On Thu, Mar 3, 2011 at 12:00 AM, Bjoern A. Zeeb
<[email protected]> wrote:
> On Sat, 5 Feb 2011, Giorgos Keramidas wrote:
>
> Hi,
>
>> On Fri, 28 Jan 2011 11:00:40 -0800, Doug Barton <[email protected]> wrote:
>>>
>>> I haven't reviewed the patch in detail yet but I wanted to first thank
>>> you for taking on this work, and being so responsive to Fernando's
>>> request (which I agreed with, and you updated before I even had a
>>> chance to say so). :)
>>
>> Thanks from me too.
>>
>>> My one comment so far is on the name of the sysctl's. There are 2
>>> problems with sysctl/variable names that use an rfc title. The first is
>>> that they are not very descriptive to the 99.9% of users who are not
>>> familiar with that particular doc. The second is more esoteric, but if
>>> the rfc is subsequently updated or obsoleted we're stuck with either an
>>> anachronism or updating code (both of which have their potential areas
>>> of confusion).
>>>
>>> So in order to avoid this issue, and make it more consistent with the
>>> existing:
>>>
>>> net.inet.ip.portrange.randomtime
>>> net.inet.ip.portrange.randomcps
>>> net.inet.ip.portrange.randomized
>>>
>>> How does net.inet.ip.portrange.randomalg sound? I would also suggest
>>> that the second sysctl be named
>>> net.inet.ip.portrange.randomalg.alg5_tradeoff so that one could do
>>> sysctl net.inet.ip.portrange.randomalg' and see both values. But I won't
>>> quibble on that. :)
>>
>> It's a usability issue too, so I'd certainly support renaming the
>> sysctls to something human-friendly. It's always bad enough to go
>> through look at a search engine to find out what net.inet.rfc1234
>> means. It's worse when RFC 1234 has been obsoleted a few years ago
>> and now it's called RFC 54321.
>
> has anything of that ever happened and led to an updated patch again?
Yes. Those recommendations are reflected in the latest version of the
patch I supplied.
I attach it again for reference. It is against RELENG-8 as of
2011-01-31. However, if you need -CURRENT-based patch, please let me
know, so I can prepare it asap.
> /bz
>
> --
> Bjoern A. Zeeb You have to have visions!
> Stop bit received. Insert coin for new address family.
> _______________________________________________
> [email protected] mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-net
> To unsubscribe, send any mail to "[email protected]"
>
diff -r 0d67f9c982f7 src/sys/netinet/in_pcb.c
--- a/src/sys/netinet/in_pcb.c Mon Jan 31 11:35:24 2011 +0200
+++ b/src/sys/netinet/in_pcb.c Mon Jan 31 14:29:52 2011 +0200
@@ -81,6 +81,8 @@
#include <netipsec/key.h>
#endif /* IPSEC */
+#include <sys/md5.h>
+
#include <security/mac/mac_framework.h>
/*
@@ -109,6 +111,8 @@
VNET_DEFINE(int, ipport_stoprandom); /* toggled by ipport_tick */
VNET_DEFINE(int, ipport_tcpallocs);
static VNET_DEFINE(int, ipport_tcplastcount);
+VNET_DEFINE(u_int, ipport_randomalg_ver) = 1; /* user controlled via sysctl */
+VNET_DEFINE(u_int, ipport_randomalg_alg5_tradeoff) = 500; /* user controlled via sysctl */
