/* name-value.c - Parser and writer for a name-value format.
* Copyright (C) 2016 g10 Code GmbH
*
* This file is part of GnuPG.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of either
*
* - the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* or
*
* - the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* or both in parallel, as here.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
*/
/*
* This module aso provides features for the extended private key
* format of gpg-agent.
*/
#include <config.h>
#include <assert.h>
#include <gcrypt.h>
#include <gpg-error.h>
#include <string.h>
#include "mischelp.h"
#include "strlist.h"
#include "util.h"
#include "name-value.h"
struct name_value_container
{
struct name_value_entry *first;
struct name_value_entry *last;
unsigned int private_key_mode:1;
};
struct name_value_entry
{
struct name_value_entry *prev;
struct name_value_entry *next;
/* The name. Comments and blank lines have NAME set to NULL. */
char *name;
/* The value as stored in the file. We store it when we parse
a file so that we can reproduce it. */
strlist_t raw_value;
/* The decoded value. */
char *value;
};
/* Helper */
static inline gpg_error_t
my_error_from_syserror (void)
{
return gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
}
static inline gpg_error_t
my_error (gpg_err_code_t ec)
{
return gpg_err_make (default_errsource, ec);
}
/* Allocation and deallocation. */
/* Allocate a private key container structure. */
nvc_t
nvc_new (void)
{
return xtrycalloc (1, sizeof (struct name_value_container));
}
/* Allocate a private key container structure for use with private keys. */
nvc_t
nvc_new_private_key (void)
{
nvc_t nvc = nvc_new ();
if (nvc)
nvc->private_key_mode = 1;
return nvc;
}
static void
nve_release (nve_t entry, int private_key_mode)
{
if (entry == NULL)
return;
xfree (entry->name);
if (entry->value && private_key_mode)
wipememory (entry->value, strlen (entry->value));
xfree (entry->value);
if (private_key_mode)
free_strlist_wipe (entry->raw_value);
else
free_strlist (entry->raw_value);
xfree (entry);
}
/* Release a private key container structure. */
void
nvc_release (nvc_t pk)
{
nve_t e, next;
if (pk == NULL)
return;
for (e = pk->first; e; e = next)
{
next = e->next;
nve_release (e, pk->private_key_mode);
}
xfree (pk);
}
/* Dealing with names and values. */
/* Check whether the given name is valid. Valid names start with a
letter, end with a colon, and contain only alphanumeric characters
and the hyphen. */
static int
valid_name (const char *name)
{
size_t i, len = strlen (name);
if (! alphap (name) || len == 0 || name[len - 1] != ':')
return 0;
for (i = 1; i < len - 1; i++)
if (! alnump (&name[i]) && name[i] != '-')
return 0;
return 1;
}
/* Makes sure that ENTRY has a RAW_VALUE. */
static gpg_error_t
assert_raw_value (nve_t entry)
{
gpg_error_t err = 0;
size_t len, offset;
#define LINELEN 70
char buf[LINELEN+3];
if (entry->raw_value)
return 0;
len = strlen (entry->value);
offset = 0;
while (len)
{
size_t amount, linelen = LINELEN;
/* On the first line we need to subtract space for the name. */
if (entry->raw_value == NULL && strlen (entry->name) < linelen)
linelen -= strlen (entry->name);
/* See if the rest of the value fits in this line. */
if (len <= linelen)
amount = len;
else
{
size_t i;
/* Find a suitable space to break on. */
for (i = linelen - 1; linelen - i < 30; i--)
if (ascii_isspace (entry->value[offset+i]))
break;
if (ascii_isspace (entry->value[offset+i]))
{
/* Found one. */
amount = i;
}
else
{
/* Just induce a hard break. */
amount = linelen;
}
}
snprintf (buf, sizeof buf, " %.*s\n", (int) amount,
&entry->value[offset]);
if (append_to_strlist_try (&entry->raw_value, buf) == NULL)
{
err = my_error_from_syserror ();
goto leave;
}
offset += amount;
len -= amount;
}
leave:
if (err)
{
free_strlist_wipe (entry->raw_value);
entry->raw_value = NULL;
}
return err;
#undef LINELEN
}
/* Computes the length of the value encoded as continuation. If
*SWALLOW_WS is set, all whitespace at the beginning of S is
swallowed. If START is given, a pointer to the beginning of the
value is stored there. */
static size_t
continuation_length (const char *s, int *swallow_ws, const char **start)
{
size_t len;
if (*swallow_ws)
{
/* The previous line was a blank line and we inserted a newline.
