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Diffstat (limited to 'common/private-keys.c')
| -rw-r--r-- | common/private-keys.c | 740 |
1 files changed, 740 insertions, 0 deletions
diff --git a/common/private-keys.c b/common/private-keys.c new file mode 100644 index 000000000..d77ce1643 --- /dev/null +++ b/common/private-keys.c @@ -0,0 +1,740 @@ +/* private-keys.c - Parser and writer for the extended private key 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 <http://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <assert.h> +#include <gcrypt.h> +#include <gpg-error.h> +#include <string.h> + +#include "private-keys.h" +#include "mischelp.h" +#include "strlist.h" +#include "util.h" + +struct private_key_container +{ + struct private_key_entry *first; + struct private_key_entry *last; +}; + + +struct private_key_entry +{ + struct private_key_entry *prev; + struct private_key_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 when we parse + a file so that we can reproduce it. */ + strlist_t raw_value; + + /* The decoded value. */ + char *value; +}; + + + +/* Allocation and deallocation. */ + +/* Allocate a private key container structure. */ +pkc_t +pkc_new (void) +{ + return xtrycalloc (1, sizeof (struct private_key_container)); +} + + +static void +pke_release (pke_t entry) +{ + if (entry == NULL) + return; + + xfree (entry->name); + if (entry->value) + wipememory (entry->value, strlen (entry->value)); + xfree (entry->value); + free_strlist_wipe (entry->raw_value); + xfree (entry); +} + + +/* Release a private key container structure. */ +void +pkc_release (pkc_t pk) +{ + pke_t e, next; + + if (pk == NULL) + return; + + for (e = pk->first; e; e = next) + { + next = e->next; + pke_release (e); + } + + 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 (pke_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 && linelen - i > offset; i--) + if (ascii_isspace (entry->value[i])) + break; + + if (ascii_isspace (entry->value[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 = gpg_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 (pke_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 gpg_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 * +pke_name (pke_t pke) +{ + return pke->name; +} + + +/* Get the value. */ +char * +pke_value (pke_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 +_pkc_add (pkc_t pk, char *name, char *value, strlist_t raw_value, + int preserve_order) +{ + gpg_error_t err = 0; + pke_t e; + + assert (value || raw_value); + + if (name && ! valid_name (name)) + { + err = gpg_error (GPG_ERR_INV_NAME); + goto leave; + } + + if (name && strcasecmp (name, "Key:") == 0 && pkc_lookup (pk, "Key:")) + { + err = gpg_error (GPG_ERR_INV_NAME); + goto leave; + } + + e = xtrycalloc (1, sizeof *e); + if (e == NULL) + { + err = gpg_error_from_syserror (); + goto leave; + } + + e->name = name; + e->value = value; + e->raw_value = raw_value; + + if (pk->first) + { + pke_t last; + + if (preserve_order) + last = pk->last; + else + { + /* See if there is already an entry with NAME. */ + last = pkc_lookup (pk, name); + + /* If so, find the last in that block. */ + if (last) + while (last->next) + { + pke_t next = last->next; + + if (next->name && strcasecmp (next->name, name) == 0) + last = next; + else + break; + } + /* Otherwise, just find the last entry. */ + else + 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 +pkc_add (pkc_t pk, const char *name, const char *value) +{ + char *k, *v; + + k = xtrystrdup (name); + if (k == NULL) + return gpg_error_from_syserror (); + + v = xtrystrdup (value); + if (v == NULL) + { + xfree (k); + return gpg_error_from_syserror (); + } + + return _pkc_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 +pkc_set (pkc_t pk, const char *name, const char *value) +{ + pke_t e; + + if (! valid_name (name)) + return