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 9446125228C; Wed, 15 Apr 2026 04:07:30 +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=1776226050; cv=none; b=FFktRwN67LsWfXGklkK4tMXGEGUtFsDHZvDDj4u24ebu/IVT7kQ/wNG2cj44No8mjGVNR+goRfxtcd+WbrADAQ4L1jI4dQmZRtHCpwkgnAfrrKnJYfHPDltPREdKxYY9J6E9jS+hu8/uR/OvOHwRp8qLnPGCB6M7+QMa7vKMJM0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776226050; c=relaxed/simple; bh=I4U/X4anEmx3t+b5a+LnHSrvGNqMgQjmdI7ZhAp2BlY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OljKLQLxVVodsFVwafARmECSXVYgs2OGI/pjHcKUDNCWeCByN5kvb2l3jxB5kcHVZXHXbQAw5/cN6ZGaVJMXPcZgmgr5VCU83EGa54BCBjQ10laaqivgcetROpg++llJwHJktfePyRuHzyVdKKoI70pqKv/M72fcyv6VqWexLWU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E0Y23FOj; 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="E0Y23FOj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0E33C19424; Wed, 15 Apr 2026 04:07:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776226050; bh=I4U/X4anEmx3t+b5a+LnHSrvGNqMgQjmdI7ZhAp2BlY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E0Y23FOjVd8T4aAqg89FmLjNMrZyV0RthL4Aa+uTP0OizulJaaP6J+ikMyAMPoxCz kKrnuCM8N/1+JcpJl+1XM0FG9Dw3SVdwgSVJT0tZmVJLNd+3nW/41WobhgkS6/GrHt nNeV1X1AONrGj3K5U3sffT4dZBhuTTLRa79tYE6SXLV6IuuJuebM51yC+GLXkLA6cp gF41mAKWxs4zVBJaL+SDrJSW2GGj8rLJKd813JZSSWGgIEhHUmqfm57HIP7zYmgd19 TNmYvHjM6kxngUZtSudrTyqVKftJL5twlB9YmdC2qe/1aQuPJ+yGkWfs+rrsdRtRN3 VwGX9RGOX31mw== From: "Carlos Bilbao (Lambda)" To: martin.petersen@oracle.com, kees@kernel.org, d.bogdanov@yadro.com Cc: pabeni@redhat.com, mlombard@redhat.com, kuniyu@google.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 v3] scsi: target: iscsi: reject invalid size Extended CDB AHS Date: Tue, 14 Apr 2026 21:07:28 -0700 Message-ID: <20260415040728.187680-1-carlos.bilbao@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: 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. Also reject ahslength values that exceed the actual AHS buffer advertised. Fixes: 8f1f7d297bce ("scsi: target: iscsi: Add support for extended CDB AHS") Signed-off-by: Carlos Bilbao (Lambda) Reviewed-by: Dmitry Bogdanov Changes in v3: - Move ahslength and cdb_length declarations to function scope following the reverse christmas tree ordering of existing locals. Changes in v2: - Add bounds check: ahslength must not exceed (hdr->hlength * 4) - 3. - Replace opaque ahslength + 15 with explicit cdb_length variable. --- drivers/target/iscsi/iscsi_target.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index e80449f6ce15..cb832fd523af 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -995,6 +995,7 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, int data_direction, payload_length; struct iscsi_ecdb_ahdr *ecdb_ahdr; struct iscsi_scsi_req *hdr; + u16 ahslength, cdb_length; int iscsi_task_attr; unsigned char *cdb; int sam_task_attr; @@ -1108,14 +1109,27 @@ 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); + } + if (ahslength > (hdr->hlength * 4) - 3) { + pr_err("Extended CDB AHS length %u exceeds available PDU buffer.\n", + ahslength); + return iscsit_add_reject_cmd(cmd, + ISCSI_REASON_PROTOCOL_ERROR, buf); + } + + cdb_length = ahslength - 1 + ISCSI_CDB_SIZE; + + cdb = kmalloc(cdb_length, 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, cdb_length - ISCSI_CDB_SIZE); } data_direction = (hdr->flags & ISCSI_FLAG_CMD_WRITE) ? DMA_TO_DEVICE : -- 2.43.0