net: add validation for the socket syscall protocol argument

[ Upstream commit 79462ad02e861803b3840cc782248c7359451cd9 ]

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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[mainline backport of commit e60ccfd9e596b48d4b9d6e2b5440261c83d10c12]
Change-Id: Ia74ccac11d64e4e107b2696661abf87787fd62eb
Signed-off-by: Jaechul Lee <jcsing.lee@samsung.com>

diff --git a/include/net/sock.h b/include/net/sock.h
index 34b8db3f77848c34d9f46f6beb303566c4d387cd..c456e44d3a385da46d900ad4d86108941dc1d33a 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -379,6 +379,7 @@ 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;

diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index c35c3f48fc0ff6e130d940b3d8b24b208250a738..1428c3ff3341a98caec2ff4f504acb0b7e93d950 100644 (file)
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -806,6 +806,9 @@ 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_eq(net, &init_net))
                return -EAFNOSUPPORT;
 

diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 25733d53814763c85e49a612df3bbcdb202992d6..2aeeb4f22e9da14a337fbd9b655ba82421b0e4d1 100644 (file)
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -678,6 +678,9 @@ 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_eq(net, &init_net))
                return -EAFNOSUPPORT;
 

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index f58d3b6606ef7dcbf4bbb2e0bad42d7b8ddb0392..7c0c17f7d80caa8ad7fc85a1b63d24e4be12e6de 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,
        if (!current_has_network())
                return -EACCES;
 
+       if (protocol < 0 || protocol >= IPPROTO_MAX)
+               return -EINVAL;
+
        sock->state = SS_UNCONNECTED;
 
        /* Look for the requested type/protocol pair. */

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 4c591c0aa3eec5b7ed452728258e7ea4af4c97dc..57851e650923cd43dd460d256a129f3769e05284 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -126,6 +126,9 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol,
        if (!current_has_network())
                return -EACCES;
 
+       if (protocol < 0 || protocol >= IPPROTO_MAX)
+               return -EINVAL;
+
        /* Look for the requested type/protocol pair. */
 lookup_protocol:
        err = -ESOCKTNOSUPPORT;

diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index 3f3a6cbdceb7e20054a9c427de10682cf67478b9..b3f6ec0df426dab042abd35973a691f3dcad40d6 100644 (file)
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -1100,6 +1100,9 @@ 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;