setkey(8) - Linux man page

Name

setkey - manually manipulate the IPsec SA/SP database

Synopsis

setkey [-knrv] file ...

setkey [-knrv] -c

setkey [-krv] -f filename

setkey [-aklPrv] -D

setkey [-Pvp] -F

setkey [-H] -x

setkey [-?V]

Description

setkey adds, updates, dumps, or flushes Security Association Database (SAD) entries as well as Security Policy Database (SPD) entries in the kernel.

setkey takes a series of operations from standard input (

if invokedwith -c) or the file named filename ( if invoked with -f filename).
(no flag) Dump the SAD entries or SPD entries contained in the specifiedfile.
-?' Print short help.
-a' setkey usually does not display dead SAD entries with -D. If-a is also specified, the dead SAD entries will be displayed aswell. A dead SAD entry is one that has expired but remains inthe system because it is referenced by some SPD entries.
-D' Dump the SAD entries. If -P is also specified, the SPDentries are dumped. If -p is specified, the ports are displayed.
-F' Flush the SAD entries. If -P is also specified, the SPDentries are flushed.
-H' Add hexadecimal dump in -x mode.
-h' On NetBSD, synonym for -H. On other systems, synonym for -?.
-k' Use semantics used in kernel. Available only in Linux. Seealso -r.
-l' Loop forever with short output on -D.
-n' No action. The program will check validity of the input, butno changes to the SPD will be made.
-r' Use semantics described in IPsec RFCs. This mode is default.For details see section RFC vs Linux kernel semantics. Availableonly in Linux. See also -k.
-x' Loop forever and dump all the messages transmitted to thePF_KEY socket. -xx prints the unformatted timestamps.
-V' Print version string.
-v' Be verbose. The program will dump messages exchanged on thePF_KEY socket, including messages sent from other processes tothe kernel.
Configuration syntax With -c or -f on the command line, setkey accepts the followingconfiguration syntax. Lines starting with hash signs ('#') are treatedas comment lines.
add [-46n] src dst protocol spi [extensions] algorithm ... ; Add an SAD entry. add can fail for multiple reasons, includingwhen the key length does not match the specified algorithm.
get [-46n] src dst protocol spi ; Show an SAD entry.
delete [-46n] src dst protocol spi ; Remove an SAD entry.
deleteall [-46n] src dst protocol ; Remove all SAD entries that match the specification.
flush [protocol] ; Clear all SAD entries matched by the options. -F on the commandline achieves the same functionality.
dump [protocol] ; Dumps all SAD entries matched by the options. -D on the commandline achieves the same functionality.
spdadd [-46n] src_range dst_range upperspec label policy ; Add an SPD entry.
spdadd tagged tag policy ; Add an SPD entry based on a PF tag. tag must be a stringsurrounded by double quotes.
spddelete [-46n] src_range dst_range upperspec -P direction ; Delete an SPD entry.
spdflush ; Clear all SPD entries. -FP on the command line achieves the samefunctionality.
spddump ; Dumps all SPD entries. -DP on the command line achieves the samefunctionality.
Meta-arguments are as follows:
src' dst' Source/destination of the secure communication is specifiedas an IPv4/v6 address, and an optional port number between squarebrackets. setkey can resolve a FQDN into numeric addresses. Ifthe FQDN resolves into multiple addresses, setkey will installmultiple SAD/SPD entries into the kernel by trying all possiblecombinations. -4, -6, and -n restrict the address resolution ofFQDN in certain ways. -4 and -6 restrict results into IPv4/v6addresses only, respectively. -n avoids FQDN resolution andrequires addresses to be numeric addresses.
protocol protocol is one of following: esp' ESP based on rfc2406 esp-old' ESP based on rfc1827 ah' AH based on rfc2402 ah-old' AH based on rfc1826 ipcomp' IPComp tcp' TCP-MD5 based on rfc2385
spi' Security Parameter Index (SPI) for the SAD and the SPD. spimust be a decimal number, or a hexadecimal number with a ''0x''prefix. SPI values between 0 and 255 are reserved for future useby IANA and cannot be used. TCP-MD5 associations must use 0x1000and therefore only have per-host granularity at this time.
extensions take some of the following: -m mode' Specify a security protocol mode for use.mode is one of following: transport, tunnel, or any.The default value is any. -r size' Specify window size of bytes for replayprevention. size must be decimal number in 32-bitword. If size is zero or not specified, replaychecks don't take place. -u id' Specify the identifier of the policy entry inthe SPD. See policy. -f pad_option defines the content of the ESP padding. pad_optionis one of following: zero-pad' All the paddings are zero. random-pad A series of randomized values are used. seq-pad' A series of sequentialincreasing numbers started from 1 areused. -f nocyclic-seq Don't allow cyclic sequence numbers. -lh time' -ls time' Specify hard/soft life time duration of theSA measured in seconds. -bh bytes -bs bytes Specify hard/soft life time duration of the SAmeasured in bytes transported. -ctx doi algorithm context-name Specify an access control label. The access controllabel is interpreted by the LSM (e.g., SELinux).Ultimately, it enables MAC on network communications. doi' The domain of interpretation, whichis used by the IKE daemon to identify thedomain in which negotiation takes place. algorithm Indicates the LSM for which the label isgenerated (e.g., SELinux). context-name The string representation of the labelthat is interpreted by the LSM.
algorithm -E ealgo key Specify an encryption algorithm ealgo for ESP. -E ealgo key -A aalgo key Specify an encryption algorithm ealgo, as well as apayload authentication algorithm aalgo, for ESP. -A aalgo key Specify an authentication algorithm for AH. -C calgo [-R] Specify a compression algorithm for IPComp. If -R isspecified, the spi field value will be used as theIPComp CPI (compression parameter index) on wireas-is. If -R is not specified, the kernel will usewell-known CPI on wire, and spi field will be usedonly as an index for kernel internal usage.
key must be a double-quoted character string, or a series ofhexadecimal digits preceded by ''0x''.
Possible values for ealgo, aalgo, and calgo are specified in theAlgorithms sections.
src_range dst_range These select the communications that should be secured by IPsec.They can be an IPv4/v6 address or an IPv4/v6 address range, andmay be accompanied by a TCP/UDP port specification. This takesthe following form:
address
address/prefixlen
address[port]
address/prefixlen[port]

