path: root/secure/lib/libcrypto/man/man3/RAND_DRBG_set_callbacks.3
diff options
authorJung-uk Kim <jkim@FreeBSD.org>2020-02-21 00:33:21 +0000
committerJung-uk Kim <jkim@FreeBSD.org>2020-02-21 00:33:21 +0000
commit6b4382c4054d7c169c6140feaa144ca360a90ead (patch)
tree176bf7fdbae226099058e11e9a429805b6e0af42 /secure/lib/libcrypto/man/man3/RAND_DRBG_set_callbacks.3
parent24722aacdb06a5ac6780beef7db856a0f99095c3 (diff)
MFC: r356963
Install man5 and man7 for OpenSSL.
Notes: svn path=/stable/12/; revision=358188
Diffstat (limited to 'secure/lib/libcrypto/man/man3/RAND_DRBG_set_callbacks.3')
1 files changed, 268 insertions, 0 deletions
diff --git a/secure/lib/libcrypto/man/man3/RAND_DRBG_set_callbacks.3 b/secure/lib/libcrypto/man/man3/RAND_DRBG_set_callbacks.3
new file mode 100644
index 000000000000..49a765968ceb
--- /dev/null
+++ b/secure/lib/libcrypto/man/man3/RAND_DRBG_set_callbacks.3
@@ -0,0 +1,268 @@
+.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.39)
+.\" Standard preamble:
+.\" ========================================================================
+.de Sp \" Vertical space (when we can't use .PP)
+.if t .sp .5v
+.if n .sp
+.de Vb \" Begin verbatim text
+.ft CW
+.ne \\$1
+.de Ve \" End verbatim text
+.ft R
+.\" Set up some character translations and predefined strings. \*(-- will
+.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
+.\" double quote, and \*(R" will give a right double quote. \*(C+ will
+.\" give a nicer C++. Capital omega is used to do unbreakable dashes and
+.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
+.\" nothing in troff, for use with C<>.
+.tr \(*W-
+.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
+.ie n \{\
+. ds -- \(*W-
+. ds PI pi
+. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
+. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
+. ds L" ""
+. ds R" ""
+. ds C` ""
+. ds C' ""
+. ds -- \|\(em\|
+. ds PI \(*p
+. ds L" ``
+. ds R" ''
+. ds C`
+. ds C'
+.\" Escape single quotes in literal strings from groff's Unicode transform.
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" If the F register is >0, we'll generate index entries on stderr for
+.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
+.\" entries marked with X<> in POD. Of course, you'll have to process the
+.\" output yourself in some meaningful fashion.
+.\" Avoid warning from groff about undefined register 'F'.
+.de IX
+.nr rF 0
+.if \n(.g .if rF .nr rF 1
+.if (\n(rF:(\n(.g==0)) \{\
+. if \nF \{\
+. de IX
+. tm Index:\\$1\t\\n%\t"\\$2"
+. if !\nF==2 \{\
+. nr % 0
+. nr F 2
+. \}
+. \}
+.rr rF
+.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
+.\" Fear. Run. Save yourself. No user-serviceable parts.
+. \" fudge factors for nroff and troff
+.if n \{\
+. ds #H 0
+. ds #V .8m
+. ds #F .3m
+. ds #[ \f1
+. ds #] \fP
+.if t \{\
+. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
+. ds #V .6m
+. ds #F 0
+. ds #[ \&
+. ds #] \&
+. \" simple accents for nroff and troff
+.if n \{\
+. ds ' \&
+. ds ` \&
+. ds ^ \&
+. ds , \&
+. ds ~ ~
+. ds /
+.if t \{\
+. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
+. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
+. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
+. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
+. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
+. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
+. \" troff and (daisy-wheel) nroff accents
+.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
+.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
+.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
+.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
+.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
+.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
+.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
+.ds ae a\h'-(\w'a'u*4/10)'e
+.ds Ae A\h'-(\w'A'u*4/10)'E
+. \" corrections for vroff
+.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
+.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
+. \" for low resolution devices (crt and lpr)
+.if \n(.H>23 .if \n(.V>19 \
+. ds : e
+. ds 8 ss
+. ds o a
+. ds d- d\h'-1'\(ga
+. ds D- D\h'-1'\(hy
+. ds th \o'bp'
+. ds Th \o'LP'
+. ds ae ae
+. ds Ae AE
+.rm #[ #] #H #V #F C
+.\" ========================================================================
+.TH RAND_DRBG_SET_CALLBACKS 3 "2019-09-10" "1.1.1d" "OpenSSL"
+.\" For nroff, turn off justification. Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+RAND_DRBG_set_callbacks, RAND_DRBG_get_entropy_fn, RAND_DRBG_cleanup_entropy_fn, RAND_DRBG_get_nonce_fn, RAND_DRBG_cleanup_nonce_fn \&\- set callbacks for reseeding
+.IX Header "SYNOPSIS"
+.Vb 1
+\& #include <openssl/rand_drbg.h>
+\& int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
+\& RAND_DRBG_get_entropy_fn get_entropy,
+\& RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
+\& RAND_DRBG_get_nonce_fn get_nonce,
+\& RAND_DRBG_cleanup_nonce_fn cleanup_nonce);
+.SS "Callback Functions"
+.IX Subsection "Callback Functions"
+.Vb 6
+\& typedef size_t (*RAND_DRBG_get_entropy_fn)(
+\& RAND_DRBG *drbg,
+\& unsigned char **pout,
+\& int entropy,
+\& size_t min_len, size_t max_len,
+\& int prediction_resistance);
+\& typedef void (*RAND_DRBG_cleanup_entropy_fn)(
+\& RAND_DRBG *drbg,
+\& unsigned char *out, size_t outlen);
+\& typedef size_t (*RAND_DRBG_get_nonce_fn)(
+\& RAND_DRBG *drbg,
+\& unsigned char **pout,
+\& int entropy,
+\& size_t min_len, size_t max_len);
+\& typedef void (*RAND_DRBG_cleanup_nonce_fn)(
+\& RAND_DRBG *drbg,
+\& unsigned char *out, size_t outlen);
+\&\fBRAND_DRBG_set_callbacks()\fR sets the callbacks for obtaining fresh entropy and
+the nonce when reseeding the given \fBdrbg\fR.
