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cli: support backslash escaping in passwd-file

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Rework parsing of nmcli's passwd-file.

1) support backslash escaping of secrets.

  - only the secret can be backslash escaped, the property and setting
    name cannot.

  This is a change in behavior for passwd-files with secrets that contain
  a backslash.

2) strip the white space around the secret. This is a change in behavior
  for secrets that had leading or trailing spaces. Note that you can
  backslash escape spaces in secrets.

3) strip white space around the setting.property key. This is also a
  change in behavior, but such keys would never have been valid
  previously (or the caller would have performed the same kind of
  stripping).

4) accept '=' as alternative delimiter beside ':'. The ':' feels really
  odd and unexpected. Also accept '='. This is a change in behavior if
  keys would contain '=', which they really shouldn't.

5) reject non-UTF-8 secrets and keys. For keys, that is not an issue,
  because such keys were never valid. For secrets, it probably didn't
  work anyway to specify non-UTF-8 secrets, because most (if not all)
  secrets are transmitted via D-Bus as strings where arbitrary binary
  is not allowed.

6) ignore empty lines and lines starting with '#'.

7) ensure we don't leak any secrets in memory.

1) to 4) are changes in behavior. 3) and 4) seem less severe, as they
only concern unusual setting.property keys, which really shouldn't be
used (although, VPN secrets can have almost arbitrary names *sigh*).
1) and 2) is more dangerous, as it changes behavior for secrets that
contain backslashes or leading/trailing white space.
This commit is contained in:
Thomas Haller 2020-05-04 09:04:20 +02:00
parent bb19f6e29c
commit 2285dd38ea
No known key found for this signature in database
GPG key ID: 29C2366E4DFC5728
1 changed files with 118 additions and 34 deletions
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152
clients/cli/connections.c
View file

