From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pz2-f42.google.com (mail-pz2-f42.google.com [74.125.228.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8544A2DC76A for ; Mon, 21 Sep 2026 01:30:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.228.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789954232; cv=none; b=fAozzcwVVqmiuQBOPH829S7OOUI7rlP3zXBKCF+J6RNKB2nR2Xy2a7syzpkO2WMzIRthEMiY9CJj4xCwRyJIYB1ngZgDIKBi7kgwaxiV2eCPMI8v2Ll13L0aOlm4ch0UKK+oPF1CnBiXgLHk+wI/btS6sqkGQ4w0/9v9fRDCI9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789954232; c=relaxed/simple; bh=t2kXYTfDoWYw6hLSMeM9i1WMUS5zpvinMMov6e67g9k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Um+/n7gTOjQ5S6oM2jlD2Wz6ep48e7HEXUpdj25iXN+yn+YoyDsi8651T2IFEEeIJj5o8b6GKy0qdfjggESIaftYA5ro4OKJ35a8cQrcogMNJUHFWdfkCizjQyA8EmzF/MIyYPruknvYLk3qbl6c4dapliA7Li7Kpvi1PvFfC+4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=GwmLPTOg; arc=none smtp.client-ip=74.125.228.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GwmLPTOg" Received: by mail-pz2-f42.google.com with SMTP id 41be03b00d2f7-cc4cacd3409so2819626a12.2 for ; Sun, 20 Sep 2026 18:30:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789954231; x=1790559031; darn=vger.kernel.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:content-type; bh=f+cTrga3fxRheLjWFEIpCVJBOqMuKdwt4xEbbBWyGpQ=; b=GwmLPTOgMCCaK3VxPfrrX1aedCgh6HG39XTL7CnTan6hxCRHg4SvV6WJu83ZeYtEyo eRFdM0ndjrXFALfoe5S/odZUQFUaHW+Q7ah3Lcoj8iK7KEcIRhZex2RTu3BVKm3038iL vzI7jmtxVUj1hP+/7YbPhW1LWxJAtkf9Kstlvsl2e2Pjy5U5eW/fSKZRcMjEuAQoAjyT 2bsxUyP5O6Br5AdVMK3orrGYgSgK3nKaoIGjjU+tteP/GdIjpDb3gyDGdogg7m4m1JZ7 NRKoA0NuxU3RCJdoW70z9qa14FMv4l2sFssnorDf2K020JeXaX1CpfQqVh+jXP/f+cOl iqgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789954231; x=1790559031; 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:content-type; bh=f+cTrga3fxRheLjWFEIpCVJBOqMuKdwt4xEbbBWyGpQ=; b=gw4Cl3zgkyzpjSLdOQUkmQ4kgSnoJC+q57BWHd4/Za5XpPRXI/mlEJo1skt9EEbXvu GM93q467SdVxo3JgH3ZcPStUrzI/KcxBofUu0TkjK5RsbyyzdLxQxwCd/Jif9Gmm1axD dp9sUOXbFJDWSTAyuvBPcJylfrc5H2ihjd0JR4dTiob/gy8h/9uCiPzJUJyhZfIqwl8L HVnKZNSogbaorEIOqt36LeKoyFwJUoWAJ6PRn1No3J4mTXBDJKtfEweF4QYyoYRQKsxX uBxMKLMDDzoVrJ+0EYn5FA/jFq1gDOPCHKAPBnoLagONS0ur2xHPVBQnXwzoOE4JO9gh 5s/w== X-Forwarded-Encrypted: i=1; AKwUvBxbaFGEviohbESQZoA07OYTB34HJVQClQOOJ2ibFzKwSHqqUN8P5o+I5cc1BclIYejLC/xBgJtrHjXyW7Y=@vger.kernel.org X-Gm-Message-State: AFuF++mH68u+xDmZk4x+HmEwv8k0xBAMXObFLyX5VsVkPTXvPiaRCwLb gR74OuFVZsGJ9CSVuPVX9DcW1IMGI6MLzwTUcnoFSZ8TZY8SoS8dLUxM X-Gm-Gg: AYBFou3F1N9qdGQ5pPc1R/b3oZD/Fr0m05l2JjMoEpqIgmxnz6KmipPDjuwR2KHGLAM 7xrrG/9NPk1y1t9WAds4Cgcki+V/NJejRv1F7c2rf9AnDpvspEa3NpGz01Yk1i3jitoodI+6q11 elYB7i50i7rVRMwhYRNKjOcS6FUuYJ1fzAwA/0w8QqS6UMptuQk6wD8r3fqdF//ZPLxt+ljo98w nnh0E6kvG/IYadwfBPUHddYhoEJsXd+QJJqlBNLIivC3ZIMttNDK+G7UP+fZvznQ2kU5aSRFOuh w4QcO8XNjCOHaEnC7dej/+LbOm1k64FWqASnNQtiW1WbUOqXc0cTO79BYVjCbXwpXWbDnv4OUvd 8wW9WBO+Z8+Rw+wtX3Ic/yQBMnzWGq2spusY5I27ibKoDSvLQIMM+k+JL08n7TdVsVQWt36i7SK