Ubuntu Manpage: setkey — manually manipulate the IPsec SA/SP database

Provided by: ipsec-tools_0.8.2+20140711-10build1_amd64

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.

spdupdate [-46n] src_range dst_range upperspec label policy ;
Updates an SPD entry.

spdupdate tagged tag policy ;
Update 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, gre, or any. any stands for “any protocol”. You can also
use the protocol number. Additional specification can be placed after the protocol
name for some protocols. You can specify a type and/or a code of ICMP or ICMPv6.
The type is separated from a code by single comma and the code must always be
specified. GRE key can be specified in dotted-quad format or as plain number. 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;

A second example of requiring transport mode encryption of specific GRE tunnel:
spdadd 0.0.0.0 0.0.0.0 gre 1234 ipsec esp/transport//require;

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, GRE, 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. Its 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 ;

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).