#define V_ipport_tcplastcount VNET(ipport_tcplastcount)
@@ -141,7 +145,68 @@
#undef RANGECHK
+/*
+ * Updates V_ipport_randomalg_ver to the provided value
+ * and ensures it is in the supported range (1 - 5)
+ */
+static int
+sysctl_net_randomalg_version_check(SYSCTL_HANDLER_ARGS)
+{
+ u_int algorithm = *(u_int *)arg1;
+ int error;
+
+#ifdef VIMAGE
+ error = vnet_sysctl_handle_uint(oidp, &algorithm, 0, req);
+#else
+ error = sysctl_handle_int(oidp, &algorithm, 0, req);
+#endif
+
+ if (error == 0) {
+ switch (algorithm) {
+ case INP_RFC6056_ALG_1:
+ case INP_RFC6056_ALG_2:
+ case INP_RFC6056_ALG_3:
+ case INP_RFC6056_ALG_4:
+ case INP_RFC6056_ALG_5:
+ V_ipport_randomalg_ver = algorithm;
+ break;
+ default:
+ return (EINVAL);
+ }
+ }
+
+ return (error);
+}
+
+/*
+ * Updates V_ipport_randomalg_alg5_tradeoff to provided value
+ * and ensures it is in the supported range (1 - 65536)
+ */
+static int
+sysctl_net_randomalg_alg5_tradeoff_check(SYSCTL_HANDLER_ARGS)
+{
+ u_int tradeoff = *(u_int *)arg1;
+ int error;
+
+#ifdef VIMAGE
+ error = vnet_sysctl_handle_uint(oidp, &tradeoff, 0, req);
+#else
+ error = sysctl_handle_int(oidp, &tradeoff, 0, req);
+#endif
+
+ if (error == 0) {
+ if (tradeoff < 1 || tradeoff > 65536)
+ return (EINVAL);
+ else
+ V_ipport_randomalg_alg5_tradeoff = tradeoff;
+ }
+
+ return (error);
+}
+
SYSCTL_NODE(_net_inet_ip, IPPROTO_IP, portrange, CTLFLAG_RW, 0, "IP Ports");
+SYSCTL_NODE(_net_inet_ip_portrange, IPPROTO_IP, randomalg, CTLFLAG_RW, 0,
+ "Port Randomization Algorithms");
SYSCTL_VNET_PROC(_net_inet_ip_portrange, OID_AUTO, lowfirst,
CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(ipport_lowfirstauto), 0,
@@ -174,6 +239,15 @@
&VNET_NAME(ipport_randomtime), 0,
"Minimum time to keep sequental port "
"allocation before switching to a random one");
+SYSCTL_VNET_PROC(_net_inet_ip_portrange_randomalg, OID_AUTO, version,
+ CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(ipport_randomalg_ver), 0,
+ &sysctl_net_randomalg_version_check, "IU",
+ "RFC 6056 Port randomization algorithm");
+SYSCTL_VNET_PROC(_net_inet_ip_portrange_randomalg, OID_AUTO,
+ alg5_tradeoff, CTLTYPE_UINT|CTLFLAG_RW,
+ &VNET_NAME(ipport_randomalg_alg5_tradeoff), 0,
+ &sysctl_net_randomalg_alg5_tradeoff_check, "IU",
+ "RFC 6056 Algorithm 5 computational trade-off");
/*
* in_pcb.c: manage the Protocol Control Blocks.
@@ -468,21 +542,177 @@
last = aux;
}
- if (dorandom)
- *lastport = first +
- (arc4random() % (last - first));
-
count = last - first;
- do {
- if (count-- < 0) /* completely used? */
- return (EADDRNOTAVAIL);
- ++*lastport;
- if (*lastport < first || *lastport > last)
- *lastport = first;
- lport = htons(*lastport);
- } while (in_pcblookup_local(pcbinfo, laddr,
- lport, wild, cred));
+ /*
+ * According to RFC 6056 there are 5 (five) possible algorithms
+ * for random port allocation. Usage of a particular algorithm
+ * is specified with the 'net.inet.ip.portrange.randomalg.version'
+ * sysctl variable. Default value is 1, which represents the
+ * legacy random port allocation algorithm in FreeBSD.
