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Diffstat (limited to 'doc/man/pam_conv.3')
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diff --git a/doc/man/pam_conv.3 b/doc/man/pam_conv.3 new file mode 100644 index 00000000..bf7ef3bf --- /dev/null +++ b/doc/man/pam_conv.3 @@ -0,0 +1,339 @@ +.\" Title: pam_conv +.\" Author: [FIXME: author] [see http://docbook.sf.net/el/author] +.\" Generator: DocBook XSL Stylesheets v1.74.0 <http://docbook.sf.net/> +.\" Date: 03/02/2009 +.\" Manual: Linux-PAM Manual +.\" Source: Linux-PAM Manual +.\" Language: English +.\" +.TH "PAM_CONV" "3" "03/02/2009" "Linux-PAM Manual" "Linux-PAM Manual" +.\" ----------------------------------------------------------------- +.\" * (re)Define some macros +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" toupper - uppercase a string (locale-aware) +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.de toupper +.tr aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ +\\$* +.tr aabbccddeeffgghhiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz +.. +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" SH-xref - format a cross-reference to an SH section +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.de SH-xref +.ie n \{\ +.\} +.toupper \\$* +.el \{\ +\\$* +.\} +.. +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" SH - level-one heading that works better for non-TTY output +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.de1 SH +.\" put an extra blank line of space above the head in non-TTY output +.if t \{\ +.sp 1 +.\} +.sp \\n[PD]u +.nr an-level 1 +.set-an-margin +.nr an-prevailing-indent \\n[IN] +.fi +.in \\n[an-margin]u +.ti 0 +.HTML-TAG ".NH \\n[an-level]" +.it 1 an-trap +.nr an-no-space-flag 1 +.nr an-break-flag 1 +\." make the size of the head bigger +.ps +3 +.ft B +.ne (2v + 1u) +.ie n \{\ +.\" if n (TTY output), use uppercase +.toupper \\$* +.\} +.el \{\ +.nr an-break-flag 0 +.\" if not n (not TTY), use normal case (not uppercase) +\\$1 +.in \\n[an-margin]u +.ti 0 +.\" if not n (not TTY), put a border/line under subheading +.sp -.6 +\l'\n(.lu' +.\} +.. +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" SS - level-two heading that works better for non-TTY output +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.de1 SS +.sp \\n[PD]u +.nr an-level 1 +.set-an-margin +.nr an-prevailing-indent \\n[IN] +.fi +.in \\n[IN]u +.ti \\n[SN]u +.it 1 an-trap +.nr an-no-space-flag 1 +.nr an-break-flag 1 +.ps \\n[PS-SS]u +\." make the size of the head bigger +.ps +2 +.ft B +.ne (2v + 1u) +.if \\n[.$] \&\\$* +.. +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" BB/BE - put background/screen (filled box) around block of text +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.de BB +.if t \{\ +.sp -.5 +.br +.in +2n +.ll -2n +.gcolor red +.di BX +.\} +.. +.de EB +.if t \{\ +.if "\\$2"adjust-for-leading-newline" \{\ +.sp -1 +.\} +.br +.di +.in +.ll +.gcolor +.nr BW \\n(.lu-\\n(.i +.nr BH \\n(dn+.5v +.ne \\n(BHu+.5v +.ie "\\$2"adjust-for-leading-newline" \{\ +\M[\\$1]\h'1n'\v'+.5v'\D'P \\n(BWu 0 0 \\n(BHu -\\n(BWu 0 0 -\\n(BHu'\M[] +.\} +.el \{\ +\M[\\$1]\h'1n'\v'-.5v'\D'P \\n(BWu 0 0 \\n(BHu -\\n(BWu 0 0 -\\n(BHu'\M[] +.\} +.in 0 +.sp -.5v +.nf +.BX +.in +.sp .5v +.fi +.\} +.. +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" BM/EM - put colored marker in margin next to block of text +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.de BM +.if t \{\ +.br +.ll -2n +.gcolor red +.di BX +.\} +.. +.de EM +.if t \{\ +.br +.di +.ll +.gcolor +.nr BH \\n(dn +.ne \\n(BHu +\M[\\$1]\D'P -.75n 0 0 \\n(BHu -(\\n[.i]u - \\n(INu - .75n) 0 0 -\\n(BHu'\M[] +.in 0 +.nf +.BX +.in +.fi +.