.\" $OpenBSD: X509_LOOKUP_new.3,v 1.12 2024/09/06 07:48:20 tb Exp $
.\"
.\" Copyright (c) 2021 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.Dd $Mdocdate: September 6 2024 $
.Dt X509_LOOKUP_NEW 3
.Os
.Sh NAME
.Nm X509_LOOKUP_free ,
.Nm X509_LOOKUP_ctrl ,
.Nm X509_LOOKUP_add_dir ,
.Nm X509_LOOKUP_load_file ,
.Nm X509_LOOKUP_add_mem ,
.Nm X509_get_default_cert_dir ,
.Nm X509_get_default_cert_file ,
.Nm X509_get_default_cert_dir_env ,
.Nm X509_get_default_cert_file_env
.\" X509_get_default_private_dir is intentionally undocumented
.\" because it appears to be unused by any real-world software
.\" and because it doesn't do much in the first place.
.Nd certificate lookup object
.Sh SYNOPSIS
.In openssl/x509_vfy.h
.Ft void
.Fn X509_LOOKUP_free "X509_LOOKUP *lookup"
.Ft int
.Fo X509_LOOKUP_ctrl
.Fa "X509_LOOKUP *lookup"
.Fa "int command"
.Fa "const char *source"
.Fa "long type"
.Fa "char **ret"
.Fc
.Ft int
.Fo X509_LOOKUP_add_dir
.Fa "X509_LOOKUP *lookup"
.Fa "const char *source"
.Fa "long type"
.Fc
.Ft int
.Fo X509_LOOKUP_load_file
.Fa "X509_LOOKUP *lookup"
.Fa "const char *source"
.Fa "long type"
.Fc
.Ft int
.Fo X509_LOOKUP_add_mem
.Fa "X509_LOOKUP *lookup"
.Fa "const struct iovec *source"
.Fa "long type"
.Fc
.In openssl/x509.h
.Ft const char *
.Fn X509_get_default_cert_dir void
.Ft const char *
.Fn X509_get_default_cert_file void
.Ft const char *
.Fn X509_get_default_cert_dir_env void
.Ft const char *
.Fn X509_get_default_cert_file_env void
.Sh DESCRIPTION
.Fn X509_LOOKUP_free
is a deprecated function that
releases the memory used by
.Fa lookup .
It is provided for compatibility only.
If
.Fa lookup
is a
.Dv NULL
pointer, no action occurs.
.Pp
The operation of
.Fn X509_LOOKUP_ctrl
depends on the
.Vt X509_LOOKUP_METHOD
used by
.Fa lookup :
.Bl -tag -width 4n
.It Xr X509_LOOKUP_hash_dir 3
The
.Fa command
is required to be
.Dv X509_L_ADD_DIR
and the
.Fa source
argument is interpreted
as a colon-separated, NUL-terminated list of directory names.
These directories are added to an internal list of directories to search
for certificate files of the given
.Fa type .
.Pp
If
.Fa type
is
.Dv X509_FILETYPE_DEFAULT ,
the
.Fa source
argument is ignored and
.Pa /etc/ssl/certs
and a type of
.Dv X509_FILETYPE_PEM
are used instead.
.Pp
.Fn X509_LOOKUP_add_dir
is a macro that calls
.Fn X509_LOOKUP_ctrl
with a
.Fa command
of
.Dv X509_L_ADD_DIR
and
.Fa ret
set to
.Dv NULL .
.Pp
This lookup method is peculiar in so far as calling
.Fn X509_LOOKUP_ctrl
on a lookup object using it does not yet add any certificates to the associated
.Vt X509_STORE
object.
.It Xr X509_LOOKUP_file 3
The
.Fa command
is required to be
.Dv X509_L_FILE_LOAD
and the
.Fa source
argument is interpreted as a NUL-terminated file name.
If the
.Fa type
is
.Dv X509_FILETYPE_PEM ,
the file is read with
.Xr BIO_new_file 3
and
.Xr PEM_X509_INFO_read_bio 3
and the certificates and revocation lists found are added to the
.Vt X509_STORE
object associated with
.Fa lookup
using
.Xr X509_STORE_add_cert 3
and
.Xr X509_STORE_add_crl 3 .
If
.Fa type
is
.Dv X509_FILETYPE_DEFAULT ,
the
.Fa source
argument is ignored and
.Pa /etc/ssl/certs.pem
and a type of
.Dv X509_FILETYPE_PEM
are used instead.
