22

✏️ Editing: PEM_write_bio.3

.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35)
.\"
.\" 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
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" 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' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
.    ds C`
.    ds C'
'br\}
.\"
.\" 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
.\" ========================================================================
.\"
.IX Title "PEM_READ 3"
.TH PEM_READ 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
PEM_write, PEM_write_bio, PEM_read, PEM_read_bio, PEM_do_header, PEM_get_EVP_CIPHER_INFO \&\- PEM encoding routines
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/pem.h>
\&
\& int PEM_write(FILE *fp, const char *name, const char *header,
\&               const unsigned char *data, long len)
\& int PEM_write_bio(BIO *bp, const char *name, const char *header,
\&                   const unsigned char *data, long len)
\&
\& int PEM_read(FILE *fp, char **name, char **header,
\&              unsigned char **data, long *len);
\& int PEM_read_bio(BIO *bp, char **name, char **header,
\&                  unsigned char **data, long *len);
\&
\& int PEM_get_EVP_CIPHER_INFO(char *header, EVP_CIPHER_INFO *cinfo);
\& int PEM_do_header(EVP_CIPHER_INFO *cinfo, unsigned char *data, long *len,
\&                   pem_password_cb *cb, void *u);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
These functions read and write PEM-encoded objects, using the \s-1PEM\s0
type \fBname\fR, any additional \fBheader\fR information, and the raw
\&\fBdata\fR of length \fBlen\fR.
.PP
\&\s-1PEM\s0 is the term used for binary content encoding first defined in \s-1IETF
RFC 1421.\s0  The content is a series of base64\-encoded lines, surrounded
by begin/end markers each on their own line.  For example:
.PP
.Vb 4
\& \-\-\-\-\-BEGIN PRIVATE KEY\-\-\-\-\-
\& MIICdg....
\& ... bhTQ==
\& \-\-\-\-\-END PRIVATE KEY\-\-\-\-\-
.Ve
.PP
Optional header line(s) may appear after the begin line, and their
existence depends on the type of object being written or read.
.PP
\&\fBPEM_write()\fR writes to the file \fBfp\fR, while \fBPEM_write_bio()\fR writes to
the \s-1BIO\s0 \fBbp\fR.  The \fBname\fR is the name to use in the marker, the
\&\fBheader\fR is the header value or \s-1NULL,\s0 and \fBdata\fR and \fBlen\fR specify
the data and its length.
.PP
The final \fBdata\fR buffer is typically an \s-1ASN.1\s0 object which can be decoded with
the \fBd2i\fR function appropriate to the type \fBname\fR; see \fBd2i_X509\fR\|(3)
for examples.
.PP
\&\fBPEM_read()\fR reads from the file \fBfp\fR, while \fBPEM_read_bio()\fR reads
from the \s-1BIO\s0 \fBbp\fR.
Both skip any non-PEM data that precedes the start of the next \s-1PEM\s0 object.
When an object is successfully retrieved, the type name from the \*(L"\-\-\-\-BEGIN
<type>\-\-\-\-\-\*(R" is returned via the \fBname\fR argument, any encapsulation headers
are returned in \fBheader\fR and the base64\-decoded content and its length are
returned via \fBdata\fR and \fBlen\fR respectively.
The \fBname\fR, \fBheader\fR and \fBdata\fR pointers are allocated via \fBOPENSSL_malloc()\fR
and should be freed by the caller via \fBOPENSSL_free()\fR when no longer needed.
.PP
\&\fBPEM_get_EVP_CIPHER_INFO()\fR can be used to determine the \fBdata\fR returned by
\&\fBPEM_read()\fR or \fBPEM_read_bio()\fR is encrypted and to retrieve the associated cipher
and \s-1IV.\s0
The caller passes a pointer to structure of type \fB\s-1EVP_CIPHER_INFO\s0\fR via the
\&\fBcinfo\fR argument and the \fBheader\fR returned via \fBPEM_read()\fR or \fBPEM_read_bio()\fR.
If the call is successful 1 is returned and the cipher and \s-1IV\s0 are stored at the
address pointed to by \fBcinfo\fR.
When the header is malformed, or not supported or when the cipher is unknown
or some internal error happens 0 is returned.
This function is deprecated, see \fB\s-1NOTES\s0\fR below.
.PP
\&\fBPEM_do_header()\fR can then be used to decrypt the data if the header
indicates encryption.
The \fBcinfo\fR argument is a pointer to the structure initialized by the previous
call to \fBPEM_get_EVP_CIPHER_INFO()\fR.
The \fBdata\fR and \fBlen\fR arguments are those returned by the previous call to
\&\fBPEM_read()\fR or \fBPEM_read_bio()\fR.
The \fBcb\fR and \fBu\fR arguments make it possible to override the default password
prompt function as described in \fBPEM_read_PrivateKey\fR\|(3).
On successful completion the \fBdata\fR is decrypted in place, and \fBlen\fR is
updated to indicate the plaintext length.
This function is deprecated, see \fB\s-1NOTES\s0\fR below.
.PP
If the data is a priori known to not be encrypted, then neither \fBPEM_do_header()\fR
nor \fBPEM_get_EVP_CIPHER_INFO()\fR need be called.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBPEM_read()\fR and \fBPEM_read_bio()\fR return 1 on success and 0 on failure, the latter
includes the case when no more \s-1PEM\s0 objects remain in the input file.
To distinguish end of file from more serious errors the caller must peek at the
error stack and check for \fB\s-1PEM_R_NO_START_LINE\s0\fR, which indicates that no more
\&\s-1PEM\s0 objects were found.  See \fBERR_peek_last_error\fR\|(3), \s-1\fBERR_GET_REASON\s0\fR\|(3).
.PP
\&\fBPEM_get_EVP_CIPHER_INFO()\fR and \fBPEM_do_header()\fR return 1 on success, and 0 on
failure.
The \fBdata\fR is likely meaningless if these functions fail.
.SH "NOTES"
.IX Header "NOTES"
The \fBPEM_get_EVP_CIPHER_INFO()\fR and \fBPEM_do_header()\fR functions are deprecated.
This is because the underlying \s-1PEM\s0 encryption format is obsolete, and should
be avoided.
It uses an encryption format with an OpenSSL-specific key-derivation function,
which employs \s-1MD5\s0 with an iteration count of 1!
Instead, private keys should be stored in PKCS#8 form, with a strong PKCS#5
v2.0 \s-1PBE.\s0
See \fBPEM_write_PrivateKey\fR\|(3) and \fBd2i_PKCS8PrivateKey_bio\fR\|(3).
.PP
\&\fBPEM_do_header()\fR makes no assumption regarding the pass phrase received from the
password callback.
It will simply be treated as a byte sequence.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBERR_peek_last_error\fR\|(3), \s-1\fBERR_GET_LIB\s0\fR\|(3),
\&\fBd2i_PKCS8PrivateKey_bio\fR\|(3),
\&\fBpassphrase\-encoding\fR\|(7)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 1998\-2018 The OpenSSL Project Authors. All Rights Reserved.
.PP
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
<https://www.openssl.org/source/license.html>.

MR SKB