Swallow all whitespace at the beginning of this line. */
while (ascii_isspace (*s))
s++;
}
else
{
/* Iff a continuation starts with more than one space, it
encodes a space. */
if (ascii_isspace (*s))
s++;
}
/* Strip whitespace at the end. */
len = strlen (s);
while (len > 0 && ascii_isspace (s[len-1]))
len--;
if (len == 0)
{
/* Blank lines encode newlines. */
len = 1;
s = "\n";
*swallow_ws = 1;
}
else
*swallow_ws = 0;
if (start)
*start = s;
return len;
}
/* Makes sure that ENTRY has a VALUE. */
static gpg_error_t
assert_value (nve_t entry)
{
size_t len;
int swallow_ws;
strlist_t s;
char *p;
if (entry->value)
return 0;
len = 0;
swallow_ws = 0;
for (s = entry->raw_value; s; s = s->next)
len += continuation_length (s->d, &swallow_ws, NULL);
/* Add one for the terminating zero. */
len += 1;
entry->value = p = xtrymalloc (len);
if (entry->value == NULL)
return my_error_from_syserror ();
swallow_ws = 0;
for (s = entry->raw_value; s; s = s->next)
{
const char *start;
size_t l = continuation_length (s->d, &swallow_ws, &start);
memcpy (p, start, l);
p += l;
}
*p++ = 0;
assert (p - entry->value == len);
return 0;
}
/* Get the name. */
char *
nve_name (nve_t pke)
{
return pke->name;
}
/* Get the value. */
char *
nve_value (nve_t pke)
{
if (assert_value (pke))
return NULL;
return pke->value;
}
/* Adding and modifying values. */
/* Add (NAME, VALUE, RAW_VALUE) to PK. NAME may be NULL for comments
and blank lines. At least one of VALUE and RAW_VALUE must be
given. If PRESERVE_ORDER is not given, entries with the same name
are grouped. NAME, VALUE and RAW_VALUE is consumed. */
static gpg_error_t
_nvc_add (nvc_t pk, char *name, char *value, strlist_t raw_value,
int preserve_order)
{
gpg_error_t err = 0;
nve_t e;
assert (value || raw_value);
if (name && ! valid_name (name))
{
err = my_error (GPG_ERR_INV_NAME);
goto leave;
}
if (name
&& pk->private_key_mode
&& !ascii_strcasecmp (name, "Key:")
&& nvc_lookup (pk, "Key:"))
{
err = my_error (GPG_ERR_INV_NAME);
goto leave;
}
e = xtrycalloc (1, sizeof *e);
if (e == NULL)
{
err = my_error_from_syserror ();
goto leave;
}
e->name = name;
e->value = value;
e->raw_value = raw_value;
if (pk->first)
{
nve_t last;
if (preserve_order || name == NULL)
last = pk->last;
else
{
/* See if there is already an entry with NAME. */
last = nvc_lookup (pk, name);
/* If so, find the last in that block. */
if (last)
{
while (last->next)
{
nve_t next = last->next;
if (next->name && ascii_strcasecmp (next->name, name) == 0)
last = next;
else
break;
}
}
else /* Otherwise, just find the last entry. */
last = pk->last;
}
if (last->next)
{
e->prev = last;
e->next = last->next;
last->next = e;
e->next->prev = e;
}
else
{
e->prev = last;
last->next = e;
pk->last = e;
}
}
else
pk->first = pk->last = e;
leave:
if (err)
{
xfree (name);
if (value)
wipememory (value, strlen (value));
xfree (value);
free_strlist_wipe (raw_value);
}
return err;
}
/* Add (NAME, VALUE) to PK. If an entry with NAME already exists, it
is not updated but the new entry is appended. */
gpg_error_t
nvc_add (nvc_t pk, const char *name, const char *value)
{
char *k, *v;
k = xtrystrdup (name);
if (k == NULL)
return my_error_from_syserror ();
v = xtrystrdup (value);
if (v == NULL)
{
xfree (k);
return my_error_from_syserror ();
}
return _nvc_add (pk, k, v, NULL, 0);
}
/* Add (NAME, VALUE) to PK. If an entry with NAME already exists, it
is updated with VALUE. If multiple entries with NAME exist, the
first entry is updated. */
gpg_error_t