+ */
+ if (dorandom) {
+ switch (V_ipport_randomalg_ver) {
+ case INP_RFC6056_ALG_5: /* Random-Increments Port Selection */
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+
+ *lastport = first + ((arc4random() % 65536) +
+ (arc4random() % V_ipport_randomalg_alg5_tradeoff) + 1);
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr,
+ lport, wild, cred));
+ break;
+ case INP_RFC6056_ALG_4: /* Double-Hash Port Selection Algorithm */
+ {
+ MD5_CTX f_ctx;
+ MD5_CTX g_ctx;
+ u_int32_t F[4] = { 0, 0, 0, 0 };
+ u_int32_t G[4] = { 0, 0, 0, 0 };
+ u_int32_t secret_f[4] = { 0, 0, 0, 0 };
+ u_int32_t secret_g[4] = { 0, 0, 0, 0 };
+ u_int16_t table[16];
+ u_int32_t index = 0;
+ u_int32_t offset = 0;
+
+ secret_f[0] = arc4random();
+ secret_f[1] = arc4random();
+ secret_f[2] = arc4random();
+ secret_f[3] = arc4random();
+
+ secret_g[0] = arc4random();
+ secret_g[1] = arc4random();
+ secret_g[2] = arc4random();
+ secret_g[3] = arc4random();
+
+ for (index = 0; index < sizeof(table); index++)
+ table[index] = arc4random() % 65536;
+
+ MD5Init(&f_ctx);
+ MD5Update(&f_ctx, (u_char *)&inp->inp_laddr,
+ sizeof(inp->inp_laddr));
+ MD5Update(&f_ctx, (u_char *)&inp->inp_faddr,
+ sizeof(inp->inp_faddr));
+ MD5Update(&f_ctx, (u_char *)&inp->inp_fport,
+ sizeof(inp->inp_fport));
+ MD5Update(&f_ctx, (u_char *)secret_f,
+ sizeof(secret_f));
+ MD5Final((u_char *)&F, &f_ctx);
+
+ offset = ((F[0] ^ F[1]) ^ (F[2] ^ F[3]));
+
+ MD5Init(&g_ctx);
+ MD5Update(&g_ctx, (u_char *)&inp->inp_laddr,
+ sizeof(inp->inp_laddr));
+ MD5Update(&g_ctx, (u_char *)&inp->inp_faddr,
+ sizeof(inp->inp_faddr));
+ MD5Update(&g_ctx, (u_char *)&inp->inp_fport,
+ sizeof(inp->inp_fport));
+ MD5Update(&g_ctx, (u_char *)secret_g,
+ sizeof(secret_g));
+ MD5Final((u_char *)&G, &g_ctx);
+
+ index = ((G[0] ^ G[1]) ^ (G[2] ^ G[3])) % sizeof(table);
+
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+
+ *lastport = first +
+ (offset + table[index]++) % count;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr,
+ lport, wild, cred));
+ }
+ break;
+ case INP_RFC6056_ALG_3: /* Simple Hash-Based Port Selection Algorithm */
+ {
+ MD5_CTX f_ctx;
+ u_int32_t F[4] = { 0, 0, 0, 0 };
+ u_int32_t secret_f[4] = { 0, 0, 0, 0 };
+ u_int32_t offset = 0;
+
+ secret_f[0] = arc4random();
+ secret_f[1] = arc4random();
+ secret_f[2] = arc4random();
+ secret_f[3] = arc4random();
+
+ MD5Init(&f_ctx);
+ MD5Update(&f_ctx, (u_char *)&inp->inp_laddr,
+ sizeof(inp->inp_laddr));
+ MD5Update(&f_ctx, (u_char *)&inp->inp_faddr,
+ sizeof(inp->inp_faddr));
+ MD5Update(&f_ctx, (u_char *)&inp->inp_fport,
+ sizeof(inp->inp_fport));
+ MD5Update(&f_ctx, (u_char *)secret_f,
+ sizeof(secret_f));
+ MD5Final((u_char *)&F, &f_ctx);
+
+ offset = ((F[0] ^ F[1]) ^ (F[2] ^ F[3]));
+
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+
+ *lastport = first + ((arc4random() % 65536) +
+ (offset % 65536)) % count;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr,
+ lport, wild, cred));
+ }
+ break;
+ case INP_RFC6056_ALG_2: /* Simple Port Randomization Algorithm II */
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+
+ *lastport = first + (arc4random() % (last - first));
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr,
+ lport, wild, cred));
+ break;
+ case INP_RFC6056_ALG_1: /* Simple Port Randomization Algorithm I */
+ default:
+ *lastport = first + (arc4random() % (last - first));
+
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+
+ ++*lastport;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr,
+ lport, wild, cred));
+ }
+ } else {
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+
+ ++*lastport;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr,