prefixlen and port must be decimal numbers. The square brackets around port are really necessary, they are not man page meta-characters. For FQDN resolution, the rules applicable to src and dst apply here as well.

upperspec Upper-layer protocol to be used. You can use one of the words in/etc/protocols as upperspec, or icmp6, ip4, or any. any standsfor ''any protocol''. You can also use the protocol number. Youcan specify a type and/or a code of ICMPv6 when the upper-layerprotocol is ICMPv6. The specification can be placed after icmp6.A type is separated from a code by single comma. A code mustalways be specified. When a zero is specified, the kernel dealswith it as a wildcard. Note that the kernel can not distinguisha wildcard from an ICPMv6 type of zero. For example, thefollowing means that the policy doesn't require IPsec for anyinbound Neighbor Solicitation.spdadd ::/0 ::/0 icmp6 135,0 -P in none;
Note: upperspec does not work against forwarding case at thismoment, as it requires extra reassembly at the forwarding node(not implemented at this moment). There are many protocols in/etc/protocols, but all protocols except of TCP, UDP, and ICMPmay not be suitable to use with IPsec. You have to considercarefully what to use.
label label is the access control label for the policy. This label isinterpreted by the LSM (e.g., SELinux). Ultimately, it enablesMAC on network communications. When a policy contains an accesscontrol label, SAs negotiated with this policy will contain thelabel. It's format: -ctx doi algorithm context-name doi' The domain of interpretation, whichis used by the IKE daemon to identify thedomain in which negotiation takes place. algorithm Indicates the LSM for which the label isgenerated (e.g., SELinux). context-name The string representation of the labelthat is interpreted by the LSM.
policy policy is in one of the following three formats:

-P direction [priority specification] discard

-P direction [priority specification] none

-P direction [priority specification] ipsec
protocol/mode/src-dst/level [...]

