| From foo@baz Mon Jan 18 21:18:36 PST 2016 |
| 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 |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| Status: RO |
| Content-Length: 4097 |
| Lines: 133 |
| |
| From: Hannes Frederic Sowa <hannes@stressinduktion.org> |
| |
| [ 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> |
| --- |
| 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(+) |
| |
| --- a/include/net/sock.h |
| +++ b/include/net/sock.h |
| @@ -352,6 +352,7 @@ 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; |
| --- a/net/ax25/af_ax25.c |
| +++ b/net/ax25/af_ax25.c |
| @@ -806,6 +806,9 @@ static int ax25_create(struct net *net, |
| struct sock *sk; |
| ax25_cb *ax25; |
| |
| + if (protocol < 0 || protocol > SK_PROTOCOL_MAX) |
| + return -EINVAL; |
| + |
| if (!net_eq(net, &init_net)) |
| return -EAFNOSUPPORT; |
| |
| --- a/net/decnet/af_decnet.c |
| +++ b/net/decnet/af_decnet.c |
| @@ -677,6 +677,9 @@ static int dn_create(struct net *net, st |
| { |
| struct sock *sk; |
| |
| + if (protocol < 0 || protocol > SK_PROTOCOL_MAX) |
| + return -EINVAL; |
| + |
| if (!net_eq(net, &init_net)) |
| return -EAFNOSUPPORT; |
| |
| --- a/net/ipv4/af_inet.c |
| +++ b/net/ipv4/af_inet.c |
| @@ -288,6 +288,9 @@ static int inet_create(struct net *net, |
| if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) |
| build_ehash_secret(); |
| |
| + if (protocol < 0 || protocol >= IPPROTO_MAX) |
| + return -EINVAL; |
| + |
| sock->state = SS_UNCONNECTED; |
| |
| /* Look for the requested type/protocol pair. */ |
| --- a/net/ipv6/af_inet6.c |
| +++ b/net/ipv6/af_inet6.c |
| @@ -113,6 +113,9 @@ static int inet6_create(struct net *net, |
| !inet_ehash_secret) |
| build_ehash_secret(); |
| |
| + if (protocol < 0 || protocol >= IPPROTO_MAX) |
| + return -EINVAL; |
| + |
| /* Look for the requested type/protocol pair. */ |
| lookup_protocol: |
| err = -ESOCKTNOSUPPORT; |
| --- a/net/irda/af_irda.c |
| +++ b/net/irda/af_irda.c |
| @@ -1105,6 +1105,9 @@ static int irda_create(struct net *net, |
| |
| IRDA_DEBUG(2, "%s()\n", __func__); |
| |
| + if (protocol < 0 || protocol > SK_PROTOCOL_MAX) |
| + return -EINVAL; |
| + |
| if (net != &init_net) |
| return -EAFNOSUPPORT; |
| |