[Devel] [PATCH RHEL7 COMMIT] net: add validation for the socket syscall protocol argument

[Kirill Tkhai]

The commit is pushed to "branch-rh7-3.10.0-327.28.2.vz7.17.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.28.2.vz7.17.11
------>
commit 561405083523c1ebdfc75318fd499aaa56cbbbab
Author: Hannes Frederic Sowa <hannes at stressinduktion.org>
Date:   Tue Sep 27 13:53:27 2016 +0000

    net: add validation for the socket syscall protocol argument
    
    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 at twopensource.com>
    Reported-by: 郭永刚 <guoyonggang at 360.cn>
    Signed-off-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
    Signed-off-by: David S. Miller <davem at davemloft.net>
    
    Commit 79462ad02e861803b3840cc782248c7359451cd9 in the mainline kernel.
    
    https://jira.sw.ru/browse/PSBM-52759
    
    Signed-off-by: Evgenii Shatokhin <eshatokhin at virtuozzo.com>
    Reviewed-by: Vasily Averin <vvs at virtuozzo.com>
---
 include/net/sock.h     | 1 +
 net/ax25/af_ax25.c     | 3 +++
 net/decnet/af_decnet.c | 3 +++
 net/ipv4/af_inet.c     | 3 +++
 net/ipv6/af_inet6.c    | 3 +++
 net/irda/af_irda.c     | 3 +++
 6 files changed, 16 insertions(+)

diff --git a/include/net/sock.h b/include/net/sock.h
index ccaacb6..7fa24cb 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -385,6 +385,7 @@ struct sock {
 #endif
 				sk_userlocks : 4,
 				sk_protocol  : 8,
+#define SK_PROTOCOL_MAX U8_MAX
 				sk_type      : 16;
 	kmemcheck_bitfield_end(flags);
 
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index ba6db78..69940a7 100644
--- 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 c21f200..ca61065 100644
--- 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 91cb5f1..cf783ad 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -259,6 +259,9 @@ 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 32c38f8..4af94df 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -113,6 +113,9 @@ 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 a5e62ef5..f8133ff 100644
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -1105,6 +1105,9 @@ 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;