+ lport, wild, cred));
+ }
}
*laddrp = laddr.s_addr;
*lportp = lport;
diff -r 0d67f9c982f7 src/sys/netinet/in_pcb.h
--- a/src/sys/netinet/in_pcb.h Mon Jan 31 11:35:24 2011 +0200
+++ b/src/sys/netinet/in_pcb.h Mon Jan 31 14:29:52 2011 +0200
@@ -452,6 +452,15 @@
#define INP_CHECK_SOCKAF(so, af) (INP_SOCKAF(so) == af)
+/*
+ * RFC6056 Port Randomization Algorithms
+ */
+#define INP_RFC6056_ALG_1 1 /* Simple Port Randomization Algorithm I */
+#define INP_RFC6056_ALG_2 2 /* Simple Port Randomization Algorithm II */
+#define INP_RFC6056_ALG_3 3 /* Simple Hash-Based Port Selection Algorithm */
+#define INP_RFC6056_ALG_4 4 /* Double-Hash Port Selection Algorithm */
+#define INP_RFC6056_ALG_5 5 /* Random-Increments Port Selection Algorithm */
+
#ifdef _KERNEL
VNET_DECLARE(int, ipport_reservedhigh);
VNET_DECLARE(int, ipport_reservedlow);
@@ -466,6 +475,8 @@
VNET_DECLARE(int, ipport_randomtime);
VNET_DECLARE(int, ipport_stoprandom);
VNET_DECLARE(int, ipport_tcpallocs);
+VNET_DECLARE(u_int, ipport_randomalg_ver);
+VNET_DECLARE(u_int, ipport_randomalg_alg5_tradeoff);
#define V_ipport_reservedhigh VNET(ipport_reservedhigh)
#define V_ipport_reservedlow VNET(ipport_reservedlow)
@@ -480,6 +491,8 @@
#define V_ipport_randomtime VNET(ipport_randomtime)
#define V_ipport_stoprandom VNET(ipport_stoprandom)
#define V_ipport_tcpallocs VNET(ipport_tcpallocs)
+#define V_ipport_randomalg_ver VNET(ipport_randomalg_ver)
+#define V_ipport_randomalg_alg5_tradeoff VNET(ipport_randomalg_alg5_tradeoff)
extern struct callout ipport_tick_callout;
diff -r 0d67f9c982f7 src/sys/netinet6/in6_src.c
--- a/src/sys/netinet6/in6_src.c Mon Jan 31 11:35:24 2011 +0200
+++ b/src/sys/netinet6/in6_src.c Mon Jan 31 14:29:52 2011 +0200
@@ -108,6 +108,8 @@
#include <netinet6/scope6_var.h>
#include <netinet6/nd6.h>
+#include <sys/md5.h>
+
static struct mtx addrsel_lock;
#define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
#define ADDRSEL_LOCK() mtx_lock(&addrsel_lock)
@@ -919,23 +921,195 @@
last = aux;
}
- if (dorandom)
- *lastport = first + (arc4random() % (last - first));
-
count = last - first;
- do {
- if (count-- < 0) { /* completely used? */
- /* Undo an address bind that may have occurred. */
- inp->in6p_laddr = in6addr_any;
- return (EADDRNOTAVAIL);
+ /*
+ * According to RFC 6056 there are 5 (five) possible algorithms
+ * for random port allocation. Usage of a particular algorithm
+ * is specified with the 'net.inet.ip.portrange.randomalg.version'
+ * sysctl variable. Default value is 1, which represents the
+ * legacy random port allocation algorithm in FreeBSD.
+ */
+ if (dorandom) {
+ switch (V_ipport_randomalg_ver) {
+ case INP_RFC6056_ALG_5: /* Random-Increments Port Selection */
+ do {
+ if (count-- < 0) { /* completely used? */
+ /* Undo an address bind that may have occurred. */
+ inp->in6p_laddr = in6addr_any;
+ return (EADDRNOTAVAIL);
+ }
+
+ *lastport = first + ((arc4random() % 65536) +
+ (arc4random() % V_ipport_randomalg_alg5_tradeoff) + 1);
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
+ lport, wild, cred));
+ break;
+ case INP_RFC6056_ALG_4: /* Double-Hash Port Selection Algorithm */
+ {
+ MD5_CTX f_ctx;
+ MD5_CTX g_ctx;
+ u_int32_t F[4] = { 0, 0, 0, 0 };
+ u_int32_t G[4] = { 0, 0, 0, 0 };
+ u_int32_t secret_f[4] = { 0, 0, 0, 0 };
+ u_int32_t secret_g[4] = { 0, 0, 0, 0 };
+ u_int16_t table[16];
+ u_int32_t index = 0;
+ u_int32_t offset = 0;
+
+ secret_f[0] = arc4random();
+ secret_f[1] = arc4random();
+ secret_f[2] = arc4random();
+ secret_f[3] = arc4random();
+
+ secret_g[0] = arc4random();
+ secret_g[1] = arc4random();
+ secret_g[2] = arc4random();
