postgresql/contrib/sslinfo/sslinfo.c
2015-09-08 11:10:20 -03:00

529 lines
13 KiB
C

/*
* module for PostgreSQL to access client SSL certificate information
*
* Written by Victor B. Wagner <vitus@cryptocom.ru>, Cryptocom LTD
* This file is distributed under BSD-style license.
*
* contrib/sslinfo/sslinfo.c
*/
#include "postgres.h"
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/asn1.h>
#include "access/htup_details.h"
#include "funcapi.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "utils/builtins.h"
PG_MODULE_MAGIC;
static Datum X509_NAME_field_to_text(X509_NAME *name, text *fieldName);
static Datum X509_NAME_to_text(X509_NAME *name);
static Datum ASN1_STRING_to_text(ASN1_STRING *str);
/*
* Function context for data persisting over repeated calls.
*/
typedef struct
{
TupleDesc tupdesc;
} SSLExtensionInfoContext;
/*
* Indicates whether current session uses SSL
*
* Function has no arguments. Returns bool. True if current session
* is SSL session and false if it is local or non-ssl session.
*/
PG_FUNCTION_INFO_V1(ssl_is_used);
Datum
ssl_is_used(PG_FUNCTION_ARGS)
{
PG_RETURN_BOOL(MyProcPort->ssl_in_use);
}
/*
* Returns SSL version currently in use.
*/
PG_FUNCTION_INFO_V1(ssl_version);
Datum
ssl_version(PG_FUNCTION_ARGS)
{
if (MyProcPort->ssl == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(cstring_to_text(SSL_get_version(MyProcPort->ssl)));
}
/*
* Returns SSL cipher currently in use.
*/
PG_FUNCTION_INFO_V1(ssl_cipher);
Datum
ssl_cipher(PG_FUNCTION_ARGS)
{
if (MyProcPort->ssl == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(cstring_to_text(SSL_get_cipher(MyProcPort->ssl)));
}
/*
* Indicates whether current client provided a certificate
*
* Function has no arguments. Returns bool. True if current session
* is SSL session and client certificate is verified, otherwise false.
*/
PG_FUNCTION_INFO_V1(ssl_client_cert_present);
Datum
ssl_client_cert_present(PG_FUNCTION_ARGS)
{
PG_RETURN_BOOL(MyProcPort->peer != NULL);
}
/*
* Returns serial number of certificate used to establish current
* session
*
* Function has no arguments. It returns the certificate serial
* number as numeric or null if current session doesn't use SSL or if
* SSL connection is established without sending client certificate.
*/
PG_FUNCTION_INFO_V1(ssl_client_serial);
Datum
ssl_client_serial(PG_FUNCTION_ARGS)
{
Datum result;
Port *port = MyProcPort;
X509 *peer = port->peer;
ASN1_INTEGER *serial = NULL;
BIGNUM *b;
char *decimal;
if (!peer)
PG_RETURN_NULL();
serial = X509_get_serialNumber(peer);
b = ASN1_INTEGER_to_BN(serial, NULL);
decimal = BN_bn2dec(b);
BN_free(b);
result = DirectFunctionCall3(numeric_in,
CStringGetDatum(decimal),
ObjectIdGetDatum(0),
Int32GetDatum(-1));
OPENSSL_free(decimal);
return result;
}
/*
* Converts OpenSSL ASN1_STRING structure into text
*
* Converts ASN1_STRING into text, converting all the characters into
* current database encoding if possible. Any invalid characters are
* replaced by question marks.
*
* Parameter: str - OpenSSL ASN1_STRING structure. Memory management
* of this structure is responsibility of caller.
*
* Returns Datum, which can be directly returned from a C language SQL
* function.
*/
static Datum
ASN1_STRING_to_text(ASN1_STRING *str)
{
BIO *membuf;
size_t size;
char nullterm;
char *sp;
char *dp;
text *result;
membuf = BIO_new(BIO_s_mem());
if (membuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create OpenSSL BIO structure")));
(void) BIO_set_close(membuf, BIO_CLOSE);
ASN1_STRING_print_ex(membuf, str,
((ASN1_STRFLGS_RFC2253 & ~ASN1_STRFLGS_ESC_MSB)
| ASN1_STRFLGS_UTF8_CONVERT));
/* ensure null termination of the BIO's content */
nullterm = '\0';
BIO_write(membuf, &nullterm, 1);
size = BIO_get_mem_data(membuf, &sp);
dp = pg_any_to_server(sp, size - 1, PG_UTF8);
result = cstring_to_text(dp);
if (dp != sp)
pfree(dp);
if (BIO_free(membuf) != 1)
elog(ERROR, "could not free OpenSSL BIO structure");
PG_RETURN_TEXT_P(result);
}
/*
* Returns specified field of specified X509_NAME structure
*
* Common part of ssl_client_dn and ssl_issuer_dn functions.