You must specify the direction of its policy as direction. Either out, in, or fwd can be used.

priority specification is used to control the placement of the policy within the SPD. Policy position is determined by a signed integer where higher priorities indicate the policy is placed closer to the beginning of the list and lower priorities indicate the policy is placed closer to the end of the list. Policies with equal priorities are added at the end of groups of such policies.

Priority can only be specified when setkey has been compiled against kernel headers that support policy priorities (Linux >= 2.6.6). If the kernel does not support priorities, a warning message will be printed the first time a priority specification is used. Policy priority takes one of the following formats:

                 {priority,prio} offset

offset is an integer in the range from -2147483647 to 214783648.

{priority,prio} base {+,-} offset
base is either low (-1073741824), def (0), or high (1073741824)

offset is an unsigned integer. It can be up to 1073741824 for positive offsets, and up to 1073741823 for negative offsets.

discard means the packet matching indexes will be discarded. none means that IPsec operation will not take place onto the packet. ipsec means that IPsec operation will take place onto the packet.

The protocol/mode/src-dst/level part specifies the rule how to process the packet. Either ah, esp, or ipcomp must be used as protocol. mode is either transport or tunnel. If mode is tunnel, you must specify the end-point addresses of the SA as src and dst with '-' between these addresses, which is used to specify the SA to use. If mode is transport, both src and dst can be omitted. level is to be one of the following: default, use, require, or unique. If the SA is not available in every level, the kernel will ask the key exchange daemon to establish a suitable SA. default means the kernel consults the system wide default for the protocol you specified, e.g. the esp_trans_deflev sysctl variable, when the kernel processes the packet. use means that the kernel uses an SA if it's available, otherwise the kernel keeps normal operation. require means SA is required whenever the kernel sends a packet matched with the policy. unique is the same as require; in addition, it allows the policy to match the unique out-bound SA. You just specify the policy level unique, racoon(8) will configure the SA for the policy. If you configure the SA by manual keying for that policy, you can put a decimal number as the policy identifier after unique separated by a colon ':' like: unique:number in order to bind this policy to the SA. number must be between 1 and 32767. It corresponds to extensions -u of the manual SA configuration. When you want to use SA bundle, you can define multiple rules. For example, if an IP header was followed by an AH header followed by an ESP header followed by an upper layer protocol header, the rule would be: esp/transport//require ah/transport//require; The rule order is very important.

When NAT-T is enabled in the kernel, policy matching for ESP over UDP packets may be done on endpoint addresses and port (this depends on the system. System that do not perform the port check cannot support multiple endpoints behind the same NAT). When using ESP over UDP, you can specify port numbers in the endpoint addresses to get the correct matching. Here is an example:

spdadd 10.0.11.0/24[any] 10.0.11.33/32[any] any -P out ipsec
esp/tunnel/192.168.0.1[4500]-192.168.1.2[30000]/require ;

These ports must be left unspecified (which defaults to 0) for anything other than ESP over UDP. They can be displayed in SPD dump using setkey -DPp.

Note that ''discard'' and ''none'' are not in the syntax described in ipsec_set_policy(3). There are a few differences in the syntax. See ipsec_set_policy(3) for detail.

Algorithms

The following list shows the supported algorithms. protocol and algorithm are almost orthogonal. These authentication algorithms can be used as aalgo in -A aalgo of the protocol parameter:

algorithm       keylen (bits)

