net: add validation for the socket syscall protocol argument

commit 79462ad02e861803b3840cc782248c7359451cd9 upstream.

é\83­æ°¸å\88\9a 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: é\83­æ°¸å\88\9a <guoyonggang@360.cn>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 2.6.32: open-code U8_MAX; adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/include/net/sock.h b/include/net/sock.h
index 78adf52ca2785bc02341a1c3f75d95249d5f17e9..0de7d227704fdcf5a5c0586049f3c52cc44a1e3d 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -230,6 +230,7 @@ struct sock {
                                sk_no_check  : 2,
                                sk_userlocks : 4,
                                sk_protocol  : 8,
+#define SK_PROTOCOL_MAX ((u8)~0U)
                                sk_type      : 16;
        kmemcheck_bitfield_end(flags);
        int                     sk_rcvbuf;

diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 6b9d62b5d820536937a43d083bc88ba9d36981db..c1cf94025628bdc45b55b16200737b6327bc30a1 100644 (file)
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -805,6 +805,9 @@ static int ax25_create(struct net *net, struct socket *sock, int protocol)
        struct sock *sk;
        ax25_cb *ax25;
 
+       if (protocol < 0 || protocol > SK_PROTOCOL_MAX)
+               return -EINVAL;
+
        if (net != &init_net)
                return -EAFNOSUPPORT;
 

diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 5df7b5453556bb489bb7ee8fb17ca7e4a3e03cc7..7bb3fc397eea881916810ae9a74950e04f84110d 100644 (file)
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -679,6 +679,9 @@ static int dn_create(struct net *net, struct socket *sock, int protocol)
 {
        struct sock *sk;
 
+       if (protocol < 0 || protocol > SK_PROTOCOL_MAX)
+               return -EINVAL;
+
        if (net != &init_net)
                return -EAFNOSUPPORT;
 

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index d1992a4d166abe285435be06afb58f5e49bb39e6..2b9b83e1602ff6e85e6f6c0cf4ee17f10d0d58da 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -273,6 +273,9 @@ static int inet_create(struct net *net, struct socket *sock, int protocol)
        int try_loading_module = 0;
        int err;
 
+       if (protocol < 0 || protocol >= IPPROTO_MAX)
+               return -EINVAL;
+
        if (unlikely(!inet_ehash_secret))
                if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
                        build_ehash_secret();

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 835590d68876b1e3d55b6d717b98528b649a4aad..02d6175b42f72202be20d5fe0faaee12f870ec85 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -107,6 +107,9 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol)
        int try_loading_module = 0;
        int err;
 
+       if (protocol < 0 || protocol >= IPPROTO_MAX)
+               return -EINVAL;
+
        if (sock->type != SOCK_RAW &&
            sock->type != SOCK_DGRAM &&
            !inet_ehash_secret)

diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index 7cb7613d2ec7fd60f1285de44906350563bd3c3e..30ffff85155f75d38b953696213da708cc49f4a5 100644 (file)
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -1069,6 +1069,9 @@ static int irda_create(struct net *net, struct socket *sock, int protocol)
 
        IRDA_DEBUG(2, "%s()\n", __func__);
 
+       if (protocol < 0 || protocol > SK_PROTOCOL_MAX)
+               return -EINVAL;
+
        if (net != &init_net)
                return -EAFNOSUPPORT;