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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EF0E7CD98C6 for ; Thu, 11 Jun 2026 03:39:33 +0000 (UTC) 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: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=w+4cm9QbNYmcZl/MXjwCiNY3TdxompycqRGjEnRpi0s=; b=bFOdu1Yv4xnNHOFbyEV4wAcWft 8ETxZnzPI8kNn/05KnLEpufovym1RT9G44ifRyqY9UAgZvXd4ptM2/h7Xy9TFV+ArzAHILynyrEG1 iy/Kf3G2dW3eUmY5hGgZpvwi62E1sOx76q1aMljsRMsmWo6VEvtIi8mUqHLTvIhAwWyIqrFNRLmhM 3WvoJEaVI22AUsV1l12ID25fZanx/Xsr1D01md1QGYKl/s/W1wx77ngRry+xKSGt9PO52VpEuAJGj rQuQAsDFwmcdzY6zbuT3rSqSza+ZaJjqPy8/DRs2s8M+EhObn7XSkL2MRcMuh87A85MuOhtP38sN9 YlnlzvnQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXWGN-00000008cn5-1xhV; Thu, 11 Jun 2026 03:39:27 +0000 Received: from mail-pf1-x42a.google.com ([2607:f8b0:4864:20::42a]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXWGH-00000008ciw-1NZl for linux-arm-kernel@lists.infradead.org; Thu, 11 Jun 2026 03:39:22 +0000 Received: by mail-pf1-x42a.google.com with SMTP id d2e1a72fcca58-84232e83ca9so3190072b3a.2 for ; Wed, 10 Jun 2026 20:39:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1781149160; x=1781753960; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=w+4cm9QbNYmcZl/MXjwCiNY3TdxompycqRGjEnRpi0s=; b=sYK2A/BWIxai1CFgnINTTM6sAzYdSZ6Vp2FhvRKsYRLRp7dtvDJKJZUNbxtlCoAv/5 XJXDwYLUxtiKFqsmXPbAMssNhuOS+WXA7OUQdqOGGkFhV5xVbwR9uEsuycezU4FFqxbR JXi6yx8tc73/CLdu3v0hZheDxO1NgukaWU9H7CW2IduPIBNwLqSeULkToc58aBHC3mtK 9/GGh5C4xnb6Avzwir82J1r9yFJSr2diwbo4Wc+BWPPpdS4BZeYqolPaEl7nrk9McpNv HM8wz76GIMICCDfJMie+lob34LxRaOQrTwGE9wKbwa/V0Mzn1bnR8HdxBp8WezgDUrUS qWLg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781149160; x=1781753960; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=w+4cm9QbNYmcZl/MXjwCiNY3TdxompycqRGjEnRpi0s=; b=lyYgwO1elqU2dl+xxyUwIb4u7uU9r/r0Vea9hPzLIz/+9m/TsE7jiueKtQ++YFsoPR Busa5irk0hyEu9Bmy202ABZTETwBykFI24BNniUh1m0MJwWVcf1I+ojLQqPsRRmqsF3v R2cmNEjo2ysPExWDnqcamyqTiaIQgkQJ5Y3TqcoKeP4nwSNDlWfm8BxyvrVapRZ6ZEHP jHgmZlixzk72M491Rkv8Wq2tvkUUdaW3IMaQPP99/VOjJ6577QKjGGZEPuxcxK23FKI4 eea4BXTHM8qjqGmc99LW8Tu2gzipSusO2jWY5zzm1C0/lLu27fhTGhUAwTBzwBeSESiM fFHQ== X-Forwarded-Encrypted: i=1; AFNElJ+S+e823m0cj63bzyht1zJptkLAq7tqzouh8vbr247OqZWl6kChgejZJcFUaIu0lcl43tKwraXO4Qd0kxEe1bwa@lists.infradead.org X-Gm-Message-State: AOJu0YzBd6MGZWLld+GWFS7eQAmi1jPv8JsJ1NWO66BTg7iwZrg1QlF0 txcNadvEXyDRD3jv/BkdXJ3Lx54qxG0RyAjjm06EfgtNETvl3VAWfIJI X-Gm-Gg: Acq92OHLRMqdK5g7UOlkN4R0Z6VRtWYqx9ERwyLsSXpJq1lAhwl7ymG1IskFl1YLD9V x621B9PRSyFbCQnf8O8QiijVhmyyH7Nd0nBwFPutsz7t8Etdil37+rxqHdkiFtQACkU/7Ofrj5D