From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F3DB33F9F47; Sat, 12 Sep 2026 11:37:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789213055; cv=none; b=Sq97VmYZN1cReii5Vh87NxiV0hoh8paJi9xECm8UXOJAmH8T6nzhUgmo+GiCmy//CvQ6tL7B7/MaZlmTBjNjN5crO48xAi+bKO+YhtR8M0DeYVXU67L09lgxwu+0PrQXn+ZeZ8Msj8KzLzpQjfzJuJzoLw3KFIjYmF1yhvTDUaE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789213055; c=relaxed/simple; bh=s3qDWmDGEEFrinKHbFR43IILrHzoMjlvG1NLKolmwc8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gYC7LP6aJTBtfboLfahax3iE3Lyln/JT5jo2opjQKr1UMxAnynQRi5YO2zCc/Mq+iet9Kx9wGYAzV2UW1zQCC7K2eir0I3Fta+2wS23ONpOuWEAGHyot4vWvQIHUFr1Bwiie/oDjtoixZwYy/4J2aSGD6ghd6qm5DOaeU4AeoG0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gkz4yo5v; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gkz4yo5v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0C111F000FF; Sat, 12 Sep 2026 11:37:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789213053; bh=SVPeTjK9nK8e9J9gxMc4S0IoVVQL92UHYWwE4TED1E4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gkz4yo5vwl2NdKegERfGrbUIeMiefNI9FTh255qAdCyexMVCbz2iRT32g+r8GuFCV Qw1NPrHJnQvpM/yuxohvXcHslSbcYsErPWrCc7xVSCVc2LQ6Jfhjl6xv5sFx113ZG8 /41mFa59WrtbjURpXwEaWZKagtz4HK8AvRsYp9O4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sujal Tuladhar , "Martin K. Petersen (Oracle)" Subject: [PATCH 6.12 0041/1376] scsi: target: iscsi: Reserve a terminator byte for the login payload Date: Sat, 12 Sep 2026 08:41:07 +0200 Message-ID: <20260912065608.467173142@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sujal Tuladhar commit f4825922d2fb371e2b969697d792077f1b62b62c upstream. iscsi_target_check_login_request() rejects a login PDU whose DataSegmentLength exceeds MAX_KEY_VALUE_PAIRS, but the test is '>' and login->req_buf is allocated with exactly MAX_KEY_VALUE_PAIRS bytes. Since iscsit_get_login_rx() receives payload_length + padding bytes, where padding = ((-payload_length) & 3); any payload_length from 8189 to 8192 fills the whole 8192 byte buffer. The write stays in bounds, but no byte is left for a NUL terminator. The buffer is subsequently consumed as a C string. In the CHAP path chap_check_algorithm() calls kstrdup(a_str), and extract_param() calls strstr(in_buf, pattern) followed by strlen_semi(), none of which take a length. convert_null_to_semi() additionally rewrites every embedded NUL to ';', so even a payload made of well formed NUL separated key=value records is left without a terminator. These walk past the end of the object into adjacent slab memory. It is reachable by an unauthenticated initiator against a portal configured for CHAP; when authentication is not required iscsi_login_zero_tsih_s2() rewrites AuthMethod to None and the CHAP path is never entered. Allocate one extra byte. kzalloc() zeroes it and nothing ever writes to it, as every writer copies to offset 0 for at most MAX_KEY_VALUE_PAIRS bytes, so the buffer is always terminated. Fixes: e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1") Assisted-by: Claude Opus5 (custom harness) Cc: stable@vger.kernel.org Signed-off-by: Sujal Tuladhar Signed-off-by: Martin K. Petersen (Oracle) Signed-off-by: Greg Kroah-Hartman --- drivers/target/iscsi/iscsi_target_login.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -48,7 +48,7 @@ static struct iscsi_login *iscsi_login_i login->conn = conn; login->first_request = 1; - login->req_buf = kzalloc(MAX_KEY_VALUE_PAIRS, GFP_KERNEL); + login->req_buf = kzalloc(MAX_KEY_VALUE_PAIRS + 1, GFP_KERNEL); if (!login->req_buf) { pr_err("Unable to allocate memory for response buffer.\n"); goto out_login;