nvc_set (nvc_t pk, const char *name, const char *value)
{
nve_t e;
if (! valid_name (name))
return GPG_ERR_INV_NAME;
e = nvc_lookup (pk, name);
if (e)
{
char *v;
v = xtrystrdup (value);
if (v == NULL)
return my_error_from_syserror ();
free_strlist_wipe (e->raw_value);
e->raw_value = NULL;
if (e->value)
wipememory (e->value, strlen (e->value));
xfree (e->value);
e->value = v;
return 0;
}
else
return nvc_add (pk, name, value);
}
/* Delete the given entry from PK. */
void
nvc_delete (nvc_t pk, nve_t entry)
{
if (entry->prev)
entry->prev->next = entry->next;
else
pk->first = entry->next;
if (entry->next)
entry->next->prev = entry->prev;
else
pk->last = entry->prev;
nve_release (entry, pk->private_key_mode);
}
/* Delete the entries with NAME from PK. */
void
nvc_delete_named (nvc_t pk, const char *name)
{
nve_t e;
if (!valid_name (name))
return;
while ((e = nvc_lookup (pk, name)))
nvc_delete (pk, e);
}
/* Lookup and iteration. */
/* Get the first non-comment entry. */
nve_t
nvc_first (nvc_t pk)
{
nve_t entry;
for (entry = pk->first; entry; entry = entry->next)
if (entry->name)
return entry;
return NULL;
}
/* Get the first entry with the given name. */
nve_t
nvc_lookup (nvc_t pk, const char *name)
{
nve_t entry;
for (entry = pk->first; entry; entry = entry->next)
if (entry->name && ascii_strcasecmp (entry->name, name) == 0)
return entry;
return NULL;
}
/* Get the next non-comment entry. */
nve_t
nve_next (nve_t entry)
{
for (entry = entry->next; entry; entry = entry->next)
if (entry->name)
return entry;
return NULL;
}
/* Get the next entry with the given name. */
nve_t
nve_next_value (nve_t entry, const char *name)
{
for (entry = entry->next; entry; entry = entry->next)
if (entry->name && ascii_strcasecmp (entry->name, name) == 0)
return entry;
return NULL;
}
/* Return the string for the first entry in NVC with NAME. If an
* entry with NAME is missing in NVC or its value is the empty string
* NULL is returned. Note that the The returned string is a pointer
* into NVC. */
const char *
nvc_get_string (nvc_t nvc, const char *name)
{
nve_t item;
if (!nvc)
return NULL;
item = nvc_lookup (nvc, name);
if (!item)
return NULL;
return nve_value (item);
}
/* Private key handling. */
/* Get the private key. */
gpg_error_t
nvc_get_private_key (nvc_t pk, gcry_sexp_t *retsexp)
{
gpg_error_t err;
nve_t e;
e = pk->private_key_mode? nvc_lookup (pk, "Key:") : NULL;
if (e == NULL)
return my_error (GPG_ERR_MISSING_KEY);
err = assert_value (e);
if (err)
return err;
return gcry_sexp_sscan (retsexp, NULL, e->value, strlen (e->value));
}
/* Set the private key. */
gpg_error_t
nvc_set_private_key (nvc_t pk, gcry_sexp_t sexp)
{
gpg_error_t err;
char *raw, *clean, *p;
size_t len, i;
if (!pk->private_key_mode)
return my_error (GPG_ERR_MISSING_KEY);
len = gcry_sexp_sprint (sexp, GCRYSEXP_FMT_ADVANCED, NULL, 0);
raw = xtrymalloc (len);
if (raw == NULL)
return my_error_from_syserror ();
clean = xtrymalloc (len);
if (clean == NULL)
{
xfree (raw);
return my_error_from_syserror ();
}
gcry_sexp_sprint (sexp, GCRYSEXP_FMT_ADVANCED, raw, len);
/* Strip any whitespace at the end. */
i = strlen (raw) - 1;
while (i && ascii_isspace (raw[i]))
{
raw[i] = 0;
i--;
}
/* Replace any newlines with spaces, remove superfluous whitespace. */
len = strlen (raw);
for (p = clean, i = 0; i < len; i++)
{
char c = raw[i];
/* Collapse contiguous and superfluous spaces. */
if (ascii_isspace (c) && i > 0
&& (ascii_isspace (raw[i-1]) || raw[i-1] == '(' || raw[i-1] == ')'))
continue;
if (c == '\n')
c = ' ';
*p++ = c;
}
*p = 0;
err = nvc_set (pk, "Key:", clean);
xfree (raw);
xfree (clean);
return err;
}
/* Parsing and serialization. */
static gpg_error_t
do_nvc_parse (nvc_t *result, int *errlinep, estream_t stream,
int for_private_key)
{
gpg_error_t err = 0;
gpgrt_ssize_t len;
char *buf = NULL;
size_t buf_len = 0;
char *name = NULL;
strlist_t raw_value = NULL;
*result = for_private_key? nvc_new_private_key () : nvc_new ();
if (*result == NULL)
return my_error_from_syserror ();
if (errlinep)
*errlinep = 0;
while ((len = es_read_line (stream, &buf, &buf_len, NULL)) > 0)
{
char *p;
if (errlinep)
*errlinep += 1;
/* Skip any whitespace. */
for (p = buf; *p && ascii_isspace (*p); p++)
/* Do nothing. */;
if (name && (spacep (buf) || *p == 0))
{
/* A continuation. */
if (append_to_strlist_try (&raw_value, buf) == NULL)
{
err = my_error_from_syserror ();
goto leave;
}
continue;
}
/* No continuation. Add the current entry if any. */
if (raw_value)
{
err = _nvc_add (*result, name, NULL, raw_value, 1);
name = NULL;
if (err)
goto leave;
}
/* And prepare for the next one. */
name = NULL;
raw_value = NULL;
if (*p != 0 && *p != '#')
{
char *colon, *value, tmp;
colon = strchr (buf, ':');
if (colon == NULL)
{
err = my_error (GPG_ERR_INV_VALUE);
goto leave;
}
value = colon + 1;
tmp = *value;
*value = 0;
name = xtrystrdup (p);
*value = tmp;
if (name == NULL)
{
err = my_error_from_syserror ();
goto leave;
}
if (append_to_strlist_try (&raw_value, value) == NULL)
{
err = my_error_from_syserror ();
goto leave;
}
continue;
}
if (append_to_strlist_try (&raw_value, buf) == NULL)
{
err = my_error_from_syserror ();
goto leave;
}
}
if (len < 0)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Add the final entry. */
if (raw_value)
{
err = _nvc_add (*result, name, NULL, raw_value, 1);
name = NULL;
}
leave:
xfree (name);
gpgrt_free (buf);
if (err)
{
nvc_release (*result);
*result = NULL;
}
return err;
}
/* Parse STREAM and return a newly allocated name value container
structure in RESULT. If ERRLINEP is given, the line number the
parser was last considering is stored there. */
gpg_error_t
nvc_parse (nvc_t *result, int *errlinep, estream_t stream)
{
return do_nvc_parse (result, errlinep, stream, 0);
}
/* Parse STREAM and return a newly allocated name value container
structure in RESULT - assuming the extended private key format. If
ERRLINEP is given, the line number the parser was last considering
is stored there. */
gpg_error_t
nvc_parse_private_key (nvc_t *result, int *errlinep, estream_t stream)
{
return do_nvc_parse (result, errlinep, stream, 1);
}
/* Helper fpr nvc_write. */
static gpg_error_t
write_one_entry (nve_t entry, estream_t stream)
{
gpg_error_t err;
strlist_t sl;
if (entry->name)
es_fputs (entry->name, stream);
err = assert_raw_value (entry);
if (err)
return err;
for (sl = entry->raw_value; sl; sl = sl->next)
es_fputs (sl->d, stream);
if (es_ferror (stream))
return my_error_from_syserror ();
return 0;
}
/* Write a representation of PK to STREAM. */
gpg_error_t
nvc_write (nvc_t pk, estream_t stream)
{
gpg_error_t err = 0;
nve_t entry;
nve_t keyentry = NULL;
for (entry = pk->first; entry; entry = entry->next)
{
if (pk->private_key_mode
&& entry->name && !ascii_strcasecmp (entry->name, "Key:"))
{
if (!keyentry)
keyentry = entry;
continue;
}
err = write_one_entry (entry, stream);
if (err)
return err;
}
/* In private key mode we write the Key always last. */
if (keyentry)
err = write_one_entry (keyentry, stream);
return err;
}