+The callback functions are implemented and provided by the caller.
+Their parameter lists need to match the function prototypes above.
+Setting the callbacks is allowed only if the \s-1DRBG\s0 has not been initialized yet.
+Otherwise, the operation will fail.
+To change the settings for one of the three shared DRBGs it is necessary to call
+\&\fBRAND_DRBG_uninstantiate()\fR first.
+The \fBget_entropy\fR() callback is called by the \fBdrbg\fR when it requests fresh
+random input.
+It is expected that the callback allocates and fills a random buffer of size
+\&\fBmin_len\fR <= size <= \fBmax_len\fR (in bytes) which contains at least \fBentropy\fR
+bits of randomness.
+The \fBprediction_resistance\fR flag indicates whether the reseeding was
+triggered by a prediction resistance request.
+The buffer's address is to be returned in *\fBpout\fR and the number of collected
+randomness bytes as return value.
+If the callback fails to acquire at least \fBentropy\fR bits of randomness,
+it must indicate an error by returning a buffer length of 0.
+If \fBprediction_resistance\fR was requested and the random source of the \s-1DRBG\s0
+does not satisfy the conditions requested by [\s-1NIST SP 800\-90C\s0], then
+it must also indicate an error by returning a buffer length of 0.
+See \s-1NOTES\s0 section for more details.
+The \fBcleanup_entropy\fR() callback is called from the \fBdrbg\fR to to clear and
+free the buffer allocated previously by \fBget_entropy()\fR.
+The values \fBout\fR and \fBoutlen\fR are the random buffer's address and length,
+as returned by the \fBget_entropy()\fR callback.
+The \fBget_nonce\fR() and \fBcleanup_nonce\fR() callbacks are used to obtain a nonce
+and free it again. A nonce is only required for instantiation (not for reseeding)
+and only in the case where the \s-1DRBG\s0 uses a derivation function.
+The callbacks are analogous to \fBget_entropy()\fR and \fBcleanup_entropy()\fR,
+except for the missing prediction_resistance flag.
+If the derivation function is disabled, then no nonce is used for instantiation,
+and the \fBget_nonce\fR() and \fBcleanup_nonce\fR() callbacks can be omitted by
+setting them to \s-1NULL.\s0
+\&\fBRAND_DRBG_set_callbacks()\fR return 1 on success, and 0 on failure
+.IX Header "NOTES"
+It is important that \fBcleanup_entropy\fR() and \fBcleanup_nonce\fR() clear the buffer
+contents safely before freeing it, in order not to leave sensitive information
+about the \s-1DRBG\s0's state in memory.
+A request for prediction resistance can only be satisfied by pulling fresh
+entropy from one of the approved entropy sources listed in section 5.5.2 of
+[\s-1NIST SP 800\-90C\s0].
+Since the default implementation of the get_entropy callback does not have access
+to such an approved entropy source, a request for prediction resistance will
+always fail.
+In other words, prediction resistance is currently not supported yet by the \s-1DRBG.\s0
+The derivation function is disabled during initialization by calling the
+\&\fBRAND_DRBG_set()\fR function with the \s-1RAND_DRBG_FLAG_CTR_NO_DF\s0 flag.
+For more information on the derivation function and when it can be omitted,
+see [\s-1NIST SP 800\-90A\s0 Rev. 1]. Roughly speaking it can be omitted if the random
+source has \*(L"full entropy\*(R", i.e., contains 8 bits of entropy per byte.
+Even if a nonce is required, the \fBget_nonce\fR() and \fBcleanup_nonce\fR()
+callbacks can be omitted by setting them to \s-1NULL.\s0
+In this case the \s-1DRBG\s0 will automatically request an extra amount of entropy
+(using the \fBget_entropy\fR() and \fBcleanup_entropy\fR() callbacks) which it will
+utilize for the nonce, following the recommendations of [\s-1NIST SP 800\-90A\s0 Rev. 1],
+section 8.6.7.
+.IX Header "SEE ALSO"
+.IX Header "HISTORY"
+The \s-1RAND_DRBG\s0 functions were added in OpenSSL 1.1.1.
+Copyright 2017\-2019 The OpenSSL Project Authors. All Rights Reserved.
+Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use
+this file except in compliance with the License. You can obtain a copy
+in the file \s-1LICENSE\s0 in the source distribution or at