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dhcp/nettools: accept any number of trailing NULs in string options

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https://tools.ietf.org/html/rfc2132#section-2 says:

   Options containing NVT ASCII data SHOULD NOT include a trailing NULL;
   however, the receiver of such options MUST be prepared to delete trailing
   nulls if they exist.

It speaks in plurals.
This commit is contained in:
Thomas Haller
2021-02-11 08:25:46 +01:00
parent 3b8882b978
commit 53f137af6e
2 changed files with 8 additions and 8 deletions
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2
src/core/dhcp/nm-dhcp-nettools.c
View File

@@ -690,7 +690,7 @@ lease_to_ip4_config(NMDedupMultiIndex *multi_idx,
if (r == 0 && nm_dhcp_lease_data_parse_cstr(l_data, l_data_len, &l_data_len)) {
/* https://tools.ietf.org/html/draft-ietf-wrec-wpad-01#section-4.4.1
*
* We reject NUL characters inside the string (except one trailing NUL).
* We reject NUL characters inside the string (except trailing NULs).
* Otherwise, we allow any encoding and backslash-escape the result to
* UTF-8. */
nm_dhcp_option_add_option_utf8safe_escape(options,

14
src/core/dhcp/nm-dhcp-utils.c
View File

@@ -873,20 +873,20 @@ gboolean
nm_dhcp_lease_data_parse_cstr(const guint8 *data, gsize n_data, gsize *out_new_len)
{
/* WARNING: this function only validates that the string does not contain
* NUL characters (and ignores one trailing NUL). It does not check character
* NUL characters (and ignores trailing NULs). It does not check character
* encoding! */
while (n_data > 0 && data[n_data - 1] == '\0')
n_data--;
if (n_data > 0) {
if (memchr(data, n_data - 1, '\0')) {
/* we accept one trailing NUL (not more).
if (memchr(data, n_data, '\0')) {
/* we accept trailing NUL, but none in between.
*
* https://tools.ietf.org/html/rfc2132#section-2
* https://github.com/systemd/systemd/issues/1337 */
return FALSE;
}
if (data[n_data - 1] == '\0')
n_data--;
}
NM_SET_OUT(out_new_len, n_data);
@@ -937,7 +937,7 @@ nm_dhcp_lease_data_parse_domain(const guint8 *data, gsize n_data, char **out_val
*
* Its minimum length is 1.
*
* Note that this is *after* we potentially stripped a trailing NUL.
* Note that this is *after* we potentially stripped trailing NULs.
*/
return FALSE;
}