+ secret_g[3] = arc4random();
+
+ for (index = 0; index < sizeof(table); index++)
+ table[index] = arc4random() % 65536;
+
+ MD5Init(&f_ctx);
+ MD5Update(&f_ctx, (u_char *)&inp->in6p_laddr,
+ sizeof(inp->in6p_laddr));
+ MD5Update(&f_ctx, (u_char *)&inp->in6p_faddr,
+ sizeof(inp->in6p_faddr));
+ MD5Update(&f_ctx, (u_char *)&inp->inp_fport,
+ sizeof(inp->inp_fport));
+ MD5Update(&f_ctx, (u_char *)secret_f,
+ sizeof(secret_f));
+ MD5Final((u_char *)&F, &f_ctx);
+
+ offset = ((F[0] ^ F[1]) ^ (F[2] ^ F[3]));
+
+ MD5Init(&g_ctx);
+ MD5Update(&g_ctx, (u_char *)&inp->in6p_laddr,
+ sizeof(inp->in6p_laddr));
+ MD5Update(&g_ctx, (u_char *)&inp->in6p_faddr,
+ sizeof(inp->in6p_faddr));
+ MD5Update(&g_ctx, (u_char *)&inp->inp_fport,
+ sizeof(inp->inp_fport));
+ MD5Update(&g_ctx, (u_char *)secret_g,
+ sizeof(secret_g));
+ MD5Final((u_char *)&G, &g_ctx);
+
+ index = ((G[0] ^ G[1]) ^ (G[2] ^ G[3])) % sizeof(table);
+
+ do {
+ if (count-- < 0) { /* completely used? */
+ /* Undo an address bind that may have occurred. */
+ inp->in6p_laddr = in6addr_any;
+ return (EADDRNOTAVAIL);
+ }
+
+ *lastport = first +
+ (offset + table[index]++) % count;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
+ lport, wild, cred));
+ }
+ break;
+ case INP_RFC6056_ALG_3: /* Simple Hash-Based Port Selection Algorithm */
+ {
+ MD5_CTX f_ctx;
+ u_int32_t F[4] = { 0, 0, 0, 0 };
+ u_int32_t secret_f[4] = { 0, 0, 0, 0 };
+ u_int32_t offset = 0;
+
+ secret_f[0] = arc4random();
+ secret_f[1] = arc4random();
+ secret_f[2] = arc4random();
+ secret_f[3] = arc4random();
+
+ MD5Init(&f_ctx);
+ MD5Update(&f_ctx, (u_char *)&inp->in6p_laddr,
+ sizeof(inp->in6p_laddr));
+ MD5Update(&f_ctx, (u_char *)&inp->in6p_faddr,
+ sizeof(inp->in6p_faddr));
+ MD5Update(&f_ctx, (u_char *)&inp->inp_fport,
+ sizeof(inp->inp_fport));
+ MD5Update(&f_ctx, (u_char *)secret_f,
+ sizeof(secret_f));
+ MD5Final((u_char *)&F, &f_ctx);
+
+ offset = ((F[0] ^ F[1]) ^ (F[2] ^ F[3]));
+
+ do {
+ if (count-- < 0) { /* completely used? */
+ /* Undo an address bind that may have occurred. */
+ inp->in6p_laddr = in6addr_any;
+ return (EADDRNOTAVAIL);
+ }
+
+ *lastport = first + ((arc4random() % 65536) +
+ (offset % 65536)) % count;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
+ lport, wild, cred));
+ }
+ break;
+ case INP_RFC6056_ALG_2: /* Simple Port Randomization Algorithm II */
+ do {
+ if (count-- < 0) { /* completely used? */
+ /* Undo an address bind that may have occurred. */
+ inp->in6p_laddr = in6addr_any;
+ return (EADDRNOTAVAIL);
+ }
+
+ *lastport = first + (arc4random() % (last - first));
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
+ lport, wild, cred));
+ break;
+ case INP_RFC6056_ALG_1: /* Simple Port Randomization Algorithm I */
+ default:
+ *lastport = first + (arc4random() % (last - first));
+
+ do {
+ if (count-- < 0) { /* completely used? */
+ /* Undo an address bind that may have occurred. */
+ inp->in6p_laddr = in6addr_any;
+ return (EADDRNOTAVAIL);
+ }
+
+ ++*lastport;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
+ lport, wild, cred));
}
- ++*lastport;
- if (*lastport < first || *lastport > last)
- *lastport = first;
- lport = htons(*lastport);
- } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
- lport, wild, cred));
+ } else {
+ do {
+ if (count-- < 0) { /* completely used? */
+ /* Undo an address bind that may have occurred. */
+ inp->in6p_laddr = in6addr_any;
+ return (EADDRNOTAVAIL);
+ }
+
+ ++*lastport;
+
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
+ lport, wild, cred));
+ }
inp->inp_lport = lport;
if (in_pcbinshash(inp) != 0) {
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