acl/lib_tls/attr/attr_scan64.c

/*++
 * NAME
 *	attr_scan64 3
 * SUMMARY
 *	recover attributes from byte stream
 * SYNOPSIS
 *	#include <attr.h>
 *
 *	int	attr_scan64(fp, flags, type, name, ..., ATTR_TYPE_END)
 *	ACL_VSTREAM	fp;
 *	int	flags;
 *	int	type;
 *	char	*name;
 *
 *	int	attr_vscan64(fp, flags, ap)
 *	ACL_VSTREAM	fp;
 *	int	flags;
 *	va_list	ap;
 * DESCRIPTION
 *	attr_scan64() takes zero or more (name, value) request attributes
 *	and recovers the attribute values from the byte stream that was
 *	possibly generated by attr_print64().
 *
 *	attr_vscan64() provides an alternative interface that is convenient
 *	for calling from within a variadic function.
 *
 *	The input stream is formatted as follows, where (item)* stands
 *	for zero or more instances of the specified item, and where
 *	(item1 | item2) stands for choice:
 *
 * .in +5
 *	attr-list :== simple-attr* newline
 * .br
 *	simple-attr :== attr-name colon attr-value newline
 * .br
 *	attr-name :== any base64 encoded string
 * .br
 *	attr-value :== any base64 encoded string
 * .br
 *	colon :== the ASCII colon character
 * .br
 *	newline :== the ASCII newline character
 * .in
 *
 *	All attribute names and attribute values are sent as base64-encoded
 *	strings. Each base64 encoding must be no longer than 4*var_line_limit
 *	characters. The formatting rules aim to make implementations in PERL
 *	and other languages easy.
 *
 *	Normally, attributes must be received in the sequence as specified with
 *	the attr_scan64() argument list.  The input stream may contain additional
 *	attributes at any point in the input stream, including additional
 *	instances of requested attributes.
 *
 *	Additional input attributes or input attribute instances are silently
 *	skipped over, unless the ATTR_FLAG_EXTRA processing flag is specified
 *	(see below). This allows for some flexibility in the evolution of
 *	protocols while still providing the option of being strict where
 *	this is desirable.
 *
 *	Arguments:
 * .IP fp
 *	Stream to recover the input attributes from.
 * .IP flags
 *	The bit-wise OR of zero or more of the following.
 * .RS
 * .IP ATTR_FLAG_MISSING
 *	Log a warning when the input attribute list terminates before all
 *	requested attributes are recovered. It is always an error when the
 *	input stream ends without the newline attribute list terminator.
 * .IP ATTR_FLAG_EXTRA
 *	Log a warning and stop attribute recovery when the input stream
 *	contains an attribute that was not requested. This includes the
 *	case of additional instances of a requested attribute.
 * .IP ATTR_FLAG_MORE
 *	After recovering the requested attributes, leave the input stream
 *	in a state that is usable for more attr_scan64() operations from the
 *	same input attribute list.
 *	By default, attr_scan64() skips forward past the input attribute list
 *	terminator.
 * .IP ATTR_FLAG_STRICT
 *	For convenience, this value combines both ATTR_FLAG_MISSING and
 *	ATTR_FLAG_EXTRA.
 * .IP ATTR_FLAG_NONE
 *	For convenience, this value requests none of the above.
 * .RE
 * .IP type
 *	The type argument determines the arguments that follow.
 * .RS
 * .IP "ATTR_TYPE_INT (char *, int *)"
 *	This argument is followed by an attribute name and an integer pointer.
 * .IP "ATTR_TYPE_LONG (char *, long *)"
 *	This argument is followed by an attribute name and a long pointer.
 * .IP "ATTR_TYPE_STR (char *, ACL_VSTRING *)"
 *	This argument is followed by an attribute name and a ACL_VSTRING pointer.
 * .IP "ATTR_TYPE_DATA (char *, ACL_VSTRING *)"
 *	This argument is followed by an attribute name and a ACL_VSTRING pointer.
 * .IP "ATTR_TYPE_FUNC (ATTR_SCAN_SLAVE_FN, void *)"
 *	This argument is followed by a function pointer and a generic data
 *	pointer. The caller-specified function returns < 0 in case of
 *	error.
 * .IP "ATTR_TYPE_HASH (ACL_HTABLE *)"
 * .IP "ATTR_TYPE_NAMEVAL (NVTABLE *)"
 *	All further input attributes are processed as string attributes.
 *	No specific attribute sequence is enforced.
 *	All attributes up to the attribute list terminator are read,
 *	but only the first instance of each attribute is stored.
 *	There can be no more than 1024 attributes in a hash table.
 * .sp
 *	The attribute string values are stored in the hash table under
 *	keys equal to the attribute name (obtained from the input stream).
 *	Values from the input stream are added to the hash table. Existing
 *	hash table entries are not replaced.
 * .sp
 *	N.B. This construct must be followed by an ATTR_TYPE_END argument.
 * .IP ATTR_TYPE_END
 *	This argument terminates the requested attribute list.
 * .RE
 * BUGS
 *	ATTR_TYPE_HASH (ATTR_TYPE_NAMEVAL) accepts attributes with arbitrary
 *	names from possibly untrusted sources.
 *	This is unsafe, unless the resulting table is queried only with
 *	known to be good attribute names.
 * DIAGNOSTICS
 *	attr_scan64() and attr_vscan64() return -1 when malformed input is
 *	detected (string too long, incomplete line, missing end marker).
 *	Otherwise, the result value is the number of attributes that were
 *	successfully recovered from the input stream (a hash table counts
 *	as the number of entries stored into the table).
 *
 *	Panic: interface violation. All system call errors are fatal.
 * SEE ALSO
 *	attr_print64(3) send attributes over byte stream.
 * LICENSE
 * .ad
 * .fi
 *	The Secure Mailer license must be distributed with this software.
 * AUTHOR(S)
 *	Wietse Venema
 *	IBM T.J. Watson Research
 *	P.O. Box 704
 *	Yorktown Heights, NY 10598, USA
 *--*/