hmac-md5 128 ah: rfc2403 128 ah-old: rfc2085 hmac-sha1 160 ah: rfc2404 160 ah-old: 128bit ICV (no document) keyed-md5 128 ah: 96bit ICV (no document) 128 ah-old: rfc1828 keyed-sha1 160 ah: 96bit ICV (no document) 160 ah-old: 128bit ICV (no document) null 0 to 2048 for debugging hmac-sha256 256 ah: 96bit ICV (draft-ietf-ipsec-ciph-sha-256-00) 256 ah-old: 128bit ICV (no document) hmac-sha384 384 ah: 96bit ICV (no document) 384 ah-old: 128bit ICV (no document) hmac-sha512 512 ah: 96bit ICV (no document) 512 ah-old: 128bit ICV (no document) hmac-ripemd160 160 ah: 96bit ICV (RFC2857) ah-old: 128bit ICV (no document) aes-xcbc-mac 128 ah: 96bit ICV (RFC3566) 128 ah-old: 128bit ICV (no document) tcp-md5 8 to 640 tcp: rfc2385

These encryption algorithms can be used as ealgo in -E ealgo of the protocol parameter:

algorithm       keylen (bits)

des-cbc 64 esp-old: rfc1829, esp: rfc2405 3des-cbc 192 rfc2451 null 0 to 2048 rfc2410 blowfish-cbc 40 to 448 rfc2451 cast128-cbc 40 to 128 rfc2451 des-deriv 64 ipsec-ciph-des-derived-01 3des-deriv 192 no document rijndael-cbc 128/192/256 rfc3602 twofish-cbc 0 to 256 draft-ietf-ipsec-ciph-aes-cbc-01 aes-ctr 160/224/288 draft-ietf-ipsec-ciph-aes-ctr-03

Note that the first 128 bits of a key for aes-ctr will be used as AES key, and the remaining 32 bits will be used as nonce.

These compression algorithms can be used as calgo in -C calgo of the protocol parameter:

algorithm

deflate rfc2394

RFC vs Linux kernel semantics

The Linux kernel uses the fwd policy instead of the in policy for packets what are forwarded through that particular box.

In kernel mode, setkey manages and shows policies and SAs exactly as they are stored in the kernel.

In RFC mode, setkey

creates fwd policies for every in policy inserted

(not implemented yet) filters out all fwd policies

Return Values

The command exits with 0 on success, and non-zero on errors.

Examples

add 3ffe:501:4819::1 3ffe:501:481d::1 esp 123457

-E des-cbc 0x3ffe05014819ffff ;

add -6 myhost.example.com yourhost.example.com ah 123456

-A hmac-sha1 "AH SA configuration!" ;

add 10.0.11.41 10.0.11.33 esp 0x10001

-E des-cbc 0x3ffe05014819ffff

-A hmac-md5 "authentication!!" ;

get 3ffe:501:4819::1 3ffe:501:481d::1 ah 123456 ;

flush ;

dump esp ;

spdadd 10.0.11.41/32[21] 10.0.11.33/32[any] any

-P out ipsec esp/tunnel/192.168.0.1-192.168.1.2/require ;

add 10.1.10.34 10.1.10.36 tcp 0x1000 -A tcp-md5 "TCP-MD5 BGP secret" ;

add 10.0.11.41 10.0.11.33 esp 0x10001

-ctx 1 1 "system_u:system_r:unconfined_t:SystemLow-SystemHigh"

-E des-cbc 0x3ffe05014819ffff;

spdadd 10.0.11.41 10.0.11.33 any

-ctx 1 1 "system_u:system_r:unconfined_t:SystemLow-SystemHigh"

-P out ipsec esp/transport//require ;

History

The setkey command first appeared in the WIDE Hydrangea IPv6 protocol stack kit. The command was completely re-designed in June 1998.

Bugs

setkey should report and handle syntax errors better.

For IPsec gateway configuration, src_range and dst_range with TCP/UDP port numbers does not work, as the gateway does not reassemble packets (it cannot inspect upper-layer headers).

BSD March 19, 2004 BSD

Referenced By

iked(8), iked.conf(5), ip6tables(8), ip6tables-1.4.7(8), iptables(8), iptables-1.4.7(8), racoon.conf(5), setkey_selinux(8), shorewall-accounting(5), shorewall-masq(5), shorewall-zones(5), shorewall6-accounting(5), shorewall6-zones(5)