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 invoked with
-c) or the file named filename (if invoked with -f filename).
(no flag)
Dump the SAD entries or SPD entries contained in the specified
file.
-? 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 as
well. A dead SAD entry is one that has expired but remains in
the system because it is referenced by some SPD entries.
-D Dump the SAD entries. If -P is also specified, the SPD entries
are dumped. If -p is specified, the ports are displayed.
-F Flush the SAD entries. If -P is also specified, the SPD entries
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. See also
-r.
-l Loop forever with short output on -D.
-n No action. The program will check validity of the input, but no
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. Available
only in Linux. See also -k.
-x Loop forever and dump all the messages transmitted to the PF_KEY
socket. -xx prints the unformatted timestamps.
-V Print version string.
-v Be verbose. The program will dump messages exchanged on the
PF_KEY socket, including messages sent from other processes to
the kernel.
Configuration syntax
With -c or -f on the command line, setkey accepts the following
configuration syntax. Lines starting with hash signs (‘#’) are treated
as comment lines.
add [-46n] src dst protocol spi [extensions] algorithm ... ;
Add an SAD entry. add can fail for multiple reasons, including
when 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 command
line achieves the same functionality.
dump [protocol] ;
Dumps all SAD entries matched by the options. -D on the command
line 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 string
surrounded 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 same
functionality.
spddump ;
Dumps all SPD entries. -DP on the command line achieves the same
functionality.
Meta-arguments are as follows:
src
dst Source/destination of the secure communication is specified as an
IPv4/v6 address, and an optional port number between square
brackets. setkey can resolve a FQDN into numeric addresses. If
the FQDN resolves into multiple addresses, setkey will install
multiple SAD/SPD entries into the kernel by trying all possible
combinations. -4, -6, and -n restrict the address resolution of
FQDN in certain ways. -4 and -6 restrict results into IPv4/v6
addresses only, respectively. -n avoids FQDN resolution and
requires addresses to be numeric addresses.
protocol
protocol is one of following:
esp ESP based on rfc2406
esp-old ESP based on rfc1827
esp-udp ESP-UDP based on rfc3948
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. spi must
be a decimal number, or a hexadecimal number with a “0x” prefix.
SPI values between 0 and 255 are reserved for future use by IANA
and cannot be used. TCP-MD5 associations must use 0x1000 and
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 replay prevention.
size must be decimal number in 32-bit word. If size
is zero or not specified, replay checks don’t take
place.
-u id Specify the identifier of the policy entry in the
SPD. See policy.
-f pad_option
defines the content of the ESP padding. pad_option
is one of following:
zero-pad All the paddings are zero.
random-pad A series of randomized values are used.
seq-pad A series of sequential increasing numbers
started from 1 are used.
-f nocyclic-seq
Don’t allow cyclic sequence numbers.
-lh time
-ls time Specify hard/soft life time duration of the SA
measured in seconds.
-bh bytes
-bs bytes Specify hard/soft life time duration of the SA
measured in bytes transported.
-ctx doi algorithm context-name
Specify an access control label. The access control
label is interpreted by the LSM (e.g., SELinux).
Ultimately, it enables MAC on network communications.
doi The domain of interpretation, which is
used by the IKE daemon to identify the
domain in which negotiation takes place.
algorithm Indicates the LSM for which the label is
generated (e.g., SELinux).
context-name
The string representation of the label
that 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 a
payload 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 is
specified, the spi field value will be used as the
IPComp CPI (compression parameter index) on wire as-
is. If -R is not specified, the kernel will use
well-known CPI on wire, and spi field will be used
only as an index for kernel internal usage.
key must be a double-quoted character string, or a series of
hexadecimal digits preceded by “0x”.
Possible values for ealgo, aalgo, and calgo are specified in the
Algorithms 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, and
may be accompanied by a TCP/UDP port specification. This takes
the 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 stands
for “any protocol”. You can also use the protocol number. You
can specify a type and/or a code of ICMPv6 when the upper-layer
protocol is ICMPv6. The specification can be placed after icmp6.
A type is separated from a code by single comma. A code must
always be specified. When a zero is specified, the kernel deals
with it as a wildcard. Note that the kernel can not distinguish
a wildcard from an ICPMv6 type of zero. For example, the
following means that the policy doesn’t require IPsec for any
inbound Neighbor Solicitation.
spdadd ::/0 ::/0 icmp6 135,0 -P in none;
Note: upperspec does not work against forwarding case at this
moment, 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 ICMP
may not be suitable to use with IPsec. You have to consider
carefully what to use.
label label is the access control label for the policy. This label is
interpreted by the LSM (e.g., SELinux). Ultimately, it enables
MAC on network communications. When a policy contains an access
control label, SAs negotiated with this policy will contain the
label. It’s format:
-ctx doi algorithm context-name
doi The domain of interpretation, which is
used by the IKE daemon to identify the
domain in which negotiation takes place.
algorithm Indicates the LSM for which the label is
generated (e.g., SELinux).
context-name
The string representation of the label
that 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 (tcp-md5 support only on BSD)
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
camellia-cbc 128/192/256 rfc4312
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 ;
SEE ALSO
ipsec_set_policy(3), racoon(8), sysctl(8)
Changed manual key configuration for IPsec, October 1999,
http://www.kame.net/newsletter/19991007/.
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).