1UPDATE-CRYPTO-POLI(8) UPDATE-CRYPTO-POLI(8)
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6 update-crypto-policies - manage the policies available to the various
7 cryptographic back-ends.
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10 update-crypto-policies [COMMAND]
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13 update-crypto-policies(8) is used to set the policy applicable for the
14 various cryptographic back-ends, such as SSL/TLS libraries. That will
15 be the default policy used by these back-ends unless the application
16 user configures them otherwise.
17 The available policies are described in the crypto-policies(7) manual
19 page.
20 The desired system policy is selected in /etc/crypto-policies/config
22 and this tool will generate the individual policy requirements for all
23 back-ends that support such configuration. After this tool is called
24 the administrator is assured that any application that utilizes the
25 supported back-ends will follow a policy that adheres to the configured
26 profile.
27 Note that the above assurance does apply to the extent that
29 applications are configured to follow the default policy (the details
30 vary on the back-end, see below for more information).
31 The generated back-end policies will be placed in
33 /etc/crypto-policies/back-ends. Currently the supported back-ends are:
34 · GnuTLS library
36 · OpenSSL library
38 · NSS library
40 · OpenJDK
42 · Libkrb5
44 · BIND
46 · OpenSSH
48 · Libreswan
50 Applications and languages which rely on any of these back-ends will
52 follow the system policies as well. Examples are apache httpd, nginx,
53 php, and others.
54 In general after changing the system crypto policies with the
56 update-crypto-policies --set command it is recommended to restart the
57 system for the effect to fully take place as the policy configuration
58 files are loaded on application start-up. Otherwise applications
59 started before the command was run need to be restarted to load the
60 updated configuration.
61
63 The following commands are available in update-crypto-policies tool.
64 · --show: Shows the currently applied crypto policy
66 · --is-applied: Returns success if the currently configured policy is
68 already applied.
69 · --set: Sets the current policy and overwrites the config file.
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73 The following options are available in update-crypto-policies tool.
74 · --no-check: By default this tool does a sanity check on whether the
76 configured policy is accepted by the supported tools. This option
77 disables those checks.
78 · --no-reload: By default this tool causes some running applications
80 to reload the configured policy. This option skips the reloading.
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83 Applications in the operating system that provide a default
84 configuration file that includes a cryptographic policy string will be
85 modified gradually to support these policies.
86 When an application provides a configuration file, the changes needed
88 to utilize the system-wide policy are the following.
89 · Applications using GnuTLS: If an application allows the
91 configuration of cipher priotities via a string, the special
92 priority string "@SYSTEM" should replace any other priority string.
93 Applications which use the default library settings automatically
94 adhere to the policy. Applications following the policy inherit the
95 settings for cipher suite preference, TLS and DTLS protocol
96 versions, allowed elliptic curves, and limits for cryptographic
97 keys.
98 · Applications using OpenSSL: If an application allows the
100 configuration of ciphersuite string, the special cipher string
101 "PROFILE=SYSTEM" should replace any other cipher string.
102 Applications which use the default library settings automatically
103 adhere to the policy. Applications following the policy inherit the
104 settings for cipher suite preference. By default the OpenSSL
105 library reads a configuration file when it is initialized. If the
106 applicaton does not override loading of the configuration file, the
107 policy also sets the minimum TLS protocol version and default
108 cipher suite preference via this file. If the application is
109 long-running such as the httpd server it has to be restarted to
110 reload the configuration file after policy is changed. Otherwise
111 the changed policy cannot take effect.
112 · Applications using NSS: Applications using NSS will load the crypto
114 policies by default. They inherit the settings for cipher suite
115 preference, TLS and DTLS protocol versions, allowed elliptic
116 curves, and limits for cryptographic keys. Note that unlike OpenSSL
117 and GnuTLS, the NSS policy is enforced by default; to prevent
118 applications from adhering to the policy the
119 NSS_IGNORE_SYSTEM_POLICY environment variable must be set to 1
120 prior to executing that application.
121 · Applications using Java: No special treatment is required.
123 Applications using Java will load the crypto policies by default.
124 These applications will then inherit the settings for allowed
125 cipher suites, allowed TLS and DTLS protocol versions, allowed
126 elliptic curves, and limits for cryptographic keys. To prevent
127 openjdk applications from adhering to the policy the
128 <java.home>/jre/lib/security/java.security file should be edited to
129 contain security.useSystemPropertiesFile=false. Alternatively one
130 can create a file containing the overridden values for
131 jdk.tls.disabledAlgorithms, jdk.certpath.disabledAlgorithms and
132 pass the location of that file to Java on the command line using
133 the -Djava.security.properties=<path to file>.
134 · Applications using libkrb5: No special treatment is required.
136 Applications will follow the crypto policies by default. These
137 applications inherit the settings for the permitted encryption
138 types for tickets as well as the cryptographic key limits for the
139 PKINIT protocol. A system-wide opt-out is available by deleting the
140 /etc/krb5.conf.d/crypto-policies link.
141 · BIND: This application inherits the set of blacklisted algorithms.
143 To opt-out from the policy, remove the policy include directive in
144 the named.conf file.
145 · OpenSSH: Both server and client application inherits the cipher
147 preferences, the key exchange algorithms as well as the GSSAPI key
148 exchange algorithms. To opt-out from the policy for client,
149 override the global ssh_config with a user-specific configuration
150 in ~/.ssh/config. See ssh_config(5) for more information. To
151 opt-out from the policy for server, uncomment the line containing
152 CRYPTO_POLICY= in /etc/sysconfig/sshd .
153 · Libreswan: Both servers and clients inherit the ESP and IKE
155 preferences, if they are not overriden in the connection
156 configuration file. Note that due to limitations of libreswan,
157 crypto policies is restricted to supporting IKEv2. To opt-out from
158 the policy, comment the line including
159 /etc/crypto-policies/back-ends/libreswan.config from
160 /etc/ipsec.conf.
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163 One of the supported profiles should be set in
164 /etc/crypto-policies/config and this script should be run afterwards.
165 In case of a parsing error no policies will be updated.
167
169 /etc/crypto-policies/config
170 The file contains the current system policy. It should contain a
171 string of one of the profiles listed in the crypto-policies(7) page
172 (e.g., DEFAULT).
173 /etc/crypto-policies/back-ends
175 Contains the generated policies in separated files, and in a format
176 readable by the supported back ends.
177 /etc/crypto-policies/local.d
179 Contains additional files to be appended to the generated policy
180 files. The files present must adhere to $app-XXX.config file
181 naming, where XXX is any arbitrary identifier. For example, to
182 append a line to GnuTLS' generated policy, create a
183 gnutls-extra-line.config file in local.d. This will be appended to
184 the generated gnutls.config during update-crypto-policies. These
185 overrides, are only functional for the gnutls, bind, java (openjdk)
186 and krb5 back-ends.
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189 crypto-policies(7), fips-mode-setup(8)
190
192 Written by Nikos Mavrogiannopoulos.
193update-crypto-policies 05/27/2019 UPDATE-CRYPTO-POLI(8)