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 392EE3815D5; Thu, 30 Jul 2026 16:02:09 +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=1785427330; cv=none; b=TYjY5fEOZLpiM06osLA2eBgQHVfWwF4zLYLCLrOWa1xJ4jsieb8RTFmUSa+2jLVSQjyrPq5vjOHGprXnwjHQQj2GP0peCVJ/4+s/TIE00cRCUuvDvWDEP42UJsrf1IPVPHyEMrVVM/LGoEoDNcE04/qWZTOWov6SvsckyWjC0FU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785427330; c=relaxed/simple; bh=gf3ZxfznkqKiB4rKaZiMm3Q5DAeyr3eu/N4yDcxg0Is=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XYlUxuGrg+aYYn6wFLigdyoQeG0T9EFWAV7MwwIFLQ7mxGJhu7XlXDW4L3DUWVeFyKP490ZxfhTzrLlyrhM7J60zViNz15xyYNkmNehocVJYqmQxn8ataHfmzHQR5yVDe5pRUn/mtA7D5Kl0o83VyZjW9V2TiRWzc/lY8MBi3yQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QMn1EYpd; 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="QMn1EYpd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BDE31F000E9; Thu, 30 Jul 2026 16:02:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785427329; bh=sHa0o8Ge89Dp4QkAeEVuEZDyh3/tr7Y5pM//WsAxTsg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QMn1EYpd1nIvP4Q8tyzDwZxiA9i9lBX49yo9cnTijc8s8j+hXRC8ugBVwcIMxkD1p h0ATzU/JGep95YU8cVX/f5ZpstfcktWsVqfyQVkqjd297R9s21KIGBjayzzDoQk5oK /a+cPgeC+eyRQrCkcfiO/AA7OoFm2XM5tdB1Cebw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Michal Luczaj , Jakub Sitnicki , John Fastabend , Kumar Kartikeya Dwivedi , Sasha Levin Subject: [PATCH 6.6 088/484] bpf, sockmap: Reject unhashed UDP sockets on sockmap update Date: Thu, 30 Jul 2026 16:09:45 +0200 Message-ID: <20260730141425.360431579@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141423.392222816@linuxfoundation.org> References: <20260730141423.392222816@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: Michal Luczaj [ Upstream commit 66efd3368ae10d05e08fbe6425b50fdec7186ac7 ] UDP sockets get SOCK_RCU_FREE set when (auto-)bound. This means sk_is_refcounted(unbound) = true, while sk_is_refcounted(bound) = false. Because sockmap accepts unbound UDP sockets, a BPF program can increment a socket's refcount via lookup. If the socket is subsequently bound, the transition from unbound to bound causes bpf_sk_release() to skip the decrement of the refcount, causing a memory leak. unreferenced object 0xffff88810bc2eb40 (size 1984): comm "test_progs", pid 2451, jiffies 4295320596 hex dump (first 32 bytes): 7f 00 00 01 7f 00 00 01 d2 04 1b b7 04 d2 00 00 ................ 02 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............ backtrace (crc bdee079d): kmem_cache_alloc_noprof+0x557/0x660 sk_prot_alloc+0x69/0x240 sk_alloc+0x30/0x460 inet_create+0x2ce/0xf80 __sock_create+0x25b/0x5c0 __sys_socket+0x119/0x1d0 __x64_sys_socket+0x72/0xd0 do_syscall_64+0xa1/0x5f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Instead of special-casing for refcounted sockets, reject unhashed UDP sockets during sockmap updates, as there is no benefit to supporting those. This effectively reverts the commit under Fixes, with two exceptions: 1. sock_map_sk_state_allowed() maintains a fall-through `return true`. 2. In the spirit of commit b8b8315e39ff ("bpf, sockmap: Remove unhash handler for BPF sockmap usage"), the proto::unhash BPF handler is not reintroduced. Historical note: this issue is related to commit 67312adc96b5 ("bpf: reject unhashed sockets in bpf_sk_assign"). Fixes: 0c48eefae712 ("sock_map: Lift socket state restriction for datagram sockets") Suggested-by: Kuniyuki Iwashima Signed-off-by: Michal Luczaj Reviewed-by: Kuniyuki Iwashima Reviewed-by: Jakub Sitnicki Reviewed-by: John Fastabend Link: https://lore.kernel.org/bpf/20260707-sockmap-lookup-udp-leak-v4-2-f878346f27ab@rbox.co Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Sasha Levin --- net/core/sock_map.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 3a53b6a0e76e2b..052057303cff11 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -539,6 +539,8 @@ static bool sock_map_sk_state_allowed(const struct sock *sk) { if (sk_is_tcp(sk)) return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN); + if (sk_is_udp(sk)) + return sk_hashed(sk); if (sk_is_stream_unix(sk)) return (1 << sk->sk_state) & TCPF_ESTABLISHED; if (sk_is_vsock(sk) && -- 2.53.0