xref: /openbsd-src/lib/libcrypto/man/X509_STORE_CTX_set_verify.3 (revision 3b7446ee9a32814042b912df65432eceda9f87ab)

.\" $OpenBSD: X509_STORE_CTX_set_verify.3,v 1.8 2024/06/07 05:51:39 tb Exp $
.\"
.\" Copyright (c) 2021, 2022 Ingo Schwarze <schwarze@openbsd.org>
.\" Copyright (c) 2023 Job Snijders <job@openbsd.org>
.\"
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.\" 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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.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: June 7 2024 $
.Dt X509_STORE_CTX_SET_VERIFY 3
.Os
.Sh NAME
.Nm X509_STORE_CTX_verify_fn ,
.Nm X509_STORE_CTX_set_verify ,
.Nm X509_STORE_CTX_get_verify ,
.Nm X509_STORE_set_verify ,
.Nm X509_STORE_set_verify_func ,
.Nm X509_STORE_get_verify ,
.Nm X509_STORE_CTX_check_issued_fn ,
.Nm X509_STORE_set_check_issued ,
.Nm X509_STORE_get_check_issued ,
.Nm X509_STORE_CTX_get_check_issued
.Nd user-defined certificate chain verification function
.Sh SYNOPSIS
.In openssl/x509_vfy.h
.Ft typedef int
.Fo (*X509_STORE_CTX_verify_fn)
.Fa "X509_STORE_CTX *ctx"
.Fc
.Ft void
.Fo X509_STORE_CTX_set_verify
.Fa "X509_STORE_CTX *ctx"
.Fa "X509_STORE_CTX_verify_fn verify"
.Fc
.Ft X509_STORE_CTX_verify_fn
.Fo X509_STORE_CTX_get_verify
.Fa "X509_STORE_CTX *ctx"
.Fc
.Ft void
.Fo X509_STORE_set_verify
.Fa "X509_STORE *store"
.Fa "X509_STORE_CTX_verify_fn verify"
.Fc
.Ft void
.Fo X509_STORE_set_verify_func
.Fa "X509_STORE *store"
.Fa "X509_STORE_CTX_verify_fn verify"
.Fc
.Ft X509_STORE_CTX_verify_fn
.Fo X509_STORE_get_verify
.Fa "X509_STORE_CTX *ctx"
.Fc
.Ft typedef int
.Fo (*X509_STORE_CTX_check_issued_fn)
.Fa "X509_STORE_CTX *ctx"
.Fa "X509 *subject"
.Fa "X509 *issuer"
.Fc
.Ft void
.Fo X509_STORE_set_check_issued
.Fa "X509_STORE *store"
.Fa "X509_STORE_CTX_check_issued_fn check_issued"
.Fc
.Ft X509_STORE_CTX_check_issued_fn
.Fo X509_STORE_get_check_issued
.Fa "X509_STORE *store"
.Fc
.Ft X509_STORE_CTX_check_issued_fn
.Fo X509_STORE_CTX_get_check_issued
.Fa "X509_STORE_CTX *ctx"
.Fc
.Sh DESCRIPTION
.Fn X509_STORE_CTX_set_verify
configures
.Fa ctx
to use the
.Fa verify
argument as the X.509 certificate chain verification function instead
of the default verification function built into the library when
.Xr X509_verify_cert 3
is called.
.Pp
The
.Fa verify
function provided by the user is only called if the
.Dv X509_V_FLAG_LEGACY_VERIFY
or
.Dv X509_V_FLAG_NO_ALT_CHAINS
flag was set on
.Fa ctx
using
.Xr X509_STORE_CTX_set_flags 3
or
.Xr X509_VERIFY_PARAM_set_flags 3 .
Otherwise, it is ignored and a different algorithm is used that does
not support replacing the verification function.
.Pp
.Fn X509_STORE_set_verify
saves the function pointer
.Fa verify
in the given
.Fa store
object.
That pointer will be copied to an
.Vt X509_STORE_CTX
object when
.Fa store
is later passed as an argument to
.Xr X509_STORE_CTX_init 3 .
.Pp
.Fn X509_STORE_set_verify_func
is an alias for
.Fn X509_STORE_set_verify
implemented as a macro.
.Pp
.Fn X509_STORE_set_check_issued
saves the function pointer
.Fa check_issued
in the given
.Fa store
object.
That pointer will be copied to an
.Vt X509_STORE_CTX
object when
.Fa store
is later passed as an argument to
.Fn X509_STORE_CTX_init 3 .
.Pp
The
.Fa check_issued
function provided by the user should check whether a given certificate
.Fa subject
was issued using the CA certificate
.Fa issuer ,
and must return 0 on failure and 1 on success.
The default implementation ignores the
.Fa ctx
argument and returns success if and only if
.Xr X509_check_issued 3
returns
.Dv X509_V_OK .
It is important to pay close attention to the order of the
.Fa issuer
and
.Fa subject
arguments.
In
.Xr X509_check_issued 3
the
.Fa issuer
precedes the
.Fa subject
while in
.Fn check_issued
the
.Fa subject
comes first.
.Sh RETURN VALUES
.Fn X509_STORE_CTX_verify_fn
is supposed to return 1 to indicate that the chain is valid
or 0 if it is not or if an error occurred.
.Pp
.Fn X509_STORE_CTX_get_verify
returns a function pointer previously set with
.Fn X509_STORE_CTX_set_verify
or
.Xr X509_STORE_CTX_init 3 ,
or
.Dv NULL
if
.Fa ctx
is uninitialized.
.Pp
.Fn X509_STORE_get_verify
returns the function pointer previously set with
.Fn X509_STORE_set_verify ,
or
.Dv NULL
if that function was not called on the
.Fa store .
.Pp
.Fn X509_STORE_get_check_issued
returns the function pointer previously set with
.Fn X509_STORE_set_check_issued ,
or
.Dv NULL
if that function was not called on the
.Fa store .
.Pp
.Fn X509_STORE_CTX_get_check_issued
returns the
.Fn check_issued
function pointer set on the
.Vt X509_STORE_CTX .
This is either the
.Fn check_issued
function inherited from the
.Fa store
used in
.Xr X509_STORE_CTX_init 3
or the library's default implementation.
.Sh SEE ALSO
.Xr X509_check_issued 3 ,
.Xr X509_STORE_CTX_init 3 ,
.Xr X509_STORE_CTX_set_error 3 ,
.Xr X509_STORE_CTX_set_flags 3 ,
.Xr X509_STORE_CTX_set_verify_cb 3 ,
.Xr X509_STORE_new 3 ,
.Xr X509_STORE_set_flags 3 ,
.Xr X509_STORE_set_verify_cb 3 ,
.Xr X509_verify_cert 3 ,
.Xr X509_VERIFY_PARAM_set_flags 3
.Sh HISTORY
.Fn X509_STORE_set_verify_func
first appeared in SSLeay 0.8.0 and has been available since
.Ox 2.4 .
.Pp
.Fn X509_STORE_CTX_set_verify
and
.Fn X509_STORE_CTX_get_verify
first appeared in OpenSSL 1.1.0 and have been available since
.Ox 7.1 .
.Pp
.Fn X509_STORE_CTX_verify_fn ,
.Fn X509_STORE_set_verify ,
and
.Fn X509_STORE_get_verify
first appeared in OpenSSL 1.1.0 and have been available since
.Ox 7.2 .
.Pp
.Fn X509_STORE_set_check_issued ,
.Fn X509_STORE_get_check_issued ,
and
.Fn X509_STORE_CTX_get_check_issued
first appeared in OpenSSL 1.1.0 and have been available since
.Ox 7.3 .
.Sh BUGS
The reversal of order of
.Fa subject
and
.Fa issuer
between
.Fn check_issued
and
.Xr X509_check_issued 3
is very confusing.
It has led to bugs and will cause many more.