From 79462ad02e861803b3840cc782248c7359451cd9 Mon Sep 17 00:00:00 2001
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Mon, 14 Dec 2015 22:03:39 +0100
Subject: net: add validation for the socket syscall protocol argument
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郭永刚 reported that one could simply crash the kernel as root by
using a simple program:
int socket_fd;
struct sockaddr_in addr;
addr.sin_port = 0;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_family = 10;
socket_fd = socket(10,3,0x40000000);
connect(socket_fd , &addr,16);
AF_INET, AF_INET6 sockets actually only support 8-bit protocol
identifiers. inet_sock's skc_protocol field thus is sized accordingly,
thus larger protocol identifiers simply cut off the higher bits and
store a zero in the protocol fields.
This could lead to e.g. NULL function pointer because as a result of
the cut off inet_num is zero and we call down to inet_autobind, which
is NULL for raw sockets.
kernel: Call Trace:
kernel: [<ffffffff816db90e>] ? inet_autobind+0x2e/0x70
kernel: [<ffffffff816db9a4>] inet_dgram_connect+0x54/0x80
kernel: [<ffffffff81645069>] SYSC_connect+0xd9/0x110
kernel: [<ffffffff810ac51b>] ? ptrace_notify+0x5b/0x80
kernel: [<ffffffff810236d8>] ? syscall_trace_enter_phase2+0x108/0x200
kernel: [<ffffffff81645e0e>] SyS_connect+0xe/0x10
kernel: [<ffffffff81779515>] tracesys_phase2+0x84/0x89
I found no particular commit which introduced this problem.
CVE: CVE-2015-8543
Cc: Cong Wang <cwang@twopensource.com>
Reported-by: 郭永刚 <guoyonggang@360.cn>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/sock.h | 1 +
1 file changed, 1 insertion(+)
(limited to 'include')
diff --git a/include/net/sock.h b/include/net/sock.h
index eaef41433d7a..c4205e0a3a2d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -403,6 +403,7 @@ struct sock {
sk_no_check_rx : 1,
sk_userlocks : 4,
sk_protocol : 8,
+#define SK_PROTOCOL_MAX U8_MAX
sk_type : 16;
kmemcheck_bitfield_end(flags);
int sk_wmem_queued;
--
cgit