From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 49C0C146D7E; Thu, 13 Jun 2024 11:55:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718279732; cv=none; b=a9yr1Nr2AutavZ7nYvWZKPwjzrOhL+YmYfA/PNXrszvRdcsRyMrUPTqpfHWgy1kAsNeplJ4T+Ie8H84daUFDeFFVwRHb0LY958wB9RiulfKz+zyCOQX1FDXqJSuHOzaisbmk5vKSYjfs91VX6gV+Bx0drAYA3In1IZdrhqf+huo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718279732; c=relaxed/simple; bh=ffTcdqgLz7rpvb4pWZSzDnlBrJ8VmWAoI5knQZGo+S4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uQuaPw+R9adeshuBBvKZrMwRc4L3v+kxcy/own7qEIjS6sND9adKatXCMsDcTsEqM08PZMEgBJQOVrTdlO6yYb6d35hHBoomRyXzthe/imIIQ7wjbm0fq9cSQ36ZNtdW2pHLrxBiP0bnBhlwNcXua1wRHkxD8icRGL2g9kl4ESs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=09MXqJVy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="09MXqJVy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3F33C2BBFC; Thu, 13 Jun 2024 11:55:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718279732; bh=ffTcdqgLz7rpvb4pWZSzDnlBrJ8VmWAoI5knQZGo+S4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=09MXqJVydN5bss9k7I2Z66FLzQblhNUefJUcNpwBmg/wTqfI3SXbwku8w/8UyKhLF 8s6Qr3IUMDE7zeYi+iRod4nN226+clpdm/781ubRP2uXqVLtcu34+IvgP2SKrQ5SlB uiDd0hdJ4gUHXzlKZJw8+Rsqz2zn5cudSOimipvE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, j51569436@gmail.com, Daniel Starke Subject: [PATCH 5.4 002/202] tty: n_gsm: fix possible out-of-bounds in gsm0_receive() Date: Thu, 13 Jun 2024 13:31:40 +0200 Message-ID: <20240613113227.857556048@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113227.759341286@linuxfoundation.org> References: <20240613113227.759341286@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Starke commit 47388e807f85948eefc403a8a5fdc5b406a65d5a upstream. Assuming the following: - side A configures the n_gsm in basic option mode - side B sends the header of a basic option mode frame with data length 1 - side A switches to advanced option mode - side B sends 2 data bytes which exceeds gsm->len Reason: gsm->len is not used in advanced option mode. - side A switches to basic option mode - side B keeps sending until gsm0_receive() writes past gsm->buf Reason: Neither gsm->state nor gsm->len have been reset after reconfiguration. Fix this by changing gsm->count to gsm->len comparison from equal to less than. Also add upper limit checks against the constant MAX_MRU in gsm0_receive() and gsm1_receive() to harden against memory corruption of gsm->len and gsm->mru. All other checks remain as we still need to limit the data according to the user configuration and actual payload size. Reported-by: j51569436@gmail.com Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218708 Tested-by: j51569436@gmail.com Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20240424054842.7741-1-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1974,8 +1974,12 @@ static void gsm0_receive(struct gsm_mux break; case GSM_DATA: /* Data */ gsm->buf[gsm->count++] = c; - if (gsm->count == gsm->len) + if (gsm->count >= MAX_MRU) { + gsm->bad_size++; + gsm->state = GSM_SEARCH; + } else if (gsm->count >= gsm->len) { gsm->state = GSM_FCS; + } break; case GSM_FCS: /* FCS follows the packet */ gsm->received_fcs = c; @@ -2055,7 +2059,7 @@ static void gsm1_receive(struct gsm_mux gsm->state = GSM_DATA; break; case GSM_DATA: /* Data */ - if (gsm->count > gsm->mru) { /* Allow one for the FCS */ + if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */ gsm->state = GSM_OVERRUN; gsm->bad_size++; } else