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 4DDB84028C8; Wed, 20 May 2026 18:48:29 +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=1779302911; cv=none; b=ZaQBfn2An31Yk4Ktcx0Bfpb7Yco831RxdPsII81MSnzdQittzaSbjcBy0CwpAESTPg2bgFkh8Gh8fP2L7qn6ICYfEEyJq2dfTe4GKvsJAYP73YiFYFC0PR6JGZ3jsONs2a3ciJ66Uegu41WaPslOyZwhhcWsALjRDwOU0T4Cn0Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779302911; c=relaxed/simple; bh=KLhr5d0Ps7RT8nkz0roukKj7yg54ju/1bzEVb1D4cPU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lkdXC4E/6KwLQfN8TX0GLxyDN1ap9Vy6fXVbvz4G0dDlJ/7sHKs/Y4/SGufaUP9Mf13CVRn8+gA+z+qYRgAnMKEUiIqhemDRgKIT5sLwLDzFxJEl8PzYMPZRsn+3bSNKdAOssXA2HPk7T7VJApFoAMI9f0UcOVvDgvS+71KftFk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=S7+CjjJM; 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="S7+CjjJM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B6091F00893; Wed, 20 May 2026 18:48:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779302909; bh=7EC9/Zbq4Qcn4motXz3k6YUwJ0lQgBTeOQNn8V2PIgs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=S7+CjjJMgm8Cp0ovdgQsO3F0UWCQUTIF/NVxTIxykrw0iz9QaqPjzQoH4sR8UcqUZ CAROjiwSt+o0zJPq66If8vLb7xumKiJSNn2g0WGsU2/BNDvozjJH/hr6uBOWAJ2LxG PdokhRXHOerwVhWTrpDMMFpV7QF6/o7gvkMN2roY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 6.6 447/508] ksmbd: validate response sizes in ipc_validate_msg() Date: Wed, 20 May 2026 18:24:30 +0200 Message-ID: <20260520162108.283856092@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162058.573354582@linuxfoundation.org> References: <20260520162058.573354582@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito [ Upstream commit d6a6aa81eac2c9bff66dc6e191179cb69a14426b ] ipc_validate_msg() computes the expected message size for each response type by adding (or multiplying) attacker-controlled fields from the daemon response to a fixed struct size in unsigned int arithmetic. Three cases can overflow: KSMBD_EVENT_RPC_REQUEST: msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz; KSMBD_EVENT_SHARE_CONFIG_REQUEST: msg_sz = sizeof(struct ksmbd_share_config_response) + resp->payload_sz; KSMBD_EVENT_LOGIN_REQUEST_EXT: msg_sz = sizeof(struct ksmbd_login_response_ext) + resp->ngroups * sizeof(gid_t); resp->payload_sz is __u32 and resp->ngroups is __s32. Each addition can wrap in unsigned int; the multiplication by sizeof(gid_t) mixes signed and size_t, so a negative ngroups is converted to SIZE_MAX before the multiply. A wrapped value of msg_sz that happens to equal entry->msg_sz bypasses the size check on the next line, and downstream consumers (smb2pdu.c:6742 memcpy using rpc_resp->payload_sz, kmemdup in ksmbd_alloc_user using resp_ext->ngroups) then trust the unverified length. Use check_add_overflow() on the RPC_REQUEST and SHARE_CONFIG_REQUEST paths to detect integer overflow without constraining functional payload size; userspace ksmbd-tools grows NDR responses in 4096-byte chunks for calls like NetShareEnumAll, so a hard transport cap is unworkable on the response side. For LOGIN_REQUEST_EXT, reject resp->ngroups outside the signed [0, NGROUPS_MAX] range up front and report the error from ipc_validate_msg() so it fires at the IPC boundary; with that bound the subsequent multiplication and addition stay well below UINT_MAX. The now-redundant ngroups check and pr_err in ksmbd_alloc_user() are removed. This is the response-side analogue of aab98e2dbd64 ("ksmbd: fix integer overflows on 32 bit systems"), which hardened the request side. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Fixes: a77e0e02af1c ("ksmbd: add support for supplementary groups") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/server/mgmt/user_config.c | 6 ------ fs/smb/server/transport_ipc.c | 16 +++++++++++++--- 2 files changed, 13 insertions(+), 9 deletions(-) diff --git a/fs/smb/server/mgmt/user_config.c b/fs/smb/server/mgmt/user_config.c index 421a4a95e216a..e9b3a8e049668 100644 --- a/fs/smb/server/mgmt/user_config.c +++ b/fs/smb/server/mgmt/user_config.c @@ -56,12 +56,6 @@ struct ksmbd_user *ksmbd_alloc_user(struct ksmbd_login_response *resp, goto err_free; if (resp_ext) { - if (resp_ext->ngroups > NGROUPS_MAX) { - pr_err("ngroups(%u) from login response exceeds max groups(%d)\n", - resp_ext->ngroups, NGROUPS_MAX); - goto err_free; - } - user->sgid = kmemdup(resp_ext->____payload, resp_ext->ngroups * sizeof(gid_t), GFP_KERNEL); diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index f0f93f76bc43d..554a6c92a1ccb 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "vfs_cache.h" #include "transport_ipc.h" @@ -497,7 +498,9 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry) { struct ksmbd_rpc_command *resp = entry->response; - msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz; + if (check_add_overflow(sizeof(struct ksmbd_rpc_command), + resp->payload_sz, &msg_sz)) + return -EINVAL; break; } case KSMBD_EVENT_SPNEGO_AUTHEN_REQUEST: @@ -516,8 +519,9 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry) if (resp->payload_sz < resp->veto_list_sz) return -EINVAL; - msg_sz = sizeof(struct ksmbd_share_config_response) + - resp->payload_sz; + if (check_add_overflow(sizeof(struct ksmbd_share_config_response), + resp->payload_sz, &msg_sz)) + return -EINVAL; } break; } @@ -526,6 +530,12 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry) struct ksmbd_login_response_ext *resp = entry->response; if (resp->ngroups) { + if (resp->ngroups < 0 || + resp->ngroups > NGROUPS_MAX) { + pr_err("ngroups(%d) from login response exceeds max groups(%d)\n", + resp->ngroups, NGROUPS_MAX); + return -EINVAL; + } msg_sz = sizeof(struct ksmbd_login_response_ext) + resp->ngroups * sizeof(gid_t); } -- 2.53.0