.\" $OpenBSD: X509_get_pubkey.3,v 1.13 2022/03/31 17:27:17 naddy Exp $ .\" selective merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2020, 2021 Ingo Schwarze .\" .\" 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. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: March 31 2022 $ .Dt X509_GET_PUBKEY 3 .Os .Sh NAME .Nm X509_get_pubkey , .Nm X509_get0_pubkey , .Nm X509_set_pubkey , .Nm X509_get_X509_PUBKEY , .Nm X509_get0_pubkey_bitstr , .Nm X509_REQ_get_pubkey , .Nm X509_REQ_get0_pubkey , .Nm X509_REQ_set_pubkey , .Nm X509_extract_key , .Nm X509_REQ_extract_key .Nd get or set certificate or certificate request public key .Sh SYNOPSIS .In openssl/x509.h .Ft EVP_PKEY * .Fo X509_get_pubkey .Fa "X509 *x" .Fc .Ft EVP_PKEY * .Fo X509_get0_pubkey .Fa "const X509 *x" .Fc .Ft int .Fo X509_set_pubkey .Fa "X509 *x" .Fa "EVP_PKEY *pkey" .Fc .Ft X509_PUBKEY * .Fo X509_get_X509_PUBKEY .Fa "const X509 *x" .Fc .Ft ASN1_BIT_STRING * .Fo X509_get0_pubkey_bitstr .Fa "const X509 *x" .Fc .Ft EVP_PKEY * .Fo X509_REQ_get_pubkey .Fa "X509_REQ *req" .Fc .Ft EVP_PKEY * .Fo X509_REQ_get0_pubkey .Fa "X509_REQ *req" .Fc .Ft int .Fo X509_REQ_set_pubkey .Fa "X509_REQ *x" .Fa "EVP_PKEY *pkey" .Fc .Ft EVP_PKEY * .Fo X509_extract_key .Fa "X509 *x" .Fc .Ft EVP_PKEY * .Fo X509_REQ_extract_key .Fa "X509_REQ *req" .Fc .Sh DESCRIPTION .Fn X509_get_pubkey attempts to decode the public key for certificate .Fa x . If successful, it returns the public key as an .Vt EVP_PKEY pointer with its reference count incremented: this means the returned key must be freed up after use. .Fn X509_get0_pubkey is similar except that it does not increment the reference count of the returned .Vt EVP_PKEY , so it must not be freed up after use. .Pp .Fn X509_get_X509_PUBKEY returns an internal pointer to the .Vt SubjectPublicKeyInfo structure contained in .Fa x . The returned value must not be freed up after use. .Pp .Fn X509_get0_pubkey_bitstr returns an internal pointer to just the public key contained in this .Vt SubjectPublicKeyInfo structure, without the information about the algorithm used. .Pp .Fn X509_set_pubkey attempts to set the public key for certificate .Fa x to .Fa pkey . The key .Fa pkey should be freed up after use. .Pp .Fn X509_REQ_get_pubkey , .Fn X509_REQ_get0_pubkey , and .Fn X509_REQ_set_pubkey are similar but operate on certificate request .Fa req . .Pp The first time a public key is decoded, the .Vt EVP_PKEY structure is cached in the certificate or certificate request itself. Subsequent calls return the cached structure with its reference count incremented to improve performance. .Pp .Fn X509_extract_key and .Fn X509_REQ_extract_key are deprecated aliases for .Fn X509_get_pubkey and .Fn X509_REQ_get_pubkey , respectively, implemented as macros. .Sh RETURN VALUES .Fn X509_get_pubkey , .Fn X509_get0_pubkey , .Fn X509_get_X509_PUBKEY , .Fn X509_get0_pubkey_bitstr , .Fn X509_REQ_get_pubkey , .Fn X509_REQ_get0_pubkey , .Fn X509_extract_key , and .Fn X509_REQ_extract_key return a public key or .Dv NULL if an error occurred. .Pp .Fn X509_set_pubkey and .Fn X509_REQ_set_pubkey return 1 for success or 0 for failure. .Pp In some cases of failure of .Fn X509_get0_pubkey , .Fn X509_set_pubkey , .Fn X509_REQ_get_pubkey , .Fn X509_REQ_get0_pubkey , and .Fn X509_REQ_set_pubkey , the reason can be determined with .Xr ERR_get_error 3 . .Sh ERRORS .Fn X509_get_pubkey , .Fn X509_get0_pubkey , .Fn X509_REQ_get_pubkey , .Fn X509_extract_key , and .Fn X509_REQ_extract_key provide diagnostics as documented for .Xr X509_PUBKEY_get 3 . If .Fa x or .Fa req is .Dv NULL or contains no certificate information, they fail without pushing an error onto the stack. .Pp .Fn X509_get_X509_PUBKEY provides no diagnostics and crashes by accessing a .Dv NULL pointer if .Fa x is .Dv NULL or contains no certificate information, .Pp .Fn X509_get0_pubkey_bitstr provides no diagnostics and fails without pushing an error onto the stack if .Fa x is .Dv NULL , but it crashes by accessing a .Dv NULL pointer if .Fa x contains no certificate information. .Sh SEE ALSO .Xr d2i_X509 3 , .Xr X509_CRL_get0_by_serial 3 , .Xr X509_NAME_add_entry_by_txt 3 , .Xr X509_NAME_ENTRY_get_object 3 , .Xr X509_NAME_get_index_by_NID 3 , .Xr X509_NAME_print_ex 3 , .Xr X509_new 3 , .Xr X509_PUBKEY_new 3 , .Xr X509_REQ_new 3 , .Xr X509_sign 3 , .Xr X509_verify_cert 3 , .Xr X509V3_get_d2i 3 .Sh STANDARDS RFC 5280, Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile, section 4.1 Basic Certificate Fields .Pp RFC 2986: PKCS #10: Certification Request Syntax Specification, section 4.1 CertificationRequestInfo .Sh HISTORY .Fn X509_extract_key and .Fn X509_REQ_extract_key first appeared in SSLeay 0.5.1 but returned a pointer to an .Vt RSA object before SSLeay 0.6.0. .Fn X509_get_pubkey , .Fn X509_set_pubkey , .Fn X509_REQ_get_pubkey , and .Fn X509_REQ_set_pubkey first appeared in SSLeay 0.6.5. .Fn X509_get_X509_PUBKEY first appeared in SSLeay 0.8.0. These functions have been available since .Ox 2.4 . .Pp .Fn X509_get0_pubkey_bitstr first appeared in OpenSSL 0.9.7 and has been available since .Ox 3.4 . .Pp .Fn X509_get0_pubkey first appeared in OpenSSL 1.1.0 and has been available since .Ox 6.3 . .Fn X509_REQ_get0_pubkey first appeared in OpenSSL 1.1.0 and has been available since .Ox 7.1 .