NAME¶
setkey —
manually manipulate the IPsec
SA/SP database
SYNOPSIS¶
setkey |
[-krv] -f
filename |
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 ;
SEE ALSO¶
ipsec_set_policy(3),
racoon(8),
sysctl(8)
Changed manual key configuration for
IPsec,
http://www.kame.net/newsletter/19991007/,
October 1999.
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).