If
.Fa type
is
.Dv X509_FILETYPE_ASN1 ,
the file is read with
.Xr d2i_X509_bio 3
and the single certificate is added to the
.Vt X509_STORE
object associated with
.Fa lookup
using
.Xr X509_STORE_add_cert 3 .
.Pp
.Fn X509_LOOKUP_load_file
is a macro calling
.Fn X509_LOOKUP_ctrl
with a
.Fa command
of
.Dv X509_L_FILE_LOAD
and
.Fa ret
set to
.Dv NULL .
.It Xr X509_LOOKUP_mem 3
The
.Fa command
and
.Fa type
are required to be
.Dv X509_L_MEM
and
.Dv X509_FILETYPE_PEM ,
respectively.
The
.Fa source
argument is interpreted as a pointer to an
.Vt iovec
structure defined in
.In sys/uio.h .
The memory area described by that structure is read with
.Xr BIO_new_mem_buf 3
and
.Xr PEM_X509_INFO_read_bio 3
and the certificates and revocation lists found are added to the
.Vt X509_STORE
object associated with
.Fa lookup
using
.Xr X509_STORE_add_cert 3
and
.Xr X509_STORE_add_crl 3 .
.Pp
.Fn X509_LOOKUP_add_mem
is a macro calling
.Fn X509_LOOKUP_ctrl
with a command of
.Dv X509_L_MEM
and
.Fa ret
set to
.Dv NULL .
.El
.Pp
With LibreSSL,
.Fn X509_LOOKUP_ctrl
always ignores the
.Fa ret
argument.
.Pp
If the
.Fa type
is
.Dv X509_LU_X509 ,
it searches the configured directories for files having that name,
with a file name extension that is a small, non-negative decimal integer
starting at
.Qq ".0" .
These files are read with
.Xr X509_load_cert_file 3 .
In each directory, the search is ended once a file with the expected name
and extension does not exists.
.Pp
If the
.Fa type
is
.Dv X509_LU_CRL ,
the file name extensions are expected to have a prefix of
.Qq "r" ,
i.e. they start with
.Qq ".r0" ,
and the files are read with
.Xr X509_load_crl_file 3 .
.Pp
In case of success, the first match is returned in the
.Pf * Fa object
provided by the caller, overwriting any previous content.
.Sh RETURN VALUES
.Fn X509_LOOKUP_ctrl
returns 1 for success or 0 for failure.
With library implementations other than LibreSSL,
it might also return \-1 for internal errors.
.Pp
.Fn X509_get_default_cert_dir
returns a pointer to the constant string
.Qq /etc/ssl/certs ,
.Fn X509_get_default_cert_file
to
.Qq /etc/ssl/certs.pem ,
.Fn X509_get_default_cert_dir_env
to
.Qq SSL_CERT_DIR ,
and
.Fn X509_get_default_cert_file_env
to
.Qq SSL_CERT_FILE .
.Sh ENVIRONMENT
For reasons of security and simplicity,
LibreSSL ignores the environment variables
.Ev SSL_CERT_DIR
and
.Ev SSL_CERT_FILE ,
but other library implementations may use their contents instead
of the standard locations for trusted certificates, and a few
third-party application programs also inspect these variables
directly and may pass their values to
.Fn X509_LOOKUP_add_dir
and
.Fn X509_LOOKUP_load_file .
.Sh FILES
.Bl -tag -width /etc/ssl/certs.pem -compact
.It Pa /etc/ssl/certs/
default directory for storing trusted certificates
.It Pa /etc/ssl/certs.pem
default file for storing trusted certificates
.El
.Sh ERRORS
The following diagnostics can be retrieved with
.Xr ERR_get_error 3 ,
.Xr ERR_GET_REASON 3 ,
and
.Xr ERR_reason_error_string 3 :
.Bl -tag -width Ds
.It Dv ERR_R_ASN1_LIB Qq "ASN1 lib"
.Xr d2i_X509_bio 3
failed in
.Fn X509_LOOKUP_ctrl .
.It Dv X509_R_BAD_X509_FILETYPE Qq "bad x509 filetype"
.Fn X509_LOOKUP_ctrl
was called with an invalid
.Fa type .
.It Dv ERR_R_BUF_LIB Qq "BUF lib"
Memory allocation failed.