\} +.. +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "Name" +pam_conv \- PAM conversation function +.SH "Synopsis" +.sp +.ft B +.fam C +.ps -1 +.nf +#include <security/pam_appl\&.h> +.fi +.fam +.ps +1 +.ft +.sp +.fam C +.ps -1 +.nf +struct pam_message { + int msg_style; + const char *msg; +}; + +struct pam_response { + char *resp; + int resp_retcode; +}; + +struct pam_conv { + int (*conv)(int num_msg, const struct pam_message **msg, + struct pam_response **resp, void *appdata_ptr); + void *appdata_ptr; +}; + +.fi +.fam +.ps +1 +.SH "DESCRIPTION" +.PP +The PAM library uses an application\-defined callback to allow a direct communication between a loaded module and the application\&. This callback is specified by the +\fIstruct pam_conv\fR +passed to +\fBpam_start\fR(3) +at the start of the transaction\&. +.PP +When a module calls the referenced conv() function, the argument +\fIappdata_ptr\fR +is set to the second element of this structure\&. +.PP +The other arguments of a call to conv() concern the information exchanged by module and application\&. That is to say, +\fInum_msg\fR +holds the length of the array of pointers, +\fImsg\fR\&. After a successful return, the pointer +\fIresp\fR +points to an array of pam_response structures, holding the application supplied text\&. The +\fIresp_retcode\fR +member of this struct is unused and should be set to zero\&. It is the caller\'s responsibility to release both, this array and the responses themselves, using +\fBfree\fR(3)\&. Note, +\fI*resp\fR +is a +\fIstruct pam_response\fR +array and not an array of pointers\&. +.PP +The number of responses is always equal to the +\fInum_msg\fR +conversation function argument\&. This does require that the response array is +\fBfree\fR(3)\'d after every call to the conversation function\&. The index of the responses corresponds directly to the prompt index in the pam_message array\&. +.PP +On failure, the conversation function should release any resources it has allocated, and return one of the predefined PAM error codes\&. +.PP +Each message can have one of four types, specified by the +\fImsg_style\fR +member of +\fIstruct pam_message\fR: +.PP +PAM_PROMPT_ECHO_OFF +.RS 4 +Obtain a string without echoing any text\&. +.RE +.PP +PAM_PROMPT_ECHO_ON +.RS 4 +Obtain a string whilst echoing text\&. +.RE +.PP +PAM_ERROR_MSG +.RS 4 +Display an error message\&. +.RE +.PP +PAM_TEXT_INFO +.RS 4 +Display some text\&. +.RE +.PP +The point of having an array of messages is that it becomes possible to pass a number of things to the application in a single call from the module\&. It can also be convenient for the application that related things come at once: a windows based application can then present a single form with many messages/prompts on at once\&. +.PP +In passing, it is worth noting that there is a descrepency between the way Linux\-PAM handles the const struct pam_message **msg conversation function argument from the way that Solaris\' PAM (and derivitives, known to include HP/UX, are there others?) does\&. Linux\-PAM interprets the msg argument as entirely equivalent to the following prototype const struct pam_message *msg[] (which, in spirit, is consistent with the commonly used prototypes for argv argument to the familiar main() function: char **argv; and char *argv[])\&. Said another way Linux\-PAM interprets the msg argument as a pointer to an array of num_msg read only \'struct pam_message\' pointers\&. Solaris\' PAM implementation interprets this argument as a pointer to a pointer to an array of num_msg pam_message structures\&. Fortunately, perhaps, for most module/application developers when num_msg has a value of one these two definitions are entirely equivalent\&. Unfortunately, casually raising this number to two has led to unanticipated compatibility problems\&. +.PP +For what its worth the two known module writer work\-arounds for trying to maintain source level compatibility with both PAM implementations are: +.sp +.RS 4 +.ie n \{\ +\h'-04'\(bu\h'+03'\c +.\} +.el \{\ +.sp -1 +.IP \(bu 2.3 +.\} +never call the conversation function with num_msg greater than one\&. +.RE +.sp +.RS 4 +.ie n \{\ +\h'-04'\(bu\h'+03'\c +.\} +.el \{\ +.sp -1 +.IP \(bu 2.3 +.\} +set up msg as doubly referenced so both types of conversation function can find the messages\&. That is, make +.sp +.if n \{\ +.RS 4 +.\} +.fam C +.ps -1 +.nf +.if t \{\ +.sp -1 +.\} +.BB lightgray adjust-for-leading-newline +.sp -1 + + msg[n] = & (( *msg )[n]) + +.EB lightgray adjust-for-leading-newline +.if t \{\ +.sp 1 +.\} +.fi +.fam +.ps +1 +.if n \{\ +.RE +.\} +.RE +.SH "RETURN VALUES" +.PP +PAM_BUF_ERR +.RS 4 +Memory buffer error\&. +.RE +.PP +PAM_CONV_ERR +.RS 4 +Conversation failure\&. The application should not set +\fI*resp\fR\&. +.RE +.PP +PAM_SUCCESS +.RS 4 +Success\&. +.RE +.SH "SEE ALSO" +.PP + +\fBpam_start\fR(3), +\fBpam_set_item\fR(3), +\fBpam_get_item\fR(3), +\fBpam_strerror\fR(3), +\fBpam\fR(8) |