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 362D81D63E4; Sat, 4 Apr 2026 01:44:34 +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=1775267074; cv=none; b=bCJbRixr3ROcAOe/dwpBEQSkoL75YemIFqx41BZlzLiFfelF9vOxzASkUZut3ulc0YaM2pijq06wcrtOxLE4ImNjUzKO9NzHn1rzW66XQRZE0EWccWPfG3OfsomS9kw/jrVfnXx9x6ZHCmPiAYgM4QpgwMaSbJdRiCSc4KYNY/k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775267074; c=relaxed/simple; bh=kGncH5QPq8GPbAkI+RMuvBe8TFeVXXpzYhHP07Hvrw0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=qZ/ozKXlEkWjcT/6CWjREFqFF7UfXqwlaQOMKgOT0u5muBKlTDf/8XEa8+lr1PWPqs1tcGuUTULHHm1nsDlL6m5OReXztfYagWeorPXUYG8ykWsoorsDM2xfi96IuinlX1iASukej1WY/EA0YbWERhLRktoMP0RuueLIGv5CT50= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DfttzlZg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DfttzlZg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A181EC4CEF7; Sat, 4 Apr 2026 01:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775267074; bh=kGncH5QPq8GPbAkI+RMuvBe8TFeVXXpzYhHP07Hvrw0=; h=From:To:Cc:Subject:Date:From; b=DfttzlZgVj6qgVps+jnHVeu3qnxnoZDZy8gdcgJEGGq5RO0rrfVLQdy88LIDXmfog corCzZGq6EAHPOzlLy+GmGtzodTIj/Y8ab0sz7kWi7J6Z8C0Iycl9vtvve7wzjPAkv djQm3ioipAhHp/J5x/a6L+yxFwm8S49D3tRC5YC+DPHGVKJB/Ps0l7rxx7b5EKIwu7 sBITT9BjQ9t7dqVFN+DXsGht/nFoeNxT+V6JH8XV9CA49KPhgnRb9aCvB8v5myzlL3 0HjG4VCcYCKvrmtUa/pubM2yf3OtQSBDfglMkAftPXfIDCzv0+A4cGCOsTXN6GSefs +f9RcCGZs+6Cw== From: carlos.bilbao@kernel.org To: martin.petersen@oracle.com, kees@kernel.org Cc: pabeni@redhat.com, mlombard@redhat.com, kuniyu@google.com, d.bogdanov@yadro.com, michael.christie@oracle.com, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-kernel@vger.kernel.org, bilbao@vt.edu, Carlos Bilbao Subject: [PATCH] scsi: target: iscsi: reject zero-length Extended CDB AHS Date: Fri, 3 Apr 2026 18:44:29 -0700 Message-ID: <20260404014429.115807-1-carlos.bilbao@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Carlos Bilbao If ecdb_ahdr->ahslength is zero, two bugs follow: kmalloc(be16_to_cpu(ecdb_ahdr->ahslength) + 15, ...) allocates 15 bytes, but the immediately following memcpy writes ISCSI_CDB_SIZE (16) bytes into it, a one-byte heap overflow. Also: memcpy(cdb + ISCSI_CDB_SIZE, ecdb_ahdr->ecdb, be16_to_cpu(ecdb_ahdr->ahslength) - 1); (u16)0 - 1 promotes to (int)-1 which converts to SIZE_MAX as size_t, causing a massive out-of-bounds write. Reject ahslength == 0 with ISCSI_REASON_PROTOCOL_ERROR before the kmalloc. Fixes: 8f1f7d297bce ("scsi: target: iscsi: Add support for extended CDB AHS") Signed-off-by: Carlos Bilbao (Lambda) --- drivers/target/iscsi/iscsi_target.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index e80449f6ce15..8db24d35c762 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -1100,6 +1100,8 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, cdb = hdr->cdb; if (hdr->hlength) { + u16 ahslength; + ecdb_ahdr = (struct iscsi_ecdb_ahdr *) (hdr + 1); if (ecdb_ahdr->ahstype != ISCSI_AHSTYPE_CDB) { pr_err("Additional Header Segment type %d not supported!\n", @@ -1108,14 +1110,19 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, ISCSI_REASON_CMD_NOT_SUPPORTED, buf); } - cdb = kmalloc(be16_to_cpu(ecdb_ahdr->ahslength) + 15, - GFP_KERNEL); + ahslength = be16_to_cpu(ecdb_ahdr->ahslength); + if (!ahslength) { + pr_err("Extended CDB AHS with zero length, protocol error.\n"); + return iscsit_add_reject_cmd(cmd, + ISCSI_REASON_PROTOCOL_ERROR, buf); + } + + cdb = kmalloc(ahslength + 15, GFP_KERNEL); if (cdb == NULL) return iscsit_add_reject_cmd(cmd, ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf); memcpy(cdb, hdr->cdb, ISCSI_CDB_SIZE); - memcpy(cdb + ISCSI_CDB_SIZE, ecdb_ahdr->ecdb, - be16_to_cpu(ecdb_ahdr->ahslength) - 1); + memcpy(cdb + ISCSI_CDB_SIZE, ecdb_ahdr->ecdb, ahslength - 1); } data_direction = (hdr->flags & ISCSI_FLAG_CMD_WRITE) ? DMA_TO_DEVICE : -- 2.43.0