#include "StdAfx.h"
#include <stdarg.h>
#include <string.h>
#include <stdio.h>

#include "attr.h"

/* Application specific. */

#define STR(x)	acl_vstring_str(x)
#define LEN(x)	ACL_VSTRING_LEN(x)

static void free_vstring_fn(void *arg)
{
    ACL_VSTRING *s = (ACL_VSTRING*) arg;

    acl_vstring_free(s);
}

/* attr_scan64_string - pull a string from the input stream */

static int attr_scan64_string(ACL_VSTREAM *fp, ACL_VSTRING *plain_buf, const char *context)
{
    const char *myname = "attr_scan64_string";
    static __thread ACL_VSTRING *base64_buf = 0;

#if 0
    extern int var_line_limit;		/* XXX */
    int     limit = var_line_limit * 4;

#endif
    int     ch;

    if (base64_buf == 0) {
	base64_buf = acl_vstring_alloc(10);
	acl_pthread_atexit_add(base64_buf, free_vstring_fn);
    }

    ACL_VSTRING_RESET(base64_buf);
    while ((ch = ACL_VSTREAM_GETC(fp)) != ':' && ch != '\n') {
	if (ch == ACL_VSTREAM_EOF) {
	    acl_msg_warn("%s: %s on %s while reading %s",
		myname, acl_vstream_ftimeout(fp) ? "timeout" : "premature end-of-input",
		     ACL_VSTREAM_PATH(fp), context);
	    return (-1);
	}
	ACL_VSTRING_ADDCH(base64_buf, ch);
#if 0
	if (LEN(base64_buf) > limit) {
	    acl_msg_warn("%s: string length > %d characters from %s while reading %s",
		     myname, limit, ACL_VSTREAM_PATH(fp), context);
	    return (-1);
	}
#endif
    }
    ACL_VSTRING_TERMINATE(base64_buf);
    if (acl_vstring_base64_decode(plain_buf, STR(base64_buf), (int) LEN(base64_buf)) == 0) {
	acl_msg_warn("%s: malformed base64 data from %s: %.100s",
		 myname, ACL_VSTREAM_PATH(fp), STR(base64_buf));
	return (-1);
    }
    if (acl_msg_verbose)
	acl_msg_info("%s: %s", context, *STR(plain_buf) ? STR(plain_buf) : "(end)");
    return (ch);
}

/* attr_scan64_number - pull a number from the input stream */

static int attr_scan64_number(ACL_VSTREAM *fp, unsigned *ptr,
	ACL_VSTRING *str_buf, const char *context)
{
    const char *myname = "attr_scan64_number";
    char    junk = 0;
    int     ch;

    if ((ch = attr_scan64_string(fp, str_buf, context)) < 0)
	return (-1);
    if (sscanf(STR(str_buf), "%u%c", ptr, &junk) != 1 || junk != 0) {
	acl_msg_warn("%s: malformed numerical data from %s while reading %s: %.100s",
		 myname, ACL_VSTREAM_PATH(fp), context, STR(str_buf));
	return (-1);
    }
    return (ch);
}

/* attr_scan64_long_number - pull a number from the input stream */

static int attr_scan64_long_number(ACL_VSTREAM *fp, unsigned long *ptr,
	ACL_VSTRING *str_buf, const char *context)
{
    const char *myname = "attr_scan64_long_number";
    char    junk = 0;
    int     ch;

    if ((ch = attr_scan64_string(fp, str_buf, context)) < 0)
	return (-1);
    if (sscanf(STR(str_buf), "%lu%c", ptr, &junk) != 1 || junk != 0) {
	acl_msg_warn("%s: malformed numerical data from %s while reading %s: %.100s",
		 myname, ACL_VSTREAM_PATH(fp), context, STR(str_buf));
	return (-1);
    }
    return (ch);
}

/* attr_vscan64 - receive attribute list from stream */

int     attr_vscan64(ACL_VSTREAM *fp, int flags, va_list ap)
{
    const char *myname = "attr_scan64";
    static __thread ACL_VSTRING *str_buf = 0;
    static __thread ACL_VSTRING *name_buf = 0;
    int     wanted_type = -1;
    char   *wanted_name = 0;
    unsigned int *number;
    unsigned long *long_number;
    ACL_VSTRING *string;
    ACL_HTABLE *hash_table = 0;
    int     ch;
    int     conversions;
    ATTR_SCAN_SLAVE_FN scan_fn;
    void   *scan_arg;

    /*
     * Sanity check.
     */
    if (flags & ~ATTR_FLAG_ALL)
	acl_msg_panic("%s: bad flags: 0x%x", myname, flags);

    /*
     * EOF check.
     */
    if ((ch = ACL_VSTREAM_GETC(fp)) == ACL_VSTREAM_EOF)
	return (0);
    acl_vstream_ungetc(fp, ch);

    /*
     * Initialize.
     */
    if (str_buf == 0) {
	str_buf = acl_vstring_alloc(10);
	name_buf = acl_vstring_alloc(10);
	acl_pthread_atexit_add(str_buf, free_vstring_fn);
	acl_pthread_atexit_add(name_buf, free_vstring_fn);
    }

    /*
     * Iterate over all (type, name, value) triples.
     */
    for (conversions = 0; /* void */ ; conversions++) {

	/*
	 * Determine the next attribute type and attribute name on the
	 * caller's wish list.
	 * 
	 * If we're reading into a hash table, we already know that the
	 * attribute value is string-valued, and we get the attribute name
	 * from the input stream instead. This is secure only when the
	 * resulting table is queried with known to be good attribute names.
	 */
	if (wanted_type != ATTR_TYPE_HASH) {
	    wanted_type = va_arg(ap, int);
	    if (wanted_type == ATTR_TYPE_END) {
		if ((flags & ATTR_FLAG_MORE) != 0)
		    return (conversions);
		wanted_name = "(list terminator)";
	    } else if (wanted_type == ATTR_TYPE_HASH) {
		wanted_name = "(any attribute name or list terminator)";
		hash_table = va_arg(ap, ACL_HTABLE *);
		if (va_arg(ap, int) != ATTR_TYPE_END)
		    acl_msg_panic("%s: ATTR_TYPE_HASH not followed by ATTR_TYPE_END",
			      myname);
	    } else if (wanted_type != ATTR_TYPE_FUNC) {
		wanted_name = va_arg(ap, char *);
	    }
	}

	/*
	 * Locate the next attribute of interest in the input stream.
	 */
	while (wanted_type != ATTR_TYPE_FUNC) {

	    /*
	     * Get the name of the next attribute. Hitting EOF is always bad.
	     * Hitting the end-of-input early is OK if the caller is prepared
	     * to deal with missing inputs.
	     */
	    if (acl_msg_verbose)
		acl_msg_info("%s: wanted attribute: %s",
			 ACL_VSTREAM_PATH(fp), wanted_name);
	    if ((ch = attr_scan64_string(fp, name_buf,
				    "input attribute name")) == ACL_VSTREAM_EOF)
		return (-1);
	    if (ch == '\n' && LEN(name_buf) == 0) {
		if (wanted_type == ATTR_TYPE_END
		    || wanted_type == ATTR_TYPE_HASH)
		    return (conversions);
		if ((flags & ATTR_FLAG_MISSING) != 0)
		    acl_msg_warn("%s: missing attribute %s in input from %s",
			     myname, wanted_name, ACL_VSTREAM_PATH(fp));
		return (conversions);
	    }

	    /*
	     * See if the caller asks for this attribute.
	     */
	    if (wanted_type == ATTR_TYPE_HASH
		|| (wanted_type != ATTR_TYPE_END
		    && strcmp(wanted_name, STR(name_buf)) == 0))
		break;
	    if ((flags & ATTR_FLAG_EXTRA) != 0) {
		acl_msg_warn("%s: unexpected attribute %s from %s (expecting: %s)",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp), wanted_name);
		return (conversions);
	    }

	    /*
	     * Skip over this attribute. The caller does not ask for it.
	     */
	    while (ch != '\n' && (ch = ACL_VSTREAM_GETC(fp)) != ACL_VSTREAM_EOF)
		 /* void */ ;
	}

	/*
	 * Do the requested conversion. If the target attribute is a
	 * non-array type, disallow sending a multi-valued attribute, and
	 * disallow sending no value. If the target attribute is an array
	 * type, allow the sender to send a zero-element array (i.e. no value
	 * at all). XXX Need to impose a bound on the number of array
	 * elements.
	 */
	switch (wanted_type) {
	case ATTR_TYPE_INT:
	    if (ch != ':') {
		acl_msg_warn("%s: missing value for number attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    number = va_arg(ap, unsigned int *);
	    if ((ch = attr_scan64_number(fp, number, str_buf,
					 "input attribute value")) < 0)
		return (-1);
	    if (ch != '\n') {
		acl_msg_warn("%s: multiple values for attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    break;
	case ATTR_TYPE_LONG:
	    if (ch != ':') {
		acl_msg_warn("%s: missing value for number attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    long_number = va_arg(ap, unsigned long *);
	    if ((ch = attr_scan64_long_number(fp, long_number, str_buf,
					      "input attribute value")) < 0)
		return (-1);
	    if (ch != '\n') {
		acl_msg_warn("%s: multiple values for attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    break;
	case ATTR_TYPE_STR:
	    if (ch != ':') {
		acl_msg_warn("%s: missing value for string attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    string = va_arg(ap, ACL_VSTRING *);
	    if ((ch = attr_scan64_string(fp, string,
					 "input attribute value")) < 0)
		return (-1);
	    if (ch != '\n') {
		acl_msg_warn("%s: multiple values for attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    break;
	case ATTR_TYPE_DATA:
	    if (ch != ':') {
		acl_msg_warn("%s: missing value for data attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    string = va_arg(ap, ACL_VSTRING *);
	    if ((ch = attr_scan64_string(fp, string,
					 "input attribute value")) < 0)
		return (-1);
	    if (ch != '\n') {
		acl_msg_warn("%s: multiple values for attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    break;
	case ATTR_TYPE_FUNC:
	    scan_fn = va_arg(ap, ATTR_SCAN_SLAVE_FN);
	    scan_arg = va_arg(ap, void *);
	    if (scan_fn(attr_scan64, fp, flags | ATTR_FLAG_MORE, scan_arg) < 0)
		return (-1);
	    break;
	case ATTR_TYPE_HASH:
	    if (ch != ':') {
		acl_msg_warn("%s: missing value for string attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    if ((ch = attr_scan64_string(fp, str_buf,
					 "input attribute value")) < 0)
		return (-1);
	    if (ch != '\n') {
		acl_msg_warn("%s: multiple values for attribute %s from %s",
			 myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		return (-1);
	    }
	    if (acl_htable_locate(hash_table, STR(name_buf)) != 0) {
		if ((flags & ATTR_FLAG_EXTRA) != 0) {
		    acl_msg_warn("%s: duplicate attribute %s in input from %s",
			     myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
		    return (conversions);
		}
	    } else if (acl_htable_used(hash_table) >= ATTR_HASH_LIMIT) {
		acl_msg_warn("%s: attribute count exceeds limit %d in input from %s",
			 myname, ATTR_HASH_LIMIT, ACL_VSTREAM_PATH(fp));
		return (conversions);
	    } else {
		acl_htable_enter(hash_table, STR(name_buf),
			     acl_mystrdup(STR(str_buf)));
	    }
	    break;
	default:
	    acl_msg_panic("%s: unknown type code: %d", myname, wanted_type);
	}
    }
}

