1MISC_CONV(3) Linux-PAM Manual MISC_CONV(3)
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6 misc_conv - text based conversation function
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9 #include <security/pam_misc.h>
10 int misc_conv(int num_msg, const struct pam_message **msgm,
12 struct pam_response **response, void *appdata_ptr);
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15 The misc_conv function is part of libpam_misc and not of the standard
16 libpam library. This function will prompt the user with the appropriate
17 comments and obtain the appropriate inputs as directed by
18 authentication modules.
19 In addition to simply slotting into the appropriate pam_conv(3), this
21 function provides some time-out facilities. The function exports five
22 variables that can be used by an application programmer to limit the
23 amount of time this conversation function will spend waiting for the
24 user to type something. The five variables are as follows:
25 time_t pam_misc_conv_warn_time;
27 This variable contains the time (as returned by time(2)) that the
28 user should be first warned that the clock is ticking. By default
29 it has the value 0, which indicates that no such warning will be
30 given. The application may set its value to sometime in the future,
31 but this should be done prior to passing control to the Linux-PAM
32 library.
33 const char *pam_misc_conv_warn_line;
35 Used in conjunction with pam_misc_conv_warn_time, this variable is
36 a pointer to the string that will be displayed when it becomes time
37 to warn the user that the timeout is approaching. Its default value
38 is a translated version of “...Time is running out...”, but this
39 can be changed by the application prior to passing control to
40 Linux-PAM.
41 time_t pam_misc_conv_die_time;
43 This variable contains the time (as returned by time(2)) that the
44 will time out. By default it has the value 0, which indicates that
45 the conversation function will not timeout. The application may set
46 its value to sometime in the future, but this should be done prior
47 to passing control to the Linux-PAM library.
48 const char *pam_misc_conv_die_line;
50 Used in conjunction with pam_misc_conv_die_time, this variable is a
51 pointer to the string that will be displayed when the conversation
52 times out. Its default value is a translated version of “...Sorry,
53 your time is up!”, but this can be changed by the application prior
54 to passing control to Linux-PAM.
55 int pam_misc_conv_died;
57 Following a return from the Linux-PAM library, the value of this
58 variable indicates whether the conversation has timed out. A value
59 of 1 indicates the time-out occurred.
60 The following two function pointers are available for supporting binary
62 prompts in the conversation function. They are optimized for the
63 current incarnation of the libpamc library and are subject to change.
64 int (*pam_binary_handler_fn)(void *appdata, pamc_bp_t *prompt_p);
66 This function pointer is initialized to NULL but can be filled with
67 a function that provides machine-machine (hidden) message exchange.
68 It is intended for use with hidden authentication protocols such as
69 RSA or Diffie-Hellman key exchanges. (This is still under
70 development.)
71 int (*pam_binary_handler_free)(void *appdata, pamc_bp_t *delete_me);
73 This function pointer is initialized to PAM_BP_RENEW(delete_me, 0,
74 0), but can be redefined as desired by the application.
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77 pam_conv(3), pam(8)
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80 The misc_conv function is part of the libpam_misc Library and not
81 defined in any standard.
82Linux-PAM 05/07/2023 MISC_CONV(3)