.It Dv X509_R_INVALID_DIRECTORY Qq "invalid directory"
The
.Fa source
argument of
.Fn X509_LOOKUP_ctrl
with
.Dv X509_L_ADD_DIR
or
.Fn X509_LOOKUP_add_dir
was
.Dv NULL
or an empty string.
.It Dv X509_R_LOADING_CERT_DIR Qq "loading cert dir"
.Fn X509_LOOKUP_ctrl
with
.Dv X509_L_ADD_DIR
or
.Fn X509_LOOKUP_add_dir
was called with
.Dv X509_FILETYPE_DEFAULT
and adding the default directories failed.
This error is added after and in addition to a more specific diagnostic.
.It Dv X509_R_LOADING_DEFAULTS Qq "loading defaults"
.Fn X509_LOOKUP_ctrl
with
.Dv X509_L_FILE_LOAD
or
.Fn X509_LOOKUP_load_file
was called with
.Dv X509_FILETYPE_DEFAULT
and adding the certificates and revocation lists failed.
This error is added after and in addition to a more specific diagnostic.
.It Dv ERR_R_MALLOC_FAILURE Qq "malloc failure"
Memory allocation failed.
.It Dv ERR_R_PEM_LIB Qq "PEM lib"
.Xr PEM_X509_INFO_read_bio 3 ,
.Xr PEM_read_bio_X509_AUX 3 ,
or
.Xr PEM_read_bio_X509_CRL 3
failed in
.Fn X509_LOOKUP_ctrl .
.It Dv ERR_R_SYS_LIB Qq "system lib"
.Xr BIO_new 3 ,
.Xr BIO_new_file 3 ,
or
.Xr BIO_read_filename 3
failed in
.Fn X509_LOOKUP_ctrl .
.It Dv X509_R_WRONG_LOOKUP_TYPE Qq "wrong lookup type"
.Xr X509_STORE_CTX_get_by_subject 3
was called with an invalid
.Fa type .
.El
.Pp
Passing an invalid
.Fa command
to
.Fn X509_LOOKUP_ctrl
causes failure but provides no diagnostics.
.Sh SEE ALSO
.Xr d2i_X509_bio 3 ,
.Xr PEM_read_bio_X509_AUX 3 ,
.Xr PEM_X509_INFO_read_bio 3 ,
.Xr X509_load_cert_file 3 ,
.Xr X509_LOOKUP_hash_dir 3 ,
.Xr X509_NAME_hash 3 ,
.Xr X509_NAME_new 3 ,
.Xr X509_new 3 ,
.Xr X509_OBJECT_get_type 3 ,
.Xr X509_STORE_add_cert 3 ,
.Xr X509_STORE_get_by_subject 3
.Sh HISTORY
.Fn X509_get_default_cert_dir ,
.Fn X509_get_default_cert_file ,
.Fn X509_get_default_cert_dir_env ,
and
.Fn X509_get_default_cert_file_env
first appeared in SSLeay 0.4.1 and have been available since
.Ox 2.4 .
.Pp
.Fn X509_LOOKUP_add_mem
first appeared in
.Ox 5.7 .
.Pp
The other functions first appeared in SSLeay 0.8.0
and have been available since
.Ox 2.4 .
.Sh BUGS
If the
.Fa type
is
.Dv X509_FILETYPE_DEFAULT
or
.Dv X509_FILETYPE_PEM ,
.Fn X509_LOOKUP_ctrl
with
.Dv X509_L_FILE_LOAD
and
.Fn X509_LOOKUP_load_file
silently ignore failure of
.Xr X509_STORE_add_cert 3
and
.Xr X509_STORE_add_crl 3
and indicate success anyway.
.Pp
Handling of a
.Dv NULL
.Fa source
is inconsistent for
.Fn X509_LOOKUP_ctrl
with
.Dv X509_L_FILE_LOAD
and for
.Fn X509_LOOKUP_load_file .
With
.Dv X509_FILETYPE_PEM ,
it causes failure, but with
.Dv X509_FILETYPE_ASN1 ,
no action occurs and success is indicated.
.Pp
When called on a
.Fa lookup
object using
.Xr X509_LOOKUP_mem 3 ,
.Fn X509_LOOKUP_ctrl
raises
.Dv ERR_R_PEM_LIB
when called with an invalid
.Fa command
or
.Fa type ,
when
.Xr BIO_new_mem_buf 3
fails, when
.Fa source
contains zero objects, or when
.Xr X509_STORE_add_cert 3
fails on the first object encountered, which is all inconsistent
with the behaviour of the other lookup methods.