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Add validation for dns.revServers
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Signed-off-by: DL6ER <[email protected]>
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@DL6ER
DL6ER committed Feb 11, 2024
1 parent 6009a1a commit fda3366
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Showing 4 changed files with 179 additions and 1 deletion.
2 changes: 1 addition & 1 deletion src/config/config.c
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Expand Up @@ -619,7 +619,7 @@ void initConfig(struct config *conf)
conf->dns.revServers.a = cJSON_CreateStringReference("array of reverse servers each one in one of the following forms: \"<enabled>,<ip-address>[/<prefix-len>],<server>[#<port>],<domain>\", e.g., \"true,192.168.0.0/24,192.168.0.1,fritz.box\"");
conf->dns.revServers.t = CONF_JSON_STRING_ARRAY;
conf->dns.revServers.d.json = cJSON_CreateArray();
conf->dns.revServers.c = validate_stub; // Only type-based checking
conf->dns.revServers.c = validate_dns_revServers; // Only type-based checking
conf->dns.revServers.f = FLAG_RESTART_FTL;

// sub-struct dns.rate_limit
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7 changes: 7 additions & 0 deletions src/config/env.c
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Expand Up @@ -48,6 +48,13 @@ void getEnvVars(void)
char *key = strtok(*env, "=");
char *value = strtok(NULL, "=");

// Log warning if value is missing
if(value == NULL)
{
log_warn("Environment variable %s has no value, substituting with empty string", key);
value = (char*)"";
}

// Add to list
struct env_item *new_item = calloc(1, sizeof(struct env_item));
new_item->used = false;
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170 changes: 170 additions & 0 deletions src/config/validator.c
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Expand Up @@ -373,3 +373,173 @@ bool validate_regex_array(union conf_value *val, const char *key, char err[VALID

return true;
}

// Validate dns.revServers array
// Each entry has to be of form "<enabled>,<ip-address>[/<prefix-len>],<server>[#<port>],<domain>"
bool validate_dns_revServers(union conf_value *val, const char *key, char err[VALIDATOR_ERRBUF_LEN])
{
if(!cJSON_IsArray(val->json))
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s: not an array", key);
return false;
}

for(int i = 0; i < cJSON_GetArraySize(val->json); i++)
{
// Get array item
cJSON *item = cJSON_GetArrayItem(val->json, i);

// Check if it's a string
if(!cJSON_IsString(item))
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: not a string", key, i);
return false;
}

// Count the number of elements in the string
unsigned int elements = 1;
for(unsigned int j = 0; j < strlen(item->valuestring); j++)
if(item->valuestring[j] == ',')
elements++;

// Check if it's in the form "<enabled>,<ip-address>[/<prefix-len>],<server>[#<port>],<domain>"
// Mandatory elements are: <enabled>, <ip-address>, <server>, and <domain>
// Optional elements are: [/<prefix-len>] and [#<port>]
char *str = strdup(item->valuestring);
char *tmp = str, *s = NULL;
unsigned int e = 0;

while((s = strsep(&tmp, ",")) != NULL)
{
// Check if it's a valid element
if(strlen(s) == 0)
{
// Contains an empty string
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: contains two commas following each other immediately", key, i);
free(str);
return false;
}
// Check if the zeroth element is a boolean
if(e == 0)
{
if(strcmp(s, "true") != 0 && strcmp(s, "false") != 0)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <enabled> not a boolean (\"%s\")", key, i, s);
free(str);
return false;
}
}
// Check if the first element is an IP address
else if(e == 1)
{
// Extract IP and prefix length (if present)
char *ip = strsep(&s, "/");
char *prefix = strsep(&s, "/");
if(strlen(ip) == 0)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <ip-address> empty", key, i);
free(str);
return false;
}

// Check if IP is valid
struct in_addr addr = { 0 };
struct in6_addr addr6 = { 0 };
const bool ipv4 = inet_pton(AF_INET, ip, &addr) == 1;
const bool ipv6 = inet_pton(AF_INET6, ip, &addr6) == 1;
if(!ipv4 && !ipv6)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <ip-address> neither a valid IPv4 nor IPv6 address (\"%s\")", key, i, ip);
free(str);
return false;
}

// Check if prefix length is valid (if present)
if(prefix != NULL)
{
if(strlen(prefix) == 0)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <prefix-len> empty", key, i);
free(str);
return false;
}
const int prefix_int = atoi(prefix);
if(prefix_int < 0 || (ipv4 && prefix_int > 32) || (ipv6 && prefix_int > 128))
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <prefix-len> not a valid prefix length (\"%s\")", key, i, prefix);
free(str);
return false;
}
}
}
// Check if the second element is a valid server (either an IP address or a domain, optionally with a port)
else if(e == 2)
{
// Extract server and port (if present)
char *server = strsep(&s, "#");
char *port = strsep(&s, "#");
if(strlen(server) == 0)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <server> empty", key, i);
free(str);
return false;
}

struct in_addr addr = { 0 };
struct in6_addr addr6 = { 0 };
const bool server_ipv4 = inet_pton(AF_INET, server, &addr) == 1;
const bool server_ipv6 = inet_pton(AF_INET6, server, &addr6) == 1;
const bool server_domain = valid_domain(server, strlen(server), false);

// Check if server is valid
if(!server_ipv4 && !server_ipv6 && !server_domain)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <server> neither a valid domain nor an IPv4 or IPv6 address (\"%s\")", key, i, server);
free(str);
return false;
}

// Check if port is valid (if present)
if(port != NULL)
{
if(strlen(port) == 0)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: specified server <port> empty", key, i);
free(str);
return false;
}
const int port_int = atoi(port);
if(port_int < 0 || port_int > 65535)
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: server <port> not a valid port (\"%s\")", key, i, port);
free(str);
return false;
}
}
}
// Check if the third element is a valid domain
else if(e == 3)
{
if(!valid_domain(s, strlen(s), false))
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: <domain> not a valid domain (\"%s\")", key, i, s);
free(str);
return false;
}
}
// Check if there are too many elements
else
{
snprintf(err, VALIDATOR_ERRBUF_LEN, "%s[%d]: too many elements", key, i);
free(str);
return false;
}

// Increment element counter
e++;
}
}

// Return success
return true;
}
1 change: 1 addition & 0 deletions src/config/validator.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,5 +24,6 @@ bool validate_filepath(union conf_value *val, const char *key, char err[VALIDATO
bool validate_filepath_empty(union conf_value *val, const char *key, char err[VALIDATOR_ERRBUF_LEN]);
bool validate_filepath_dash(union conf_value *val, const char *key, char err[VALIDATOR_ERRBUF_LEN]);
bool validate_regex_array(union conf_value *val, const char *key, char err[VALIDATOR_ERRBUF_LEN]);
bool validate_dns_revServers(union conf_value *val, const char *key, char err[VALIDATOR_ERRBUF_LEN]);

#endif // CONFIG_VALIDATOR_H

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