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 8F353224239; Tue, 8 Apr 2025 11:32:39 +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=1744111959; cv=none; b=FlM1NZHeVvU6rwpnN6FC3gYilp5NrQWKiuKqlBWqwg2byvCVm+puRjVXo/1XE7Md1v3ngpC12epRC4sCD49anB8i/gLatzvhfyaR3t1BxvOxWhqetzGEyNYsd59Jj3VV/ejjXThUrHaL6QPmOSo2PqmwvQbT8tynBhkQI4tHtmc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744111959; c=relaxed/simple; bh=Gcdh2G5oxd1xktUyGOm4Q29r4sa8kAfTXbalz9zAjmw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gEbbmkNgeZO3o+xiPpSvB0iX5bm5QIkhgu07SwMOy86z/dycaXA2kIdDUte5m616JHYDYR6iAk48XQDE9vZRx3obQRnWakfX9CqchbAtaTArZfwFlMJ755is5jhQRQmpIu/EQXn0xBeYYLSOWvr55gDh+8DmbQchhoaIDPJICIg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=trBP1vot; 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="trBP1vot" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2468C4CEE5; Tue, 8 Apr 2025 11:32:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744111959; bh=Gcdh2G5oxd1xktUyGOm4Q29r4sa8kAfTXbalz9zAjmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=trBP1votgQJYOoUmJ6/uGY3WhWcZwmGf+KgJkRAXgFz6HYh3OgHu8AjgLQ1qCdnHF HKqXuKfvGt7Fe9gMHX+YjQxKfSW7T8kwuB4Zml3kj9ZGePwlHTLJODtd5t6UN/1U4T UN6QLo9oJNud0EBahhcANOtYCT84R9TD+85t6SiU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+fae49d997eb56fa7c74d@syzkaller.appspotmail.com, Eric Dumazet , Marcelo Ricardo Leitner , Xin Long , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.14 622/731] sctp: add mutual exclusion in proc_sctp_do_udp_port() Date: Tue, 8 Apr 2025 12:48:39 +0200 Message-ID: <20250408104928.740995229@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104914.247897328@linuxfoundation.org> References: <20250408104914.247897328@linuxfoundation.org> User-Agent: quilt/0.68 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 6.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 10206302af856791fbcc27a33ed3c3eb09b2793d ] We must serialize calls to sctp_udp_sock_stop() and sctp_udp_sock_start() or risk a crash as syzbot reported: Oops: general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 1 UID: 0 PID: 6551 Comm: syz.1.44 Not tainted 6.14.0-syzkaller-g7f2ff7b62617 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:kernel_sock_shutdown+0x47/0x70 net/socket.c:3653 Call Trace: udp_tunnel_sock_release+0x68/0x80 net/ipv4/udp_tunnel_core.c:181 sctp_udp_sock_stop+0x71/0x160 net/sctp/protocol.c:930 proc_sctp_do_udp_port+0x264/0x450 net/sctp/sysctl.c:553 proc_sys_call_handler+0x3d0/0x5b0 fs/proc/proc_sysctl.c:601 iter_file_splice_write+0x91c/0x1150 fs/splice.c:738 do_splice_from fs/splice.c:935 [inline] direct_splice_actor+0x18f/0x6c0 fs/splice.c:1158 splice_direct_to_actor+0x342/0xa30 fs/splice.c:1102 do_splice_direct_actor fs/splice.c:1201 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1227 do_sendfile+0xafd/0xe50 fs/read_write.c:1368 __do_sys_sendfile64 fs/read_write.c:1429 [inline] __se_sys_sendfile64 fs/read_write.c:1415 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1415 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] Fixes: 046c052b475e ("sctp: enable udp tunneling socks") Reported-by: syzbot+fae49d997eb56fa7c74d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/67ea5c01.050a0220.1547ec.012b.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Cc: Marcelo Ricardo Leitner Acked-by: Xin Long Link: https://patch.msgid.link/20250331091532.224982-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sctp/sysctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c index 8e1e97be4df79..ee3eac338a9de 100644 --- a/net/sctp/sysctl.c +++ b/net/sctp/sysctl.c @@ -525,6 +525,8 @@ static int proc_sctp_do_auth(const struct ctl_table *ctl, int write, return ret; } +static DEFINE_MUTEX(sctp_sysctl_mutex); + static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -549,6 +551,7 @@ static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write, if (new_value > max || new_value < min) return -EINVAL; + mutex_lock(&sctp_sysctl_mutex); net->sctp.udp_port = new_value; sctp_udp_sock_stop(net); if (new_value) { @@ -561,6 +564,7 @@ static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write, lock_sock(sk); sctp_sk(sk)->udp_port = htons(net->sctp.udp_port); release_sock(sk); + mutex_unlock(&sctp_sysctl_mutex); } return ret; -- 2.39.5