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 27FAE146592; Tue, 25 Jun 2024 10:01:20 +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=1719309680; cv=none; b=b1TLi4AZrpjIJeInuq4jswx6HQ5AIJv4VKBi/afHelbuseVRIFeFAavd2Y7AvMpW7Tz8Dblhmovh2crYVXVUCXb4wWmSVLnCLklN+NdhLYVFmoIJSpNP3FYjg9nj0VKetxf/GcAq4xz8OEL6pJNvJy+pgJ1BEUrDH4ZLxKkwIEc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719309680; c=relaxed/simple; bh=i98mFc0bTw53nti6LunVphLiR9saeA2hNtd5HUCtj7Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f5du9DZZ8F2aJKtWXycniJJ0/yEkRpsfRySNiXGN0viCgpx1XZ+Z5DU1Y0PY39rh2z4JVP8/QOUyLc4WSvYVUU3QbjkaVOpwxoWg2knLWrUBUPUOFS5eWsLY962p0fV8hB6qWAz03soriGpbjwmMoAqak4r+BGV7wFCxAihGOeA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1FpAiLxT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1FpAiLxT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A240C32781; Tue, 25 Jun 2024 10:01:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1719309680; bh=i98mFc0bTw53nti6LunVphLiR9saeA2hNtd5HUCtj7Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1FpAiLxTBNz6R9CZBPUmGv4SilctG06o+Hx8iRO4HJsZDaos+TbsSD6hKt19FxHKb m8owVYovMh21g1fxhzgSABE4CcheHykfkwuRm7szxwF8yV8fuNZFsza2Zq1wXbNap1 rE0AAF9/nPiViIp83dw6QVmYG3UKK6W/xCuHBh4M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Ignat Korchagin , "D. Wythe" , Paolo Abeni Subject: [PATCH 6.1 096/131] net: do not leave a dangling sk pointer, when socket creation fails Date: Tue, 25 Jun 2024 11:34:11 +0200 Message-ID: <20240625085529.586796147@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240625085525.931079317@linuxfoundation.org> References: <20240625085525.931079317@linuxfoundation.org> User-Agent: quilt/0.67 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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ignat Korchagin commit 6cd4a78d962bebbaf8beb7d2ead3f34120e3f7b2 upstream. It is possible to trigger a use-after-free by: * attaching an fentry probe to __sock_release() and the probe calling the bpf_get_socket_cookie() helper * running traceroute -I 1.1.1.1 on a freshly booted VM A KASAN enabled kernel will log something like below (decoded and stripped): ================================================================== BUG: KASAN: slab-use-after-free in __sock_gen_cookie (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-instrumented.h:1611 net/core/sock_diag.c:29) Read of size 8 at addr ffff888007110dd8 by task traceroute/299 CPU: 2 PID: 299 Comm: traceroute Tainted: G E 6.10.0-rc2+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:117 (discriminator 1)) print_report (mm/kasan/report.c:378 mm/kasan/report.c:488) ? __sock_gen_cookie (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-instrumented.h:1611 net/core/sock_diag.c:29) kasan_report (mm/kasan/report.c:603) ? __sock_gen_cookie (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-instrumented.h:1611 net/core/sock_diag.c:29) kasan_check_range (mm/kasan/generic.c:183 mm/kasan/generic.c:189) __sock_gen_cookie (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-instrumented.h:1611 net/core/sock_diag.c:29) bpf_get_socket_ptr_cookie (./arch/x86/include/asm/preempt.h:94 ./include/linux/sock_diag.h:42 net/core/filter.c:5094 net/core/filter.c:5092) bpf_prog_875642cf11f1d139___sock_release+0x6e/0x8e bpf_trampoline_6442506592+0x47/0xaf __sock_release (net/socket.c:652) __sock_create (net/socket.c:1601) ... Allocated by task 299 on cpu 2 at 78.328492s: kasan_save_stack (mm/kasan/common.c:48) kasan_save_track (mm/kasan/common.c:68) __kasan_slab_alloc (mm/kasan/common.c:312 mm/kasan/common.c:338) kmem_cache_alloc_noprof (mm/slub.c:3941 mm/slub.c:4000 mm/slub.c:4007) sk_prot_alloc (net/core/sock.c:2075) sk_alloc (net/core/sock.c:2134) inet_create (net/ipv4/af_inet.c:327 net/ipv4/af_inet.c:252) __sock_create (net/socket.c:1572) __sys_socket (net/socket.c:1660 net/socket.c:1644 net/socket.c:1706) __x64_sys_socket (net/socket.c:1718) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Freed by task 299 on cpu 2 at 78.328502s: kasan_save_stack (mm/kasan/common.c:48) kasan_save_track (mm/kasan/common.c:68) kasan_save_free_info (mm/kasan/generic.c:582) poison_slab_object (mm/kasan/common.c:242) __kasan_slab_free (mm/kasan/common.c:256) kmem_cache_free (mm/slub.c:4437 mm/slub.c:4511) __sk_destruct (net/core/sock.c:2117 net/core/sock.c:2208) inet_create (net/ipv4/af_inet.c:397 net/ipv4/af_inet.c:252) __sock_create (net/socket.c:1572) __sys_socket (net/socket.c:1660 net/socket.c:1644 net/socket.c:1706) __x64_sys_socket (net/socket.c:1718) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Fix this by clearing the struct socket reference in sk_common_release() to cover all protocol families create functions, which may already attached the reference to the sk object with sock_init_data(). Fixes: c5dbb89fc2ac ("bpf: Expose bpf_get_socket_cookie to tracing programs") Suggested-by: Kuniyuki Iwashima Signed-off-by: Ignat Korchagin Cc: stable@vger.kernel.org Link: https://lore.kernel.org/netdev/20240613194047.36478-1-kuniyu@amazon.com/T/ Reviewed-by: Kuniyuki Iwashima Reviewed-by: D. Wythe Link: https://lore.kernel.org/r/20240617210205.67311-1-ignat@cloudflare.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/core/sock.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3695,6 +3695,9 @@ void sk_common_release(struct sock *sk) sk->sk_prot->unhash(sk); + if (sk->sk_socket) + sk->sk_socket->sk = NULL; + /* * In this point socket cannot receive new packets, but it is possible * that some packets are in flight because some CPU runs receiver and