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pam_fail_delay - ???顼?????ٱ????׵?

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#include <security/pam_appl.h>
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#include <security/pam_modules.h>

int pam_fail_delay(pam_handle_t *pamh, unsigned int usec);

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?????桼???Υ????????򥹥????ब???ݤ????????ˤ????????֤????Ѥ??뤳?Ȥǡ? ???Ф???ǧ?ڥ????????˹?????ǽ?Ǥ??? ?????ॢ???Ȥ? û?? ???硢 ???Ϥˤ??? ???񹶷⤬??ǽ?ʾ??礬?????ޤ??? ??ư?????ˤ????ͤ????????ѥ???ɤ򤹤٤ƻ?ơ??????Ԥ??????ƥ??? ???????????褦?Ȥ????ΤǤ??? ???????ġ??μ??Ԥ? (???Ԥ??????򼨤??褦??) ??¬??ǽ?ʻ??֤??񤹾??硢 ǧ?ڽ????˴ؤ???ͭ?Ѥʾ????򹶷??Ԥ???????ǽ?Ǥ??? ???Ԥι????ϡ????פʾ????? ?????̿?ϩ (covert channel) ?Ǥ??롢??³???ٱ??????Ѥ??뤳?ȤǤ???

???Τ褦?ʹ????θ??̤??????¤??ޤ????ˤϡ????顼?Ȥʤä?ǧ?ڥץ??????? ???????????ٱ???Ƴ?????뤳?Ȥ?ͭ???Ǥ??? PAM ?ˤϡ????????????ٱ???Ƴ?????뵡ǽ???????ޤ????ٱ??ϡ? pam_authenticate(3) ?ؿ??? pam_chauthtok(3) ?ؿ??? ???顼????ȯ?????ޤ??????٤Ƥ?ǧ?ڥ⥸?塼?뤬?ƤӽФ??줿 ?? ?ǡ????椬?????ӥ????ץꥱ?????????????? ?? ??ȯ?????ޤ???

pam_fail_delay(3) ?ؿ??????Ѥ????ȡ????顼?ٱ???ɬ?פʺ??????? ( usec ????) ???????Ǥ??ޤ??????δؿ??ϡ??桼???ˤ??륵???ӥ??κƿ????? ?٤餻?뤳?Ȥ????פȤʤ륵???ӥ????ץꥱ??????????ǧ?ڥ⥸?塼?뤫???Ƥ? ?Ф??ޤ????ٱ???Ĺ????ɬ?פʤȤ??˻??Ф????ޤ??? Ĺ???ϡ? ???? ?׵??ͤ??Ф??뵼????????????ʬ?ۤˤʤ??ޤ??? ?????׵??ͤξ岼 25% ?ޤǤ?ʬ?????????ΤǤ???

pam_authenticate(3) ?? pam_chauthtok(3) ???????????硢??????̵ͭ?˴ط??ʤ??????????׵??ٱ??? ?ǥե??????ͤ? 0 ?˥ꥻ?åȤ????ޤ???

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???????? ???ץꥱ???????????? 3 ?ô֤Υ??顼?ٱ䤬ɬ?פȤʤ????硢 ???Υ??ץꥱ?????????ˤϰʲ??Υ????ɤ??ޤޤ??ޤ???

pam_fail_delay(pamh, 3000000 /* micro-seconds */ );
pam_authenticate(pamh, 0);

?⥸?塼?뤬?ٱ????׵ᤷ?ʤ????硢???顼?ٱ??? 2.25 ?ä? 3.75 ?ä? ?֤ˤʤ??ޤ???

ǧ?ڥץ??????ǸƤӽФ??????⥸?塼???Ǥ⡢?ʲ??Τ褦???ٱ䤬 ?׵ᤵ???뤳?Ȥ??????ޤ???

(?⥸?塼?? #1) pam_fail_delay(pamh, 2000000);

(?⥸?塼?? #2) pam_fail_delay(pamh, 4000000);

???ξ??硢?ºݤΥ??顼?ٱ??λ??Ф˻??Ѥ??????ΤϺ????׵??ͤǤ??? ?????Ǥ? 3 ?ä??? 5 ?äǤ???

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pam_fail_delay(3) ?????꤬ȯ?????ʤ??ä??????ϡ? PAM_SUC-CESS ???ᤵ???ޤ???????¾???٤Ƥ??????ͤϡ??????ʥ??顼?Ȥߤʤ??Ƥ?????????

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pam_strerror(3) ?ǥƥ????Ȥ??Ѵ??Ǥ??ޤ???

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X/Open ???롼?פ???PAM RFC. 1996/1/10 ???Ȥ߹??ळ?Ȥ???Ƥ???Ǥ???

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pam_start(3), pam_get_item(3), pam_strerror(3)

?????ƥ??????? ?? ?⥸?塼?볫ȯ?? ?? ???ץꥱ??????????ȯ?? ?Ѥ? Linux-PAM ?????ɤ⻲?Ȥ??Ƥ?????????