X-Git-Url: https://gitweb.dragonflybsd.org/~nant/dragonfly.git/blobdiff_plain/061051cd1ed7ae7a5cd792cb3d903b60492ba7f5..e056f0e078e2d15643b32cec492df270f88b9a17:/secure/lib/libssl/man/SSL_CTX_set_tmp_dh_callback.3 diff --git a/secure/lib/libssl/man/SSL_CTX_set_tmp_dh_callback.3 b/secure/lib/libssl/man/SSL_CTX_set_tmp_dh_callback.3 index 6a45291dd8..2adb53d0e0 100644 --- a/secure/lib/libssl/man/SSL_CTX_set_tmp_dh_callback.3 +++ b/secure/lib/libssl/man/SSL_CTX_set_tmp_dh_callback.3 @@ -1,9 +1,8 @@ -.rn '' }` -''' $RCSfile$$Revision$$Date$ -''' -''' $Log$ -''' -.de Sh +.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.14 +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sh \" Subsection heading .br .if t .Sp .ne 5 @@ -11,150 +10,98 @@ \fB\\$1\fR .PP .. -.de Sp +.de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. -.de Ip -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb +.de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. -.de Ve +.de Ve \" End verbatim text .ft R - .fi .. -''' -''' -''' Set up \*(-- to give an unbreakable dash; -''' string Tr holds user defined translation string. -''' Bell System Logo is used as a dummy character. -''' +.\" 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. | will give a +.\" real vertical bar. \*(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-|\(bv\*(Tr +.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" "" -''' \*(M", \*(S", \*(N" and \*(T" are the equivalent of -''' \*(L" and \*(R", except that they are used on ".xx" lines, -''' such as .IP and .SH, which do another additional levels of -''' double-quote interpretation -.ds M" """ -.ds S" """ -.ds N" """"" -.ds T" """"" -.ds L' ' -.ds R' ' -.ds M' ' -.ds S' ' -.ds N' ' -.ds T' ' +. 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' "" 'br\} .el\{\ -.ds -- \(em\| -.tr \*(Tr -.ds L" `` -.ds R" '' -.ds M" `` -.ds S" '' -.ds N" `` -.ds T" '' -.ds L' ` -.ds R' ' -.ds M' ` -.ds S' ' -.ds N' ` -.ds T' ' -.ds PI \(*p +. ds -- \|\(em\| +. ds PI \(*p +. ds L" `` +. ds R" '' 'br\} -.\" If the F register is turned on, we'll generate -.\" index entries out stderr for the following things: -.\" TH Title -.\" SH Header -.\" Sh Subsection -.\" Ip Item -.\" X<> Xref (embedded -.\" Of course, you have to process the output yourself -.\" in some meaninful fashion. -.if \nF \{ -.de IX -.tm Index:\\$1\t\\n%\t"\\$2" +.\" +.\" If the F register is turned on, we'll generate index entries on stderr for +.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index +.\" entries marked with X<> in POD. Of course, you'll have to process the +.\" output yourself in some meaningful fashion. +.if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" .. -.nr % 0 -.rr F +. nr % 0 +. rr F .\} -.TH SSL_CTX_set_tmp_dh_callback 3 "0.9.7d" "2/Sep/2004" "OpenSSL" -.UC -.if n .hy 0 +.\" +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.hy 0 .if n .na -.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' -.de CQ \" put $1 in typewriter font -.ft CW -'if n "\c -'if t \\&\\$1\c -'if n \\&\\$1\c -'if n \&" -\\&\\$2 \\$3 \\$4 \\$5 \\$6 \\$7 -'.ft R -.. -.\" @(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2 -. \" AM - accent mark definitions -.bd B 3 -. \" fudge factors for nroff and troff +.\" +.\" 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 +. 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 #] \& +. ds #H ((1u-(\\\\n(.fu%2u))*.13m) +. ds #V .6m +. ds #F 0 +. ds #[ \& +. ds #] \& .\} -. \" simple accents for nroff and troff +. \" simple accents for nroff and troff .if n \{\ -. ds ' \& -. ds ` \& -. ds ^ \& -. ds , \& -. ds ~ ~ -. ds ? ? -. ds ! ! -. ds / -. ds q +. 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 ? \s-2c\h'-\w'c'u*7/10'\u\h'\*(#H'\zi\d\s+2\h'\w'c'u*8/10' -. ds ! \s-2\(or\s+2\h'-\w'\(or'u'\v'-.8m'.\v'.8m' -. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' -. ds q o\h'-\w'o'u*8/10'\s-4\v'.4m'\z\(*i\v'-.4m'\s+4\h'\w'o'u*8/10' +. 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 +. \" 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 v \\k:\h'-(\\n(.wu*9/10-\*(#H)'\v'-\*(#V'\*(#[\s-4v\s0\v'\*(#V'\h'|\\n:u'\*(#] -.ds _ \\k:\h'-(\\n(.wu*9/10-\*(#H+(\*(#F*2/3))'\v'-.4m'\z\(hy\v'.4m'\h'|\\n:u' -.ds . \\k:\h'-(\\n(.wu*8/10)'\v'\*(#V*4/10'\z.\v'-\*(#V*4/10'\h'|\\n:u' -.ds 3 \*(#[\v'.2m'\s-2\&3\s0\v'-.2m'\*(#] .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' @@ -162,131 +109,133 @@ .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 -.ds oe o\h'-(\w'o'u*4/10)'e -.ds Oe O\h'-(\w'O'u*4/10)'E -. \" corrections for vroff +. \" 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) +. \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ -. ds : e -. ds 8 ss -. ds v \h'-1'\o'\(aa\(ga' -. ds _ \h'-1'^ -. ds . \h'-1'. -. ds 3 3 -. 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 -. ds oe oe -. ds Oe OE +. 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 +.\" ======================================================================== +.\" +.IX Title "SSL_CTX_set_tmp_dh_callback 3" +.TH SSL_CTX_set_tmp_dh_callback 3 "2004-12-22" "0.9.7e" "OpenSSL" .SH "NAME" SSL_CTX_set_tmp_dh_callback, SSL_CTX_set_tmp_dh, SSL_set_tmp_dh_callback, SSL_set_tmp_dh \- handle DH keys for ephemeral key exchange .SH "SYNOPSIS" -.PP +.IX Header "SYNOPSIS" .Vb 1 \& #include .Ve +.PP .Vb 3 \& void SSL_CTX_set_tmp_dh_callback(SSL_CTX *ctx, \& DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength)); \& long SSL_CTX_set_tmp_dh(SSL_CTX *ctx, DH *dh); .Ve +.PP .Vb 3 \& void SSL_set_tmp_dh_callback(SSL_CTX *ctx, \& DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength)); \& long SSL_set_tmp_dh(SSL *ssl, DH *dh) .Ve +.PP .Vb 1 \& DH *(*tmp_dh_callback)(SSL *ssl, int is_export, int keylength)); .Ve .SH "DESCRIPTION" -\fISSL_CTX_set_tmp_dh_callback()\fR sets the callback function for \fBctx\fR to be -used when a DH parameters are required to \fBtmp_dh_callback\fR. +.IX Header "DESCRIPTION" +\&\fISSL_CTX_set_tmp_dh_callback()\fR sets the callback function for \fBctx\fR to be +used when a \s-1DH\s0 parameters are required to \fBtmp_dh_callback\fR. The callback is inherited by all \fBssl\fR objects created from \fBctx\fR. .PP -\fISSL_CTX_set_tmp_dh()\fR sets DH parameters to be used to be \fBdh\fR. +\&\fISSL_CTX_set_tmp_dh()\fR sets \s-1DH\s0 parameters to be used to be \fBdh\fR. The key is inherited by all \fBssl\fR objects created from \fBctx\fR. .PP -\fISSL_set_tmp_dh_callback()\fR sets the callback only for \fBssl\fR. +\&\fISSL_set_tmp_dh_callback()\fR sets the callback only for \fBssl\fR. .PP -\fISSL_set_tmp_dh()\fR sets the parameters only for \fBssl\fR. +\&\fISSL_set_tmp_dh()\fR sets the parameters only for \fBssl\fR. .PP -These functions apply to SSL/TLS servers only. +These functions apply to \s-1SSL/TLS\s0 servers only. .SH "NOTES" -When using a cipher with RSA authentication, an ephemeral DH key exchange -can take place. Ciphers with DSA keys always use ephemeral DH keys as well. +.IX Header "NOTES" +When using a cipher with \s-1RSA\s0 authentication, an ephemeral \s-1DH\s0 key exchange +can take place. Ciphers with \s-1DSA\s0 keys always use ephemeral \s-1DH\s0 keys as well. In these cases, the session data are negotiated using the -ephemeral/temporary DH key and the key supplied and certified +ephemeral/temporary \s-1DH\s0 key and the key supplied and certified by the certificate chain is only used for signing. -Anonymous ciphers (without a permanent server key) also use ephemeral DH keys. +Anonymous ciphers (without a permanent server key) also use ephemeral \s-1DH\s0 keys. .PP -Using ephemeral DH key exchange yields forward secrecy, as the connection -can only be decrypted, when