@ -16,6 +16,8 @@
#include <readline/history.h>
#include <fcntl.h>
#include "nm-glib-aux/nm-secret-utils.h"
#include "nm-glib-aux/nm-io-utils.h"
#include "nm-client-utils.h"
#include "nm-vpn-helpers.h"
#include "nm-meta-setting-access.h"
@ -2710,70 +2712,152 @@ activate_connection_cb (GObject *client, GAsyncResult *result, gpointer user_dat
static GHashTable *
parse_passwords (const char *passwd_file, GError **error)
{
nm_auto_clear_secret_ptr NMSecretPtr contents = { 0 };
gs_unref_hashtable GHashTable *pwds_hash = NULL;
gs_free char *contents = NULL;
gsize len = 0;
GError *local_err = NULL;
gs_free const char **strv = NULL;
const char *const*iter;
char *pwd_spec, *pwd, *prop;
const char *setting;
gs_free_error GError *local = NULL;
const char *contents_str;
gsize contents_line;
pwds_hash = g_hash_table_new_full (nm_str_hash, g_str_equal, g_free, g_free);
pwds_hash = g_hash_table_new_full (nm_str_hash, g_str_equal, g_free, (GDestroyNotify) nm_free_secret);
if (!passwd_file)
return g_steal_pointer (&pwds_hash);
if (!g_file_get_contents (passwd_file, &contents, &len, &local_err)) {
if (!nm_utils_file_get_contents (-1,
passwd_file,
1024*1024,
NM_UTILS_FILE_GET_CONTENTS_FLAG_SECRET,
&contents.str,
&contents.len,
NULL,
&local)) {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("failed to read passwd-file '%s': %s"),
passwd_file, local_err->message);
g_error_free (local_err);
passwd_file, local->message);
return NULL;
}
strv = nm_utils_strsplit_set (contents, "\r\n");
for (iter = strv; strv && *iter; iter++) {
gs_free char *iter_s = g_strdup (*iter);
contents_str = contents.str;
contents_line = 0;
while (contents_str[0]) {
nm_auto_free_secret char *l_hash_key = NULL;
nm_auto_free_secret char *l_hash_val = NULL;
const char *l_content_line;
const char *l_setting;
const char *l_prop;
const char *l_val;
const char *s;
gsize l_hash_val_len;
pwd = strchr (iter_s, ':');
if (!pwd) {
/* consume first line. As line delimiters we accept "\r\n", "\n", and "\r". */
l_content_line = contents_str;
s = l_content_line;
while (!NM_IN_SET (s[0], '\0', '\r', '\n'))
s++;
if (s[0] != '\0') {
if ( s[0] == '\r'
&& s[1] == '\n') {
((char *) s)[0] = '\0';
s += 2;
} else {
((char *) s)[0] = '\0';
s += 1;
}
}
contents_str = s;
contents_line++;
l_content_line = nm_str_skip_leading_spaces (l_content_line);
if (NM_IN_SET (l_content_line[0], '\0', '#')) {
/* a comment or empty line. Ignore. */
continue;
}
l_setting = l_content_line;
s = l_setting;
while (!NM_IN_SET (s[0], '\0', ':', '='))
s++;
if (s[0] == '\0') {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("missing colon in 'password' entry '%s'"), *iter);
_("missing colon in 'password' entry of passwd-file '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
*(pwd++) = '\0';
((char *) s)[0] = '\0';
s++;
prop = strchr (iter_s, '.');
if (!prop) {
l_val = s;
g_strchomp ((char *) l_setting);
nm_assert (nm_str_is_stripped (l_setting));
s = strchr (l_setting, '.');
if (!s) {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("missing dot in 'password' entry '%s'"), *iter);
_("missing dot in 'password' entry of passwd-file '%s', line %zu"), passwd_file, contents_line);
return NULL;
} else if (s == l_setting) {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("missing setting name in 'password' entry of passwd-file '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
((char *) s)[0] = '\0';
s++;
l_prop = s;
if (l_prop[0] == '\0') {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("missing property name in 'password' entry of passwd-file '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
*(prop++) = '\0';
setting = iter_s;
while (g_ascii_isspace (*setting))
setting++;
/* Accept wifi-sec or wifi instead of cumbersome '802-11-wireless-security' */
if (!strcmp (setting, "wifi-sec") || !strcmp (setting, "wifi"))
setting = NM_SETTING_WIRELESS_SECURITY_SETTING_NAME;
if (nm_setting_lookup_type (setting) == G_TYPE_INVALID) {
if (NM_IN_STRSET (l_setting, "wifi-sec", "wifi"))
l_setting = NM_SETTING_WIRELESS_SECURITY_SETTING_NAME;
if (nm_setting_lookup_type (l_setting) == G_TYPE_INVALID) {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("invalid setting name in 'password' entry '%s'"), setting);
_("invalid setting name in 'password' entry '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
if ( nm_streq (setting, "vpn")
&& g_str_has_prefix (prop, "secret.")) {
if ( nm_streq (l_setting, "vpn")
&& NM_STR_HAS_PREFIX (l_prop, "secret.")) {
/* in 1.12.0, we wrongly required the VPN secrets to be named
* "vpn.secret". It should be "vpn.secrets". Work around it
* (rh#1628833). */
pwd_spec = g_strdup_printf ("vpn.secrets.%s", &prop[NM_STRLEN ("secret.")]);
l_hash_key = g_strdup_printf ("vpn.secrets.%s", &l_prop[NM_STRLEN ("secret.")]);
} else
pwd_spec = g_strdup_printf ("%s.%s", setting, prop);
l_hash_key = g_strdup_printf ("%s.%s", l_setting, l_prop);
g_hash_table_insert (pwds_hash, pwd_spec, g_strdup (pwd));
if (!g_utf8_validate (l_hash_key, -1, NULL)) {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("invalid non UTF-8 setting name in 'password' entry '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
/* Support backslash escaping in the secret value. We strip non-escaped leading/trailing whitespaces. */
s = nm_utils_buf_utf8safe_unescape (l_val, NM_UTILS_STR_UTF8_SAFE_UNESCAPE_STRIP_SPACES, &l_hash_val_len, (gpointer *) &l_hash_val);
if (!l_hash_val)
l_hash_val = g_strdup (s);
if (!g_utf8_validate (l_hash_val, -1, NULL)) {
/* In some cases it might make sense to support binary secrets (like the WPA-PSK which has no
* defined encoding. However, all API that follows can only handle UTF-8, and no mechanism
* to escape the secrets. Reject non-UTF-8 early. */
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("invalid non UTF-8 secret in 'password' entry '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
if (strlen (l_hash_val) != l_hash_val_len) {
g_set_error (error, NMCLI_ERROR, NMC_RESULT_ERROR_USER_INPUT,
_("invalid non UTF-8 secret with NUL bytes in 'password' entry '%s', line %zu"), passwd_file, contents_line);
return NULL;
}
g_hash_table_insert (pwds_hash, g_steal_pointer (&l_hash_key), g_steal_pointer (&l_hash_val));
}
return g_steal_pointer (&pwds_hash);