*
* Parameter: X509_NAME *name - either subject or issuer of certificate
* Parameter: text fieldName - field name string like 'CN' or commonName
* to be looked up in the OpenSSL ASN1 OID database
*
* Returns result of ASN1_STRING_to_text applied to appropriate
* part of name
*/
static Datum
X509_NAME_field_to_text(X509_NAME *name, text *fieldName)
{
char *string_fieldname;
int nid,
index;
ASN1_STRING *data;
string_fieldname = text_to_cstring(fieldName);
nid = OBJ_txt2nid(string_fieldname);
if (nid == NID_undef)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid X.509 field name: \"%s\"",
string_fieldname)));
pfree(string_fieldname);
index = X509_NAME_get_index_by_NID(name, nid, -1);
if (index < 0)
return (Datum) 0;
data = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, index));
return ASN1_STRING_to_text(data);
}
/*
* Returns specified field of client certificate distinguished name
*
* Receives field name (like 'commonName' and 'emailAddress') and
* returns appropriate part of certificate subject converted into
* database encoding.
*
* Parameter: fieldname text - will be looked up in OpenSSL object
* identifier database
*
* Returns text string with appropriate value.
*
* Throws an error if argument cannot be converted into ASN1 OID by
* OpenSSL. Returns null if no client certificate is present, or if
* there is no field with such name in the certificate.
*/
PG_FUNCTION_INFO_V1(ssl_client_dn_field);
Datum
ssl_client_dn_field(PG_FUNCTION_ARGS)
{
text *fieldname = PG_GETARG_TEXT_P(0);
Datum result;
if (!(MyProcPort->peer))
PG_RETURN_NULL();
result = X509_NAME_field_to_text(X509_get_subject_name(MyProcPort->peer), fieldname);
if (!result)
PG_RETURN_NULL();
else
return result;
}
/*
* Returns specified field of client certificate issuer name
*
* Receives field name (like 'commonName' and 'emailAddress') and
* returns appropriate part of certificate subject converted into
* database encoding.
*
* Parameter: fieldname text - would be looked up in OpenSSL object
* identifier database
*
* Returns text string with appropriate value.
*
* Throws an error if argument cannot be converted into ASN1 OID by
* OpenSSL. Returns null if no client certificate is present, or if
* there is no field with such name in the certificate.
*/
PG_FUNCTION_INFO_V1(ssl_issuer_field);
Datum
ssl_issuer_field(PG_FUNCTION_ARGS)
{
text *fieldname = PG_GETARG_TEXT_P(0);
Datum result;
if (!(MyProcPort->peer))
PG_RETURN_NULL();
result = X509_NAME_field_to_text(X509_get_issuer_name(MyProcPort->peer), fieldname);
if (!result)
PG_RETURN_NULL();
else
return result;
}
/*
* Equivalent of X509_NAME_oneline that respects encoding
*
* This function converts X509_NAME structure to the text variable
* converting all textual data into current database encoding.
*
* Parameter: X509_NAME *name X509_NAME structure to be converted
*
* Returns: text datum which contains string representation of
* X509_NAME
*/
static Datum
X509_NAME_to_text(X509_NAME *name)
{
BIO *membuf = BIO_new(BIO_s_mem());
int i,
nid,
count = X509_NAME_entry_count(name);
X509_NAME_ENTRY *e;
ASN1_STRING *v;
const char *field_name;
size_t size;
char nullterm;
char *sp;
char *dp;
text *result;
if (membuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create OpenSSL BIO structure")));
(void) BIO_set_close(membuf, BIO_CLOSE);
for (i = 0; i < count; i++)
{
e = X509_NAME_get_entry(name, i);
nid = OBJ_obj2nid(X509_NAME_ENTRY_get_object(e));
if (nid == NID_undef)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not get NID for ASN1_OBJECT object")));
v = X509_NAME_ENTRY_get_data(e);
field_name = OBJ_nid2sn(nid);
if (field_name == NULL)
field_name = OBJ_nid2ln(nid);
if (field_name == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not convert NID %d to an ASN1_OBJECT structure", nid)));
BIO_printf(membuf, "/%s=", field_name);
ASN1_STRING_print_ex(membuf, v,
((ASN1_STRFLGS_RFC2253 & ~ASN1_STRFLGS_ESC_MSB)
| ASN1_STRFLGS_UTF8_CONVERT));
}
/* ensure null termination of the BIO's content */
nullterm = '\0';
BIO_write(membuf, &nullterm, 1);
size = BIO_get_mem_data(membuf, &sp);
dp = pg_any_to_server(sp, size - 1, PG_UTF8);
result = cstring_to_text(dp);
if (dp != sp)
pfree(dp);
if (BIO_free(membuf) != 1)
elog(ERROR, "could not free OpenSSL BIO structure");
PG_RETURN_TEXT_P(result);
}
/*
* Returns current client certificate subject as one string
*
* This function returns distinguished name (subject) of the client
* certificate used in the current SSL connection, converting it into
* the current database encoding.
