From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 01 Feb 2024 09:35:02 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rVSXF-00FLs4-1p for lore@lore.pengutronix.de; Thu, 01 Feb 2024 09:35:02 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rVSXG-000163-65 for lore@pengutronix.de; Thu, 01 Feb 2024 09:35:02 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jzElzUNCtFAoIFyeql2NdIPJoiUG+/SFTAcxme5p8E4=; b=tZQr0RlblWSmF4Vq3ZRKX+VPWA C68KXUNBtsWZs5Gyk3EX+MskIClhRr8pMtfP7wisbJoQXvUC5Sj1zPXkE5j4uhcFi+VK9e+ctM9HX b9p1fhrJTGhszqDpHklnKnt2fsvlbzgeZKi0ABfIbgctc9f6VJlGA1rOP8GaRmA70Ew4v8COVw2q9 G4ko+lx6mC2pgiRoQKqm3E2Ekmp4qLdbU2g1/5Nzz/Eo5y4bi+rhk3MK5ywpKZxGHSTxWBfBhyb4P uTWcnf3hSKaqO/J2BCSoaKwwyB0BtiaHfdPzRkkO8h3cu0fvj3zZ0tnipe3/J7gq1oLfcp7o67Jxm BCkCZiZA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVSWj-000000075nm-482L; Thu, 01 Feb 2024 08:34:29 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVSWg-000000075le-39Th for barebox@lists.infradead.org; Thu, 01 Feb 2024 08:34:28 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[IPV6:::1]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1rVSWf-00011W-Eb; Thu, 01 Feb 2024 09:34:25 +0100 Message-ID: <4efd89d7-2bf8-4448-96f2-2fcd91241411@pengutronix.de> Date: Thu, 1 Feb 2024 09:34:24 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Ahmad Fatoum , Sascha Hauer , BAREBOX References: <20240131-fix-fdt-memory-safety-v1-0-3d3a2c797eec@pengutronix.de> <20240131-fix-fdt-memory-safety-v1-1-3d3a2c797eec@pengutronix.de> <7ff7301e-1594-40c0-8c39-bbd51ee53b54@pengutronix.de> Content-Language: en-US, de-DE From: Stefan Kerkmann In-Reply-To: <7ff7301e-1594-40c0-8c39-bbd51ee53b54@pengutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240201_003426_844092_CDD79DC3 X-CRM114-Status: GOOD ( 21.51 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-6.2 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 1/2] of: fdt: fix memory leak in fdt_ensure_space X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hello Ahmad, On 31.01.24 18:15, Ahmad Fatoum wrote: > Hello Stefan, > > On 31.01.24 17:56, Stefan Kerkmann wrote: >> If the reallocation failed the old memory remains allocated and is never >> freed, this is fixed by freeing the old memory on error. >> >> Signed-off-by: Stefan Kerkmann >> --- >> drivers/of/fdt.c | 27 ++++++++++++++++++++------- >> 1 file changed, 20 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >> index 5c21bab5de..4f79a6120f 100644 >> --- a/drivers/of/fdt.c >> +++ b/drivers/of/fdt.c >> @@ -375,24 +375,37 @@ static void *memalign_realloc(void *orig, size_t oldsize, size_t newsize) >> >> static int fdt_ensure_space(struct fdt *fdt, int dtsize) >> { >> + size_t new_size; >> + void *previous; >> + >> /* >> * We assume strings and names have a maximum length of 1024 >> * whereas properties can be longer. We allocate new memory >> * if we have less than 1024 bytes (+ the property size left. >> */ >> if (fdt->str_size - fdt->str_nextofs < 1024) { >> - fdt->strings = realloc(fdt->strings, fdt->str_size * 2); >> - if (!fdt->strings) >> + previous = fdt->strings; >> + new_size = fdt->str_size * 2; >> + >> + if ((fdt->strings = realloc(previous, new_size)) == NULL) { > > IMO, it's less readable this way. I'd prefer we leave the realloc line and > then !fdt->strings check on separate lines as before. Applied. >> + free(previous); > > This could happen later in the callers (look for out_free) if one wouldn't > set fdt->strings to NULL on error. I don't feel strongly either way, so doing > it this way is fine too. > Freeing the previous memory should happen in this function IMHO. In this way `fdt->[strings|dt]` can be set to `NULL` and the caller will get a segfaulty reminder if they choose to ignore error returned from the function and still access `fdt->[strings|dt]`. > Change looks good otherwise, so with first comment addressed: > Thank you :-). > Reviewed-by: Ahmad Fatoum > > Cheers, > Ahmad > >> return -ENOMEM; >> - fdt->str_size *= 2; >> + } >> + >> + fdt->str_size = new_size; >> } >> >> if (fdt->dt_size - fdt->dt_nextofs < 1024 + dtsize) { >> - fdt->dt = memalign_realloc(fdt->dt, fdt->dt_size, >> - fdt->dt_size * 2); >> - if (!fdt->dt) >> + previous = fdt->dt; >> + new_size = fdt->dt_size * 2; >> + >> + if ((fdt->dt = memalign_realloc(previous, fdt->dt_size, >> + new_size)) == NULL) { >> + free(previous); >> return -ENOMEM; >> - fdt->dt_size *= 2; >> + } >> + >> + fdt->dt_size = new_size; >> } >> >> return 0; >> > Cheers Stefan -- Pengutronix e.K. | Stefan Kerkmann | Steuerwalder Str. 21 | https://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-128 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |