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dhcp: make host/domain name validity checks stricter

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Also don't permit host/domain names that reference the root domain, and unify the codepaths for this.
This commit is contained in:
Lennart Poettering 2016-01-25 20:48:07 +01:00
parent 482d1aeb67
commit 978c64777a
1 changed files with 36 additions and 40 deletions
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76
src/libsystemd-network/sd-dhcp-lease.c
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@ -353,6 +353,38 @@ static int lease_parse_string(const uint8_t *option, size_t len, char **ret) {
return 0;
}
static int lease_parse_domain(const uint8_t *option, size_t len, char **ret) {
_cleanup_free_ char *name = NULL, *normalized = NULL;
int r;
assert(option);
assert(ret);
r = lease_parse_string(option, len, &name);
if (r < 0)
return r;
if (!name) {
*ret = mfree(*ret);
return 0;
}
r = dns_name_normalize(name, &normalized);
if (r < 0)
return r;
if (is_localhost(normalized))
return -EINVAL;
if (dns_name_is_root(normalized))
return -EINVAL;
free(*ret);
*ret = normalized;
normalized = NULL;
return 0;
}
static int lease_parse_in_addrs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *n_ret) {
assert(option);
assert(ret);
@ -547,59 +579,23 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void
log_debug_errno(r, "Failed to parse MTU, ignoring: %m");
break;
case SD_DHCP_OPTION_DOMAIN_NAME: {
_cleanup_free_ char *domainname = NULL, *normalized = NULL;
r = lease_parse_string(option, len, &domainname);
case SD_DHCP_OPTION_DOMAIN_NAME:
r = lease_parse_domain(option, len, &lease->domainname);
if (r < 0) {
log_debug_errno(r, "Failed to parse domain name, ignoring: %m");
return 0;
}
r = dns_name_normalize(domainname, &normalized);
if (r < 0) {
log_debug_errno(r, "Failed to normalize domain name '%s': %m", domainname);
return 0;
}
if (is_localhost(normalized)) {
log_debug_errno(r, "Detected 'localhost' as suggested domain name, ignoring.");
break;
}
free(lease->domainname);
lease->domainname = normalized;
normalized = NULL;
break;
}
case SD_DHCP_OPTION_HOST_NAME: {
_cleanup_free_ char *hostname = NULL, *normalized = NULL;
r = lease_parse_string(option, len, &hostname);
case SD_DHCP_OPTION_HOST_NAME:
r = lease_parse_domain(option, len, &lease->hostname);
if (r < 0) {
log_debug_errno(r, "Failed to parse host name, ignoring: %m");
return 0;
}
r = dns_name_normalize(hostname, &normalized);
if (r < 0) {
log_debug_errno(r, "Failed to normalize host name '%s', ignoring: %m", hostname);
return 0;
}
if (is_localhost(normalized)) {
log_debug_errno(r, "Detected 'localhost' as suggested host name, ignoring.");
return 0;
}
free(lease->hostname);
lease->hostname = normalized;
normalized = NULL;
break;
}
case SD_DHCP_OPTION_ROOT_PATH:
r = lease_parse_string(option, len, &lease->root_path);