*
* Returns text datum.
*/
PG_FUNCTION_INFO_V1(ssl_client_dn);
Datum
ssl_client_dn(PG_FUNCTION_ARGS)
{
if (!(MyProcPort->peer))
PG_RETURN_NULL();
return X509_NAME_to_text(X509_get_subject_name(MyProcPort->peer));
}
/*
* Returns current client certificate issuer as one string
*
* This function returns issuer's distinguished name of the client
* certificate used in the current SSL connection, converting it into
* the current database encoding.
*
* Returns text datum.
*/
PG_FUNCTION_INFO_V1(ssl_issuer_dn);
Datum
ssl_issuer_dn(PG_FUNCTION_ARGS)
{
if (!(MyProcPort->peer))
PG_RETURN_NULL();
return X509_NAME_to_text(X509_get_issuer_name(MyProcPort->peer));
}
/*
* Returns information about available SSL extensions.
*
* Returns setof record made of the following values:
* - name of the extension.
* - value of the extension.
* - critical status of the extension.
*/
PG_FUNCTION_INFO_V1(ssl_extension_info);
Datum
ssl_extension_info(PG_FUNCTION_ARGS)
{
X509 *cert = MyProcPort->peer;
FuncCallContext *funcctx;
int call_cntr;
int max_calls;
MemoryContext oldcontext;
SSLExtensionInfoContext *fctx;
STACK_OF(X509_EXTENSION) *ext_stack = NULL;
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* Switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* Create a user function context for cross-call persistence */
fctx = (SSLExtensionInfoContext *) palloc(sizeof(SSLExtensionInfoContext));
/* Construct tuple descriptor */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context that cannot accept type record")));
fctx->tupdesc = BlessTupleDesc(tupdesc);
/* Get all extensions of certificate */
if (cert && cert->cert_info)
ext_stack = cert->cert_info->extensions;
/* Set max_calls as a count of extensions in certificate */
max_calls = cert != NULL ? X509_get_ext_count(cert) : 0;
if (cert != NULL &&
ext_stack != NULL &&
max_calls > 0)
{
/* got results, keep track of them */
funcctx->max_calls = max_calls;
funcctx->user_fctx = fctx;
}
else
{
/* fast track when no results */
MemoryContextSwitchTo(oldcontext);
SRF_RETURN_DONE(funcctx);
}
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* Initialize per-call variables.
*/
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
fctx = funcctx->user_fctx;
ext_stack = cert->cert_info->extensions;
/* do while there are more left to send */
if (call_cntr < max_calls)
{
Datum values[3];
bool nulls[3];
char *buf;
HeapTuple tuple;
Datum result;
BIO *membuf;
X509_EXTENSION *ext;
ASN1_OBJECT *obj;
int nid;
int len;
/* need a BIO for this */
membuf = BIO_new(BIO_s_mem());
if (membuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create OpenSSL BIO structure")));
/* Get the extension from the certificate */
ext = sk_X509_EXTENSION_value(ext_stack, call_cntr);
obj = X509_EXTENSION_get_object(ext);
/* Get the extension name */
nid = OBJ_obj2nid(obj);
if (nid == NID_undef)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unknown OpenSSL extension in certificate at position %d",
call_cntr)));
values[0] = CStringGetTextDatum(OBJ_nid2sn(nid));
nulls[0] = false;
/* Get the extension value */
if (X509V3_EXT_print(membuf, ext, 0, 0) <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not print extension value in certificate at position %d",
call_cntr)));
len = BIO_get_mem_data(membuf, &buf);
values[1] = PointerGetDatum(cstring_to_text_with_len(buf, len));
nulls[1] = false;
/* Get critical status */
values[2] = BoolGetDatum(X509_EXTENSION_get_critical(ext));
nulls[2] = false;
/* Build tuple */
tuple = heap_form_tuple(fctx->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
if (BIO_free(membuf) != 1)
elog(ERROR, "could not free OpenSSL BIO structure");
SRF_RETURN_NEXT(funcctx, result);
}
/* All done */
SRF_RETURN_DONE(funcctx);
}