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Correct issue where flood detection could become unreliable

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The static 'pos' variable in check_flooding() would not stay in sync with the number of entries in
flood_list after clean_flood_list() was called.  This meant that check_flooding() would always end up
removing all previous entries if it tried to add a new one.

Fix this by removing the tracking of number of flood_list entries, and just removing stale ones (older
than /SET FLOOD_RATE).
This commit is contained in:
Kevin Easton
2016-11-26 00:08:59 +11:00
parent 966f1c6c27
commit 21a12c004b
3 changed files with 50 additions and 94 deletions
Download Patch File Download Diff File Expand all files Collapse all files

140
source/flood.c
View File

@@ -57,18 +57,10 @@ static char *ignore_types[] =
HashEntry no_flood_list[FLOOD_HASHSIZE];
HashEntry flood_list[FLOOD_HASHSIZE];
static int remove_oldest_flood_hashlist(HashEntry *, time_t, int);
extern char *FromUserHost;
extern unsigned int window_display;
extern int from_server;
static double allow_flood = 0.0;
static double this_flood = 0.0;
#define NO_RESET 0
#define RESET 1
@@ -354,6 +346,39 @@ int flood_rate = 0, flood_count = 0;
return 0;
}
/* Prune any flood entries older than FLOOD_RATE_VAR (or from the future, in case the clock has
* gone backwards). */
static int remove_oldest_flood_hashlist(HashEntry *list)
{
const double flood_rate = get_int_var(FLOOD_RATE_VAR);
Flooding *ptr;
int total = 0;
unsigned long x;
for (x = 0; x < FLOOD_HASHSIZE; x++)
{
ptr = list[x].list;
if (!ptr || !*ptr->name)
continue;
while (ptr)
{
double elapsed = time_since(&ptr->start);
if (elapsed > flood_rate || elapsed < 0)
{
if (!(ptr = find_name_in_floodlist(ptr->name, ptr->host, flood_list, FLOOD_HASHSIZE, 1)))
continue;
new_free(&(ptr->channel));
new_free(&(ptr->name));
new_free(&ptr->host);
new_free((char **)&ptr);
total++;
ptr = list[x].list;
} else ptr = ptr->next;
}
}
return total;
}
/*
* check_flooding: This checks for message flooding of the type specified for
* the given nickname. This is described above. This will return 0 if no
@@ -364,32 +389,22 @@ int flood_rate = 0, flood_count = 0;
int BX_check_flooding(char *nick, int type, char *line, char *channel)
{
static int users = 0,
pos = 0;
time_t flood_time = now,
diff = 0;
Flooding *tmp;
int flood_rate;
int flood_count;
Flooding *tmp;
int flood_rate,
flood_count;
if (!(users = get_int_var(FLOOD_USERS_VAR)) || !*FromUserHost)
if (!get_int_var(FLOOD_USERS_VAR) || !*FromUserHost)
return 1;
if (find_name_in_genericlist(nick, no_flood_list, FLOOD_HASHSIZE, 0))
return 1;
if (!(tmp = find_name_in_floodlist(nick, FromUserHost, flood_list, FLOOD_HASHSIZE, 0)))
{
if (pos >= users)
{
pos -= remove_oldest_flood_hashlist(&flood_list[0], 0, (users + 1 - pos));
}
remove_oldest_flood_hashlist(&flood_list[0]);
tmp = add_name_to_floodlist(nick, FromUserHost, channel, flood_list, FLOOD_HASHSIZE);
tmp->type = type;
tmp->cnt = 1;
tmp->start = flood_time;
get_time(&tmp->start);
tmp->flood = 0;
pos++;
return 1;
}
if (!(tmp->type & type))
@@ -398,10 +413,6 @@ int flood_rate,
return 1;
}
#if 0
flood_count = get_flood_count(type, NULL); /* FLOOD_AFTER_VAR */
flood_rate = get_flood_rate(type, NULL); /* FLOOD_RATE_VAR */
#endif
get_flood_val(NULL, type, &flood_count, &flood_rate);
if (!flood_count || !flood_rate)
return 1;
@@ -409,13 +420,13 @@ int flood_rate,
if (tmp->cnt > flood_count)
{
int ret;
diff = flood_time - tmp->start;
double diff = time_since(&tmp->start);
double allow_flood = (double)flood_count / (double)flood_rate;
double this_flood = 0.0;
if (diff != 0)
this_flood = (double)tmp->cnt / (double)diff;
else
this_flood = 0;
allow_flood = (double)flood_count / (double)flood_rate;
if (!diff || !this_flood || (this_flood > allow_flood))
this_flood = (double)tmp->cnt / diff;
if (!diff || this_flood > allow_flood)
{
if (tmp->flood == 0)
{
@@ -447,7 +458,7 @@ int flood_rate,
{
tmp->flood = 0;
tmp->cnt = 1;
tmp->start = flood_time;
get_time(&tmp->start);
}
}
return 1;
@@ -546,64 +557,7 @@ int kick_on_flood = 1;
return 1;
}
static int remove_oldest_flood_hashlist(HashEntry *list, time_t timet, int count)
{
Flooding *ptr;
register time_t t;
int total = 0;
register unsigned long x;
t = now;
if (!count)
{
for (x = 0; x < FLOOD_HASHSIZE; x++)
{
ptr = (Flooding *) (list + x)->list;
if (!ptr || !*ptr->name)
continue;
while (ptr)
{
if ((ptr->start + timet) <= t)
{
if (!(ptr = find_name_in_floodlist(ptr->name, ptr->host, flood_list, FLOOD_HASHSIZE, 1)))
continue;
new_free(&(ptr->channel));
new_free(&(ptr->name));
new_free(&ptr->host);
new_free((char **)&ptr);
total++;
ptr = (Flooding *) (list + x)->list;
} else ptr = ptr->next;
}
}
}
else
{
for (x = 0; x < FLOOD_HASHSIZE; x++)
{
Flooding *next = NULL;
ptr = (Flooding *) (list + x)->list;
if (!ptr || !*ptr->name)
continue;
while(ptr && count)
{
if ((ptr = find_name_in_floodlist(ptr->name, ptr->host, flood_list, FLOOD_HASHSIZE, 1)))
{
next = ptr->next;
new_free(&(ptr->channel));
new_free(&(ptr->name));
new_free(&ptr->host);
new_free((char **)&ptr);
total++; count--;
ptr = (Flooding *) (list + x)->list;
ptr = next;
}
}
}
}
return total;
}
void clean_flood_list()
{
remove_oldest_flood_hashlist(&flood_list[0], get_int_var(FLOOD_RATE_VAR)+1, 0);
remove_oldest_flood_hashlist(&flood_list[0]);
}