GPG_ERR_INV_NAME; + + e = pkc_lookup (pk, name); + if (e) + { + char *v; + + v = xtrystrdup (value); + if (v == NULL) + return gpg_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 pkc_add (pk, name, value); +} + + +/* Delete the given entry from PK. */ +void +pkc_delete (pkc_t pk, pke_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; + + pke_release (entry); +} + + + +/* Lookup and iteration. */ + +/* Get the first non-comment entry. */ +pke_t +pkc_first (pkc_t pk) +{ + pke_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. */ +pke_t +pkc_lookup (pkc_t pk, const char *name) +{ + pke_t entry; + for (entry = pk->first; entry; entry = entry->next) + if (entry->name && strcasecmp (entry->name, name) == 0) + return entry; + return NULL; +} + + +/* Get the next non-comment entry. */ +pke_t +pke_next (pke_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. */ +pke_t +pke_next_value (pke_t entry, const char *name) +{ + for (entry = entry->next; entry; entry = entry->next) + if (entry->name && strcasecmp (entry->name, name) == 0) + return entry; + return NULL; +} + + + +/* Private key handling. */ + +/* Get the private key. */ +gpg_error_t +pkc_get_private_key (pkc_t pk, gcry_sexp_t *retsexp) +{ + gpg_error_t err; + pke_t e; + + e = pkc_lookup (pk, "Key:"); + if (e == NULL) + return gpg_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 +pkc_set_private_key (pkc_t pk, gcry_sexp_t sexp) +{ + gpg_error_t err; + char *raw, *clean, *p; + size_t len, i; + + len = gcry_sexp_sprint (sexp, GCRYSEXP_FMT_ADVANCED, NULL, 0); + + raw = xtrymalloc (len); + if (raw == NULL) + return gpg_error_from_syserror (); + + clean = xtrymalloc (len); + if (clean == NULL) + { + xfree (raw); + return gpg_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 = pkc_set (pk, "Key:", clean); + xfree (raw); + xfree (clean); + return err; +} + + + +/* Parsing and serialization. */ + +/* Parse STREAM and return a newly allocated private key container + structure in RESULT. If ERRLINEP is given, the line number the + parser was last considering is stored there. */ +gpg_error_t +pkc_parse (pkc_t *result, int *errlinep, estream_t stream) +{ + 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 = pkc_new (); + if (*result == NULL) + return gpg_error_from_syserror (); + + if (errlinep) + *errlinep = 0; + while ((len = es_read_line (stream, &buf, &buf_len, NULL))) + { + 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 = gpg_error_from_syserror (); + goto leave; + } + continue; + } + + /* No continuation. Add the current entry if any. */ + if (raw_value) + { + err = _pkc_add (*result, name, NULL, raw_value, 1); + 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 = gpg_error (GPG_ERR_INV_VALUE); + goto leave; + } + + value = colon + 1; + tmp = *value; + *value = 0; + name = xstrdup (p); + *value = tmp; + + if (name == NULL) + { + err = gpg_error_from_syserror (); + goto leave; + } + + if (append_to_strlist (&raw_value, value) == NULL) + { + err = gpg_error_from_syserror (); + goto leave; + } + continue; + } + + if (append_to_strlist (&raw_value, buf) == NULL) + { + err = gpg_error_from_syserror (); + goto leave; + } + } + + /* Add the final entry. */ + if (raw_value) + err = _pkc_add (*result, name, NULL, raw_value, 1); + + leave: + gpgrt_free (buf); + if (err) + { + pkc_release (*result); + *result = NULL; + } + + return err; +} + + +/* Write a representation of PK to STREAM. */ +gpg_error_t +pkc_write (pkc_t pk, estream_t stream) +{ + gpg_error_t err; + pke_t entry; + strlist_t s; + + for (entry = pk->first; entry; entry = entry->next) + { + if (entry->name) + es_fputs (entry->name, stream); + + err = assert_raw_value (entry); + if (err) + return err; + + for (s = entry->raw_value; s; s = s->next) + es_fputs (s->d, stream); + + if (es_ferror (stream)) + return gpg_error_from_syserror (); + } + + return 0; +} |