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 00DD5582BA5; Wed, 9 Sep 2026 14:15:34 +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=1788963335; cv=none; b=ks8Sw+NRhg66nFCJISF96KEWvS7r3DogFZcmtaDHo22p4WdiKdOF8h4tu4xQrsNyd/q70Y4VYVRPLDvaLmIMj5ZnNg0JegGsjoOG8IOTrtvIJG5ZSQ+CchK3G9NpXQtxz++ZgKV+T6Tp7IW4RqaOeuHNI2odB5XJdKOflWin+bc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788963335; c=relaxed/simple; bh=G0TEcpRUA3thbL57EDU6dsPmHW1CF/heD69sooQidOI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XFFXoGXeUfmwxwtW+YKDdJF9p3zbcOglfedJ9YaD/vtCtvFyov1pW/8ShZucgfn9Gu1bhMHV5bEC0TVpAsbGsLqULGFc1pU8Y3AP5Qhr5PgbZdIZL4hucqxpQ6vPYRASIdVZReOpyEAXDmD+Lm9Lhrx0HCAvUVXgp3IFR/0N5hg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rq5bhqhN; 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="rq5bhqhN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 582BC1F00A3A; Wed, 9 Sep 2026 14:15:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788963333; bh=mZycmEFDx+gnfHbWwslz9uIflnRIPYZKvSb8ZQPKR4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rq5bhqhN1LIlHtJxis7suMrbCw1R7tPn7kwnltS5qfpnd0uCzeFm8xSCoJlXC5gQ3 jAVXhC+/PaKK2awA94f/RYbi2sI/PMshdh2GqjSSFHGarkVB5oRIcVxe6G59Dg1mDa 6haoRyl8zZJquMdqqlVFDIwAMFPozypsjGm+eD88= 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 6.18 044/583] scsi: target: iscsi: Reserve a terminator byte for the login payload Date: Wed, 9 Sep 2026 15:35:29 +0200 Message-ID: <20260909134239.451083691@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134237.773280130@linuxfoundation.org> References: <20260909134237.773280130@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 6.18-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 @@ -47,7 +47,7 @@ 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;