ZicUbcwQKehLTlMtAVx6Tn5vhhzSTuv79SQH5aCbwZY/m5t+fpVkXj6Y2EsnKx88giVHBxC3ygC zH84nRduZ8N8LXUm+WMo0/Zag5O7SVkJYtZhmiCNtkIpXfMFbSmCofjhxWsl9Dr6NlKo8/LZzB/ wMSjazYBzQ== X-Received: by 2002:a17:90b:37cb:b0:39e:6c69:9b9a with SMTP id 98e67ed59e1d1-39e6c69b2eamr9095109a91.63.1789954230752; Sun, 20 Sep 2026 18:30:30 -0700 (PDT) Received: from phui-2.c.googlers.com.com (67.51.127.34.bc.googleusercontent.com. [34.127.51.67]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39e6c3145dasm11291460a91.4.2026.09.20.18.30.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Sep 2026 18:30:30 -0700 (PDT) From: Hui Peng To: Greg Kroah-Hartman , Jiri Slaby , John Ogness Cc: Hui Peng , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Andy Shevchenko , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2 3/3] serial: core: reject baud_base values that overflow port->uartclk in uart_set_info() Date: Mon, 21 Sep 2026 01:30:27 +0000 Message-ID: <20260921013027.659965-3-benquike@gmail.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog In-Reply-To: <20260919222627.3797854-1-benquike@gmail.com> References: <20260919222627.3797854-1-benquike@gmail.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In uart_set_info(), new_info->baud_base is multiplied by 16 and stored in uport->uartclk (an unsigned int): uport->uartclk = new_info->baud_base * 16; While uart_set_info() checks if (uartclk == 0) and if (new_info->baud_base < 9600), when new_info->baud_base exceeds UINT_MAX / 16 with low bits set (for example, 0x10000001), multiplying by 16 wraps around in 32-bit unsigned arithmetic to a small non-zero value (16), bypassing both uartclk == 0 and new_info->baud_base < 9600 and setting uport->uartclk = 16 (baud_base = 1, well below the required minimum of 9600 * 16). Reject new_info->baud_base > UINT_MAX / 16 with -EINVAL in uart_set_info(). Tested in QEMU against Linux 7.3.0-rc3 by calling ioctl(fd, TIOCSSERIAL, &ss) with ss.baud_base = 0x10000001 on /dev/ttyS1: on the unfixed kernel TIOCSSERIAL succeeds (ret = 0) and wraps uport->uartclk to 16 (TIOCGSERIAL reports baud_base = 1), whereas with the fix applied TIOCSSERIAL returns -EINVAL and preserves the existing uport->uartclk. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: 6eabce6608d6 ("serial: core: check uartclk for zero to avoid divide by zero") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Hui Peng --- Changes in v2: - Split out into patch 3/3 of the series, add Cc: stable@vger.kernel.org, and document the QEMU test method, as requested by Greg Kroah-Hartman. drivers/tty/serial/serial_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 128fc056f5c9..4cd4fb0f7ee3 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -965,7 +965,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, } if ((new_info->irq >= irq_get_nr_irqs()) || (new_info->irq < 0) || - (new_info->baud_base < 9600)) + (new_info->baud_base < 9600) || (new_info->baud_base > UINT_MAX / 16)) return -EINVAL; if (change_port || change_irq) { -- 2.49.0