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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/sock.h b/include/net/sock.h
index 44d514556004bbad924af79d90b51f0e0994a11e..031717ab68cb9638ba6a1573ade2756a75feea80 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -374,6 +374,7 @@ struct sock {
                                sk_no_check  : 2,
                                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 4c04848953bdb4caddeae9debd195ea3d004ee0d..630f972c20d2aaf90c8a94ec7f670804ebdb54aa 100644 (file)
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -677,6 +677,9 @@ 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 f4c804dbd3b4416d21e9343ed7802ff506c9e23a..a91e465b744940a54cb36846b7852ab47849f3a4 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -260,6 +260,9 @@ 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;
+
        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 d935889f1008ae93ff1efe52badeedf41352f257..e56aa09f04d189db3131d63216ae083be3313e8b 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -110,6 +110,9 @@ 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;
+
        /* 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 54747c25c86c47709f875cf1a7c1f37872fb8fa1..f945293c17f001f18c944e90c8f897c773cae518 100644 (file)
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -1103,6 +1103,9 @@ 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;