From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+A19iNnOZQZu75SVyGpLcCWPQQBJ4bN0Nae7bcUh2GBOWNsKybzvbHnuwtPpXBp+nElkoT ARC-Seal: i=1; a=rsa-sha256; t=1523399531; cv=none; d=google.com; s=arc-20160816; b=TgCaDxJ5VFcXLrDQ4Qq9Q1AvKFjh2EPLPdWqFMhegbnm7koxnQfykxs98Tm4S+X1vb C458tmo0Uhd9eqvUvbLHcYNFvbHN/NRVEkoFxG7wpJ5oa1TQWzxJ6IbkGH39SfDm9pHO TkO0QtboPelEHFHIYxHaroZ3T++MdEw4esUc2CznJOi8CJkjanXBmw51eLShbO1MDm2c YaXaiQfC22iBB+r1puXkzKt8t3jMQEDirusgHMiVUBn2g9wqy4FCfVulHYF3b6tdo+yB vakhna/GKr4QiQafdY07YMPwpD5vr6i22j+Wrm+O5k9ovSQbg07lZwImhEfTY/Li6sxx vsmw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=pJxoq604Q9g/NVRaCRXKPEv79o/eCpE68yM1ONTHi8o=; b=XLfk54s9YV3trCUEe5QIeeGgCEKcgQKkLPNfSglPQWDF2Bmz7+ShX9p6tIQPKixCKk buyaRyPK5A0gDHEzq7R7WxFE1bhh4QerB7eI4ht/zk0a7AHLvqK+7JjdxrBUie03P9OU W9AWiKmUw0lnZVwJRknJbcuM6j6CjvAuzjSS7mWcOSoWzE2tXeJKq8+67ZjDGWvOXWKn +c7GcEhny02lLn1EI6Wn5vCBJiDU+qH45LZGC5I+MGDp1pz6gP0/CD3ntqrTDbQwco/H X6iLFXWHULGdORS/0eLDKeLTTAC3UF9lo0meOEchFMF29+gHEOapv/bH892+BlsfLctg uUoA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Vlad Yasevich , Neil Horman , syzbot , "David S. Miller" Subject: [PATCH 4.15 134/168] sctp: do not leak kernel memory to user space Date: Wed, 11 Apr 2018 00:24:36 +0200 Message-Id: <20180410212806.755664896@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180410212800.144079021@linuxfoundation.org> References: <20180410212800.144079021@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597399707487357504?= X-GMAIL-MSGID: =?utf-8?q?1597400187585781836?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 6780db244d6b1537d139dea0ec8aad10cf9e4adb ] syzbot produced a nice report [1] Issue here is that a recvmmsg() managed to leak 8 bytes of kernel memory to user space, because sin_zero (padding field) was not properly cleared. [1] BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184 [inline] BUG: KMSAN: uninit-value in move_addr_to_user+0x32e/0x530 net/socket.c:227 CPU: 1 PID: 3586 Comm: syzkaller481044 Not tainted 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 kmsan_internal_check_memory+0x164/0x1d0 mm/kmsan/kmsan.c:1176 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199 copy_to_user include/linux/uaccess.h:184 [inline] move_addr_to_user+0x32e/0x530 net/socket.c:227 ___sys_recvmsg+0x4e2/0x810 net/socket.c:2211 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313 SYSC_recvmmsg+0x29b/0x3e0 net/socket.c:2394 SyS_recvmmsg+0x76/0xa0 net/socket.c:2378 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x4401c9 RSP: 002b:00007ffc56f73098 EFLAGS: 00000217 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401c9 RDX: 0000000000000001 RSI: 0000000020003ac0 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000020003bc0 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000401af0 R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000 Local variable description: ----addr@___sys_recvmsg Variable was created at: ___sys_recvmsg+0xd5/0x810 net/socket.c:2172 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313 Bytes 8-15 of 16 are uninitialized ================================================================== Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 3586 Comm: syzkaller481044 Tainted: G B 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 panic+0x39d/0x940 kernel/panic.c:183 kmsan_report+0x238/0x240 mm/kmsan/kmsan.c:1083 kmsan_internal_check_memory+0x164/0x1d0 mm/kmsan/kmsan.c:1176 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199 copy_to_user include/linux/uaccess.h:184 [inline] move_addr_to_user+0x32e/0x530 net/socket.c:227 ___sys_recvmsg+0x4e2/0x810 net/socket.c:2211 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313 SYSC_recvmmsg+0x29b/0x3e0 net/socket.c:2394 SyS_recvmmsg+0x76/0xa0 net/socket.c:2378 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Cc: Vlad Yasevich Cc: Neil Horman Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sctp/ipv6.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -728,8 +728,10 @@ static int sctp_v6_addr_to_user(struct s sctp_v6_map_v4(addr); } - if (addr->sa.sa_family == AF_INET) + if (addr->sa.sa_family == AF_INET) { + memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero)); return sizeof(struct sockaddr_in); + } return sizeof(struct sockaddr_in6); }