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Fix freeing regex pointers to free the global objects #971

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merged 1 commit into from
Dec 10, 2020
Merged

Fix freeing regex pointers to free the global objects #971

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58 changes: 43 additions & 15 deletions src/regex.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,8 +33,7 @@ static regex_data *white_regex = NULL;
static regex_data *black_regex = NULL;
static regex_data *cli_regex = NULL;

regex_data *get_regex_from_type(const enum regex_type regexid);
inline regex_data *get_regex_from_type(const enum regex_type regexid)
static inline regex_data *get_regex_ptr(const enum regex_type regexid)
{
switch (regexid)
{
Expand All @@ -50,12 +49,39 @@ inline regex_data *get_regex_from_type(const enum regex_type regexid)
}
}

static inline void free_regex_ptr(const enum regex_type regexid)
{
regex_data **regex;
switch (regexid)
{
case REGEX_BLACKLIST:
regex = &black_regex;
break;
case REGEX_WHITELIST:
regex = &white_regex;
break;
case REGEX_CLI:
regex = &cli_regex;
break;
case REGEX_MAX: // Fall through
default: // This is not possible
return;
}

// Free pointer (if not already NULL)
if(*regex != NULL)
{
free(*regex);
*regex = NULL;
}
}

#define FTL_REGEX_SEP ";"
/* Compile regular expressions into data structures that can be used with
regexec() to match against a string */
static bool compile_regex(const char *regexin, const enum regex_type regexid)
{
regex_data *regex = get_regex_from_type(regexid);
regex_data *regex = get_regex_ptr(regexid);
int index = counters->num_regex[regexid]++;

// Extract possible Pi-hole extensions
Expand Down Expand Up @@ -163,7 +189,7 @@ int match_regex(const char *input, const DNSCacheData* dns_cache, const int clie
const enum regex_type regexid, const bool regextest)
{
int match_idx = -1;
regex_data *regex = get_regex_from_type(regexid);
regex_data *regex = get_regex_ptr(regexid);
#ifdef USE_TRE_REGEX
regmatch_t match = { 0 }; // This also disables any sub-matching
#endif
Expand Down Expand Up @@ -309,11 +335,20 @@ static void free_regex(void)

// Free regex datastructure
// Loop over regex types
for(unsigned char regexid = 0; regexid < REGEX_MAX; regexid++)
for(enum regex_type regexid = REGEX_BLACKLIST; regexid < REGEX_MAX; regexid++)
{
regex_data *regex = get_regex_from_type(regexid);
regex_data *regex = get_regex_ptr(regexid);

// Reset counter for number of regex
const unsigned int oldcount = counters->num_regex[regexid];
counters->num_regex[regexid] = 0;

// Exit early if the regex has already been freed (or has never been used)
if(regex == NULL)
continue;

// Loop over entries with this regex type
for(unsigned int index = 0; index < counters->num_regex[regexid]; index++)
for(unsigned int index = 0; index < oldcount; index++)
{
if(!regex[index].available)
continue;
Expand All @@ -329,14 +364,7 @@ static void free_regex(void)
}

// Free array with regex datastructure
if(regex != NULL)
{
free(regex);
regex = NULL;
}

// Reset counter for number of regex
counters->num_regex[regexid] = 0;
free_regex_ptr(regexid);
}
}

Expand Down