zRwLzfHp4FJszjuc68w1Qmu5Je0j3DrfrAj2457rOiaewvENM9GNBZ0izg7nbK2ZAXV3WLLxKw0 Ze9/YhmjlPqYaTLhWjFbUFpfQoz0BdURACo3F8fldPqYUaDbMNQ2zxFbX30m7MDicQ5wDh64P+0 MM7+nQ1NcVEn5O91Z7eYr3alc3S8IozsJ1zRDVKTpjmS9SsnYYAHVo2kHGxzBbFv3glWqdYbMjp nWdhqbm3PGq6Utt5n3AGlp8KPhIuPHfp1nLSWJElodObKTeOqKDagnoe5xR7vvlZkF7y091tFxC 2taY/+iAnXp8ZinUtkpaPKO+xyydwwOELJLH9XKIusg5lJwoojwDoOcS9O/KvT/3hcNgB+4R3j2 aCO0EsCwt6DdMQkCs/NJ4+D3vORpF4dFIeizTvVP4UdZg== X-Received: by 2002:a05:6a00:194a:b0:842:5ea5:5ff8 with SMTP id d2e1a72fcca58-84336bc62c8mr967189b3a.42.1781149160353; Wed, 10 Jun 2026 20:39:20 -0700 (PDT) Received: from ryzen ([2601:644:8000:5b5d:7285:c2ff:fe45:8a32]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84337bb47eesm334548b3a.13.2026.06.10.20.39.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jun 2026 20:39:19 -0700 (PDT) From: Rosen Penev To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman , Jiri Slaby , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , linux-kernel@vger.kernel.org (open list:TTY LAYER AND SERIAL DRIVERS), imx@lists.linux.dev (open list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE) Subject: [PATCHv3 5/6] serial: mxs-auart: clamp RX DMA count to buffer size Date: Wed, 10 Jun 2026 20:38:55 -0700 Message-ID: <20260611033856.6476-6-rosenp@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260611033856.6476-1-rosenp@gmail.com> References: <20260611033856.6476-1-rosenp@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260610_203921_387002_E35F8630 X-CRM114-Status: GOOD ( 12.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In dma_rx_callback(), the RX count from the hardware status register (AUART_STAT_RXCOUNT_MASK = 0xffff) is passed directly to tty_insert_flip_string() without any bounds check. Since rx_dma_buf is allocated with UART_XMIT_SIZE (4096 bytes), a hardware fault or compromised peripheral reporting a count larger than 4096 would cause an out-of-bounds read, potentially leaking kernel memory. Clamp the count to UART_XMIT_SIZE before use. Assisted-by: opencode:big-pickle Signed-off-by: Rosen Penev --- drivers/tty/serial/mxs-auart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index e2b656638ab3..fe48a372d022 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -823,7 +823,7 @@ static void dma_rx_callback(void *arg) stat &= ~(AUART_STAT_OERR | AUART_STAT_BERR | AUART_STAT_PERR | AUART_STAT_FERR); - count = stat & AUART_STAT_RXCOUNT_MASK; + count = min_t(u32, stat & AUART_STAT_RXCOUNT_MASK, UART_XMIT_SIZE); tty_insert_flip_string(port, s->rx_dma_buf, count); mxs_write(stat, s, REG_STAT); -- 2.54.0