1PWQUALITY(3) Libpwquality API Manual PWQUALITY(3)
2
6 pwquality - Documentation of the libpwquality API
7
9 #include <pwquality.h>
10 pwquality_settings_t *pwquality_default_settings(void);
12 void pwquality_free_settings(pwquality_settings_t *pwq);
13 int pwquality_read_config(pwquality_settings_t *pwq, const char *cfgfile,
15 void **auxerror);
16 int pwquality_set_option(pwquality_settings_t *pwq, const char *option);
18 int pwquality_set_int_value(pwquality_settings_t *pwq, int setting, int value);
19 int pwquality_set_str_value(pwquality_settings_t *pwq, int setting,
20 const char *value);
21 int pwquality_get_int_value(pwquality_settings_t *pwq, int setting, int *value);
22 int pwquality_get_str_value(pwquality_settings_t *pwq, int setting, const char **value);
23 int pwquality_generate(pwquality_settings_t *pwq, int entropy_bits,
25 char **password);
26 int pwquality_check(pwquality_settings_t *pwq, const char *password,
28 const char *oldpassword, const char *user, void **auxerror);
29 const char *pwquality_strerror(char *buf, size_t len, int errcode, void *auxerror);
31
33 Function pwquality_default_settings() allocates and returns default
34 pwquality settings to be used in other library calls. The allocated
35 opaque structure has to be freed with the pwquality_free_settings()
36 call.
37 The pwquality_read_config() parses the configuration file (if cfgfile
39 is NULL then the default one). If auxerror is not NULL it also possibly
40 returns auxiliary error information that must be passed into
41 pwquality_strerror() function.
42 New in 1.3.0:
44 The library first tries to parse all *.conf configuration files
45 from <cfgfile>.d directory if it exists. Order of parsing
46 determines what values will be in effect - the latest wins.
47 Function pwquality_set_option() is useful for setting the options as
49 configured on a pam module command line in form of opt=val.
50 Getter and setter functions for the individual integer and string
52 setting values are: pwquality_set_int_value(),
53 pwquality_set_str_value(), pwquality_get_int_value(), and
54 pwquality_get_str_value(). In case of the string getter the caller must
55 copy the string before another calls that can manipulate the pwq
56 settings object.
57 The pwquality_generate() function generates a random password of
59 entropy_bits entropy and checks it according to the settings. The
60 *password is allocated on the heap by the library. The entropy_bits
61 value is adjusted to fit within the PWQ_MIN_ENTROPY_BITS and
62 PWQ_MAX_ENTROPY_BITS range before generating a password.
63 The pwquality_check() function checks the password according to the
65 settings. It returns either score (value between 0 and 100), negative
66 error number, and possibly also auxiliary error information that must
67 be passed into the pwquality_strerror() function. The oldpassword is
68 optional and can be NULL. The user is used for checking the password
69 against the user name and potentially other passwd(5) information and
70 can be NULL. The auxerror can be NULL - in that case the auxiliary
71 error information is not returned. However if it is non-NULL not
72 passing the returned *auxerror into pwquality_strerror() can lead to
73 memory leaks.
74 The score of a password depends on the value of the setting
76 PWQ_SETTING_MIN_LENGTH. If it is set higher, the score for the same
77 passwords will be lower.
78 Function pwquality_strerror() translates the errcode and auxerror
80 auxiliary data into a localized text message. If buf is NULL the
81 function uses an internal static buffer which makes the function non-
82 reentrant in that case. The returned pointer is not guaranteed to point
83 to the buf. The function deallocates eventual auxerror data passed into
84 it, thus it must not be called twice with the same auxerror data.
85
87 In general the functions which return int return 0 as success value and
88 negative values as concrete PWQ_ERROR error code. pwquality_strerror()
89 does not allocate data and so it cannot fail.
90 The returned positive or zero score from pwquality_check() should not
92 be used for rejection of passwords, it should be used only as
93 approximate indicator of entropy present in the password with values
94 such as 0-30 being low, 30-60 medium, and 60-100 high.
95
97 Typical use of the libpwquality API:
98 #include <pwquality.h>
100 ...
102 pwquality_settings_t *pwq;
104 int rv;
105 void *auxerror;
106 char buf[PWQ_MAX_ERROR_MESSAGE_LEN];
107 pwq = pwquality_default_settings();
109 if (pwq == NULL) {
110 fprintf(stderr, "Error: %s\n", pwquality_strerror(buf, sizeof(buf), PWQ_ERROR_MEM_ALLOC, NULL));
111 return -1;
112 }
113 if ((rv=pwquality_read_config(pwq, NULL, &auxerror)) != 0) {
115 pwquality_free_settings(pwq);
116 fprintf(stderr, "Error: %s\n", pwquality_strerror(buf, sizeof(buf), rv, auxerror));
117 return -1;
118 }
119 rv = pwquality_check(pwq, buf, NULL, user, &auxerror);
121 pwquality_free_settings(pwq);
122 if (rv >= 0) {
124 fprintf(stderr, "Password entropy score is: %d\n", rv);
125 } else {
126 fprintf(stderr, "Password is rejected with error: %s\n", pwquality_strerror(buf, sizeof(buf), rv, auxerror));
127 }
128
130 pwquality.conf(5)
131
133 Tomas Mraz <tmraz@redhat.com>
134Red Hat, Inc. 2021-04-01 PWQUALITY(3)