the DH key is known. By generating a temporary -DH key inside the server application that is lost when the application +Using ephemeral \s-1DH\s0 key exchange yields forward secrecy, as the connection +can only be decrypted, when the \s-1DH\s0 key is known. By generating a temporary +\&\s-1DH\s0 key inside the server application that is lost when the application is left, it becomes impossible for an attacker to decrypt past sessions, even if he gets hold of the normal (certified) key, as this key was only used for signing. .PP -In order to perform a DH key exchange the server must use a DH group -(DH parameters) and generate a DH key. The server will always generate a new -DH key during the negotiation, when the DH parameters are supplied via -callback and/or when the SSL_OP_SINGLE_DH_USE option of -SSL_CTX_set_options(3) is set. It will -immediately create a DH key, when DH parameters are supplied via -\fISSL_CTX_set_tmp_dh()\fR and SSL_OP_SINGLE_DH_USE is not set. In this case, +In order to perform a \s-1DH\s0 key exchange the server must use a \s-1DH\s0 group +(\s-1DH\s0 parameters) and generate a \s-1DH\s0 key. The server will always generate a new +\&\s-1DH\s0 key during the negotiation, when the \s-1DH\s0 parameters are supplied via +callback and/or when the \s-1SSL_OP_SINGLE_DH_USE\s0 option of +\&\fISSL_CTX_set_options\fR\|(3) is set. It will +immediately create a \s-1DH\s0 key, when \s-1DH\s0 parameters are supplied via +\&\fISSL_CTX_set_tmp_dh()\fR and \s-1SSL_OP_SINGLE_DH_USE\s0 is not set. In this case, it may happen that a key is generated on initialization without later being needed, while on the other hand the computer time during the negotiation is being saved. .PP -If \*(L"strong\*(R" primes were used to generate the DH parameters, it is not strictly +If \*(L"strong\*(R" primes were used to generate the \s-1DH\s0 parameters, it is not strictly necessary to generate a new key for each handshake but it does improve forward secrecy. If it is not assured, that \*(L"strong\*(R" primes were used (see especially -the section about DSA parameters below), SSL_OP_SINGLE_DH_USE must be used -in order to prevent small subgroup attacks. Always using SSL_OP_SINGLE_DH_USE +the section about \s-1DSA\s0 parameters below), \s-1SSL_OP_SINGLE_DH_USE\s0 must be used +in order to prevent small subgroup attacks. Always using \s-1SSL_OP_SINGLE_DH_USE\s0 has an impact on the computer time needed during negotiation, but it is not very large, so application authors/users should consider to always enable this option. .PP -As generating DH parameters is extremely time consuming, an application +As generating \s-1DH\s0 parameters is extremely time consuming, an application should not generate the parameters on the fly but supply the parameters. -DH parameters can be reused, as the actual key is newly generated during -the negotiation. The risk in reusing DH parameters is that an attacker -may specialize on a very often used DH group. Applications should therefore -generate their own DH parameters during the installation process using the -openssl dhparam(1) application. In order to reduce the computer -time needed for this generation, it is possible to use DSA parameters -instead (see dhparam(1)), but in this case SSL_OP_SINGLE_DH_USE +\&\s-1DH\s0 parameters can be reused, as the actual key is newly generated during +the negotiation. The risk in reusing \s-1DH\s0 parameters is that an attacker +may specialize on a very often used \s-1DH\s0 group. Applications should therefore +generate their own \s-1DH\s0 parameters during the installation process using the +openssl \fIdhparam\fR\|(1) application. In order to reduce the computer +time needed for this generation, it is possible to use \s-1DSA\s0 parameters +instead (see \fIdhparam\fR\|(1)), but in this case \s-1SSL_OP_SINGLE_DH_USE\s0 is mandatory. .PP -Application authors may compile in DH parameters. Files dh512.pem, -dh1024.pem, dh2048.pem, and dh4096 in the \*(L'apps\*(R' directory of current -version of the OpenSSL distribution contain the \*(L'SKIP\*(R' DH parameters, -which use safe primes and were generated verifiably pseudo-randomly. +Application authors may compile in \s-1DH\s0 parameters. Files dh512.pem, +dh1024.pem, dh2048.pem, and dh4096 in the 'apps' directory of current +version of the OpenSSL distribution contain the '\s-1SKIP\s0' \s-1DH\s0 parameters, +which use safe primes and were generated verifiably pseudo\-randomly. These files can be converted into C code using the \fB\-C\fR option of the -dhparam(1) application. +\&\fIdhparam\fR\|(1) application. Authors may also generate their own set of parameters using -dhparam(1), but a user may not be sure how the parameters were -generated. The generation of DH parameters during installation is therefore +\&\fIdhparam\fR\|(1), but a user may not be sure how the parameters were +generated. The generation of \s-1DH\s0 parameters during installation is therefore recommended. .PP -An application may either directly specify the DH parameters or -can supply the DH parameters via a callback function. The callback approach -has the advantage, that the callback may supply DH parameters for different +An application may either directly specify the \s-1DH\s0 parameters or +can supply the \s-1DH\s0 parameters via a callback function. The callback approach +has the advantage, that the callback may supply \s-1DH\s0 parameters for different key lengths. .PP The \fBtmp_dh_callback\fR is called with the \fBkeylength\fR needed and the \fBis_export\fR information. The \fBis_export\fR flag is set, when the -ephemeral DH key exchange is performed with an export cipher. +ephemeral \s-1DH\s0 key exchange is performed with an export cipher. .SH "EXAMPLES" -Handle DH parameters for key lengths of 512 and 1024 bits. (Error handling +.IX Header "EXAMPLES" +Handle \s-1DH\s0 parameters for key lengths of 512 and 1024 bits. (Error handling partly left out.) .PP .Vb 5 @@ -296,6 +245,7 @@ partly left out.) \& DH *dh_1024 = NULL; \& FILE *paramfile; .Ve +.PP .Vb 14 \& ... \& /* "openssl dhparam -out dh_param_512.pem -2 512" */ @@ -312,16 +262,19 @@ partly left out.) \& } \& ... .Ve +.PP .Vb 3 \& /* "openssl dhparam -C -2 512" etc... */ \& DH *get_dh512() { ... } \& DH *get_dh1024() { ... } .Ve +.PP .Vb 3 \& DH *tmp_dh_callback(SSL *s, int is_export, int keylength) \& { \& DH *dh_tmp=NULL; .Ve +.PP .Vb 17 \& switch (keylength) { \& case 512: @@ -342,32 +295,15 @@ partly left out.) \& } .Ve .SH "RETURN VALUES" -\fISSL_CTX_set_tmp_dh_callback()\fR and \fISSL_set_tmp_dh_callback()\fR do not return +.IX Header "RETURN VALUES" +\&\fISSL_CTX_set_tmp_dh_callback()\fR and \fISSL_set_tmp_dh_callback()\fR do not return diagnostic output. .PP -\fISSL_CTX_set_tmp_dh()\fR and \fISSL_set_tmp_dh()\fR do return 1 on success and 0 +\&\fISSL_CTX_set_tmp_dh()\fR and \fISSL_set_tmp_dh()\fR do return 1 on success and 0 on failure. Check the error queue to find out the reason of failure. .SH "SEE ALSO" -ssl(3), SSL_CTX_set_cipher_list(3), -SSL_CTX_set_tmp_rsa_callback(3), -SSL_CTX_set_options(3), -ciphers(1), dhparam(1) - -.rn }` '' -.IX Title "SSL_CTX_set_tmp_dh_callback 3" -.IX Name "SSL_CTX_set_tmp_dh_callback, SSL_CTX_set_tmp_dh, SSL_set_tmp_dh_callback, SSL_set_tmp_dh - handle DH keys for ephemeral key exchange" - -.IX Header "NAME" - -.IX Header "SYNOPSIS" - -.IX Header "DESCRIPTION" - -.IX Header "NOTES" - -.IX Header "EXAMPLES" - -.IX Header "RETURN VALUES" - .IX Header "SEE ALSO" - +\&\fIssl\fR\|(3), \fISSL_CTX_set_cipher_list\fR\|(3), +\&\fISSL_CTX_set_tmp_rsa_callback\fR\|(3), +\&\fISSL_CTX_set_options\fR\|(3), +\&\fIciphers\fR\|(1), \fIdhparam\fR\|(1)