From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793214731; b=0IgiUJNkorI/n4/HlfTxNrcccdVioEQw74pyWqdJLuKntdV28r2FqE3L8PSEQQPyW4eW a2A39yHxcySwl4ZnHjLQYwOFTGL/LbEFwx0SoDnb/Enf9fFoZ9XbDX95BQeeLN9ZRTUKe 0aaJoAg7JLGS/bDTyhZgONCWzFpxrMo45L0fWeoDcCl6krQ2uh/m1wy+QluK0ivc5irlR UUpw/Tr0DqZj9sdDuxfOIMhb2jRDmYAaxXvKgFZ7wF+lEa10UZd/rR7J3mo989aJ17SXx Bfd2oD2L1Up44Jk8MObpnPzUFF3+ohqcRxRxwuWTlm4xKzHzOa5jOm7a+9YAnUH9a5Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793214731; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=j7F42CH9/Gubo2jkLX0lqsGTAoOUZJaUTVjT8DdGV5Q=; b=E7y7IA1AxSXP+eq8yMIp3E3RyWA+HyHk5IGouzNHO95w5YFBkwryMgBSbfsd5tPoL0ZC 8ZtQkcCciH5Nq94QDtFAV3OYoI4pDvZ9myDK4Scaa6WLdMf8KkqmTunulEvERBWY8lkmc jO+05CeW4BvHP6ppIvDcTc1XgJTKuFwxcyKtBdzdNopzG4bd3nY7MsTU6WAOjchvjOhUT JFYCmKIzHiQeJZ410Kao0CSSHGjPBbXJzjwejQFzMKfzUKLXVlYXMbT8uVL7e4YGn9JKW HEBrx8CQPZmsYpT6WS3KAV81mLVhlEpWuoMGEJi+kHQPq+FkGCB/CXJwuGXGbtd/now== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=kwWB13sY; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9BE46606AB31; Wed, 28 Oct 2026 19:12:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=kwWB13sY Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED23D1F01825; Wed, 28 Oct 2026 19:12:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793214731; bh=j7F42CH9/Gubo2jkLX0lqsGTAoOUZJaUTVjT8DdGV5Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kwWB13sYUWEHG1Umqqw5tgWGM+m8iSaWDGzS7u4rGXD1a6h7sVctd6/+oPs0fcB7Q TiCcWFhlGH5LQafzFeleKTR6t8Yu04mcUSWyp90V9xkS5dFYpPxsDQeaOiDmakaaD2 Ks0rJgBjl66mjT262EUZVOGK3DNoiaS1vXmL1JAc= 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 6.1 0963/1887] ksmbd: validate response sizes in ipc_validate_msg() Date: Wed, 28 Oct 2026 17:50:59 +0100 Message-ID: <20261028170521.322538788@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-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/transport_ipc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 89fae5e1886ae..63d0e8bf39aa5 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" @@ -478,7 +479,9 @@ static int ipc_validate_msg(struct ipc_msg_table_entry *entry) if (entry->type == KSMBD_EVENT_RPC_REQUEST) { 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; } else if (entry->type == KSMBD_EVENT_SPNEGO_AUTHEN_REQUEST) { struct ksmbd_spnego_authen_response *resp = entry->response; -- 2.53.0