/* attr_scan64 - read attribute list from stream */

int     attr_scan64(ACL_VSTREAM *fp, int flags,...)
{
    va_list ap;
    int     ret;

    va_start(ap, flags);
    ret = attr_vscan64(fp, flags, ap);
    va_end(ap);
    return (ret);
}

#ifdef TEST

 /*
  * Proof of concept test program.  Mirror image of the attr_scan64 test
  * program.
  */
#include <acl_msg_vstream.h>

int     var_line_limit = 2048;

int     main(int unused_argc, char **used_argv)
{
    ACL_VSTRING *data_val = acl_vstring_alloc(1);
    ACL_VSTRING *str_val = acl_vstring_alloc(1);
    ACL_HTABLE *table = acl_htable_create(1);
    ACL_HTABLE_INFO **ht_info_list;
    ACL_HTABLE_INFO **ht;
    int     int_val;
    long    long_val;
    int     ret;

    acl_msg_verbose = 1;
    acl_msg_acl_vstream_init(used_argv[0], ACL_VSTREAM_ERR);
    if ((ret = attr_scan64(ACL_VSTREAM_IN,
			   ATTR_FLAG_STRICT,
			   ATTR_TYPE_INT, ATTR_NAME_INT, &int_val,
			   ATTR_TYPE_LONG, ATTR_NAME_LONG, &long_val,
			   ATTR_TYPE_STR, ATTR_NAME_STR, str_val,
			   ATTR_TYPE_DATA, ATTR_NAME_DATA, data_val,
			   ATTR_TYPE_HASH, table,
			   ATTR_TYPE_END)) > 4) {
	acl_vstream_printf("%s %d\n", ATTR_NAME_INT, int_val);
	acl_vstream_printf("%s %ld\n", ATTR_NAME_LONG, long_val);
	acl_vstream_printf("%s %s\n", ATTR_NAME_STR, STR(str_val));
	acl_vstream_printf("%s %s\n", ATTR_NAME_DATA, STR(data_val));
	ht_info_list = acl_htable_list(table);
	for (ht = ht_info_list; *ht; ht++)
	    acl_vstream_printf("(hash) %s %s\n", ht[0]->key, ht[0]->value);
	myfree((char *) ht_info_list);
    } else {
	acl_vstream_printf("return: %d\n", ret);
    }
    if ((ret = attr_scan64(ACL_VSTREAM_IN,
			   ATTR_FLAG_STRICT,
			   ATTR_TYPE_INT, ATTR_NAME_INT, &int_val,
			   ATTR_TYPE_LONG, ATTR_NAME_LONG, &long_val,
			   ATTR_TYPE_STR, ATTR_NAME_STR, str_val,
			   ATTR_TYPE_DATA, ATTR_NAME_DATA, data_val,
			   ATTR_TYPE_END)) == 4) {
	acl_vstream_printf("%s %d\n", ATTR_NAME_INT, int_val);
	acl_vstream_printf("%s %ld\n", ATTR_NAME_LONG, long_val);
	acl_vstream_printf("%s %s\n", ATTR_NAME_STR, STR(str_val));
	acl_vstream_printf("%s %s\n", ATTR_NAME_DATA, STR(data_val));
	ht_info_list = acl_htable_list(table);
	for (ht = ht_info_list; *ht; ht++)
	    acl_vstream_printf("(hash) %s %s\n", ht[0]->key, ht[0]->value);
	myfree((char *) ht_info_list);
    } else {
	acl_vstream_printf("return: %d\n", ret);
    }
    if (acl_vstream_fflush(ACL_VSTREAM_OUT) != 0)
	acl_msg_fatal("%s: write error: %s", __FUNCTION__, acl_last_serror());

    acl_vstring_free(data_val);
    acl_vstring_free(str_val);
    acl_htable_free(table, myfree);

    return (0);
}

#endif