >> array in function acpi_gtdt_init(), making sure that both their entry >> and length actually fit in the table. >> >> Suggested-by: Lorenzo Pieralisi >> Co-developed-by: Marc Zyngier >> Signed-off-by: Marc Zyngier >> Signed-off-by: Zheng Zengkai >> --- >> Changes in v3: >> - based on Marc's patch and reuse the for_each_platform_timer() loop >> >> Changes in v2: >> - Check against gtdt_end for both entry and len of each array element >> Link to v2: https://lore.kernel.org/linux-arm-kernel/20241012085343.6594-1-zhengzengkai@huawei.com/ >> >> Link to v1: https://lore.kernel.org/all/20241010144703.113728-1-zhengzengkai@huawei.com/ >> --- >> drivers/acpi/arm64/gtdt.c | 32 +++++++++++++++++++++----------- >> 1 file changed, 21 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c >> index c0e77c1c8e09..3583c99afb0d 100644 >> --- a/drivers/acpi/arm64/gtdt.c >> +++ b/drivers/acpi/arm64/gtdt.c >> @@ -36,19 +36,25 @@ struct acpi_gtdt_descriptor { >> >> static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata; >> >> -static inline __init void *next_platform_timer(void *platform_timer) >> +static __init bool platform_timer_valid(void *platform_timer) >> { >> struct acpi_gtdt_header *gh = platform_timer; >> >> - platform_timer += gh->length; >> - if (platform_timer < acpi_gtdt_desc.gtdt_end) >> - return platform_timer; >> + return (platform_timer >= (void *)(acpi_gtdt_desc.gtdt + 1) && >> + platform_timer < acpi_gtdt_desc.gtdt_end && >> + gh->length != 0 && >> + platform_timer + gh->length <= acpi_gtdt_desc.gtdt_end); >> +} >> + >> +static __init void *next_platform_timer(void *platform_timer) >> +{ >> + struct acpi_gtdt_header *gh = platform_timer; >> >> - return NULL; >> + return platform_timer + gh->length; >> } >> >> -#define for_each_platform_timer(_g) \ >> - for (_g = acpi_gtdt_desc.platform_timer; _g; \ >> +#define for_each_platform_timer(_g, first_entry) \ >> + for (_g = first_entry; platform_timer_valid(_g); \ >> _g = next_platform_timer(_g)) >> >> static inline bool is_timer_block(void *platform_timer) >> @@ -155,8 +161,9 @@ bool __init acpi_gtdt_c3stop(int type) >> int __init acpi_gtdt_init(struct acpi_table_header *table, >> int *platform_timer_count) >> { >> - void *platform_timer; >> + void *platform_timer, *tmp; > It makes more sense - thank you and Marc. > > Nit: you don't really need another pointer (ie tmp) but you may keep > it if that makes the code clearer - all you need to do is using > platform_timer as an iterator and initialize Yes, the tmp pointer can be removed for conciseness. Thanks! > > acpi_gtdt_desc.platform_timer = (void *)gtdt + gtdt->platform_timer_offset; > > if all checks passed (you are using tmp just because after the loop > platform_timer can't be used to initialize acpi_gtdt_desc.platform_timer). > > Reviewed-by: Lorenzo Pieralisi > > (now let's see if this survives GTDTs out there :)) >> struct acpi_table_gtdt *gtdt; >> + int cnt = 0; >> >> gtdt = container_of(table, struct acpi_table_gtdt, header); >> acpi_gtdt_desc.gtdt = gtdt; >> @@ -177,7 +184,10 @@ int __init acpi_gtdt_init(struct acpi_table_header *table, >> } >> >> platform_timer = (void *)gtdt + gtdt->platform_timer_offset; >> - if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) { >> + for_each_platform_timer(tmp, platform_timer) >> + cnt++; >> + >> + if (cnt != gtdt->platform_timer_count) { >> pr_err(FW_BUG "invalid timer data.\n"); >> return -EINVAL; >> } >> @@ -305,7 +315,7 @@ int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem, >> void *platform_timer; >> >> *timer_count = 0; >> - for_each_platform_timer(platform_timer) { >> + for_each_platform_timer(platform_timer, acpi_gtdt_desc.platform_timer) { >> if (is_timer_block(platform_timer)) { >> ret = gtdt_parse_timer_block(platform_timer, timer_mem); >> if (ret) >> @@ -398,7 +408,7 @@ static int __init gtdt_sbsa_gwdt_init(void) >> if (ret || !timer_count) >> goto out_put_gtdt; >> >> - for_each_platform_timer(platform_timer) { >> + for_each_platform_timer(platform_timer, acpi_gtdt_desc.platform_timer) { >> if (is_non_secure_watchdog(platform_timer)) { >> ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count); >> if (ret) >> -- >> 2.20.1 >> > . >