From nobody Mon Jun 15 07:33:46 2026 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 05AB635C1BC; Thu, 9 Apr 2026 02:42:57 +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=1775702578; cv=none; b=GXUAxLmNjIRBCZOnN8nXRYGcc18OH+UkQ1WlarFYbrksHCJN2og2/aWEx9CBEz4Dxx+kL1qCuYxeefCj2AsH5E5YH11j0hmdejUAUFdq5scqSNuZfir7sumTqiioADaDY5+zKOeLJXjFC4Tefx+U76eKq1URPByazxRH495M/9U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775702578; c=relaxed/simple; bh=/4TUkqIj714VbpV3V5urDLV51x5ECDI2r8DsaLqIsNE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VAlb2vaxgRBm/gllwdUXi1CccC8ejyBGhBolg7465uQ4HbZpzftnY2g1QwI5aEx2KRMsp9YvK02G0Lc6ZiGY8WEaBT50LG/FYHkaFpHOKCW4e5k42H9RQUuHPCF7vlcQPD6zwRwMMmTRmXd0/Woru5ZaOA6tWZd9I4E3ihA29H4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bs8F/qqW; 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="bs8F/qqW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75E0BC19421; Thu, 9 Apr 2026 02:42:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775702577; bh=/4TUkqIj714VbpV3V5urDLV51x5ECDI2r8DsaLqIsNE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bs8F/qqWvYdrx+qlDCNY67jEvotytKjibYcs8gkw6O1NYLQ68f/furFfZ7n6CJThW 2YGg6c4IzBUydNp+wGhpRGk4Pl6NXlwxc4A0jr/d3wIumDkMwirwdJWvfm5budEXM5 v7NAgBOSiCUf42CsPQIL9ONNuo3IrQo0jUwb/pfnR0YN3cTNNu/14bDJnUGTMakPYp fX1Q1pybuXL2PqHfsus1JYbLkjBtlm5bs9mfBseHkkemL4dRT2TzsEyJkgb6TJfohC LCKJTN5V2rCXmpGh5zRYWRrC6uvC1m8Lqny9L6Ay6GnGaWnuqy6zkGCufbOGd2sBQp NLLphehooVH/Q== From: carlos.bilbao@kernel.org To: d.bogdanov@yadro.com Cc: bilbao@vt.edu, martin.petersen@oracle.com, kees@kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Carlos Bilbao Subject: [PATCH v2] scsi: target: iscsi: reject invalid size Extended CDB AHS Date: Wed, 8 Apr 2026 19:42:53 -0700 Message-ID: <20260409024253.34926-1-carlos.bilbao@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260404014429.115807-1-carlos.bilbao@kernel.org> References: <20260404014429.115807-1-carlos.bilbao@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 =3D=3D 0 with ISCSI_REASON_PROTOCOL_ERROR before the kmall= oc. Also reject ahslength values that exceed the actual AHS buffer advertised. Changes in v2: - Add bounds check: ahslength must not exceed (hdr->hlength * 4) - 3. - Replace opaque ahslength + 15 with explicit cdb_length variable. Fixes: 8f1f7d297bce ("scsi: target: iscsi: Add support for extended CDB AHS= ") Signed-off-by: Carlos Bilbao (Lambda) Reviewed-by: Dmitry Bogdanov --- drivers/target/iscsi/iscsi_target.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/isc= si_target.c index e80449f6ce15..1a492965ebdf 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, s= truct iscsit_cmd *cmd, cdb =3D hdr->cdb; =20 if (hdr->hlength) { + u16 ahslength; + ecdb_ahdr =3D (struct iscsi_ecdb_ahdr *) (hdr + 1); if (ecdb_ahdr->ahstype !=3D ISCSI_AHSTYPE_CDB) { pr_err("Additional Header Segment type %d not supported!\n", @@ -1108,14 +1110,27 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn,= struct iscsit_cmd *cmd, ISCSI_REASON_CMD_NOT_SUPPORTED, buf); } =20 - cdb =3D kmalloc(be16_to_cpu(ecdb_ahdr->ahslength) + 15, - GFP_KERNEL); + ahslength =3D 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 buffer.\n", + ahslength); + return iscsit_add_reject_cmd(cmd, + ISCSI_REASON_PROTOCOL_ERROR, buf); + } + + u16 cdb_length =3D ahslength - 1 + ISCSI_CDB_SIZE; + + cdb =3D kmalloc(cdb_length, GFP_KERNEL); if (cdb =3D=3D 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_SIZ= E); } =20 data_direction =3D (hdr->flags & ISCSI_FLAG_CMD_WRITE) ? DMA_TO_DEVICE : --=20 2.43.0