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 7CCFBDDA9; Mon, 27 May 2024 19:00:26 +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=1716836426; cv=none; b=hVXfDiyQfRky5wDOtC3hww7kMC81dMs4bF0Gm+gKI6qvB1T7bcv9T1GRQvOeKL6FkO8Cv/2+p1LO22HFWadUH1uS7l8dYl9w+EHB53o0RjxJGz6hkaLxAR3t6N9du8Zr1Qjtk6Pun+/9qJ9Sx7+/vqNFeKD26p5+dPrgjz60Kvw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716836426; c=relaxed/simple; bh=5vW1KYp1wCvaBDwogPG4pgTatb2LENQkuqIfkC0yUnY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fDaz0LlDmAXgvcmncmxyMHgNj6MzZGw0IOqphZDIkVBDJNBFn1TPsfJEdk4TcpzfX0/jsxeHhdBN9sl8g7NPdZmx+wpxME6HAB5e/K1I8v7/sUUgVtuEIW6TYrRRU0vKVswJHM7pWSqdtp174DzqQdxeK/ZGhv/uXgRct7BZ/Yk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hMwvO+0a; 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="hMwvO+0a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12F20C2BBFC; Mon, 27 May 2024 19:00:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1716836426; bh=5vW1KYp1wCvaBDwogPG4pgTatb2LENQkuqIfkC0yUnY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hMwvO+0aaS5dL2437jiMy0+YcPCz/s/dZx0n4xXaGkRWjlAxiUGAeE7At3/37KCsq 9zFfEKsGwV+/IbxxPlmMHMTFpHmGDFmkRK6JVJQVnGRX0JMQo2ZP2t9LPZqghM1hlP FUSW3A7p11h0pY/H7FW5iFkIeIlDtmDHOzmpDXuc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, j51569436@gmail.com, Daniel Starke Subject: [PATCH 6.9 008/427] tty: n_gsm: fix possible out-of-bounds in gsm0_receive() Date: Mon, 27 May 2024 20:50:55 +0200 Message-ID: <20240527185602.591947094@linuxfoundation.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240527185601.713589927@linuxfoundation.org> References: <20240527185601.713589927@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.9-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 | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2913,7 +2913,10 @@ 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) { /* Calculate final FCS for UI frames over all data */ if ((gsm->control & ~PF) != UIH) { gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, @@ -3026,7 +3029,7 @@ 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